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1

JOURNAL OF STRUCTURAL ENGINEERING / MAY 2001 / 527 APPARENT PERIODS OF A BUILDING. II: TIME-FREQUENCY ANALYSIS  

E-Print Network (OSTI)

of a two-part paper, the analysis of the apparent frequency of a seven-story reinforced-concrete hotel. The results also suggest ``self healing'' believed to result from settlement of the soil with time and dynamic compaction from aftershock shaking. Implications of such high variability of the system frequency

Southern California, University of

2

High?frequency cutoff periodic dielectric waveguides  

Science Journals Connector (OSTI)

We report high?frequency cutoff in periodic dielectric waveguides. The guides consisted of 1?? photoresist film with a surface corrugation of up to 500 Å overlaid on fused silica substrates. At a wavelength of 1.064 ? we obtained transition between complete cutoff and propagation by variation in the periodicity of the guide of ± 30 Å. For gratings having 500?Å corrugation unobstructed propagation at 1.32 ? occurred with complete stopping of 1.064?? light.

F.W. Dabby; M.A. Saifi; A. Kestenbaum

1973-01-01T23:59:59.000Z

3

Property:TimePeriod | Open Energy Information  

Open Energy Info (EERE)

TimePeriod TimePeriod Jump to: navigation, search This is a property of type String. Pages using the property "TimePeriod" Showing 25 pages using this property. (previous 25) (next 25) 0 0.4 kV remote control (Smart Grid Project) + Not available + 2 220 kV SSSC device for power flow control (Smart Grid Project) + Jul 2009 Jul 2014 + A A complete and normalized 61850 substation (Smart Grid Project) + Oct 2009 Dec 2015 + ADELE Project AACAES (Smart Grid Project) + Dec 2009 Dec 2013 + AFTER A Framework for electrical power sysTems vulnerability identification, dEfense and Restoration (Smart Grid Project) + 2011-2014 + AFTER A Framework for electrical power sysTems vulnerability identification, dEfense and Restoration (Smart Grid Project) (Belgium) + 2011-2014 +

4

Audio classification from time-frequency texture  

E-Print Network (OSTI)

Time-frequency representations of audio signals often resemble texture images. This paper derives a simple audio classification algorithm based on treating sound spectrograms as texture images. The algorithm is inspired ...

Slotine, Jean-Jacques E.

5

Emissions from Idling Trucks for Extended Time Periods | Department...  

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

Idling Trucks for Extended Time Periods Emissions from Idling Trucks for Extended Time Periods 2002 DEER Conference Presentation: Oak Ridge National Laboratory 2002deerlewis.pdf...

6

A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical Parameters  

E-Print Network (OSTI)

A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical of Mechanical Engineering) ABSTRACT Within a wave energy converter's operational bandwidth, device operation

Victoria, University of

7

Study on Characteristics of Ultra-Long-Period Fiber Gratings Written by High-Frequency CO2 Laser Pulses  

Science Journals Connector (OSTI)

A novel ultra-long-period fiber grating with periods of up to several millimeters induced by high-frequency

Zhu, Tao; Rao, Yunjiang; Mo, Qiu-Ju

8

Real-time Multi-period truckload routing problems  

E-Print Network (OSTI)

In this thesis we consider a multi-period truckload pick-up and delivery problem dealing with real-time requests over a finite time horizon. We introduce the notion of postponement of requests, whereby the company can ...

Limpaitoon, Tanachai

2008-01-01T23:59:59.000Z

9

Time period Annual mean [DOC] 95% CI (mg l-1)  

E-Print Network (OSTI)

.3 Time period Annual mean [SRP] ± 95% CI (mg l-1) SEPA EQS category mean Oct 2006 - Sept 2007* 16.8 ± 4 of different development activities. Building up a time series of DOC and soluble reactive phosphorus (SRP, SRP, total oxidised nitrogen and alkalinity. In addition, streamwater sampling has continued at five

10

Particle energization through time-periodic helical magnetic fields  

E-Print Network (OSTI)

We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients A=B=C=1 are chaotic, and we show ...

Mitra, Dhrubaditya

11

Revisiting CoRoT RR Lyrae stars: detection of period doubling and temporal variation of additional frequencies  

E-Print Network (OSTI)

We search for signs of period doubling in CoRoT RR Lyrae stars. The occurrence of this dynamical effect in modulated RR Lyrae stars might help us to gain more information about the mysterious Blazhko effect. The temporal variability of the additional frequencies in representatives of all subtypes of RR Lyrae stars is also investigated. We pre-process CoRoT light curves by applying trend and jump correction and outlier removal. Standard Fourier technique is used to analyze the frequency content of our targets and follow the time dependent phenomena. The most comprehensive collection of CoRoT RR Lyrae stars, including new discoveries is presented and analyzed. We found alternating maxima and in some cases half-integer frequencies in four CoRoT Blazhko RR Lyrae stars, as clear signs of the presence of period doubling. This reinforces that period doubling is an important ingredient to understand the Blazhko effect - a premise we derived previously from the Kepler RR Lyrae sample. As expected, period doubling is d...

Szabó, R; Paparó, M; Chapellier, E; Poretti, E; Baglin, A; Weiss, W W; Kolenberg, K; Guggenberger, E; Borgne, J -F Le

2014-01-01T23:59:59.000Z

12

LOW-FREQUENCY OBSERVATIONS OF TRANSIENT QUASI-PERIODIC RADIO EMISSION FROM THE SOLAR ATMOSPHERE  

SciTech Connect

We report low-frequency observations of quasi-periodic, circularly polarized, harmonic type III radio bursts whose associated sunspot active regions were located close to the solar limb. The measured periodicity of the bursts at 80 MHz was ?5.2 s, and their average degree of circular polarization (dcp) was ?0.12. We calculated the associated magnetic field B (1) using the empirical relationship between the dcp and B for the harmonic type III emission, and (2) from the observed quasi-periodicity of the bursts. Both the methods result in B ? 4.2 G at the location of the 80 MHz plasma level (radial distance r ? 1.3 R{sub ?}) in the active region corona.

Sasikumar Raja, K.; Ramesh, R., E-mail: sasikumar@iiap.res.in [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034 (India)

2013-09-20T23:59:59.000Z

13

Nonlinear Time-Frequency Control Theory with Applications  

E-Print Network (OSTI)

amplitude . 30 2.8 Phase portrait and Poincar? section for (a) periodic motion (b) 2T period doubling bifurcation (c) 4T period doubling bifurcation (d) fractal (e) fractal before unbounded... ..................................................... 31 2.9 FFT and marginal spectrum for (a) periodic motion (b) 2T period doubling bifurcation (c) 4T period doubling bifurcation (d) fractal (e) fractal before unbounded...

Liu, Mengkun 1978-

2012-10-04T23:59:59.000Z

14

A method for the frequency control in time-resolved two-dimensional gigahertz surface acoustic wave imaging  

SciTech Connect

We describe an extension of the time-resolved two-dimensional gigahertz surface acoustic wave imaging based on the optical pump-probe technique with periodic light source at a fixed repetition frequency. Usually such imaging measurement may generate and detect acoustic waves with their frequencies only at or near the integer multiples of the repetition frequency. Here we propose a method which utilizes the amplitude modulation of the excitation pulse train to modify the generation frequency free from the mentioned limitation, and allows for the first time the discrimination of the resulted upper- and lower-side-band frequency components in the detection. The validity of the method is demonstrated in a simple measurement on an isotropic glass plate covered by a metal thin film to extract the dispersion curves of the surface acoustic waves.

Kaneko, Shogo; Tomoda, Motonobu; Matsuda, Osamu, E-mail: omatsuda@eng.hokudai.ac.jp [Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan)] [Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan)

2014-01-15T23:59:59.000Z

15

Further applications of time?frequency methods in acoustics  

Science Journals Connector (OSTI)

Time?frequency (t?f) methods have been repeatedly established as effective tools to successfully analyze a variety of signatures from many types of sources or scatterers. Many such signatures have been acoustic in nature and we have studied these most extensively in the past. We have presented several of these examples before [viz. G. C. Gaunaurd and H. C. Strifors J. Acoust. Soc. Am. 104 1746 136th ASA Mtg. (1998)]. Here we will cover acoustical applications that we have analyzed but which were not adequately covered in 1998. We will also outline additional ones—more extensively discussed in Appl. Mech. Rev. 50 131–149 (1997)—and a recent radar application [i.e. ibid. IEEE Trans. Antennas Propag. 46 1252–1262 (1998)]. In this case the present t?f processing was shown capable of successfully identifying an air target that had been covered with a dielectric RCS?reducing layer. We believe that this general approach jointly with the way we have used it to physically interpret broadband sonar/radar signatures can lead to straightforward implementations for many practical target?classification problems associated with many types of sensors. [Work partially supported by the ILIR Program of the authors’ Institutions and the ONR.

G. C. Gaunaurd; H. C. Strifors

1999-01-01T23:59:59.000Z

16

Attractiveness of periodic orbits in parametrically forced systems with time-increasing friction  

E-Print Network (OSTI)

Attractiveness of periodic orbits in parametrically forced systems with time-increasing friction-dimensional systems subject to a periodic force and study numer- ically how a time-varying friction affects oscillator in the presence of friction. We find that, if the damping coefficient increases in time up

17

Frequency-doubling in femtosecond laser inscribed periodically-poled potassium titanyl  

E-Print Network (OSTI)

, Sweden *Corresponding author: d.t.reid@hw.ac.uk Abstract: Frequency doubling has been achieved and M. Pierrou, " High power blue light generation in segmented KTiOPO4 waveguides," 8th European waveguides written with a femtosecond laser for flexible interconnection in a planar light-wave circuit," Opt

18

Attractiveness of periodic orbits in parametrically forced systems with time-increasing friction  

E-Print Network (OSTI)

Attractiveness of periodic orbits in parametrically forced systems with time- increasing friction with time-increasing friction Michele Bartuccelli,1,a) Jonathan Deane,1,b) and Guido Gentile2,c) 1 oscillator in the presence of friction, and study numerically how time-varying friction affects the dynamics

Bartuccelli, Michele

19

System and method for constructing filters for detecting signals whose frequency content varies with time  

DOE Patents (OSTI)

A system and method for constructing a bank of filters which detect the presence of signals whose frequency content varies with time. The present invention includes a novel system and method for developing one or more time templates designed to match the received signals of interest and the bank of matched filters use the one or more time templates to detect the received signals. Each matched filter compares the received signal x(t) with a respective, unique time template that has been designed to approximate a form of the signals of interest. The robust time domain template is assumed to be of the order of w(t)=A(t)cos{2.pi..phi.(t)} and the present invention uses the trajectory of a joint time-frequency representation of x(t) as an approximation of the instantaneous frequency function {.phi.'(t). First, numerous data samples of the received signal x(t) are collected. A joint time frequency representation is then applied to represent the signal, preferably using the time frequency distribution series (also known as the Gabor spectrogram). The joint time-frequency transformation represents the analyzed signal energy at time t and frequency .function., P(t,f), which is a three-dimensional plot of time vs. frequency vs. signal energy. Then P(t,f) is reduced to a multivalued function f(t), a two dimensional plot of time vs. frequency, using a thresholding process. Curve fitting steps are then performed on the time/frequency plot, preferably using Levenberg-Marquardt curve fitting techniques, to derive a general instantaneous frequency function .phi.'(t) which best fits the multivalued function f(t), a trajectory of the joint time-frequency domain representation of x(t). Integrating .phi.'(t) along t yields .phi.(t), which is then inserted into the form of the time template equation. A suitable amplitude A(t) is also preferably determined. Once the time template has been determined, one or more filters are developed which each use a version or form of the time template.

Qian, Shie (Austin, TX); Dunham, Mark E. (Los Alamos, NM)

1996-01-01T23:59:59.000Z

20

Recognition of Human Periodic Motion -a Frequency Domain Approach Baihua Li and Horst Holstein  

E-Print Network (OSTI)

-structural approaches, human motion, specifically walking, has been studied extensively using various spatio with the problems of human motion irregularities or change in speed, techniques such as scale space or Dynamic Time of a set of feature power vectors extracted from unidentified vertical component tra- jectories of feature

Li, Baihua

Note: This page contains sample records for the topic "frequency time period" 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

QUANTUM ENERGY EXPECTATION IN PERIODIC TIME-DEPENDENT HAMILTONIANS VIA GREEN  

E-Print Network (OSTI)

QUANTUM ENERGY EXPECTATION IN PERIODIC TIME-DEPENDENT HAMILTONIANS VIA GREEN FUNCTIONS C´ESAR R. DE. Introduction 1 2. Average Energy and Green Functions 4 3. Applications 10 3.1. Time-Independent Hamiltonians 10(t). For each positive and discrete observable A (which we call a probe energy), we derive a formula

22

System and method for constructing filters for detecting signals whose frequency content varies with time  

DOE Patents (OSTI)

A system and method are disclosed for constructing a bank of filters which detect the presence of signals whose frequency content varies with time. The present invention includes a novel system and method for developing one or more time templates designed to match the received signals of interest and the bank of matched filters use the one or more time templates to detect the received signals. Each matched filter compares the received signal x(t) with a respective, unique time template that has been designed to approximate a form of the signals of interest. The robust time domain template is assumed to be of the order of w(t)=A(t)cos(2{pi}{phi}(t)) and the present invention uses the trajectory of a joint time-frequency representation of x(t) as an approximation of the instantaneous frequency function {phi}{prime}(t). First, numerous data samples of the received signal x(t) are collected. A joint time frequency representation is then applied to represent the signal, preferably using the time frequency distribution series. The joint time-frequency transformation represents the analyzed signal energy at time t and frequency f, P(t,f), which is a three-dimensional plot of time vs. frequency vs. signal energy. Then P(t,f) is reduced to a multivalued function f(t), a two dimensional plot of time vs. frequency, using a thresholding process. Curve fitting steps are then performed on the time/frequency plot, preferably using Levenberg-Marquardt curve fitting techniques, to derive a general instantaneous frequency function {phi}{prime}(t) which best fits the multivalued function f(t). Integrating {phi}{prime}(t) along t yields {phi}{prime}(t), which is then inserted into the form of the time template equation. A suitable amplitude A(t) is also preferably determined. Once the time template has been determined, one or more filters are developed which each use a version or form of the time template. 7 figs.

Qian, S.; Dunham, M.E.

1996-11-12T23:59:59.000Z

23

Global Clock, Physical Time Order and Pending Period Analysis in Multiprocessor Systems  

E-Print Network (OSTI)

In multiprocessor systems, various problems are treated with Lamport's logical clock and the resultant logical time orders between operations. However, one often needs to face the high complexities caused by the lack of logical time order information in practice. In this paper, we utilize the \\emph{global clock} to infuse the so-called \\emph{pending period} to each operation in a multiprocessor system, where the pending period is a time interval that contains the performed time of the operation. Further, we define the \\emph{physical time order} for any two operations with disjoint pending periods. The physical time order is obeyed by any real execution in multiprocessor systems due to that it is part of the truly happened operation orders restricted by global clock, and it is then proven to be independent and consistent with traditional logical time orders. The above novel yet fundamental concepts enables new effective approaches for analyzing multiprocessor systems, which are named \\emph{pending period analy...

Chen, Yunji; Hu, Weiwu

2009-01-01T23:59:59.000Z

24

Quantum Energy Expectation in Periodic Time-Dependent hamiltonians via Green Functions  

E-Print Network (OSTI)

Let $U_F$ be the Floquet operator of a time periodic hamiltonian $H(t)$. For each positive and discrete observable $A$ (which we call a {\\em probe energy}), we derive a formula for the Laplace time average of its expectation value up to time $T$ in terms of its eigenvalues and Green functions at the circle of radius $e^{1/T}$. Some simple applications are provided which support its usefulness.

Cesar R. de Oliveira; Mariza S. Simsen

2009-07-31T23:59:59.000Z

25

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting  

E-Print Network (OSTI)

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting}@binghamton.edu Abstract In this paper, an energy aware dynamic voltage and frequency selection (EA-DVFS) algorithm energy and the harvested energy in a future duration. Specifically, if the system has sufficient energy

Qiu, Qinru

26

Peculiarities of periodic and aperiodic energy-exchange regimes in the cascade quasi-synchronous parametric frequency conversion  

SciTech Connect

The domains of existence and peculiarities of exact analytic solutions of the problem of quasi-synchronous interaction of four plane collinear monochromatic waves - modes in a quadratically nonlinear medium during cascade frequency conversion are analysed. It is shown that the unusual types of multicomponent cnoidal and solitary soliton-like waves (of periodic and aperiodic energy-exchange regimes) are realised. Two of the four components of the latter are proportional to the real and imaginary parts of the well-known Lorentzian dependence, which is commonly used to describe the dispersion of contributions from resonance transitions to the complex permittivity in the case of homogeneous line broadening. (special issue devoted to the 80th birthday of s.a. akhmanov)

Petnikova, V M; Shuvalov, Vladimir V [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

2009-07-31T23:59:59.000Z

27

Correlated tuning of high-frequency integrated continuous-time filters  

E-Print Network (OSTI)

CORRELATED TUNING OF HIGH ? FREQUENCY INTEGRATED CONTINUOUS ? TIME FILTERS A Thesis TODD LEE BROOKS Submitted to the Once of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 1992 Major Subject: Electrical Engineering CORRELATED TUNING OF HIGH ? FREQUENCY INTEGRATED CONTINUOUS ? TIME FILTERS A Thesis by TODD LEE BROOKS Approved as to style and content by: Ran 11 L. Geiger (Co-Chair of Committee) William G...

Brooks, Todd Lee

2012-06-07T23:59:59.000Z

28

A Gaussian Process Based Online Change Detection Algorithm for Monitoring Periodic Time Series  

SciTech Connect

Online time series change detection is a critical component of many monitoring systems, such as space and air-borne remote sensing instruments, cardiac monitors, and network traffic profilers, which continuously analyze observations recorded by sensors. Data collected by such sensors typically has a periodic (seasonal) component. Most existing time series change detection methods are not directly applicable to handle such data, either because they are not designed to handle periodic time series or because they cannot operate in an online mode. We propose an online change detection algorithm which can handle periodic time series. The algorithm uses a Gaussian process based non-parametric time series prediction model and monitors the difference between the predictions and actual observations within a statistically principled control chart framework to identify changes. A key challenge in using Gaussian process in an online mode is the need to solve a large system of equations involving the associated covariance matrix which grows with every time step. The proposed algorithm exploits the special structure of the covariance matrix and can analyze a time series of length T in O(T^2) time while maintaining a O(T) memory footprint, compared to O(T^4) time and O(T^2) memory requirement of standard matrix manipulation methods. We experimentally demonstrate the superiority of the proposed algorithm over several existing time series change detection algorithms on a set of synthetic and real time series. Finally, we illustrate the effectiveness of the proposed algorithm for identifying land use land cover changes using Normalized Difference Vegetation Index (NDVI) data collected for an agricultural region in Iowa state, USA. Our algorithm is able to detect different types of changes in a NDVI validation data set (with ~80% accuracy) which occur due to crop type changes as well as disruptive changes (e.g., natural disasters).

Chandola, Varun [ORNL; Vatsavai, Raju [ORNL

2011-01-01T23:59:59.000Z

29

Time series study of urban rainfall suppression during clean-up periods  

E-Print Network (OSTI)

and relatively clean sites through the time range before and during their clean-up periods to see how the air quality may affect the precipitation amount. By comparing the annual precipitation amount between two polluted sites with different elevations we...

Geng, Jun

2008-10-10T23:59:59.000Z

30

Time series study of urban rainfall suppression during clean-up periods  

E-Print Network (OSTI)

and relatively clean sites through the time range before and during their clean-up periods to see how the air quality may affect the precipitation amount. By comparing the annual precipitation amount between two polluted sites with different elevations we...

Geng, Jun

2009-05-15T23:59:59.000Z

31

LINEAR TIME PERIODIC MODELLING OF POWER ELECTRONIC DEVICES FOR POWER SYSTEM HARMONIC ANALYSIS AND SIMULATION  

E-Print Network (OSTI)

LINEAR TIME PERIODIC MODELLING OF POWER ELECTRONIC DEVICES FOR POWER SYSTEM HARMONIC ANALYSIS by simulation. 1. INTRODUCTION The variety and the wide spread use of power electronic devices in the power networks is due to their diverse and multiple functions: compensation, protection and interface

Boyer, Edmond

32

Periodic Charging Scheme for Fixed-Priority Real-Time Systems with Renewable Energy  

E-Print Network (OSTI)

to the limited capacity of the energy storage unit. With energy harvesting, in theory it becomes possiblePeriodic Charging Scheme for Fixed-Priority Real-Time Systems with Renewable Energy Mario Bambagini, Fairfax, VA, USA e-mail: aydin@cs.gmu.edu Abstract--Energy harvesting systems are gaining increasing

Aydin, Hakan

33

Periodicity detection and localization using spike timing from the AER EAR  

E-Print Network (OSTI)

Periodicity detection and localization using spike timing from the AER EAR Theodore Yu1 , Andrew Event Representation (AER) where each spike carries the identity of the sender. There are a handful of silicon cochleae with an Address Event type representation [4][5][6][7]. The AER EAR chip that we use

Liu, Shih-Chii

34

Single shot time stamping of ultrabright radio frequency compressed electron pulses  

SciTech Connect

We demonstrate a method of time-stamping Radio Frequency compressed electron bunches for Ultrafast Electron Diffraction experiments in the sub-pC regime. We use an in-situ ultra-stable photo-triggered streak camera to directly track the time of arrival of each electron pulse and correct for the timing jitter in the radio frequency synchronization. We show that we can correct for timing jitter down to 30 fs root-mean-square with minimal distortion to the diffraction patterns, and performed a proof-of-principle experiment by measuring the ultrafast electron-phonon coupling dynamics of silicon.

Gao, M.; Dwayne Miller, R. J. [Department of Chemistry and Physics, University of Toronto, Toronto, ON. M5S 3H6 (Canada); Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany); Jiang, Y.; Kassier, G. H. [Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany)

2013-07-15T23:59:59.000Z

35

Relationship between cutoff frequency and accuracy in time-interval photon statistics applied to oscillating signals  

Science Journals Connector (OSTI)

In this paper the accuracy in the determination of the period of an oscillating signal, when obtained from the photon statistics time-interval probability, is studied as a function of...

Rebolledo, M A; Martinez-Betorz, J A

1989-01-01T23:59:59.000Z

36

Comprehensive Joint Time-Frequency Analysis toward Condition Based Maintenance Regimes for Electrical and  

E-Print Network (OSTI)

measure is proposed for comparing vibration data from multiple sensors toward the creation of new and classification technique is proposed using mutual information measures in the time-frequency domain. The time bounding regions. Electrical, reflectometry-based methods of health evaluation are proposed

Almor, Amit

37

A strontium lattice clock with $3 \\times 10^{-17}$ inaccuracy and its frequency  

E-Print Network (OSTI)

We have measured the absolute frequency of the optical lattice clock based on $^{87}$Sr at PTB with an uncertainty of $3.9\\times 10^{-16}$ using two caesium fountain clocks. This is close to the accuracy of today's best realizations of the SI second. The absolute frequency of the 5s$^2$ $^1$S$_0$-5s5p $^3$P$_0$ transition in $^{87}$Sr is 429,228,004,229,873.13(17) Hz. Our result is in excellent agreement with recent measurements performed in different laboratories worldwide. We improved the total systematic uncertainty of our Sr frequency standard by a factor of five and reach $3\\times 10^{-17}$, opening new prospects for frequency ratio measurements between optical clocks for fundamental research, geodesy, or optical clock evaluation.

Falke, Stephan; Grebing, Christian; Lipphardt, Burghard; Weyers, Stefan; Gerginov, Vladislav; Huntemann, Nils; Hagemann, Christian; Al-Masoudi, Ali; Häfner, Sebastian; Vogt, Stefan; Sterr, Uwe; Lisdat, Christian

2013-01-01T23:59:59.000Z

38

The VLSI design of the minimal dimension, cost and power consumption system for time-frequency signal analysis  

Science Journals Connector (OSTI)

Multiple clock cycle implementation (MCI) of a flexible system for time-frequency (TF) signal analysis is presented. Some very important and frequently used time-frequency distributions (TFDs) can be realized by using the proposed architecture: the spectrogram ... Keywords: FPGA devices, S-method, hardware realization, multiple clock cycle implementation, time-frequency analysis

Veselin N. Ivanovi?; Radovan Stojanovi?

2005-08-01T23:59:59.000Z

39

Method for estimation of gravitational-wave transient model parameters in frequency-time maps  

E-Print Network (OSTI)

A common technique for detection of gravitational-wave signals is searching for excess power in frequency-time maps of gravitational-wave detector data. In the event of a detection, model selection and parameter estimation will be performed in order to explore the properties of the source. In this paper, we develop a Bayesian statistical method for extracting model-dependent parameters from observed gravitational-wave signals in frequency-time maps. We demonstrate the method by recovering the parameters of model gravitational-wave signals added to simulated advanced LIGO noise. We also characterize the performance of the method and discuss prospects for future work.

Michael Coughlin; Nelson Christensen; Jonathan Gair; Shivaraj Kandhasamy; Eric Thrane

2014-04-17T23:59:59.000Z

40

LONG-TIME SOLVABILITY OF THE NAVIER-STOKES-BOUSSINESQ EQUATIONS WITH ALMOST PERIODIC INITIAL LARGE DATA  

E-Print Network (OSTI)

LONG-TIME SOLVABILITY OF THE NAVIER-STOKES-BOUSSINESQ EQUATIONS WITH ALMOST PERIODIC INITIAL LARGE Sapporo 060-0810, Japan Keywords: Navier-Stokes equation, Boussinesq approximation, almost periodic of solutions of the Navier-Stokes-Boussinesq equations with spatially almost periodic large data when

Ibrahim, Slim

Note: This page contains sample records for the topic "frequency time period" 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

-transform MATLAB Laboratory Experiment Purpose: This experiment presents the frequency domain analysis of discrete-time  

E-Print Network (OSTI)

5.6 -transform MATLAB Laboratory Experiment Purpose: This experiment presents the frequency domain analysis of discrete-time systems using MATLAB. The impulse, step, sinusoidal, and exponential on the ¡ -transform. In addition, MATLAB will be used to perform the partial fraction expansion and to find

Gajic, Zoran

42

Auditory Time-Frequency Masking: Psychoacoustical Data and Application to Audio  

E-Print Network (OSTI)

Auditory Time-Frequency Masking: Psychoacoustical Data and Application to Audio Representations models of TF masking currently implemented in some percep- tual audio codecs. In the context of audio models currently implemented in some perceptual audio codecs like MP3 and develop a perceptually relevant

Paris-Sud XI, Université de

43

Unsupervised learning of time-frequency patches as a noise-robust representation of speech  

Science Journals Connector (OSTI)

We present a self-learning algorithm using a bottom-up based approach to automatically discover, acquire and recognize the words of a language. First, an unsupervised technique using non-negative matrix factorization (NMF) discovers phone-sized time-frequency ... Keywords: Acoustic signal analysis, Automatic speech recognition, Language acquisition, Matrix factorization, Noise robustness

Maarten Van Segbroeck; Hugo Van hamme

2009-11-01T23:59:59.000Z

44

Website link prediction using a Markov chain model based on multiple time periods  

Science Journals Connector (OSTI)

Growing size and complexity of many websites have made navigation through these sites increasingly difficult. Attempting to automatically predict the next page for a website user to visit has many potential benefits, for example in site navigation, automatic tour generation, adaptive web applications, recommendation systems, web server optimisation, web search and web pre-fetching. This paper describes an approach to link prediction using a Markov chain model based on an exponentially smoothed transition probability matrix which incorporates site usage statistics collected over multiple time periods. The improved performance of this approach compared to earlier methods is also discussed.

Shantha Jayalal; Chris Hawksley; Pearl Brereton

2007-01-01T23:59:59.000Z

45

Development of periodic response factors for use with the radiant time series method  

SciTech Connect

Harris and McQuiston (1988) developed conduction transfer function (CTF) coefficients corresponding to 41 representative wall assemblies and 42 representative roof assemblies for use with the transfer function method (TFM). They also developed a grouping procedure that allows design engineers to determine the correct representative wall or roof assembly that most closely matches a specific wall or roof assembly. The CTF coefficients and the grouping procedure have been summarized in the ASHRAE Handbook--Fundamentals (1989, 1993, 1997) and the ASHRAE Cooling and Heating Load Calculation Manual, second edition. More recently, a new, simplified design cooling load calculation procedure, the radiant time series method (RTSM), has been developed. The RTSM uses periodic response factors to model transient conductive heat transfer. While not a true manual load calculation procedure, it is quite feasible to implement the RTSM in a spreadsheet. To be useful in such an environment, it would be desirable to have a pre-calculated set of periodic response factors. Accordingly, a set of periodic response factors has been calculated and is presented in this paper.

Spitler, J.D.; Fisher, D.E.

1999-07-01T23:59:59.000Z

46

Output-Only Modal Analysis of Linear Time Periodic Systems with Application to Wind Turbine Simulation Data  

Science Journals Connector (OSTI)

Many important systems, such as turbomachinery, helicopters and wind turbines, must be modeled with linear time ... predict resonance phenomena. Time periodic effects in wind turbines might arise due to stratific...

Matthew S. Allen; Michael W. Sracic…

2011-01-01T23:59:59.000Z

47

Attractiveness of periodic orbits in parametrically forced systemswith time-increasing friction  

E-Print Network (OSTI)

We consider dissipative one-dimensional systems subject to a periodic force and study numerically how a time-varying friction affects the dynamics. As a model system, particularly suited for numerical analysis, we investigate the driven cubic oscillator in the presence of friction. We find that, if the damping coefficient increases in time up to a final constant value, then the basins of attraction of the leading resonances are larger than they would have been if the coefficient had been fixed at that value since the beginning. From a quantitative point of view, the scenario depends both on the final value and the growth rate of the damping coefficient. The relevance of the results for the spin-orbit model are discussed in some detail.

Michele Bartuccelli; Jonathan Deane; Guido Gentile

2012-07-18T23:59:59.000Z

48

Time-varying autoregressive model for spectral analysis of microseismic experiments and long-period volcanic events  

Science Journals Connector (OSTI)

......parts of the signal. The study of long-term phenomena, such as resonance...operations, carbon capture and storage and waste water disposal, suffers from...experiments, or CO2 injection and storage. Likewise, a better time-frequency......

J. B. Tary; R. H. Herrera; M. van der Baan

2014-01-01T23:59:59.000Z

49

Multi-start iterated local search for the periodic vehicle routing problem with time windows and time spread constraints on services  

Science Journals Connector (OSTI)

In the field of high-value shipment transportation, companies are faced to the malevolence problem. The risk of ambush increases with the predictability of vehicle routes. This paper addresses a very hard periodic vehicle routing problem with time windows, ... Keywords: Iterated local search, Periodic vehicle routing, Security constraints, Time window

Julien Michallet; Christian Prins; Lionel Amodeo; Farouk Yalaoui; Grégoire Vitry

2014-01-01T23:59:59.000Z

50

Time-delayed feedback control of unstable periodic orbits near a subcritical Hopf bifurcation  

E-Print Network (OSTI)

We show that Pyragas delayed feedback control can stabilize an unstable periodic orbit (UPO) that arises from a generic subcritical Hopf bifurcation of a stable equilibrium in an n-dimensional dynamical system. This extends results of Fiedler et al. [PRL 98, 114101 (2007)], who demonstrated that such feedback control can stabilize the UPO associated with a two-dimensional subcritical Hopf normal form. Pyragas feedback requires an appropriate choice of a feedback gain matrix for stabilization, as well as knowledge of the period of the targeted UPO. We apply feedback in the directions tangent to the two-dimensional center manifold. We parameterize the feedback gain by a modulus and a phase angle, and give explicit formulae for choosing these two parameters given the period of the UPO in a neighborhood of the bifurcation point. We show, first heuristically, and then rigorously by a center manifold reduction for delay differential equations, that the stabilization mechanism involves a highly degenerate Hopf bifurcation problem that is induced by the time-delayed feedback. When the feedback gain modulus reaches a threshold for stabilization, both of the genericity assumptions associated with a two-dimensional Hopf bifurcation are violated: the eigenvalues of the linearized problem do not cross the imaginary axis as the bifurcation parameter is varied, and the real part of the cubic coefficient of the normal form vanishes. Our analysis of this degenerate bifurcation problem reveals two qualitatively distinct cases when unfolded in a two-parameter plane. In each case, Pyragas-type feedback successfully stabilizes the branch of small-amplitude UPOs in a neighborhood of the original bifurcation point, provided that the phase angle satisfies a certain restriction.

Genevieve Brown; Claire M. Postlethwaite; Mary Silber

2010-06-17T23:59:59.000Z

51

Time-frequency analyses of transient-evoked stimulus-frequency and distortion-product otoacoustic emissions: Testing  

E-Print Network (OSTI)

97239and Rush University, Chicago, Illinoisb ,c Douglas H. Keefe Boys Town National Research Hospital-frequency SF and distortion-product DP OAEs to test cochlear model predictions. SFOAEs and DPOAEs were elicited

Allen, Jont

52

Using high-frequency data and time series models to improve yield management  

Science Journals Connector (OSTI)

High-frequency (less than monthly) time series data provide valuable information for designing the adequate yield policy of the organisation. However, it is not easy to extract this information from raw data; although the evolution of the series is usually induced by stable patterns of behaviour of the economic agents, these patterns are so complex that simple smoothing techniques or subjective forecasting cannot consider all underlying factors. In this paper, we discuss time series models as a tool for carrying out a full and efficient analysis. The main ideas are illustrated with an application to Spanish daily electricity consumption.

Jose Ramon Cancelo; Antoni Espasa

2001-01-01T23:59:59.000Z

53

Running time variability and resource allocation : a data-driven analysis of high-frequency bus operations  

E-Print Network (OSTI)

Running time variability is one of the most important factors determining service quality and operating cost of high-frequency bus transit. This research aims to improve performance analysis tools currently used in the bus ...

Sánchez-Martínez, Gabriel Eduardo

2013-01-01T23:59:59.000Z

54

Numerical study on global motion of Truss Spar in frequency and time domains for the Liwan 3-1 area  

Science Journals Connector (OSTI)

Using frequency and time domain analysis, the authors analyzed the hydrodynamics and motion behavior of a Truss Spar platform at a water depth of 1500 m ... the hull’s hydrodynamics and comparing with a semi-submersible

Lu Li; Binbin Li; Jinping Ou

2011-06-01T23:59:59.000Z

55

A new time-frequency approach for hybrid differential and impedance protection of transmission lines  

Science Journals Connector (OSTI)

A new current differential protection of transmission lines is presented in this paper using an S-transform variant having very fast computational speed suitable for real-time applications. The conventional S-transform used earlier for transmission line protection has large computational overhead and thus is not suitable for generating decisions regarding the occurrence of a fault and its type on a transmission line. The new S-transform variant is based on different types of frequency scaling, band pass filtering, and interpolation techniques to achieve a significant reduction of computation time in comparison to the original S-transform. For wide area protection as in the case of smart grid the current differential protection is realised by extracting the relevant features from the current signals at both the sending end and receiving end terminals from the new S-transform generated contours. This paper focuses on the fault detection, classification, and location aspects using a new S-transform variant applied to synchronised measurement of the differential and average energy of current signals. Digital simulation results using EMTP for a long distance transmission line show the computational speed and efficiency of this new algorithm.

S.K. Swain; P.K. Dash

2014-01-01T23:59:59.000Z

56

A compact, robust, and transportable ultra-stable laser with a fractional frequency instability of $1\\times10^{-15}$  

E-Print Network (OSTI)

We present a compact and robust transportable ultra-stable laser system with minimum fractional frequency instability of $1\\times10^{-15}$ at integration times between 1 to 10 s. The system was conceived as a prototype of a subsystem of a microwave-optical local oscillator to be used on the satellite mission STE-QUEST (Space-Time Explorer and QUantum Equivalence Principle Space Test, http://sci.esa.int/ste-quest/). It was therefore designed to be compact, to sustain accelerations occurring during rocket launch, to exhibit low vibration sensitivity, and to reach a low frequency instability. Overall dimensions of the optical system are $40\\textrm{ cm}\\times20\\textrm{ cm}\\times30\\textrm{ cm}$. The acceleration sensitivities of the optical frequency in the three directions were measured to be $1.7\\times10^{-11}/g$, $8.0\\times10^{-11}/g$, and $3.9\\times10^{-10}/g$, and the absolute frequency instability was determined via a three-cornered hat measurement. The design is also appropriate and useful for terrestrial a...

Chen, Qun-Feng; Cardace, Marco; Schiller, Stephan; Legero, Thomas; Häfner, Sebastian; Uhde, Andre; Sterr, Uwe

2014-01-01T23:59:59.000Z

57

High-Frequency (140-GHz) Time Domain EPR and ENDOR Spectroscopy: The Tyrosyl Radical-Diiron Cofactor in  

E-Print Network (OSTI)

High-Frequency (140-GHz) Time Domain EPR and ENDOR Spectroscopy: The Tyrosyl Radical EPR and ENDOR have been employed to characterize the tyrosyl radical (Y·)-diiron cofactor in the Y2 of 140-GHz time domain EPR and ENDOR to examine this system and demonstrates the capabilities

Griffin, Robert G.

58

Non-preemptive scheduling of periodic and aperiodic tasks in the hard real-time systems  

E-Print Network (OSTI)

S. 38 40 11 Enumeration tree search . 42 12 Optimizing two requests in the LOQS globally. 13 Identifying dynamic dominant requests. 14 Dispatching requests in ZOgS. 50 51 15 Extraction algorithm. 53 16 Extraction algorithm by heuristic... in hard real ? time environment, the measure- ment criteria for a good algorithm can be a success ratio and a decision time required for dispatching. The success ratio, when a certain algorithm is used, is the ratio of number of tash sets which...

Oh, Hoon

1992-01-01T23:59:59.000Z

59

4.6 MATLAB Laboratory Experiment Purpose: This experiment presents the frequency domain analysis of continuous-time  

E-Print Network (OSTI)

4.6 MATLAB Laboratory Experiment Purpose: This experiment presents the frequency domain analysis of continuous-time linear systems using MATLAB. The impulse, step, sinusoidal, and exponential responses. In addition, MATLAB will be used to perform the partial fraction expansion and to find the inverse Laplace

Gajic, Zoran

60

Design of Rotor-side Controller Using Adaptive Time-frequency Method for DFIG Bearing Fault Detection  

Science Journals Connector (OSTI)

To ensure the reliable operation and power quality of wind power systems, the fault-tolerant control for DFIG is studied in this paper. Based on measured motor currents data, an adaptive statistical time-frequency method is then used to detect the fault ... Keywords: Doubly-fed induction generator, monitoring, wind turbine, rotor side inverter

Suratsavadee K. Korkua

2013-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Numerical simulation of borehole acoustic logging in the frequency and time domains with hp-adaptive finite elements  

E-Print Network (OSTI)

Numerical simulation of borehole acoustic logging in the frequency and time domains with hp elasticity Coupled problems hp-adaptive finite elements a b s t r a c t Accurate numerical simulation physical modeling combined with accurate and efficient numerical dis- cretization and solution techniques

Torres-Verdín, Carlos

62

A Generic Space-Time-Frequency Correlation Model and Its Corresponding Simulation Model for Narrowband MIMO Channels  

E-Print Network (OSTI)

A Generic Space-Time-Frequency Correlation Model and Its Corresponding Simulation Model.Laurenson d9ed. ac. uk Keyword: Wireless channels, NIIMO, STF correlation, deterministic simulation model theoretical reference model, a deterministic simulation model is then proposed and its 3-D STF correlation

Wang, Cheng-Xiang

63

Extended-time multi-taper frequency domain cross-correlation receiver function estimation  

E-Print Network (OSTI)

produced by the incident wave field, also called 1 #12;the receiver function. The concept is simple function. They include frequency domain division with a spectral water level (Langston, 1979; Owens et al; 2005). This defeats MTRF's direct use for transition zone structure studies, but there are remedies

Helffrich, George

64

Differentiated Time-Frequency Characteristics Based Real-Time Motion Decoding for Lower Extremity Rehabilitation Exoskeleton Robot  

Science Journals Connector (OSTI)

Decode the human motion intension precisely in real time is the ... the biomechanism of skeletal muscle; DPSE (Differentiated Power Spectrum Estimation) method is applied to extract ... Results show the human-mac...

Yuanjie Fan; Yuehong Yin

2012-01-01T23:59:59.000Z

65

Intermediate frequency band digitized high dynamic range radiometer system for plasma diagnostics and real-time Tokamak control  

SciTech Connect

An intermediate frequency (IF) band digitizing radiometer system in the 100-200 GHz frequency range has been developed for Tokamak diagnostics and control, and other fields of research which require a high flexibility in frequency resolution combined with a large bandwidth and the retrieval of the full wave information of the mm-wave signals under investigation. The system is based on directly digitizing the IF band after down conversion. The enabling technology consists of a fast multi-giga sample analog to digital converter that has recently become available. Field programmable gate arrays (FPGA) are implemented to accomplish versatile real-time data analysis. A prototype system has been developed and tested and its performance has been compared with conventional electron cyclotron emission (ECE) spectrometer systems. On the TEXTOR Tokamak a proof of principle shows that ECE, together with high power injected and scattered radiation, becomes amenable to measurement by this device. In particular, its capability to measure the phase of coherent signals in the spectrum offers important advantages in diagnostics and control. One case developed in detail employs the FPGA in real-time fast Fourier transform (FFT) and additional signal processing. The major benefit of such a FFT-based system is the real-time trade-off that can be made between frequency and time resolution. For ECE diagnostics this corresponds to a flexible spatial resolution in the plasma, with potential application in smart sensing of plasma instabilities such as the neoclassical tearing mode (NTM) and sawtooth instabilities. The flexible resolution would allow for the measurement of the full mode content of plasma instabilities contained within the system bandwidth.

Bongers, W. A.; Beveren, V. van; Westerhof, E.; Goede, A. P. H.; Krijger, B.; Berg, M. A. van den; Graswinckel, M. F.; Schueller, F. C. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Thoen, D. J. [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Nuij, P. J. W. M. [Eindhoven University of Technology, Control Systems Technology Group, and Applied Physics Department, PO Box 513, NL-5600 MB Eindhoven (Netherlands); Baar, M. R. de; Donne, A. J. H.; Hennen, B. A. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, Control Systems Technology Group, and Applied Physics Department, PO Box 513, NL-5600 MB Eindhoven (Netherlands); Kantor, M. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Forschungszentrum Juelich GMBH, Institute of Energy and Climate research, Plasma Physics, Association EURATOM-FZJ, Trilateral Euregio Cluster, 52425 Juelich (Germany); Ioffe Institute, RAS, Saint-Petersburg, 195256 (Russian Federation)

2011-06-15T23:59:59.000Z

66

Detecting Abnormal Vibration in a Gearbox Using Time-Frequency Domain.  

E-Print Network (OSTI)

??The gearbox of Volvo Construction Equipment vehicles may be considered as a critical mechanical component. Gear failures may cause costly down time while the gearbox… (more)

Ibeh, Elisabeth

2012-01-01T23:59:59.000Z

67

Summary of Time Period-Based and Other Approximation Methods for Determining the Capacity Value of Wind and Solar in the United States: September 2010 - February 2012  

SciTech Connect

This paper updates previous work that describes time period-based and other approximation methods for estimating the capacity value of wind power and extends it to include solar power. The paper summarizes various methods presented in utility integrated resource plans, regional transmission organization methodologies, regional stakeholder initiatives, regulatory proceedings, and academic and industry studies. Time period-based approximation methods typically measure the contribution of a wind or solar plant at the time of system peak - sometimes over a period of months or the average of multiple years.

Rogers, J.; Porter, K.

2012-03-01T23:59:59.000Z

68

Calculation of HVDC-converter harmonics in frequency domain with regard to asymmetries and comparison with time domain simulations  

SciTech Connect

In order to study the effects of large HVDC converters to the feeding ac networks, it is of importance to explain and to calculate harmonic phenomena which are a result of converter operation. During commissioning of real HVDC converters it could be seen, that harmonics resulting from unsymmetries in the system voltages or from unsymmetries in converter operation led to significant difficulties concerning the system design. For this reason, not only the effects of characteristic but also the effects of noncharacteristic converter harmonics must be taken into account. The aim is to describe the steady state harmonic behavior of the converter. The harmonic spectra are not determined by time domain analysis but instead the solution is found by frequency domain calculations. This can result in reduced calculation time in comparison to conventional fourier analysis of the time functions. The converter is interpreted as an amplitude modulator with voltage and current converter functions which describe the coupling of the dc circuit and the ac network through the converter. To verify the theory, comparison of frequency domain with time domain calculations were carried out.

Rittiger, J. [Siemens AG, Erlangen (Germany)] [Siemens AG, Erlangen (Germany); Kulicke, B. [Technische Univ. Berlin (Germany)] [Technische Univ. Berlin (Germany)

1995-10-01T23:59:59.000Z

69

DIAGNOSING THE TIME-DEPENDENCE OF ACTIVE REGION CORE HEATING FROM THE EMISSION MEASURE. I. LOW-FREQUENCY NANOFLARES  

SciTech Connect

Observational measurements of active region emission measures contain clues to the time dependence of the underlying heating mechanism. A strongly nonlinear scaling of the emission measure with temperature indicates a large amount of hot plasma relative to warm plasma. A weakly nonlinear (or linear) scaling of the emission measure indicates a relatively large amount of warm plasma, suggesting that the hot active region plasma is allowed to cool and so the heating is impulsive with a long repeat time. This case is called low-frequency nanoflare heating, and we investigate its feasibility as an active region heating scenario here. We explore a parameter space of heating and coronal loop properties with a hydrodynamic model. For each model run, we calculate the slope {alpha} of the emission measure distribution EM(T){proportional_to}T {sup {alpha}}. Our conclusions are: (1) low-frequency nanoflare heating is consistent with about 36% of observed active region cores when uncertainties in the atomic data are not accounted for; (2) proper consideration of uncertainties yields a range in which as many as 77% of observed active regions are consistent with low-frequency nanoflare heating and as few as zero; (3) low-frequency nanoflare heating cannot explain observed slopes greater than 3; (4) the upper limit to the volumetric energy release is in the region of 50 erg cm{sup -3} to avoid unphysical magnetic field strengths; (5) the heating timescale may be short for loops of total length less than 40 Mm to be consistent with the observed range of slopes; (6) predicted slopes are consistently steeper for longer loops.

Bradshaw, S. J.; Reep, J. W. [Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States); Klimchuk, J. A., E-mail: stephen.bradshaw@rice.edu, E-mail: jeffrey.reep@rice.edu, E-mail: james.a.klimchuk@nasa.gov [NASA Goddard Space Flight Center, Solar Physics Lab., Code 671, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

2012-10-10T23:59:59.000Z

70

CLASSIFICATION OF HAZELNUT KERNELS BY USING IMPACT ACOUSTIC TIME-FREQUENCY PATTERNS  

E-Print Network (OSTI)

Service, KS 66502 USA ABSTRACT Hazelnuts with damaged or cracked shells are more prone to infection the discrimination power of different segmentations. In each resulting time segment, the signal is further decomposed into sub-bands using an undecimated wavelet transform. The most discriminative sub-bands are selected

Minnesota, University of

71

Single Antenna Target Detection Using Broadband Frequency Selection Time Reversal Method  

E-Print Network (OSTI)

transmitter to probe the environment. In the absence of target, the background channel response is given by Hw/o(f) in Figure 2(b). When target comes into this environment, channel response changes to Hw/(f). The difference as shown in Figure 2(c). The target response is time-reversed and re-broadcasted into the environment

Moura, José

72

Measurement of higher harmonics in periodic vibrations using phase-modulated TV holography with digital image processing  

Science Journals Connector (OSTI)

We separately measure the higher harmonics vibration patterns of a periodic vibrating object by using time-average TV holography and phase modulation. During measurements the frequency...

Løkberg, Ole J; Pedersen, Hans M; Valø, Hilde; Wang, Gunnar

1994-01-01T23:59:59.000Z

73

Time-, Frequency-, and Wavevector-Resolved X-Ray Diffraction from Single Molecules  

E-Print Network (OSTI)

Using a quantum electrodynamic framework, we calculate the off-resonant scattering of a broad-band X-ray pulse from a sample initially prepared in an arbitrary superposition of electronic states. The signal consists of single-particle (incoherent) and two-particle (coherent) contributions that carry different particle form factors that involve different material transitions. Single-molecule experiments involving incoherent scattering are more influenced by inelastic processes compared to bulk measurements. The conditions under which the technique directly measures charge densities (and can be considered as diffraction) as opposed to correlation functions of the charge-density are specified. The results are illustrated with time- and wavevector-resolved signals from a single amino acid molecule (cysteine) following an impulsive excitation by a stimulated X-ray Raman process resonant with the sulfur K-edge. Our theory and simulations can guide future experimental studies on the structures of nano-particles and ...

Bennett, Kochise; Zhang, Yu; Dorfman, Konstantin E; Mukamel, Shaul

2014-01-01T23:59:59.000Z

74

Determination of surface-induced platelet activation by applying time-dependency dissipation factor versus frequency using quartz crystal microbalance with dissipation  

Science Journals Connector (OSTI)

...dissipation versus frequency plots (Df-t...protein-modified surfaces. The responses showed the predominant...processing and storage. The above mentioned...factor coupled with frequency changes over time...to determine the energy dissipation factor...involved in the QCM-D response during platelet...

2011-01-01T23:59:59.000Z

75

A systematic periodicity and time-variable modulation search in RXTE ASM data : methods, findings, and implications for astrophysical X-ray sources  

E-Print Network (OSTI)

In this work, we present the results of a general search for periodicities and for time-variable modulation strength in X-ray sources using data from the All-Sky Monitor onboard the Rossi X-ray Timing Explorer. New findings, ...

Harris, Robert J., S.M. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

76

Long-Period Solar Variability  

SciTech Connect

Terrestrial climate records and historical observations of the Sun suggest that the Sun undergoes aperiodic oscillations in radiative output and size over time periods of centuries and millenia. Such behavior can be explained by the solar convective zone acting as a nonlinear oscillator, forced at the sunspot-cycle frequency by variations in heliomagnetic field strength. A forced variant of the Lorenz equations can generate a time series with the same characteristics as the solar and climate records. The timescales and magnitudes of oscillations that could be caused by this mechanism are consistent with what is known about the Sun and terrestrial climate.

GAUTHIER,JOHN H.

2000-07-20T23:59:59.000Z

77

Time-varying autoregressive model for spectral analysis of microseismic experiments and long-period volcanic events  

Science Journals Connector (OSTI)

......than the brittle failure energy corresponding to the...a part of the missing energy. Fluid injection monitoring...applications, such as geothermal operations, carbon capture...limitation. As the needs in energy are growing and climate...and their computational cost. 2 METHODS 2.1 Short-time......

J. B. Tary; R. H. Herrera; M. van der Baan

2014-01-01T23:59:59.000Z

78

Time?differential radio?frequency muon spin resonance (TD?RF?SR) technique at a pulsed muon beam  

Science Journals Connector (OSTI)

Longitudinal?field ?SR methods, e.g., radio?frequency ?+...spin resonance (RF?SR), are well suited to investigate dynamic processes that destroy the phase coherence of the muon spin ensemble. Additional informati...

R. Scheuermann; J. Schmidl; A. Seeger; Th. Stammler; D. Herlach…

79

The Parkes multibeam pulsar survey: VII. Timing of four millisecond pulsars and the underlying spin period distribution of the Galactic millisecond pulsar population  

E-Print Network (OSTI)

We present timing observations of four millisecond pulsars discovered in the Parkes 20-cm multibeam pulsar survey of the Galactic plane. PSRs J1552-4937 and J1843-1448 are isolated objects with spin periods of 6.28 and 5.47 ms respectively. PSR J1727-2946 is in a 40-day binary orbit and has a spin period of 27 ms. The 4.43-ms pulsar J1813-2621 is in a circular 8.16-day binary orbit around a low-mass companion star with a minimum companion mass of 0.2 solar masses. Combining these results with detections from five other Parkes multibeam surveys, gives a well-defined sample of 56 pulsars with spin periods below 20 ms. We develop a likelihood analysis to constrain the functional form which best describes the underlying distribution of spin periods for millisecond pulsars. The best results were obtained with a log-normal distribution. A gamma distribution is less favoured, but still compatible with the observations. Uniform, power-law and Gaussian distributions are found to be inconsistent with the data. Galactic...

Lorimer, D R; Manchester, R N; Possenti, A; Lyne, A G; McLaughlin, M A; Kramer, M; Hobbs, G; Stairs, I H; Burgay, M; Eatough, R P; Keith, M J; Faulkner, A J; D'Amico, N; Camilo, F; Corongiu, A; Crawford, F

2015-01-01T23:59:59.000Z

80

Modeling the time and energy behavior of the GCR intensity in the periods of low activity around the last three solar minima  

E-Print Network (OSTI)

Using the simple model for the description of the GCR modulation in the heliosphere and the sets of parameters discussed in the accompanying paper we model some features of the time and energy behavior of the GCR intensity near the Earth observed during periods of low solar activity around three last solar minima. In order to understand the mechanisms underlying these features in the GCR behavior, we use the suggested earlier decomposition of the calculated intensity into the partial intensities corresponding to the main processes (diffusion, adiabatic losses, convection and drifts).

Krainev, M B; Kalinin, M S; Svirzhevskaya, A K; Svirzhevsky, N S

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

All-Sky LIGO Search for Periodic Gravitational Waves in the Early Fifth-Science-Run Data  

E-Print Network (OSTI)

We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1100 Hz and with the frequency’s time derivative in the range -5×10[superscript -9]–0??Hz?s[superscript -1]. ...

Zucker, Michael E.

82

All-sky search for periodic gravitational waves in the full S5 LIGO data  

E-Print Network (OSTI)

We report on an all-sky search for periodic gravitational waves in the frequency band 50–800 Hz and with the frequency time derivative in the range of 0 through -6×10[superscript -9]??Hz/s. Such a signal could be produced ...

Barsotti, Lisa

83

Optimization of high-order harmonic generation by genetic algorithm and wavelet time-frequency analysis of quantum dipole emission  

E-Print Network (OSTI)

-order har- monic generation ~HHG! of orders as high as 300 has been observed @5,6#, with photon energies in excess of 500 eV. A novel concept of ‘‘intra-atomic’’ phase matching has been recently introduced, allowing the enhancement of the inten- sity of a..., as shown in Fig. 2, the major time domain contributing to the total har- monic intensity is the central part of the laser pulse with significant field intensity ~for example, between 24 to 14 optical cycles!. Beyond this central time regime, the har- monic...

Chu, Xi; Chu, Shih-I

2001-07-13T23:59:59.000Z

84

The driving frequency effects on the atmospheric pressure corona jet plasmas from low frequency to radio frequency  

Science Journals Connector (OSTI)

Lately the atmospheric pressure jet type coronaplasma which has been typically driven by dc to low frequency (LF: several tens of kHz) is often generated by using radio frequency of 13.56 MHz. Yet the relationship between the plasma and its driving frequency has seldom been investigated. Hence in this study dependence of the atmospheric pressurecoronaplasmacharacteristics on the driving frequency was explored experimentally from LF to rf (5 kHz–13.56 MHz). The plasmas generated by the driving frequency under 2 MHz were cylindrical shape of several tens of millimeters long while the 13.56 MHz plasma is spherical and a few millimeters long. As the driving frequency was increased the plasma length became shortened. At the lower driving frequencies (below 2 MHz) the plasmas existed as positive streamer and negative glow for each half period of the applied voltage but the discharge was more continuous in time for the 13.56 MHz plasma. It was inferred from the measured I–V curves that the higher driving frequency induced higher discharge currents and the gas temperature was increased as the driving frequency was increased.

Dan Bee Kim; H. Jung; B. Gweon; S. Y. Moon; J. K. Rhee; W. Choe

2011-01-01T23:59:59.000Z

85

Spectral inhomogeneity induced by vacancies and thermal phonons and associated observables in time-and frequency-domain nonlinear  

E-Print Network (OSTI)

Spectral inhomogeneity induced by vacancies and thermal phonons and associated observables in time by vacancies and thermally populated phonons, specializing to molecular iodine isolated in an Ar matrix. At experimentally relevant temperatures, for a vacancy concentration of 1.4%, both defect-induced and phonon

Apkarian, V. Ara

86

Doppler Effect removal based on instantaneous frequency estimation and time domain re-sampling for wayside acoustic defective bearing detector system  

Science Journals Connector (OSTI)

Abstract The phenomenon of Doppler Effect in the acoustic signal recorded by the wayside acoustic defective bearing detector (ADBD) leads to the difficulty for fault diagnosis of train bearings with a high moving speed, which is a barrier that would badly reduce the effectiveness of online defect detection. In order to improve the performance of condition monitoring of the bearings on a passing train with microphones amounted besides the railway, the elimination of the Doppler Effect should be solved firstly. An effective method for removing the Doppler Effect embedded in the source signal is presented in this paper. The Short Time Fourier Transform-Viterbi Algorithm (STFT-VA) is applied to obtain instantaneous frequency estimation of the distorted signal. According to the acoustic theory of Morse, the non-linear data fitting is then carried out to get the fitting instantaneous frequencies. The necessary parameters for time domain interpolation re-sampling, which is totally based on the kinematic analysis, are acquired from the fitting curve and the re-sampling sequence could be established in the time domain. As a result of the preceding steps, the fault diagnosis for the train bearings could be implemented with the restored signal. The effectiveness of this proposed method is verified by means of a simulation with three adjacent frequencies and an experiment with practical acoustic signals of train bearings with a crack on the outer race and the inner race. The results of the simulation and the experiment indicate that the proposed method has an excellent performance in removing Doppler Effect, and could be well employed to the condition monitoring and fault diagnosis of train bearings with a high moving speed.

Chao Wang; Fanrang Kong; Qingbo He; Fei Hu; Fang Liu

2014-01-01T23:59:59.000Z

87

Frequency Combs for Astronomy  

Science Journals Connector (OSTI)

For the first time a mode filtered frequency comb has been used to calibrate an astronomical spectrometer online. Solar and calibration spectra have been recorded simultaneously.

Wilken, Tobias; Hänsch, Theodor W; Udem, Thomas; Steinmetz, Tilo; Holzwarth, Ronald; Araujo-Hauck, Constanza; Pasquini, Luca; D'Odorico, Sandro; Manescau, Antonio; Murphy, Michael T; Kentischer, Thomas; Schmidt, Wolfgang

88

Down hole periodic seismic generator  

DOE Patents (OSTI)

A down hole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.

Hardee, Harry C. (Albuquerque, NM); Hills, Richard G. (Las Cruces, NM); Striker, Richard P. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

89

Advanced downhole periodic seismic generator  

DOE Patents (OSTI)

An advanced downhole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.

Hardee, Harry C. (Albuquerque, NM); Hills, Richard G. (Las Cruces, NM); Striker, Richard P. (Albuquerque, NM)

1991-07-16T23:59:59.000Z

90

On a periodicity measure and superoscillations  

E-Print Network (OSTI)

The phenomenon of superoscillation, where band limited signals can oscillate over some time period with a frequency higher than the band limit, is not only very interesting but it also seems to offer many practical applications. The first reason is that the superoscillation frequency can be exploited to perform tasks beyond the limits imposed by the lower bandwidth of the signal. The second reason is that it is generic and applies to any wave form, be it optical, electrical, sonic, or quantum mechanical. For practical applications, it is important to overcome two problems. The first problem is that an overwhelming proportion of the energy goes into the non superoscillating part of the signal. The second problem is the control of the shape of the superoscillating part of the signal. The first problem has been recently addressed by optimization of the super oscillation yield, the ratio of the energy in the superoscillations to the total energy of the signal. The second problem may arise when the superoscillation, is to mimic a high frequency purely perodic signal. This may be required, for example, when a superoscillating force is to drive a harmonic oscillator at a high resonance frequency. In this paper the degree of periodicity of a signal is defined and applied to some yield optimized superoscillating signals.

Nehemia Schwartz; Moshe Schwartz

2014-02-13T23:59:59.000Z

91

Quantum theory of optical temporal phase and instantaneous frequency. II. Continuous-time limit and state-variable approach to phase-locked loop design  

SciTech Connect

We consider the continuous-time version of our recently proposed quantum theory of optical temporal phase and instantaneous frequency [M. Tsang et al., Phys. Rev. A 78, 053820 (2008)]. Using a state-variable approach to estimation, we design homodyne phase-locked loops that can measure the temporal phase with quantum-limited accuracy. We show that postprocessing can further improve the estimation performance if delay is allowed in the estimation. We also investigate the fundamental uncertainties in the simultaneous estimation of harmonic-oscillator position and momentum via continuous optical phase measurements from the classical estimation theory perspective. In the case of delayed estimation, we find that the inferred uncertainty product can drop below that allowed by the Heisenberg uncertainty relation. Although this result seems counterintuitive, we argue that it does not violate any basic principle of quantum mechanics.

Tsang, Mankei; Shapiro, Jeffrey H. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Lloyd, Seth [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2009-05-15T23:59:59.000Z

92

Effects of variations in holding time, curing temperature, and treatment period on selected physical properties of concrete made with type III cement and steam cured at atmospheric pressure  

E-Print Network (OSTI)

g H a t4 0 lV FI I og . ng ~9 g~) o sn IS% Rl HZOIMX8 fhISSRlJRXl 5400 5000 140% 4600 4200 3$00 165 F IE54 r 3400 3000 2600 2 3 4 5 6 HOLDING TINE IN HOURS FIGURE 16 COHSRESSIVE STRENGTH vS RUINING TINE, TREATNRNT PERIOD... 3800 3400 $000 3 2 4 5 6 HOLDING TINE IN HOURS PIGURE 1$. OPPRESSIVE STRENGTH vs HOLDING TINE, TREATNENT PERIOD - 16 HRS, ) AGE - 7 DAYS 39 6200 140 F 5000 4600 4200 3SOO 3400 2 3 4 3, 6 HOLDING TINE IN HOURS 'FIGURE 19. CQNFRESSIVE...

Burleson, Kenneth Stewart

2012-06-07T23:59:59.000Z

93

Standard Frequency Broadcasts  

Science Journals Connector (OSTI)

... Mc./sec., at least three of which are available at any time; standard audio frequencies of 440 and 4,000 c./sec. broadcast on these carriers; and ... second of every minute the pulse is omitted. The 1-min. interval in the audio-frequency transmission is used to give the station announcement, either in Morse or (at ...

1944-09-02T23:59:59.000Z

94

Phase-Resolved Measurements of Ion Velocity in a Radio-Frequency Sheath Brett Jacobs,1,* Walter Gekelman,1  

E-Print Network (OSTI)

-induced fluorescence in a commercial plasma process- ing tool. Discharge parameters were such that the 2.2 MHz rf upon the ratio of the ion transit time through the sheath to the rf period (ion=rf) [11]. In the high-frequencyPhase-Resolved Measurements of Ion Velocity in a Radio-Frequency Sheath Brett Jacobs,1,* Walter

California at Los Angles, University of

95

Release and Phase Partitioning of Metals from Anoxic Estuarine Sediments during Periods of Simulated Resuspension  

Science Journals Connector (OSTI)

Periodically, marine sediments are subjected to physical processes which resuspend them into the water column, releasing previously sequestered metals. ... Resuspension energies vary greatly over time, with particle dynamics affected by the changing force and frequency of collisions sustained by particles, along with the quantity of sediment resuspended (13). ... A particle entrainment simulator (PES) was used to perform sediment resuspensions (16). ...

Mark G. Cantwell; Robert M. Burgess; Dana R. Kester

2002-11-06T23:59:59.000Z

96

Gene Frequency  

NLE Websites -- All DOE Office Websites (Extended Search)

Gene Frequency Gene Frequency Name: donna Location: N/A Country: N/A Date: N/A Question: If six fingers is a dominant human trait why do we have only five? Replies: This is simple. There are just not many genes in the human population for six fingers. Steve Sample Look in any high school biology book for what is known as Hardy-Weinberg equilibrium. These two scientists (separately) said that gene frequencies do not change much unless something in the environment selects them over other genes. In other words, unless 6 fingers somehow becomes an advantage, and five-fingered people have less of an advantage, the frequency of six fingered people in the population will not necessarily increase. This is the same reason that recessive traits don't disappear from the population. Also, six fingers is not considered attractive and they may not get as many mates. Also, more people are born with six fingers than you might imagine but just have them amputated shortly after birth.

97

Optimal Checkpointing Period: Time vs. Energy  

E-Print Network (OSTI)

is focusing on the characteris- tics, features, and challenges of High Performance Computing (HPC) systems-purpose error recovery technique in high performance computing is checkpoint and rollback recovery

Paris-Sud XI, Université de

98

Periodicity extraction in the anuran auditory nerve. II: Phase and temporal fine structure  

Science Journals Connector (OSTI)

Discharge patterns of single eighth nerve fibers in the bullfrog Rana catesbeiana were analyzed in response to signals consisting of multiple harmonics of a common low?amplitude fundamental frequency. The signals were chosen to reflect the frequency and amplitude spectrum of the bullfrog’s species?specific advertisement call. The phase spectrum of the signals was manipulated to produce envelopes that varied in their shapes from impulselike (sharp) to noiselike (flattened). Peripheral responses to these signals were analyzed by computing the autocorrelation functions of the spike trains and their power spectra as well as by constructing period histograms over the time intervals of the low?frequency harmonics. In response to a phase aligned signal with an impulsive envelope most fibers regardless of their characteristic frequencies or place of origin within the inner ear synchronize to the fundamental frequency of the signal. The temporal patterns of fiber discharge to these stimuli are not typically captured by that stimulus harmonic closest to the fiber characteristic frequency as would be expected from a spectral coding mechanism for periodicity extraction but instead directly reflect the periodicity of the stimulus envelope.

Andrea Megela Simmons; Gita Reese; Michael Ferragamo

1993-01-01T23:59:59.000Z

99

Motion Cyclification by Time Frequency Warping FERNANDO WAGNER DA SILVA1 2 LUIZ VELHO1 JONAS GOMES1 SIOME GOLDENSTEIN3  

E-Print Network (OSTI)

of a real object at uniformly spaced instants of time. In the case of human motion capture, the position an im- portant field of research in recent years [4]. The crescent demand of powerful tools for motion

100

Motion Cyclification by Time \\Theta Frequency Warping FERNANDO WAGNER DA SILVA 1;2 LUIZ VELHO 1 JONAS GOMES 1 SIOME GOLDENSTEIN 3  

E-Print Network (OSTI)

and global orientation of a real object at uniformly spaced instants of time. In the case of human motion processing has become an im­ portant field of research in recent years [4]. The crescent demand of powerful

Note: This page contains sample records for the topic "frequency time period" 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

astroph/9610086 Quasar Proper Motions and LowFrequency Gravitational Waves  

E-Print Network (OSTI)

astro­ph/9610086 11 Oct 1996 Quasar Proper Motions and Low­Frequency Gravitational Waves Carl R observational upper limits on the mass­energy of the cosmological gravitational­wave background, from limits on proper motions of quasars. Gravitational waves with periods longer than the time span of observations

Fygenson, Deborah Kuchnir

102

Periodic forcing of graphene as geometric ripples on its surface  

E-Print Network (OSTI)

We explore the possibility of using modulated high frequency periodic driving of mono-layer graphene to create effects of curved geometry. The low energy continuum limit of graphene is modeled using Dirac equation in (2+1) dimensions. We suggest that the modifications to the Dirac equation when written in a curved background space can also be induced by a suitable driving scheme. The time dependent system yields, in the approximate limit of high frequency pulsing, an effective time independent Hamiltonian that governs the time evolution, except for an initial and a final kick. We use a specific form of 4-phase pulsed forcing with suitably tuned choice of modulating operators to mimic the effects of weak metric perturbations and thereby effectively induce mild wrinkles on the surface. The strength of the perturbation is found to be directly related to omega^{-1} the time period of the driving field at the leading order. We apply the method to engineer some specific `nearly flat' metrics and we find that the imprint of curvilinear geometry modifies the band structure significantly. The emergence of band gap at the Dirac point is crucial in this regard. We suggest that this method shall be useful in studying the response of various properties of such materials to non-trivial geometry without requiring any actual physical deformations.

Tridev Mishra; Tapomoy Guha Sarkar; Jayendra N. Bandyopadhyay

2014-10-27T23:59:59.000Z

103

Modulation of redox status and calcium handling by extremely low frequency electromagnetic fields in C2C12 muscle cells: A real-time, single-cell approach  

Science Journals Connector (OSTI)

The biological effects of electric and magnetic fields, which are ubiquitous in modern society, remain poorly understood. Here, we applied a single-cell approach to study the effects of short-term exposure to extremely low frequency electromagnetic fields (ELF-EMFs) on muscle cell differentiation and function using C2C12 cells as an in vitro model of the skeletal muscle phenotype. Our focus was on markers of oxidative stress and calcium (Ca2+) handling, two interrelated cellular processes previously shown to be affected by such radiation in other cell models. Collectively, our data reveal that ELF-EMFs (1) induced reactive oxygen species production in myoblasts and myotubes with a concomitant decrease in mitochondrial membrane potential; (2) activated the cellular detoxification system, increasing catalase and glutathione peroxidase activities; and (3) altered intracellular Ca2+homeostasis, increasing the spontaneous activity of myotubes and enhancing cellular reactivity to a depolarizing agent (KCl) or an agonist (caffeine) of intracellular store Ca2+channels. In conclusion, our data support a possible link between exposure to ELF-EMFs and modification of the cellular redox state, which could, in turn, increase the level of intracellular Ca2+and thus modulate the metabolic activity of C2C12 cells.

Caterina Morabito; Francesca Rovetta; Mariano Bizzarri; Giovanna Mazzoleni; Giorgio Fanò; Maria A. Mariggiò

2010-01-01T23:59:59.000Z

104

Report on an all-sky LIGO search for periodic gravitational waves in the S4 data  

E-Print Network (OSTI)

We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50-1000 Hz and having a negative frequency time derivative with magnitude between zero and $10^{-8}$ Hz/s. Data from the fourth LIGO science run have been used in this search. Three different semi-coherent methods of summing strain power were applied. Observing no evidence for periodic gravitational radiation, we report upper limits on strain amplitude and interpret these limits to constrain radiation from rotating neutron stars.

Alicia M. Sintes; for the LIGO Scientific Collaboration

2007-10-25T23:59:59.000Z

105

Frequency Control Performance Measurement and Requirements  

E-Print Network (OSTI)

changes in dispatch to follow load, implement interchangerequired for load frequency regulation, it follows that afollows [4]: “System frequency deviation and the resulting time error indicated the total imbalance of generation and load

Illian, Howard F.

2011-01-01T23:59:59.000Z

106

Light beam frequency comb generator  

DOE Patents (OSTI)

A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics.

Priatko, Gordon J. (Cupertino, CA); Kaskey, Jeffrey A. (Livermore, CA)

1992-01-01T23:59:59.000Z

107

Quasar Proper Motions and Low-Frequency Gravitational Waves  

E-Print Network (OSTI)

We report observational upper limits on the mass-energy of the cosmological gravitational-wave background, from limits on proper motions of quasars. Gravitational waves with periods longer than the time span of observations produce a simple pattern of apparent proper motions over the sky, composed primarily of second-order transverse vector spherical harmonics. A fit of such harmonics to measured motions yields a 95%-confidence limit on the mass-energy of gravitational waves with frequencies <2e-9 Hz, of <0.11/h*h times the closure density of the universe.

Carl R. Gwinn; T. Marshall Eubanks; Ted Pyne; Mark Birkinshaw; Demetrios N. Matsakis

1996-10-12T23:59:59.000Z

108

Down-hole periodic seismic generator  

DOE Patents (OSTI)

A down hole periodic seismic generator system is disclosed for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.

Hardee, H.C.; Hills, R.G.; Striker, R.P.

1982-10-28T23:59:59.000Z

109

Solutions to Test 1 Review Problems 1. Here are two sound waves. Identify which is periodic. For the periodic wave, sketch a  

E-Print Network (OSTI)

in Hz and BPM. Is the frequency within the range of human hearing? Answer. The periodic wave frequency is 1/0.01 = 100 Hz = 6000 BPM. 2. Functions. (a) For each function, determine whether and frequency =3 BPM (2) amplitude = 10 and fundamental period = 0.005 seconds. Answer. (1) since 3 BPM = 180 Hz

Hall, Rachel W.

110

Periodically-driven quantum matter: the case of resonant modulations  

E-Print Network (OSTI)

Quantum systems can show qualitatively new forms of behavior when they are driven by fast time-periodic modulations. In the limit of large driving frequency, the long-time dynamics of such systems can often be described by a time-independent effective Hamiltonian, which is generally identified through a perturbative treatment. Here, we present a general formalism that describes time-modulated physical systems, in which the driving frequency is large, but resonant with respect to energy spacings inherent to the system at rest. Such a situation is currently exploited in optical-lattice setups, where superlattice (or Wannier-Stark-ladder) potentials are resonantly modulated so as to control the tunneling matrix elements between lattice sites, offering a powerful method to generate artificial fluxes for cold-atom systems. The formalism developed in this work identifies the basic ingredients needed to generate interesting flux patterns and band structures using resonant modulations. We also discuss the micro-motion underlying the dynamics, and illustrate its characteristics based on diverse dynamic-lattice configurations. It is shown that the impact of the micro-motion on physical observables strongly depends on the implemented scheme, suggesting that a theoretical description in terms of the effective Hamiltonian alone is generally not sufficient to capture the full time-evolution of the system.

N. Goldman; J. Dalibard; M. Aidelsburger; N. R. Cooper

2014-10-30T23:59:59.000Z

111

Effective phase control of silicon films during high-rate deposition in atmospheric-pressure very high-frequency plasma: Impacts of gas residence time on the performance of bottom-gate thin film transistors  

Science Journals Connector (OSTI)

Abstract Hydrogenated amorphous silicon (a-Si) and microcrystalline silicon (?c-Si) films were grown in atmospheric-pressure (AP) He/H2/SiH4 plasma excited by a 150-MHz very high-frequency (VHF) power at a temperature of 220 °C. The variations in thickness and crystallinity of the deposited Si films along the gas flow direction were studied as functions of gas residence time in the plasma, VHF power density and H2 flow rate. Furthermore, the electrical characteristics of bottom-gate thin film transistors (TFTs) were investigated to evaluate the film quality. The results revealed that the chemical reactions both in gas phase and on the growing film surface were significantly enhanced in AP-VHF plasma, promoting phase transition from amorphous to microcrystalline in a time of the order of 0.1 ms. The performance of the \\{TFTs\\} showed that a-Si layers formed in the upstream portion of the plasma zone had reasonably good electrical property (field-effect mobility of approximately 2 cm2/V s) despite very high deposition rates around 20 nm/s. While ?c-Si layers deposited in the downstream portion were very defective, which might come from the insufficient passivation of grain boundaries with a-Si tissues due to a too long gas residence time in the plasma. The precise control of gas residence time by adjusting the length of plasma will be effective for the phase control of Si films with desired quality.

H. Kakiuchi; H. Ohmi; T. Yamada; A. Hirano; T. Tsushima; W. Lin; K. Yasutake

2013-01-01T23:59:59.000Z

112

The characteristics of atmospheric radio frequency discharges with frequency increasing at a constant power density  

SciTech Connect

A computational model is used to investigate the characteristics of atmospheric radio frequency discharges by increasing frequency from 20 to 100 MHz at a constant power density. The simulation results show that increasing frequency can effectively enhance electron density before the transition frequency but after it the ignition is quenched then the electron density decreases. However this simulation also indicates the maximum time-averaged electron energy reduces monotonically with the excitation frequency increasing at a constant power density.

Zhang Yuantao; Li Qingquan; Lou Jie; Li Qingmin [School of Electrical Engineering, Shandong University, Jinan, Shandong Province 250061 (China)

2010-10-04T23:59:59.000Z

113

Many-body energy localization transition in periodically driven systems  

SciTech Connect

According to the second law of thermodynamics the total entropy of a system is increased during almost any dynamical process. The positivity of the specific heat implies that the entropy increase is associated with heating. This is generally true both at the single particle level, like in the Fermi acceleration mechanism of charged particles reflected by magnetic mirrors, and for complex systems in everyday devices. Notable exceptions are known in noninteracting systems of particles moving in periodic potentials. Here the phenomenon of dynamical localization can prevent heating beyond certain threshold. The dynamical localization is known to occur both at classical (Fermi–Ulam model) and at quantum levels (kicked rotor). However, it was believed that driven ergodic systems will always heat without bound. Here, on the contrary, we report strong evidence of dynamical localization transition in both classical and quantum periodically driven ergodic systems in the thermodynamic limit. This phenomenon is reminiscent of many-body localization in energy space. -- Highlights: •A dynamical localization transition in periodically driven ergodic systems is found. •This phenomenon is reminiscent of many-body localization in energy space. •Our results are valid for classical and quantum systems in the thermodynamic limit. •At critical frequency, the short time expansion for the evolution operator breaks down. •The transition is associated to a divergent time scale.

D’Alessio, Luca, E-mail: dalessio@buphy.bu.edu [Physics Department, Boston University, Boston, MA 02215 (United States) [Physics Department, Boston University, Boston, MA 02215 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States); Polkovnikov, Anatoli, E-mail: asp@bu.edu [Physics Department, Boston University, Boston, MA 02215 (United States)] [Physics Department, Boston University, Boston, MA 02215 (United States)

2013-06-15T23:59:59.000Z

114

THE QUASI-BIENNIAL PERIODICITY AS A WINDOW ON THE SOLAR MAGNETIC DYNAMO CONFIGURATION  

SciTech Connect

Manifestations of the solar magnetic activity through periodicities of about 11 and 2 years are now clearly seen in all solar activity indices. In this paper, we add information about the mechanism driving the 2-year period by studying the time and latitudinal properties of acoustic modes that are sensitive probes of the subsurface layers. We use almost 17 years of high-quality resolved data provided by the Global Oscillation Network Group to investigate the solar cycle changes in p-mode frequencies for spherical degrees l from 0 to 120 and 1600 {mu}Hz {<=}{nu} {<=} 3500 {mu}Hz. For both periodic components of solar activity, we locate the origin of the frequency shift in the subsurface layers and find evidence that a sudden enhancement in amplitude occurs in just the last few hundred kilometers. We also show that, in both cases, the size of the shift increases toward equatorial latitudes and from minimum to maximum solar activity, but, in agreement with previous findings, the quasi-biennial periodicity (QBP) causes a weaker shift in mode frequencies and a slower enhancement than that caused by the 11-year cycle. We compare our observational findings with the features predicted by different models, that try to explain the origin of this QBP and conclude that the observed properties could result from the beating between a dipole and quadrupole magnetic configuration of the dynamo.

Simoniello, R.; Turck-Chieze, S. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, CEA, IRFU, SAp, Centre de Saclay, F-91191 Gif-sur-Yvette (France); Jain, K.; Tripathy, S. C.; Hill, F. [National Solar Observatory, Tucson, AZ 85719 (United States); Baldner, C. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States); Finsterle, W. [PMOD/WRC Physikalisch-Meteorologisches Observatorium Davos-World Radiation Center, 7260 Davos Dorf (Switzerland); Roth, M., E-mail: rosaria.simoniello@cea.fr [Kiepenheuer Institute for Solar Physics, Freiburg (Germany)

2013-03-10T23:59:59.000Z

115

What are the frequencies of standing magnetopause surface waves?  

E-Print Network (OSTI)

We estimate, for the first time, the distribution of standing magnetopause surface wave (also called Kruskal-Schwartzschild mode) frequencies using realistic models of the magnetosphere and magnetosheath utilising an entire solar cycle's worth of solar wind data. Under non-storm times or northward interplanetary magnetic field (IMF), the most likely fundamental frequency is calculated to be 0.64$\\pm$0.06 mHz, consistent with that previously inferred from observed oscillation periods of the boundary. However, the distributions exhibit significant spread (of order $\\pm$0.3 mHz), much larger than suggested by proponents of discrete, stable "magic" frequencies of magnetospheric oscillation. The frequency is found to be most dependent on the solar wind speed, southward component of the IMF and the Dst index, with the latter two being due to the erosion of the magnetosphere by reconnection and the former an effect of the expression for the surface wave phase speed. Finally, the occurrence of Kruskal-Schwartzschild ...

Archer, Martin

2014-01-01T23:59:59.000Z

116

Investigation of periodic multilayers  

E-Print Network (OSTI)

Periodic multilayers of various periods were prepared according to an algorithm proposed by the authors. The reflectivity properties of these systems were investigated using neutron reflectometry.The obtained experimental results were compared with the theoretical expectations. In first approximation, the results proved the main features of the theoretical predictions. These promising results initiate further research of such systems.

Bodnarchuck, V; Ignatovich, V; Veres, T; Yaradaykin, S

2009-01-01T23:59:59.000Z

117

High frequency rectenna  

DOE Patents (OSTI)

The invention provides an inexpensive array of rectifying antennas which employ field emission diodes for rectifying electromagnetic waves of microwave frequencies and higher frequencies.

Logan, B. Grant (Danville, CA); Orvis, William J. (Livermore, CA)

1991-01-01T23:59:59.000Z

118

Testing for Change in the Frequency of El Niño Events  

Science Journals Connector (OSTI)

This note describes and applies a test for trend in the frequency of El Niño events over the period 1525–1987. Although there appears to have been a significant increase in frequency over this period, this result is consistent with an overall ...

Andrew R. Solow

1995-10-01T23:59:59.000Z

119

Tracking multiple generation and suppression of secondary electrons on periodic triangular surface  

SciTech Connect

To research the dynamic course of multipactor suppression on the periodically patterned surface, tens of electron collision processes are tracked by numerical calculation. The influences of microwave frequency, amplitude of RF electric field, slope angle, the local field enhancement, and the tilted incident electric field on the multipactor suppression are studied by tracking multi-generation electrons' trajectories, hopping and flight time, collision energy, and secondary emission yield. Meanwhile, the dynamic processes of secondary electrons on the periodic surface are analyzed by particle-in-cell (PIC) simulation. The PIC results are consistent with the analytical results in which the electrons fly reciprocatingly between the slopes and impact on the slopes; the methods of increasing the slope angle, enlarging the RF field, and lowering the frequency in a certain range are helpful to enhance the multipactor suppression steadily and persistently.

Li, S.; Wang, J. G.; Zhu, M.; Peng, J. C.; Xie, J. L.; Wu, X. L.; Guo, L. T. [Laboratory on Science and Technology of High Power Microwave, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China)] [Laboratory on Science and Technology of High Power Microwave, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China); Chang, C.; Xiong, Z. F. [Laboratory on Science and Technology of High Power Microwave, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China) [Laboratory on Science and Technology of High Power Microwave, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China); Department of Engineering Physics, Tsinghua University, Beijing 10084 (China)

2013-12-15T23:59:59.000Z

120

Analysis of Heart Rate Variability Using Time-Varying Filtering of Heart Transplanted Patients  

E-Print Network (OSTI)

Analysis of Heart Rate Variability Using Time-Varying Filtering of Heart Transplanted Patients the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "frequency time period" 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

Budget Period 1  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Budget Period 1 Budget Period 1 Budget Period 2 Budget Period 3 0.0% 0.0% 0.0% PMC123.1 - Budget Justification for SF 424A Budget 0 Additional Explanations/Comments (as necessary) *IMPORTANT: In the space provided below (or as an attachment) provide a complete explanation and the full calculations used to derive the total indirect costs. If the total indirect costs are a cumulative amount of more than one calculation or rate application, the explanation and calculations should identify all rates used, along with the base they were applied to (and how the base was derived), and a total for each (along with grand total). The rates and how they are applied should not be averaged to get one indirect cost percentage. NOTE: The indirect rate should be applied to both the Federal Share and Recipient Cost Share.

122

Low-frequency piezoelectric energy harvesting prototype suitable for the MEMS implementation  

Science Journals Connector (OSTI)

A low-frequency piezoelectric energy harvester based on impact vibration assembled with a compliant driving beam and two rigid generating beams is presented. The ambient low frequency is up-converted to high resonant frequency by the periodic impact ... Keywords: Energy harvester, Frequency up-conversion, Low frequency

Lei Gu

2011-02-01T23:59:59.000Z

123

Study of cavity type antenna structure of large-area 915 MHz ultra-high frequency wave plasma device based on three-dimensional finite difference time-domain analysis  

SciTech Connect

A large-area planar plasma source with a resonant cavity type launcher driven by a 915 MHz ultra-high frequency wave was developed. Theoretical analysis with the three-dimensional finite difference time-domain simulation was carried out to determine the optimized launcher structure by analyzing the resonant transverse magnetic mode in the resonant cavity. Numerical result expects that the resonant electric field distribution inside the cavity dominantly consists of the TM{sub 410} mode. The resonant cavity type launcher having 8 holes in an octagonal geometry was designed to fit the resonant transverse magnetic mode. Adjusting 8 hole positions of the launcher to the field pattern of the resonant TM{sub 410} mode, we found that the plasma density increased about 40%?50% from 1.0?1.1 × 10{sup 11} cm{sup ?3} to ?1.5 × 10{sup 11} cm{sup ?3} at the same incident power of 2.5 kW, compared with the previous results with the launcher having 6 holes in the hexagonal geometry. It is also noted that the electron density changes almost linearly with the incident wave power without any mode jumps.

Chang, Xijiang [Department of Light Sources and Illuminating Engineering, Fudan University, 220 Handan Road, Shanghai 200433 (China) [Department of Light Sources and Illuminating Engineering, Fudan University, 220 Handan Road, Shanghai 200433 (China); Graduate School of Science and Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan); Kunii, Kazuki [Graduate School of Engineering, Shizuoka University,3-5-1 Johoku, Hamamatsu 432-8561 (Japan)] [Graduate School of Engineering, Shizuoka University,3-5-1 Johoku, Hamamatsu 432-8561 (Japan); Liang, Rongqing [Department of Light Sources and Illuminating Engineering, Fudan University, 220 Handan Road, Shanghai 200433 (China)] [Department of Light Sources and Illuminating Engineering, Fudan University, 220 Handan Road, Shanghai 200433 (China); Nagatsu, Masaaki [Graduate School of Science and Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan) [Graduate School of Science and Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan); Graduate School of Engineering, Shizuoka University,3-5-1 Johoku, Hamamatsu 432-8561 (Japan)

2013-11-14T23:59:59.000Z

124

Periodic pumping tests  

Science Journals Connector (OSTI)

......pumping period. The considered penetration depth (eq. 6) constitutes...well transmitted beyond the penetration depth. It is only a question...measurable. In contrast, flow rate measured at the pumping well...subsurface volume represented by penetration depth.) We cannot exclude......

Jörg Renner; Mareike Messar

2006-10-01T23:59:59.000Z

125

Eastern Frequency Response Study  

SciTech Connect

This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.

2013-05-01T23:59:59.000Z

126

Frequency selective infrared sensors  

DOE Patents (OSTI)

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2013-05-28T23:59:59.000Z

127

Frequency selective infrared sensors  

SciTech Connect

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2014-11-25T23:59:59.000Z

128

Effective Rate Period  

NLE Websites -- All DOE Office Websites (Extended Search)

Fiscal Year 2014 Fiscal Year 2014 Effective Rate Period As of Beginning of the FY 10/01/2013 - 09/30/2014 Mid-Year Changes (if applicable) 10/01/2013 - 09/30/2014 Power Rates Annual Revenue Requirement Rate Schedule Power Revenue Requirement $73,441,557 CV-F13 Base Resource Revenue Requirement $69,585,875 First Preference Revenue Requirement $3,855,682

129

Oscillator Architectures and Enhanced Frequency Synthesizer  

E-Print Network (OSTI)

A voltage controlled oscillator (VCO), that generates a periodic signal whose frequency is tuned by a voltage, is a key building block in any integrated circuit systems. A sine wave oscillator can be used for a built-in self testing where high...

Park, Sang Wook

2009-11-16T23:59:59.000Z

130

The shortest modulation period Blazhko RR Lyrae star: SS Cnc  

E-Print Network (OSTI)

Extended BV(RI)c CCD observations of SS Cnc, a short period RRab star are presented. Nearly 1400 data points in each band have been obtained spanning over 79 days during the spring of 2005. The star exhibits light curve modulation, the so called Blazhko effect with small amplitude (B maximum brightness varies 0.1 mag) and with the shortest modulation period (5.309 d) ever observed. In the Fourier spectrum of the V light curve the pulsation frequency components are detected up to the 24th harmonic order, and modulation side lobe frequencies with significantly asymmetric amplitudes are seen up to the 15th and 9th orders for the lower and higher frequency components, respectively. Detailed comparison of the modulation behavior of SS Cnc and RR Gem, the two recently discovered small amplitude, short modulation period Blazhko stars is presented. The modulation frequency (f_m) appears in the Fourier spectrum of both stars with similar amplitude. We also demonstrate that the modulation frequencies have basically different properties as the pulsation and modulation side lobe frequencies have, indicating that the physics behind these frequency components are not the same. The discovery of small amplitude modulations of RRab stars cautions that the large photometric surveys (MACHO, OGLE) may seriously underestimate the number of modulated RR Lyrae stars.

J. Jurcsik; B. Szeidl; Á. Sódor; I. Dékány; Zs. Hurta; K. Posztobányi; K. Vida; M. Váradi; A. Szing

2006-03-20T23:59:59.000Z

131

Time lags of the kilohertz quasi-periodic oscillations in the low-mass X-ray binaries 4U 1608–52 and 4U 1636–53  

Science Journals Connector (OSTI)

......the rms spectra of both kHz QPOs under the assumption that the time lags of both kHz QPOs are due to reflection...down-scattered by cold plasma in the accretion disc...apply to the case of the kHz QPOs, as long as the...down-scattering medium is the atmosphere of the disc. If we fit......

Marcio G. B. de Avellar; Mariano Méndez; Andrea Sanna; Jorge E. Horvath

2013-01-01T23:59:59.000Z

132

Balloon observations of ultra-low-frequency waves in the electric field above the South Pole  

SciTech Connect

The physics of ultra-low-frequency waves in the magnetosphere, near the cusp and in the polar cap, is important because this region is one where ultra-low-frequency wave energy from the magnetopause can most easily enter the magnetosphere. During the 1985-1986 South Pole balloon campaign, eight stratospheric balloon payloads were launched from Amundsen-Scott Station, South Geographic Pole, Antarctica, to record data on ultra-low-frequency waves. The payloads were instrumented with three-axis double-probe electric field detectors and X-ray scintillation counters. This paper concentrates on the third flight of this series, which was launched at 2205 universal time on 21 December 1985. Good data were received from the payload until the transmitter failed at 0342 universal time on 22 December. During most of the four hours that the balloon was afloat, an intense ultra-low-frequency wave event was in progress. The electric-field data from this period have been examined in detail and compared with magnetic field data, obtained with ground-based fluxgate and induction magnetometers to determine the characteristics of the waves. After float was reached, the electric-field data in figure 1 show large-amplitude, quasi-periodic fluctuations suggesting the presence of intense ultra-low-frequency wave activity. In conclusion, the electric-field signature observed from flight 3 appears to have been essentially an electrostatic event or possibly a short-wavelength hydromagnetic wave with a varying and interesting polarization character. The authors are continuing the analysis of the data to determine the source of the observed ultra-low-frequency waves.

Liao, B.; Benbrrook, J.R.; Bering E.A. III; Byrne, G.J.; Theall, J.R. (Univ. of Houston, TX (USA))

1988-01-01T23:59:59.000Z

133

Ball Packings with Periodic Constraints  

Science Journals Connector (OSTI)

We call a periodic ball packing in $$d$$d-dimensional Euclidean space periodically (resp. strictly) jammed with respect to a period lattice $$\\varLambda $$¿ if there are no nontrivial motions of the balls that preserve $$\\varLambda $$¿ (resp. that maintain ... Keywords: 52C17, Ball packings, Jamming, Periodic packings, Rigidity, Tensegrities

Robert Connelly, Jeffrey D. Shen, Alexander D. Smith

2014-12-01T23:59:59.000Z

134

Seasonal frequency of ciguatoxic barracuda in southwest Puerto Rico  

Science Journals Connector (OSTI)

Ciguatoxicity of barracuda (Sphyraena barracuda) head, viscera and flesh tissues has been determined in 219 specimens caught along the southwest coast of Puerto Rico from March 1985 through May 1987. Twenty-nine percent of these specimens were toxic. Monthly frequencies of ciguatoxic barracuda showed an apparent seasonal variability, with peak values (60–70% toxic fish) in the late winter-early spring (January–May) and fall (August–November). Minimal frequencies (0–10% toxic fish) were observed during June–July and December. The most frequently toxic tissues in poisonous animals were the viscera and head. Viscera tissue was the only toxic tissue found in 31% of the posionous fish assayed, and this tissue was poisonous in all toxic fish. In no case was a poisonous specimen found to have toxic flesh alone. Marked temporal variation in frequency of ciguatoxicity suggests that ciguatera toxins, at least in their active form, are not accumulated in barracuda tissues for extended periods of time. Variability in barracuda ciguatoxicity may reflect fluctuations in the toxicity of smaller reef fish prey, seasonal fluctuations in toxic benthic dinoflagellates and/or changes in the ability of the barracuda to detoxify ingested poisons or their precursors.

T.R. Tosteson; D.L. Ballantine; H.D. Durst

1988-01-01T23:59:59.000Z

135

DURING THIS REPORTING PERIOD, WE ISSUED 45 REPORTS; IDENTIFIED...  

Energy Savers (EERE)

components that have a limited lifetime due to their use of tritium, a radioactive gas which decays over time. Periodic replacement of these components is necessary to...

136

Near-Infrared and X-ray Quasi-Periodic Oscillations in Numerical Models of Sgr A*  

E-Print Network (OSTI)

We report transient quasi-periodic oscillations (QPOs) on minute timescales in relativistic, radiative models of the galactic center source Sgr A*. The QPOs result from nonaxisymmetric $m=1$ structure in the accretion flow excited by MHD turbulence. Near-infrared (NIR) and X-ray power spectra show significant peaks at frequencies comparable to the orbital frequency at the innermost stable circular orbit (ISCO) $f_o$. The excess power is associated with inward propagating magnetic filaments inside the ISCO. The amplitudes of the QPOs are sensitive to the electron distribution function. We argue that transient QPOs appear at a range of frequencies in the neighborhood of $f_o$ and that the power spectra, averaged over long times, likely show a broad bump near $f_o$ rather than distinct, narrow QPO features.

Joshua C. Dolence; Charles F. Gammie; Hotaka Shiokawa; Scott C. Noble

2012-01-09T23:59:59.000Z

137

New subdwarf B star periods  

E-Print Network (OSTI)

Subdwarf B (sdB) stars are thought to be helium burning stars with low mass hydrogen envelopes. Several evolutionary paths have been proposed to explain the formation of these systems. One of these scenarios is the evolution of the sdB progenitor within a binary system. We have looked systematically at bright sdB stars from the PG survey. By taking spectra at several different epochs we have measured the radial velocity shifts caused by the motion of the sdB star within the binary. Our data have been taken over a long time base line (2 years) which allowed us to find longer period binaries than known before. Here we present results for 29 sdB systems.

L. Morales-Rueda; P. F. L. Maxted; T. R. Marsh; R. C. North

2002-09-26T23:59:59.000Z

138

Stabilized radio frequency quadrupole  

DOE Patents (OSTI)

Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1984-12-25T23:59:59.000Z

139

PERIODIC HEAT REPORT  

NLE Websites -- All DOE Office Websites (Extended Search)

186.00 TripHigh tc Date MO:DAY 1.00: 16.00 TripHigh tc Time HR:MIN 10.00: 9.00 Ports Temp: Avg, High, Low 19.00, 21.00, 17.00 Coils Temp: Avg, High, Low 19.00, 21.00,...

140

Ball Packings with Periodic Constraints  

E-Print Network (OSTI)

We call a periodic ball packing in d-dimensional Euclidean space periodically (strictly) jammed with respect to a period lattice if there are no nontrivial motions of the balls that preserve the period (that maintain some period with smaller or equal volume). In particular, we call a packing consistently periodically (strictly) jammed if it is periodically (strictly) jammed on every one of its periods. After extending a well-known bar framework and stress condition to strict jamming, we prove that a packing with period Lambda is consistently strictly jammed if and only if it is strictly jammed with respect to Lambda and consistently periodically jammed. We next extend a result about rigid unit mode spectra in crystallography to characterize periodic jamming on sublattices. After that, we prove that there are finitely many strictly jammed packings of m unit balls and other similar results. An interesting example shows that the size of the first sublattice on which a packing is first periodically unjammed is not bounded. Finally, we find an example of a consistently periodically jammed packing of low density \\delta = \\frac{4 \\pi}{6 \\sqrt{3} + 11} + \\epsilon ~ 0.59, where \\epsilon is an arbitrarily small positive number. Throughout the paper, the statements for the closely related notions of periodic infinitesimal rigidity and affine infinitesimal rigidity for tensegrity frameworks are also given.

Robert Connelly; Jeffrey D. Shen; Alexander D. Smith

2013-01-04T23:59:59.000Z

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141

Frequency chirp and pulse shape effects in self-modulated laser wakefield accelerators  

SciTech Connect

The effect of asymmetric laser pulses on plasma wave excitation in a self-modulated laser wakefield accelerator is examined. Laser pulse shape and frequency chirp asymmetries, controlled experimentally in the laser system through a grating pair compressor, are shown to strongly enhance measured electron yields for certain asymmetries. It is shown analytically that a positive (negative) frequency chirp enhances (suppresses) the growth rate of the Raman forward scattering and near-forward Raman sidescatter instabilities, but is of minimal importance for the experimental parameters. Temporal laser pulse shapes with fast rise times (< plasma period) are shown to generate larger wakes (compared to slow rise time pulses) which seed the growth of the plasma wave, resulting in enhanced electron yield.

Schroeder, C.B.; Esarey, E.; Geddes, C.G.R.; Toth, Cs.; Shadwick, B.A.; van Tilborg, J.; Faure, J.; Leemans, W.P.

2002-11-07T23:59:59.000Z

142

Measurements of spatial and frequency coherence of an equatorial hf path during spread-F  

SciTech Connect

In August 1990, the authors set up an hf path on the equatorial path between Maloelap Atoll and Bikini Atoll. This path, which had a range of 702 km, reflected in the ionosphere approximately 100 km north of the Altair radar location on Kwajalein. Transmitters at Maloelap broadcasted four cw tones within bandwidth of either 4 kHz, 9 kHz, or 70 kHz to be used to determine frequency coherence and also a phase-coded pseudo random sequence with a bandwidth of 60 kHz (channel probe) to be used to determine time delay spread. A spatial array of antennas was deployed at Bikini to measure spatial and frequency coherence using the cw broadcasts. The system was run in the post-sunset time period over two weeks during which almost every night showed significant degradation due to spread F resulting in rapid fading, decreased spatial and frequency coherence, and increased time delay spread. Doppler spreads of greater than 20 Hz were not uncommon, and the spatial correlation distances and frequency coherence bandwidths became so small (50 meters and 1 kHz respectively) that the experiment had to be readjusted. Measurements taken by the Altair incoherent scatter radar and the CUPRI 50 MHz coherent scatter radar indicate that although the bistatic hf channel is affected by the large scale plume structures, most of the [open quotes]damage[close quotes] is done by the bottomside spread F.

Fitzgerald, T.J.; Argo, P.E.; Carlos, R.C.

1993-01-01T23:59:59.000Z

143

Measurements of spatial and frequency coherence of an equatorial hf path during spread-F  

SciTech Connect

In August 1990, the authors set up an hf path on the equatorial path between Maloelap Atoll and Bikini Atoll. This path, which had a range of 702 km, reflected in the ionosphere approximately 100 km north of the Altair radar location on Kwajalein. Transmitters at Maloelap broadcasted four cw tones within bandwidth of either 4 kHz, 9 kHz, or 70 kHz to be used to determine frequency coherence and also a phase-coded pseudo random sequence with a bandwidth of 60 kHz (channel probe) to be used to determine time delay spread. A spatial array of antennas was deployed at Bikini to measure spatial and frequency coherence using the cw broadcasts. The system was run in the post-sunset time period over two weeks during which almost every night showed significant degradation due to spread F resulting in rapid fading, decreased spatial and frequency coherence, and increased time delay spread. Doppler spreads of greater than 20 Hz were not uncommon, and the spatial correlation distances and frequency coherence bandwidths became so small (50 meters and 1 kHz respectively) that the experiment had to be readjusted. Measurements taken by the Altair incoherent scatter radar and the CUPRI 50 MHz coherent scatter radar indicate that although the bistatic hf channel is affected by the large scale plume structures, most of the {open_quotes}damage{close_quotes} is done by the bottomside spread F.

Fitzgerald, T.J.; Argo, P.E.; Carlos, R.C.

1993-07-01T23:59:59.000Z

144

The Joint Owners' Group Program on MOV Periodic Verification  

SciTech Connect

To address long-term motor operated valve (MOV) performance, the Babcock and Wilcox, Boiling Water Reactor, Combustion Engineering and Westinghouse Groups (B and WOG, BWROG, CEOG and WOG) teamed in 1997 to form the Joint Group (JOG) MOV Periodic Verification (PV) Program. This program is nearing completion, with 98 of the 103 operating U.S. reactor units participating. The goal of the program is to provide a justified approach for periodically testing MOVs, that addresses potential degradation. The program defines an interim approach that specifies periodic tests without flow and differential pressure (DP), at a frequency determined by the s risk significance and margin. To justify this approach, each participating plant is also DP testing 2 valves per unit. Each valve is tested three times over five years, with at least one year between tests. The data are evaluated jointly to confirm or adjust the initial guidance. The majority of the tests are complete and conclusions are coming into focus. For gate valves, when the valve factor is initially low, increases can occur between one test and a later test. One common way that the valve factor becomes low is disassembling and reassembling the valve. The data show that, following valve disassembly and re-assembly, the valve factor tends to be reduced, and it tends to increase in subsequent service. Outside of the valves disassembled and reassembled, some gate valves have low valve factors apparently because the valves are not stroked under DP conditions in service. For butterfly valves, there have been no observations of degradation in bearing friction coefficient. A few valves with bronze bearings in raw (untreated) water service have shown significant variations in friction, but they tend to be a mixture of increases and decreases with no pattern of degradation. Globe valves, both unbalanced and balanced, tend to show a constant valve factor with no indication of degradation. (authors)

Damerell, Paul S.; Spears, Todd A. [MPR Associates Inc., 140 Mustang Circle, Simpsonville, SC 29681 (United States)

2002-07-01T23:59:59.000Z

145

Variable Frequency Pump Drives  

E-Print Network (OSTI)

-frequency electric motor drive. What is happenin9 with variable frequency driven pun,ps is a classical illustration that evolution in technical products takes place not only because of changes in the processes served by these products, or because of innovations...-pole 3550 rpm squirrel caqe induction motor became available in the early 1930s that high pressure pumps operating at that speed could be buil t. And now, in the 1980s, the development of the solid-state, variable frequency electric motor drive...

Karassik, I. J.; Petraccaro, L. L.; McGuire, J. T.

146

The frequency dependent impedance of an HVdc converter  

SciTech Connect

A linear and direct method of determining the frequency dependent impedance of a 12 pulse HVdc converter is presented. Terms are developed for both the dc and ac side impedances of the converter, including the effect of the firing angle control system, the commutation period, and the variability of the commutation period. The impedance predictions are verified by dynamic simulation.

Wood, A.R.; Arrillaga, J. [Univ. of Canterbury, Christchurch (New Zealand)] [Univ. of Canterbury, Christchurch (New Zealand)

1995-07-01T23:59:59.000Z

147

PERIODIC GLOW DISCHARGE REPORT  

NLE Websites -- All DOE Office Websites (Extended Search)

GLOW DISCHARGE REPORT GLOW DISCHARGE REPORT TIME: Jan 11 2014 11:29:09:000PM Power Supply ON/OFF Status OFF Power Supply Fault Status FAULT Power Supply Standby Status ON Power Supply Interlock Status NOT OK HV Power Resistors Status NORMAL Power Supply Voltage 52.00 Power Supply Current -71.00 Electrode 1 Voltage -15.00 Electrode 1 Current -79.00 Electrode 2 Voltage -14.00 Electrode 2 Current -70.00 ROSS 1 Status OPEN ROSS 2 Status OPEN ROSS 1 Common Line OPEN ROSS 2 Common Line OPEN IGBT1 Enable DISABLE IGBT2 Enable DISABLE

148

Graphene Frequency Multipliers  

E-Print Network (OSTI)

In this letter, the ambipolar transport properties of graphene flakes have been used to fabricate full-wave signal rectifiers and frequency-doubling devices. By correctly biasing an ambipolar graphene field-effect transistor ...

Wang, Han

149

Variable Frequency Drives  

NLE Websites -- All DOE Office Websites (Extended Search)

How BPA Supports VFDs Rebates are available from your utility for Variable Frequency Drives on pumps 20hp or greater and storage fans.. Energy savings from VFDs vary and can...

150

Mechanically tunable plasma frequency  

E-Print Network (OSTI)

in S12 phases. function [eps, x] = FindPerm(Thru, Sample,It returns the permittivity (eps) and a frequency matrix %0; % Initialize results matrix eps = zeros(n,1); for i = 1:n

Schuil, Crystal Joy

2009-01-01T23:59:59.000Z

151

Broadband low?frequency sound radiator with high?frequency pump resonator.  

Science Journals Connector (OSTI)

A new type of underwater low?frequency radiator is described. Operation of the radiator is based on the nonlinear conversion of high?frequency acoustic pump energy to low?frequency sound pulsation of the water volume of the open acoustic pump resonator. High?intensity pump waves in the resonator produce cavitation. Water containing bubbles is highly nonlinear (hundreds and even thousands of times more than pure water) and dispersive. Both of these factors and also the use of the pump resonator promote much stronger conversion of pump energy to low?frequency sound in comparison with a parametric radiator. The calculation of the acoustical characteristics is presented.

Dimitri M. Donskoy

1992-01-01T23:59:59.000Z

152

PERIODIC CRYO REPORT  

NLE Websites -- All DOE Office Websites (Extended Search)

CRYO REPORT CRYO REPORT TIME: Jan 11 2014 11:29:09:000PM LN2 tank pressure, psi 63.00 LN2 main tank level,inch 48.05 LN2 resv tank level,inch 179.00 Cryostat pressure, psi 0.01 LN2 sump level, inch 0.00 LN2 pump speed, rpm 0.27 LN2 pump pressure, psi 0.00 Scanner OK DIBORANE SYSTEM CRYBOR CONC1 OK CRYBOR CONC2 OK CRYBOR INST1 OK CRYBOR INST2 OK RESISTANCE COIL TEMPERATURES, deg C EF1U, deg C 34.66 EF1L 21.94 EF2U 26.93 EF2L 21.70 EF3U 41.54 EF3L 36.42 EFCU 18.28 EFCL 8.16

153

Forward period analysis and the long term simulation of a periodic Hamiltonian system  

E-Print Network (OSTI)

The period of a Morse oscillator and mathematical pendulum system are obtained, accurate to 100 significant digits, by forward period analysis (FPA). From these results, the long-term [0, 10^60] (time unit) solutions, which overlap from the Planck time to the age of the universe, are computed reliably and quickly with a parallel multiple-precision Taylor series (PMT) scheme. The application of FPA to periodic systems can reduce the computation loops of long-term reliable simulation from O(t^(1+1/M)) to O(lnt+t/h0) where T is the period, M the order and h0 a constant step-size. This scheme provides a way to generate reference solutions to test other schemes' long-term simulations.

Pengfei Wang

2014-10-23T23:59:59.000Z

154

Spiking mode operation for a uniform-period wiggler  

SciTech Connect

The onset of saturation in a uniform-period wiggler has been examined experimentally and through numerical simulations. Models have been constructed that explain the observations in simple and consistent ways. The models are based upon the development of strong frequency and amplitude modulation of the optical wave as a way to increase extraction efficiency and optical power.

Warren, R.W.; Goldstein, J.C.; Newnam, B.E.

1985-01-01T23:59:59.000Z

155

Embedding a chaotic signature in a periodic train: can periodic signals be chaotic?  

E-Print Network (OSTI)

We show how a chaotic system can be locked to emit a periodic waveform belonging to its chaotic attractor. We numerically demonstrate our idea in a system composed of a semiconductor laser driven to chaos by optical feedback from a short external cavity. The clue is the injection of an appropriate periodic signal that modulates the phase and amplitude of the intra-cavity radiation, a chaotic analogy of conventional mode-locking. The result is a time process that manifests a chaotic signature embedded in a long-scale periodic train.

Antonio Mecozzi; Cristian Antonelli

2008-12-11T23:59:59.000Z

156

Temporally resolved ion velocity distribution measurements in a radio-frequency plasma sheath  

SciTech Connect

The ion velocity distribution function (IVDF) above and within a radio-frequency (RF) biased plasma sheath is studied experimentally with a pulsed laser-induced fluorescence diagnostic in an industrial plasma etch tool. Temporally resolved measurements taken at eight different phases of the 2.2 MHz bias waveform show that the ion dynamics vary dramatically throughout the RF cycle (the ratio of the average ion transit time through the sheath to the RF period is {tau}{sub ion}/{tau}{sub RF} = 0.3). The position of the presheath/sheath edge is constant throughout the RF cycle and the time-averaged ion flux is conserved within the sheath region. The characteristic bimodal structure of the time-averaged ion distributions found in previous experiments is observed to arise from the time-dependent ion dynamics, in accord with existing theory. The large temporal variation of the IVDF has implications for the plasma chemistry and etching quality.

Jacobs, B.; Gekelman, W.; Pribyl, P. [University of California, Los Angeles, California 90095 (United States); Barnes, M. [MS Barnes Engineering, San Ramon, California 94583 (United States)

2011-05-15T23:59:59.000Z

157

The long time behavior of diffusion in tilted periodic potentials  

E-Print Network (OSTI)

Sep 18, 2013 ... as front propagation describing the evolution of an interface driven by an external force through ... and T is the absolute temperature), and ?W is a standard d-

2013-09-18T23:59:59.000Z

158

PERIOD ERROR ESTIMATION FOR THE KEPLER ECLIPSING BINARY CATALOG  

SciTech Connect

The Kepler Eclipsing Binary Catalog (KEBC) describes 2165 eclipsing binaries identified in the 115 deg{sup 2} Kepler Field based on observations from Kepler quarters Q0, Q1, and Q2. The periods in the KEBC are given in units of days out to six decimal places but no period errors are provided. We present the PEC (Period Error Calculator) algorithm, which can be used to estimate the period errors of strictly periodic variables observed by the Kepler Mission. The PEC algorithm is based on propagation of error theory and assumes that observation of every light curve peak/minimum in a long time-series observation can be unambiguously identified. The PEC algorithm can be efficiently programmed using just a few lines of C computer language code. The PEC algorithm was used to develop a simple model that provides period error estimates for eclipsing binaries in the KEBC with periods less than 62.5 days: log {sigma}{sub P} Almost-Equal-To - 5.8908 + 1.4425(1 + log P), where P is the period of an eclipsing binary in the KEBC in units of days. KEBC systems with periods {>=}62.5 days have KEBC period errors of {approx}0.0144 days. Periods and period errors of seven eclipsing binary systems in the KEBC were measured using the NASA Exoplanet Archive Periodogram Service and compared to period errors estimated using the PEC algorithm.

Mighell, Kenneth J. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Plavchan, Peter [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States)

2013-06-15T23:59:59.000Z

159

Frequencies for Radio Astronomy  

Science Journals Connector (OSTI)

... must therefore be achieved through the combined action of three international scientific unions, IAU (astronomy), COSPAR (space) and URSI (radio), which jointly delegate members to an ... jointly delegate members to an Inter-Union Commission for the Allocation of Frequencies for Radio Astronomy and Space Science (IUCAF). This Commission discusses the scientific case for protecting various ...

F. G. SMITH

1970-10-31T23:59:59.000Z

160

Component external leakage and rupture frequency estimates  

SciTech Connect

In order to perform detailed internal flooding risk analyses of nuclear power plants, external leakage and rupture frequencies are needed for various types of components - piping, valves, pumps, flanges, and others. However, there appears to be no up-to-date, comprehensive source for such frequency estimates. This report attempts to fill that void. Based on a comprehensive search of Licensee Event Reports (LERs) contained in Nuclear Power Experience (NPE), and estimates of component populations and exposure times, component external leakage and rupture frequencies were generated. The remainder of this report covers the specifies of the NPE search for external leakage and rupture events, analysis of the data, a comparison with frequency estimates from other sources, and a discussion of the results.

Eide, S.A.; Khericha, S.T.; Calley, M.B.; Johnson, D.A.; Marteeny, M.L.

1991-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Periodicities in gamma ray bursts  

Science Journals Connector (OSTI)

Gamma ray burst models based on magnetic neutron stars face a problem of account for the scarcity of observed periods. Both this scarcity and the typical period found when any is detected are explained if the neutron stars are accreting in binary systems

Kent S. Wood

1984-01-01T23:59:59.000Z

162

Periodic gravitational waves from small cosmic string loops  

Science Journals Connector (OSTI)

We consider a population of small, high-velocity cosmic string loops. We assume the typical length of these loops is determined by the gravitational radiation scale and use the results of Polchinski and Rocha which pointed out their highly relativistic nature. A study of the gravitational wave emission from such a population is carried out. The large Lorentz boost involved causes the lowest harmonics of the loops to fall within the frequency band of the Laser Interferometer Gravitational Wave Observatory detector. Because of this feature the gravitational waves emitted by such loops can be detected in a periodic search rather than in burst or stochastic analysis. It is shown that, for interesting values of the string tension (10-10?G??10-8), the detector can observe loops at reasonably high redshifts and that detection is, in principle, possible. We compute the number of expected observations produced by such a process. For a 10 h search we find that this number is of order O(10-4). This is a consequence of the low effective number density of the loops traveling along the line of sight. However, small probabilities of reconnection and longer observation times can improve the result.

Florian Dubath and Jorge V. Rocha

2007-07-02T23:59:59.000Z

163

Periodic  

NLE Websites -- All DOE Office Websites (Extended Search)

04 04 by C.G. Wohl (LBNL). Adapted from the Commission of Atomic Weights and Isotopic Abundances, "Atomic Weights of the Elements 1995," Pure and Applied Chemistry 68, 2339 (1996), and G. Audi and A.H. Wapstra, "The 1993 Mass Evaluation," Nucl. Phys. A565, 1 (1993). The atomic number (top left) is the number of protons in the nucleus. The atomic mass (bottom) is weighted by isotopic abundances in the Earth's surface. For a new determination of atomic masses, not weighted by abundances, see G. Audi, A.H. Wapstra, and C. Thibault, Nucl. Phys. A729, 337 (2003). Atomic masses are relative to the mass of the carbon-12 isotope, defined to be exactly 12 unified atomic mass units (u). Errors range from 1 to 9 in the last digit quoted. Relative isotopic abundances often vary considerably, both in natural and commercial samples. A number in parentheses is the mass of the longest-lived

164

All-sky search for periodic gravitational waves in LIGO S4 data  

E-Print Network (OSTI)

We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50-1000 Hz and with the frequency's time derivative in the range -1.0E-8 Hz/s to zero. Data from the fourth LIGO science run (S4) have been used in this search. Three different semi-coherent methods of transforming and summing strain power from Short Fourier Transforms (SFTs) of the calibrated data have been used. The first, known as "StackSlide", averages normalized power from each SFT. A "weighted Hough" scheme is also developed and used, and which also allows for a multi-interferometer search. The third method, known as "PowerFlux", is a variant of the StackSlide method in which the power is weighted before summing. In both the weighted Hough and PowerFlux methods, the weights are chosen according to the noise and detector antenna-pattern to maximize the signal-to-noise ratio. The respective advantages and disadvantages of these methods are discussed. Observing no evidence of periodic gravitationa...

Abbott, B; Adhikari, R; Agresti, J; Ajith, P; Allen, B; Amin, R; Anderson, S B; Anderson, W G; Arain, M; Araya, M; Armandula, H; Ashley, M; Aston, S; Aufmuth, P; Aulbert, C; Babak, S; Ballmer, S; Bantilan, H; Barish, B C; Barker, C; Barker, D; Barr, B; Barriga, P; Barton, M A; Bayer, K; Belczynski, K; Betzwieser, J; Beyersdorf, P T; Bhawal, B; Bilenko, I A; Billingsley, G; Biswas, R; Black, E; Blackburn, K; Blackburn, L; Blair, D; Bland, B; Bogenstahl, J; Bogue, L; Bork, R; Boschi, V; Bose, S; Brady, P R; Braginsky, V B; Brau, J E; Brinkmann, M; Brooks, A; Brown, D A; Bullington, A; Bunkowski, A; Buonanno, A; Burmeister, O; Busby, D; Byer, R L; Cadonati, L; Cagnoli, G; Camp, J B; Cannizzo, J; Cannon, K; Cantley, C A; Cao, J; Cardenas, L; Casey, M M; Castaldi, G; Cepeda, C; Chalkey, E; Charlton, P; Chatterji, S; Chelkowski, S; Chen, Y; Chiadini, F; Chin, D; Chin, E; Chow, J; Christensen, N; Clark, J; Cochrane, P; Cokelaer, T; Colacino, C N; Coldwell, R; Conte, R; Cook, D; Corbitt, T; Coward, D; Coyne, D; Creighton, J D E; Creighton, T D; Croce, R P; Crooks, D R M; Cruise, A M; Cumming, A; Dalrymple, J; D'Ambrosio, E; Danzmann, K; Davies, G; De Bra, D; Degallaix, J; Degree, M; Demma, T; Dergachev, V; Desai, S; DeSalvo, R; Dhurandhar, S; Daz, M; Dickson, J; Di Credico, A; Diederichs, G; Dietz, A; Doomes, E E; Drever, R W P; Dumas, J C; Dupuis, R J; Dwyer, J G; Ehrens, P; Espinoza, E; Etzel, T; Evans, M; Evans, T; Fairhurst, S; Fan, Y; Fazi, D; Fejer, M M; Finn, L S; Fiumara, V; Fotopoulos, N; Franzen, A; Franzen, K Y; Freise, A; Frey, R; Fricke, T; Fritschel, P; Frolov, V V; Fyffe, M; Galdi, V; Garofoli, J; Gholami, I; Giaime, J A; Giampanis, S; Giardina, K D; Goda, K; Goetz, E; Goggin, L M; González, G; Gossler, S; Grant, A; Gras, S; Gray, a C; Gray, M; Greenhalgh, J; Gretarsson, A M; Grosso, R; Grote, H; Grünewald, S; Günther, M; Gustafson, R; Hage, B; Hammer, D; Hanna, C; Hanson, J; Harms, J; Harry, G; Harstad, E; Hayler, T; Heefner, J; Heng, I S; Heptonstall, A; Heurs, M; Hewitson, M; Hild, S; Hirose, E; Hoak, D; Hosken, D; Hough, J; Howell, E; Hoyland, D; Huttner, S H; Ingram, D; Innerhofer, E; Ito, M; Itoh, Y; Ivanov, A; Jackrel, D; Johnson, B; Johnson, W W; Jones, D I; Jones, G; Jones, R; Ju, L; Kalmus, Peter Ignaz Paul; Kalogera, V; Kasprzyk, D; Katsavounidis, E; Kawabe, K; Kawamura, S; Kawazoe, F; Kells, W; Keppel, D G; Khalili, F Ya; Kim, C; King, P; Kissel, J S; Klimenko, S; Kokeyama, K; Kondrashov, V; Kopparapu, R K; Kozak, D; Krishnan, B; Kwee, P; Lam, P K; Landry, M; Lantz, B; Lazzarini, A; Lee, B; Lei, M; Leiner, J; Leonhardt, V; Leonor, I; Libbrecht, K; Lindquist, P; Lockerbie, N A; Longo, M; Lormand, M; Lubinski, M; Luck, H; Machenschalk, B; MacInnis, M; Mageswaran, M; Mailand, K; Malec, M; Mandic, V; Marano, S; Marka, S; Markowitz, J; Maros, E; Martin, I; Marx, J N; Mason, K; Matone, L; Matta, V; Mavalvala, a N; McCarthy, R; McClelland, D E; McGuire, S C; McHugh, M; McKenzie, K; McNabb, J W C; McWilliams, S; Meier, T; Melissinos, A; Mendell, G; Mercer, R A; Meshkov, S; Messaritaki, E; Messenger, C J; Meyers, D; Mikhailov, E; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Miyakawa, O; Mohanty, S; Moreno, G; Mossavi, K; Mow Lowry, C; Moylan, A; Mudge, D; Müller, G; Mukherjee, S; Muller-Ebhardt, H; Munch, J; Murray, P; Myers, E; Myers, J; Nash, T; Newton, G; Nishizawa, A; Numata, K; O'Reilly, B; O'Shaughnessy, R; Ottaway, D J; Overmier, H; Owen, B J; Pan, Y; Papa, M A; Parameshwaraiah, V; Patel, P; Pedraza, M; Penn, S; Pierro, V; Pinto, I M; Pitkin, M; Pletsch, H; Plissi, M V; Postiglione, F; Prix, R; Quetschke, V; Raab, F; Rabeling, D; Radkins, H; Rahkola, R; Rainer, N; Rakhmanov, M; Ramsunder, M; Rawlins, K; Ray-Majumder, S; Re, V; Rehbein, H; Reid, S; Reitze, D H; Ribichini, L; Riesen, R; Riles, K; Rivera, B; Robertson, N A; Robinson, C; Robinson, E L; Roddy, S; Rodríguez, A; Rogan, A M; Rollins, J; Romano, J D; Romie, J; Route, R; Rowan, S; Rüdiger, A; Ruet, L; Russell, P; Ryan, K; Sakata, S; Samidi, M; Sancho de la Jordana, L; Sandberg, V; Sannibale, V; Saraf, S; Sarin, P; Sathyaprakash, B S; Sato, S; Saulson, P R; Savage, R; Savov, P; Schediwy, S; Schilling, R; Schnabel, R; Schofield, R; Schutz, B F; Schwinberg, P; Scott, S M; Searle, A C; Sears, B; Seifert, F; Sellers, D; Sengupta, A S; Shawhan, P; Shoemaker, D H; Sibley, A; Sidles, J A; Siemens, X; Sigg, D; Sinha, S; Sintes, A M; Slagmolen, B J J; Slutsky, J; Smith, J R; Smith, M R; Somiya, K; Strain, K A; Strom, D M; Stuver, A; Summerscales, T Z; Sun, K X; Sung, M; Sutton, P J; Takahashi, H; Tanner, D B; Tarallo, M; Taylor, R; Taylor, R; Thacker, J; Thorne, K A; Thorne, K S; Thüring, A; Tokmakov, K V; Torres, C; Torrie, C; Traylor, G; Trias, M; Tyler, W; Ugolini, D; Ungarelli, C; Urbanek, K; Vahlbruch, H; Vallisneri, M; Van Den Broeck, C; Varvella, M; Vass, S; Vecchio, A; Veitch, J; Veitch, P; Villar, A; Vorvick, C

2007-01-01T23:59:59.000Z

165

Quantized Spiral Tip Motion in Excitable Systems with Periodic Heterogeneities Brent T. Ginn and Oliver Steinbock*  

E-Print Network (OSTI)

and frequencies that exhibit a devil's staircase. The plateaus of the staircase correspond to pinned or complex length. These quantized orbits follow a devil's staircase [10] as the refractory period of the sys- tem

Steinbock, Oliver

166

Can Bohmian trajectories account for quantum recurrences having classical periodicities?  

E-Print Network (OSTI)

Quantum systems in specific regimes display recurrences at the period of the periodic orbits of the corresponding classical system. We investigate the excited hydrogen atom in a magnetic field -- a prototypical system of 'quantum chaos' -- from the point of view of the de Broglie Bohm (BB) interpretation of quantum mechanics. The trajectories predicted by BB theory are computed and contrasted with the time evolution of the wavefunction, which shows pronounced features at times matching the period of closed orbits of the classical hydrogen in a magnetic field problem. Individual BB trajectories do not possess these periodicities and cannot account for the quantum recurrences. These recurrences can however be explained by BB theory by considering the ensemble of trajectories compatible with an initial statistical distribution, although none of the trajectories of the ensemble are periodic, rendering unclear the dynamical origin of the classical periodicities.

A. Matzkin

2006-07-14T23:59:59.000Z

167

CHAPTER XV - TIME SERIES  

Science Journals Connector (OSTI)

Publisher Summary This chapter provides an overview of time series. A time series is a set of observations of a variable made at different points of time and arranged in chronological order, each observation representing the value of the variable either at a given moment or during the interval of time between this observation and the preceding one. In general, the observations forming a time-series as made at equidistant intervals of time are considered. The factors affecting time-series may be recurring or nonrecurring, or evolutionary, periodic, or random. The method of moving averages consists in determining the average value for a certain number of terms of a time series and taking this average as the trend normal value for the middle of the period covered in the calculation of the average, that is, the period extent of the moving average.

ISAAC PAENSON

1970-01-01T23:59:59.000Z

168

High frequency reference electrode  

DOE Patents (OSTI)

A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or halo' at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes. 4 figs.

Kronberg, J.W.

1994-05-31T23:59:59.000Z

169

The orbital period of the eclipsing dwarf nova CG Draconis  

E-Print Network (OSTI)

We have performed time resolved photometry on the dwarf nova CG Dra and have established for the first time that it is an eclipsing system. By measuring the times of the eclipses, we determined the orbital period as 0.18864(4) d, or 4h 31m 38 +/- 3s. This value is consistent with the shorter of two periods proposed from earlier spectroscopic studies. The orbital period places CG Dra above the period gap. The symmetrical eclipses are of short duration (FWHM 18+/-2 min, or 0.066(7) of the orbital period) and shallow (average 0.16+/-0.02 mag), suggesting a grazing eclipse which is consistent with an orbital inclination just above the critical value. Flickering persists through the eclipse which means that the flickering source is not occulted by the secondary star.

Jeremy Shears; David Boyd; Steve Brady; Roger Pickard

2008-02-04T23:59:59.000Z

170

High-Frequency Transient Eddies and Blocking  

Science Journals Connector (OSTI)

In this paper we investigate the role of high-frequency transient eddies in the maintenance of the blocking high which occurred over Europe on 16-25 February 1979. Time-filtering is used to decompose the atmospheric large-scale flow into ...

Eero Holopainen; Carl Fortelius

1987-06-01T23:59:59.000Z

171

Encoding Communication Signals with Timescale Separation by Spike Frequency Adaptation  

E-Print Network (OSTI)

Apteronotus leptorhynchus pro- duces a continuous quasi-sinusoidal electric field (EOD, 600 - 1100Hz) which the EOD frequency is raised by about 30 to 150 Hz during 10 to 20 ms, resulting in a phase advance by as little as 1/2 to 1 1/2 EOD period. In the presence of a second fish with EOD frequency f2 a beat arises

Benda, Jan

172

Statistical Features of the Wind Field over the Indian Ccean for the period 1998-2008  

E-Print Network (OSTI)

We have done a statistical analysis of the wind field from the archive of NCEP/NOAA over the Indian Ocean for the period 1998-2008yy, which is given on a grid 1x1.25 of latitude-longitude with 3h time-step. Initial analysis includes mapping the average wind fields and fields of mean density of the wind-kinetic-energy flux , obtained with different periods of time averaging T, as well as the assessment of 11-year trends in these fields. The subsequent analysis is concerned with partition of the Indian ocean area into 6 zones, provided by the spatial inhomogeneity of the analyzed wind field. This analysis includes: a) an assessment of temporal variations for the wind speed field averaged over the Ocean and the zones and for the field of wind-energy flux; b) construction of time history series of these fields averaged with different scales, and estimating frequency spectra of these series; c) finding the extremes of the wind field (in the zones of Indian Ocean); d) construction of histograms of the wind field; ...

Polnikov, Vladislav; Sannasiraj, S A

2011-01-01T23:59:59.000Z

173

Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data  

E-Print Network (OSTI)

This paper presents results of an all-sky search for periodic gravitational waves in the frequency range [50,1?190]??Hz and with frequency derivative range of ?[-20,1.1]×10[superscript -10]??Hz?s[superscript -1] for the ...

Barsotti, Lisa

174

FROM LARGE-SCALE LOOPS TO THE SITES OF DENSE FLARING LOOPS: PREFERENTIAL CONDITIONS FOR LONG-PERIOD PULSATIONS IN SOLAR FLARES  

SciTech Connect

Long-period quasi-periodic pulsations (QPPs) of solar flares are a class apart from shorter period events. By involving an external resonator, the mechanism they call upon differs from traditional QPP models, but has wider applications. We present a multi-wavelength analysis of spatially resolved QPPs, with periods around 10 minutes, observed in the X-ray spectrum primarily at energies between 3 and 25 keV. Complementary observations obtained in H{alpha} and radio emission in the kHz to GHz frequency range, together with an analysis of the X-ray plasma properties provide a comprehensive picture that is consistent with a dense flaring loop subject to periodic energization and thermalization. The QPPs obtained in H{alpha} and type III radio bursts, with similar periods as the QPPs in soft X-rays, have the longest periods ever reported for those types of data sets. We also report 1-2 GHz radio emission, concurrent with but unrestricted to the QPP time intervals, which is multi-structured at regularly separated narrowband frequencies and modulated with {approx}18 minute periods. This radio emission can be attributed to the presence of multiple 'quiet' large-scale loops in the background corona. Large scale but shorter inner loops below may act as preferential resonators for the QPPs. The observations support interpretations consistent with both inner and outer loops subject to fast kink magnetohydrodynamic waves. Finally, X-ray imaging indicates the presence of double coronal sources in the flaring sites, which could be the particular signatures of the magnetically linked inner loops. We discuss the preferential conditions and the driving mechanisms causing the repeated flaring.

Foullon, C.; Verwichte, E.; Nakariakov, V. M. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Fletcher, L.; Hannah, I. G. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Cecconi, B. [LESIA, CNRS, UPMC, Universite Paris Diderot, Observatoire de Paris, 5 Place Jules Janssen, 92190 Meudon (France); Phillips, K. J. H. [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); Tan, B. L., E-mail: claire.foullon@warwick.ac.u [Key Laboratory of Solar Activity, National Astronomical Observatories of Chinese Academy of Sciences, Beijing 100012 (China)

2010-08-10T23:59:59.000Z

175

Dynamic Scheduling of Skippable Periodic Tasks: Issues and Proposals  

E-Print Network (OSTI)

-Chetto and Audrey Marchand IRCCyN, University of Nantes, Nantes, FRANCE Email: {maryline.chetto, audrey.marchand Scheduling of Skippable Periodic Tasks in Weakly-Hard Real-Time Systems," by M. Silly-Chetto, and A. Marchand

Paris-Sud XI, Université de

176

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy.

Lauf, Robert J. (Oak Ridge, TN); McMillan, April D. (Knoxville, TN); Paulauskas, Felix L. (Oak Ridge, TN); Fathi, Zakaryae (Cary, NC); Wei, Jianghua (Raleigh, NC)

1998-01-01T23:59:59.000Z

177

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-09-08T23:59:59.000Z

178

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-08-25T23:59:59.000Z

179

Inhomogeneous High Frequency Expansion-Free Gravitational Waves  

E-Print Network (OSTI)

We describe a natural inhomogeneous generalization of high frequency plane gravitational waves. The waves are high frequency waves of the Kundt type whose null propagation direction in space-time has vanishing expansion, twist and shear but is not covariantly constant. The introduction of a cosmological constant is discussed in some detail and a comparison is made with high frequency gravity waves having wave fronts homeomorphic to 2-spheres.

C. Barrabes; P. A. Hogan

2007-06-18T23:59:59.000Z

180

Performance Period Total Fee Paid  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Period Period Total Fee Paid 4/29/2012 - 9/30/2012 $418,348 10/1/2012 - 9/30/2013 $0 10/1/2013 - 9/30/2014 $0 10/1/2014 - 9/30/2015 $0 10/1/2015 - 9/30/2016 $0 Cumulative Fee Paid $418,348 Contract Type: Cost Plus Award Fee Contract Period: $116,769,139 November 2011 - September 2016 $475,395 $0 Fee Information Total Estimated Contract Cost $1,141,623 $1,140,948 $1,140,948 $5,039,862 $1,140,948 Maximum Fee $5,039,862 Minimum Fee Fee Available Portage, Inc. DE-DT0002936 EM Contractor Fee Site: MOAB Uranium Mill Tailings - MOAB, UT Contract Name: MOAB Uranium Mill Tailings Remedial Action Contract September 2013 Contractor: Contract Number:

Note: This page contains sample records for the topic "frequency time period" 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

Periodic ripples in suspended graphene  

Science Journals Connector (OSTI)

We study the mechanism of wrinkling of suspended graphene, by means of atomistic simulations. We argue that the structural instability under edge compression is the essential physical reason for the formation of periodic ripples in graphene. The ripple wavelength and out-of-plane amplitude are found to obey 1/4-power scaling laws with respect to edge compression. Our results also show that parallel displacement of the clamped boundaries can induce periodic ripples, with oscillation amplitude roughly proportional to the 1/4 power of edge displacement.

Zhao Wang and Michel Devel

2011-03-23T23:59:59.000Z

182

Architecture, implementation and parallelization of the software to search for periodic gravitational wave signals  

E-Print Network (OSTI)

The parallelization, design and scalability of the \\sky code to search for periodic gravitational waves from rotating neutron stars is discussed. The code is based on an efficient implementation of the F-statistic using the Fast Fourier Transform algorithm. To perform an analysis of data from the advanced LIGO and Virgo gravitational wave detectors' network, which will start operating in 2015, hundreds of millions of CPU hours will be required - the code utilizing the potential of massively parallel supercomputers is therefore mandatory. We have parallelized the code using the Message Passing Interface standard, implemented a mechanism for combining the searches at different sky-positions and frequency bands into one extremely scalable program. The parallel I/O interface is used to escape bottlenecks, when writing the generated data into file system. This allowed to develop a highly scalable computation code, which would enable the data analysis at large scales on acceptable time scales. Benchmarking of the c...

Poghosyan, Gevorg; Streit, Achim; Bejger, Micha?; Królak, Andrzej

2014-01-01T23:59:59.000Z

183

An infinite-period phase transition versus nucleation in a stochastic model of collective oscillations  

E-Print Network (OSTI)

A lattice model of three-state stochastic phase-coupled oscillators has been shown by Wood et al (2006 Phys. Rev. Lett. 96 145701) to exhibit a phase transition at a critical value of the coupling parameter, leading to stable global oscillations. We show that, in the complete graph version of the model, upon further increase in the coupling, the average frequency of collective oscillations decreases until an infinite-period (IP) phase transition occurs, at which point collective oscillations cease. Above this second critical point, a macroscopic fraction of the oscillators spend most of the time in one of the three states, yielding a prototypical nonequilibrium example (without an equilibrium counterpart) in which discrete rotational (C_3) symmetry is spontaneously broken, in the absence of any absorbing state. Simulation results and nucleation arguments strongly suggest that the IP phase transition does not occur on finite-dimensional lattices with short-range interactions.

Vladimir R. V. Assis; Mauro Copelli; Ronald Dickman

2011-06-16T23:59:59.000Z

184

What's the Frequency, Kenneth?: Sublinear Fourier Sampling Off the Grid  

E-Print Network (OSTI)

What's the Frequency, Kenneth?: Sublinear Fourier Sampling Off the Grid Petros Boufounos1 , Volkan Fourier sampling algorithm for a case of sparse off-grid frequency recovery. These are signals {j} satisfy j [, 2-] and mini=j |i -j| for some > 0. We design a sublinear time randomized

Boufounos, Petros T.

185

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

186

Study of a dual frequency atmospheric pressure corona plasma  

Science Journals Connector (OSTI)

Radio frequency mixing of 2 and 13.56 MHz was investigated by performing experimental measurements on the atmospheric pressurecoronaplasma. As a result of the dual frequency length current density and electron excitation temperature of the plasma were increased while the gas temperature was maintained at roughly the same level when compared to the respective single frequency plasmas. Moreover observation of time-resolvedimages revealed that the dual frequency plasma has a discharge mode of 2 MHz positive streamer 2 MHz negative glow and 13.56 MHz continuous glow.

Dan Bee Kim; S. Y. Moon; H. Jung; B. Gweon; Wonho Choe

2010-01-01T23:59:59.000Z

187

Study of a dual frequency atmospheric pressure corona plasma  

SciTech Connect

Radio frequency mixing of 2 and 13.56 MHz was investigated by performing experimental measurements on the atmospheric pressure corona plasma. As a result of the dual frequency, length, current density, and electron excitation temperature of the plasma were increased, while the gas temperature was maintained at roughly the same level when compared to the respective single frequency plasmas. Moreover, observation of time-resolved images revealed that the dual frequency plasma has a discharge mode of 2 MHz positive streamer, 2 MHz negative glow, and 13.56 MHz continuous glow.

Kim, Dan Bee; Moon, S. Y.; Jung, H.; Gweon, B.; Choe, Wonho [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2010-05-15T23:59:59.000Z

188

Particle-in-cell simulation of hydrogen discharge driven by combined radio frequency and pulse sources  

SciTech Connect

A particle-in-cell plus Monte Carlo collision model is employed to investigate the low pressure hydrogen capacitive discharge driven by combined radio frequency (rf) and pulse sources. This work focuses on the evolutions of electron energy and density in the discharge to illustrate the role that a short pulse source plays. The simulation results show that an extra short pulse source can modulate the electron energy effectively: in the early and late pulse-on times, the electron energy is much higher than that in the single rf source discharge; during the pulse-off time, the electron energy can drop gradually to a low value. It is also found that a few peaks of attenuated electron energy appear periodically just after the pulse voltage drops to zero. The similar phenomena can also be found in the production rate of highly vibrationally excited hydrogen molecules. Physical mechanisms responsible for these phenomena are discussed.

Sun Jizhong; Li Xiantao; Sang Chaofeng; Jiang Wei; Zhang Pengyun; Wang Dezhen [School of Physics and Optoelectronic Engineering and College of Advanced Science and Technology, Dalian University of Technology, Dalian 116024 (China)

2010-10-15T23:59:59.000Z

189

Observations of long period earthquakes accompanying hydraulic fracturing  

SciTech Connect

Waveforms of most seismic events accompanying hydraulic fracturing have been reported to contain clear P and S waves and have fault plane solutions consistent with shear displacement across a fault. This observation is surprising since classical hydraulic fracturing theory predicts the creation of a tensile opening of a cavity in response to fluid pressure. Very small long period events, similar to long period earthquakes observed at volcanoes, were found to occur during four hydraulic fracturing experiments carried out at Fenton Hill, New Mexico. Since the long period earthquakes occur in the same region as the shear type events, it is concluded that the unusual character of the long period earthquake waveforms is due to a source effect and not a path effect. The occurrence of long period earthquakes during hydraulic fracturing could indicate tensile fracturing. Many waveforms of these events are identical, which implies that these events represent repeated activation of a given source. A proposed source for these long period events is the sudden opening of a channel that connects two cracks filled with fluid at different pressures. The sizes of the two cracks differ, which causes two or more peaks to appear in the spectra, each peak being associated with one physical dimension of each crack. From the frequencies at which spectral peaks occur, crack lengths are estimated to be between 3 and 20m.

Bame, D.; Fehler, M.

1986-02-01T23:59:59.000Z

190

Frequency locking in the injection-locked frequency divider equation  

E-Print Network (OSTI)

We consider a model for the injection-locked frequency divider, and study analytically the locking onto rational multiples of the driving frequency. We provide explicit formulae for the width of the plateaux appearing in the devil's staircase structure of the lockings, and in particular show that the largest plateaux correspond to even integer values for the ratio of the frequency of the driving signal to the frequency of the output signal. Our results prove the experimental and numerical results available in the literature.

Bartuccelli, Michele V; Gentile, Guido

2008-01-01T23:59:59.000Z

191

The Periods Discovered by RXTE in Thermonuclear Flash Bursts  

E-Print Network (OSTI)

Oscillations in the X-ray flux of thermonuclear X-ray bursts have been observed with RXTE from at least 6 low-mass binaries, at frequencies from 330 Hz to 589 Hz. There appear to be preferred relations between the frequencies present during the bursts and those seen in the persistent flux. The amplitude of the oscillations can exceed 50 % near burst onset. Except for a systematic increase in oscillation frequency as the burst progresses, the frequency is stable. Time resolved spectra track increases in the X-ray emitting area due to propagation of the burning front over the neutron star surface, as well as radiation driven expansion of the photosphere. The neutron star mass, radius, and distance can be inferred when spectra are compared to theoretical expectations.

T. E. Strohmayer; J. H. Swank; W. Zhang

1998-01-23T23:59:59.000Z

192

Laser frequency combs for astronomical observations  

E-Print Network (OSTI)

A direct measurement of the universe's expansion history could be made by observing in real time the evolution of the cosmological redshift of distant objects. However, this would require measurements of Doppler velocity drifts of about 1 centimeter per second per year, and astronomical spectrographs have not yet been calibrated to this tolerance. We demonstrate the first use of a laser frequency comb for wavelength calibration of an astronomical telescope. Even with a simple analysis, absolute calibration is achieved with an equivalent Doppler precision of approximately 9 meters per second at about 1.5 micrometers - beyond state-of-the-art accuracy. We show that tracking complex, time-varying systematic effects in the spectrograph and detector system is a particular advantage of laser frequency comb calibration. This technique promises an effective means for modeling and removal of such systematic effects to the accuracy required by future experiments to see direct evidence of the universe's putative acceleration.

Tilo Steinmetz; Tobias Wilken; Constanza Araujo-Hauck; Ronald Holzwarth; Theodor W. Hänsch; Luca Pasquini; Antonio Manescau; Sandro D'Odorico; Michael T. Murphy; Thomas Kentischer; Wolfgang Schmidt; Thomas Udem

2008-09-09T23:59:59.000Z

193

Effective switching frequency multiplier inverter  

DOE Patents (OSTI)

A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

Su, Gui-Jia (Oak Ridge, TN); Peng, Fang Z. (Okemos, MI)

2007-08-07T23:59:59.000Z

194

Recognition of human periodic movements from unstructured information using a motion-based frequency domain approach  

E-Print Network (OSTI)

the parameter domain in the presence of human motion irregularities. q 2006 Elsevier B.V. All rights reserved processing of feature detection. Motion power spectral analysis is applied to a set of unidentified trajectories of feature points representing whole body kinematics. Feature power vectors are extracted from

Li, Baihua

195

Comment on 'Q for short-period P waves: is it frequency dependent?' by A. Douglas  

Science Journals Connector (OSTI)

......recorded from explosions at the Shagan River Test Site (STS), USSR and the Nevada Test Site (NTS), USA from which he has concluded...Shagan River Test Site (STS), USSR and the Nevada Test Site (NTS), USA from which he has concluded......

John R. Murphy

1993-05-01T23:59:59.000Z

196

Q for short-period P-waves: is it frequency dependent?  

Science Journals Connector (OSTI)

......Test Site (STS), USSR and the Nevada Test Site (NTS) USA. One type assumes...Empirical mb :Ms relations at the Nevada Test Site site with applications to mb -yield...areas and media at the USERDA Nevada Test Site, 1975. University of California......

A. Douglas

1992-01-01T23:59:59.000Z

197

Frequency Scalable Non-Linear Waveform Generator for Mixed-Simal Power-Factor-Correction IC Controller'  

E-Print Network (OSTI)

operates with a fixed switching frequency fs and variable duty ratio R, and can be analyzed using standard of a switching period, a fixed-frequency clock pulse sets the switch drive high. A signal proportionalFrequency Scalable Non-Linear Waveform Generator for Mixed-Simal Power-Factor-Correction IC

198

Forcing and Sampling of Ocean General Circulation Models: Impact of High-Frequency Motions  

Science Journals Connector (OSTI)

Significant inertial oscillations are present in all primitive equation ocean general circulation models when they are forced with high-frequency (period order of days) wind stress fields. At specific latitudes the energy of the wind stress ...

Steven R. Jayne; Robin Tokmakian

1997-06-01T23:59:59.000Z

199

Fluidic Tuning of a Four-Arm Spiral-Based Frequency Selective Surface  

E-Print Network (OSTI)

Frequency selective surfaces (FSSs) provide a variety of spatial filtering functions, such as band-pass or band-stop properties in a radome or other multilayer structure. This filtering is typically achieved through closely-spaced periodic...

Wells, Elizabeth Christine

2011-08-08T23:59:59.000Z

200

Audio-Frequency Power Measurements  

Science Journals Connector (OSTI)

... " prepared by the National Physical Laboratory, Teddington, is a brief pamphlet dealing with "Audio-Frequency Power Measurements" (pp. 16. London: H.M.S.O., 1954; ...

1955-09-10T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

High frequency and high dynamic range continuous time filters  

E-Print Network (OSTI)

subscriber line (ADSL), very high bit rate DSL (VDSL) and power line communications (PLC). However, a major challenge is the design of the analog frontend; for these systems a large dynamic range is required due to the significant peak to average ratio...

Lewinski Komincz, Artur Juliusz

2007-09-17T23:59:59.000Z

202

Is It Time to Abandon the Food Frequency Questionnaire?  

Science Journals Connector (OSTI)

...records or 24-hour recalls, is generally not good. Correlations between FFQ- and recall-derived...Computer-administered questionnaires, delivered via internet or on touch-screen tablet computers...24-hour recall could be delivered over the internet or on a pocket PC. Distributing small...

Alan R. Kristal; Ulrike Peters; and John D. Potter

2005-12-01T23:59:59.000Z

203

Parallel Algorithms for Time and Frequency Domain Circuit Simulation  

E-Print Network (OSTI)

solution to circuit simulation besides the known application of distributed-memory clustered computing platforms, which provides abundant hardware computing resources. This research addresses the limitations of traditional serial circuit simulations...

Dong, Wei

2010-10-12T23:59:59.000Z

204

Stochastic Approach to Square Timing Estimation with Frequency Uncertainty  

E-Print Network (OSTI)

of the Spanish/Catalan Science and Technology Commissions (CICYT/CIRIT): TIC2002-04594-, TIC2001-2356-, TIC2000

Vázquez, Gregori

205

AFGa: Time and frequency transfer (ATF2010 joint session)  

E-Print Network (OSTI)

of Astronomy and Astrophysics, China (SRS), 2 Karoo Array Telescope, South Africa, 3 Brigham Young University) V. K. Jordanova, Los Alamos National Laboratory, United States 2. PLASMA WAVES AND HIGH ENERGY TO A SOLAR POWER SATELLITE (Invited) T. Takano1 , T. Yamada2 , Y. Kazama2 , K. Ikeda2 , S. Kawasaki3 , N

Choi, Woo-Young

206

High-frequency response and the possibilities of frequency-tunable narrow-band terahertz amplification in resonant tunneling nanostructures  

SciTech Connect

The characteristics of the high-frequency response of single- and double-well resonant tunneling structures in a dc electric field are investigated on the basis of the numerical solution of a time-dependent Schroedinger equation with open boundary conditions. The frequency dependence of the real part of high frequency conductivity (high-frequency response) in In{sub 0.53}Ga{sub 0.47}As/AlAs/InP structures is analyzed in detail for various values of the dc voltage V{sub dc} in the negative differential resistance (NDR) region. It is shown that double-well three-barrier structures are promising for the design of terahertz-band oscillators. The presence of two resonant states with close energies in such structures leads to a resonant (in frequency) response whose frequency is determined by the energy difference between these levels and can be controlled by varying the parameters of the structure. It is shown that, in principle, such structures admit narrow-band amplification, tuning of the amplification frequency, and a fine control of the amplification (oscillation) frequency in a wide range of terahertz frequencies by varying a dc electric voltage applied to the structure. Starting from a certain width of the central intermediate barrier in double-well structures, one can observe a collapse of resonances, where the structure behaves like a single-well system. This phenomenon imposes a lower limit on the oscillation frequency in three-barrier resonant tunneling structures.

Kapaev, V. V., E-mail: kapaev@sci.lebedev.ru; Kopaev, Yu. V.; Savinov, S. A.; Murzin, V. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2013-03-15T23:59:59.000Z

207

Discovery of a ~2 hr high frequency X-ray QPO and iron K alpha reverberation in the active galaxy MS 2254.9-3712  

E-Print Network (OSTI)

We report the discovery of a $\\sim 1.5 \\times 10^{-4}$ Hz ($\\sim 2$ hr) X-ray quasi-periodic oscillation (QPO) in the active galaxy MS 2254.9-3712, using a $\\sim 70$ ks XMM-Newton observation. The QPO is significantly detected in the $1.2 - 5.0$ keV band only, connecting its origin with the primary X-ray power-law continuum. We detect a highly coherent soft lag between the $0.3 - 0.7$ keV and $1.2 - 5.0$ keV energy bands at the QPO and harmonic frequencies, with a 3:2 frequency ratio. An iron K$\\alpha$ reverberation lag is found at the harmonic frequency, indicating the reflecting material subtends some angle to the primary continuum, which is modulated by the QPO mechanism. The coherence at the QPO and harmonic frequencies is ~ unity, whereas the coherence in the broadband noise is decreasing with increasing frequency. Frequency resolved spectroscopy reveals the QPO and harmonic to have a hard energy dependence. These properties of the QPO variability, together with the current black hole mass estimate, $M_{...

Alston, W N; Markeviciute, J; Fabian, A C; Middleton, M; Lohfink, A; Kara, E; Pinto, C

2014-01-01T23:59:59.000Z

208

A finite difference model for low frequency sound measurement in kraft recovery boilers.  

Science Journals Connector (OSTI)

Kraft recovery boilers greatly enhance the efficiency of paper pulp mills by burning the organic wastes recovered from the pulp making process and generating electricity but significant smelt?water explosion hazards exist when steam is used as the working fluid due to sodiumcompounds in the sludge from the waste incineration process. Current practice is to use acoustic emission sensors to monitor for leaks in the bottom wall and to initiate an automatic shutdown sequence for the boiler once a leak is detected. A high?frequency model previously developed by the authors and verified by measurements performed in Skoghall Sweden indicated strong attenuation in the sludge between the point of leakage and the detectors but experimental results demonstrated a pass band at low frequencies (under 20 kHz). In this paper the authors develop a two?degree?of?freedom finite difference model for the prediction of acoustic attenuation at low frequencies. The bottom wall is modeled as a periodic tube and fin arrangement and a time?domain finite difference method is used whereby the fin and tube are simple lumped elements. The model is then compared to previous experimental results with which excellent agreement is obtained.

Robert Hildebrand; Matthew Carroll; Ville Jarvinen; Juha Miettinen

2010-01-01T23:59:59.000Z

209

SOLAR CYCLE VARIABILITY AND SURFACE DIFFERENTIAL ROTATION FROM Ca II K-LINE TIME SERIES DATA  

SciTech Connect

Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period {approx} 11 yr), (b) quasi-periodic variations (periods {approx} 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range {approx}0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak{sub m}on/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

Scargle, Jeffrey D.; Worden, Simon P. [NASA Ames Research Center, Moffett Field, CA, 94035 (United States); Keil, Stephen L. [National Solar Observatory, P.O. Box 57, Sunspot, NM 88349 (United States)

2013-07-01T23:59:59.000Z

210

An Autonomous Adaptive Scheduling Agent for Period Searching  

E-Print Network (OSTI)

We describe the design and implementation of an autonomous adaptive software agent that addresses the practical problem of observing undersampled, periodic, time-varying phenomena using a network of HTN-compliant robotic telescopes. The algorithm governing the behaviour of the agent uses an optimal geometric sampling technique to cover the period range of interest, but additionally implements proactive behaviour that maximises the optimality of the dataset in the face of an uncertain and changing operating environment.

Eric S. Saunders; Tim Naylor; Alasdair Allan

2008-01-24T23:59:59.000Z

211

Stabilized radio-frequency quadrupole  

DOE Patents (OSTI)

A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1982-09-29T23:59:59.000Z

212

Processing electromagnetic data in the time domain  

Science Journals Connector (OSTI)

......necessary to allot storage for the full...the two impulse response functions A and...functions of frequency) that can be...components over all frequencies but a unique...in either the frequency or the time domain...and there is no energy in the direction...unknown impulse response vector A......

George A. McMechan; Ian Barrodale

1985-04-01T23:59:59.000Z

213

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

SciTech Connect

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

214

Slow-light transmission in one-dimensional periodic structures  

SciTech Connect

We have analyzed the transmission properties of pulses through one-dimensional periodic structures in order to systematically explore the best conditions to achieve the maximum delay with the minimum possible distortion. In the absence of absorption and no layer variation, the transmission coefficient t{sub N} can be well approximated by a sum of Lorentzian resonances. The ratio between their width {Gamma}{sub r} and their separation {Delta}{omega}{sub r} is a crucial parameter to characterize the distortion of the transmitted pulse. For typical values of the parameters used in telecommunications and high index of refraction contrasts n{sub 2}/n{sub 1}, the distortion of the transmitted pulse is unacceptably large for frequencies near the edge of the transmission window. We estimate fractional delays achievables in terms of the central frequency used and the pulse bandwidth.

Barco, O. del; Ortuno, M. [Departamento de Fisica-CIOyN, Universidad de Murcia (Spain)

2010-02-15T23:59:59.000Z

215

Dynamically tunable Fano resonance in periodically asymmetric graphene nanodisk pair  

E-Print Network (OSTI)

We present a dynamically frequency tunable Fano resonance planar device composed of periodically asymmetric graphene nanodisk pair for the mid-infrared region. There are two kinds of modes in this structure, that is, the symmetric mode and the antisymmetric mode. The resonance coupling between the symmetric and antisymmetric modes creates a classical Fano resonance. Both of the Fano resonance amplitude and frequency of the structure can be dynamically controlled by varying the Fermi energy of graphene. Resonance transition in the structure is studied to reveal the physical mechanism behind the dynamically tunable Fano resonance. The features of the Fano resonant graphene nanostructures should have promising applications in tunable THz filters, switches, and modulators.

Zhang, Zhengren; Fan, Yuancheng; Yin, Pengfei; Zhang, Liwei; Shi, Xi

2015-01-01T23:59:59.000Z

216

An Ultra Short -Period Seismograph  

Science Journals Connector (OSTI)

...the passage of a cold front. It hes been...the com- plete weather picture at the time...been in continuous operation at Palisades for...satisfactory unattended operation. It is possible...amplifier. If battery operation is not desired...furnish the plate and heater voltages. The heaters...

Frank Press

217

Compact, flexible, frequency agile parametric wavelength converter  

DOE Patents (OSTI)

This improved Frequency Agile Optical Parametric Oscillator provides near on-axis pumping of a single QPMC with a tilted periodically poled grating to overcome the necessity to find a particular crystal that will permit collinear birefringence in order to obtain a desired tuning range. A tilted grating design and the elongation of the transverse profile of the pump beam in the angle tuning plane of the FA-OPO reduces the rate of change of the overlap between the pumped volume in the crystal and the resonated and non-resonated wave mode volumes as the pump beam angle is changed. A folded mirror set relays the pivot point for beam steering from a beam deflector to the center of the FA-OPO crystal. This reduces the footprint of the device by as much as a factor of two over that obtained when using the refractive telescope design.

Velsko, Stephan P. (Livermore, CA); Yang, Steven T. (Danville, CA)

2002-01-01T23:59:59.000Z

218

Microwave and Radio Frequency Workshop  

Energy.gov (U.S. Department of Energy (DOE))

At the Microwave and Radio Frequency Workshop (held in Long Beach, CA, on July 25, 2012), academic and industry experts discussed the existing and emerging electrotechnologies – such as microwave ...

219

AUTO ID FUTURE - FREQUENCY AGNOSTIC  

E-Print Network (OSTI)

Identification of information is one key to the development of intelligent decision systems of the future. Frequency agnostic automatic identification is only one step in the physical world to make physical objects identify ...

DATTA, SHOUMEN

220

Frequency regulator for synchronous generators  

DOE Patents (OSTI)

The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices.

Karlicek, Robert F. (1920 Camino Centroloma, Fullerton, CA 92633)

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Frequency regulator for synchronous generators  

DOE Patents (OSTI)

The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices. 11 figs.

Karlicek, R.F.

1982-08-10T23:59:59.000Z

222

Planar resonant periodic orbits in Kuiper belt dynamics  

E-Print Network (OSTI)

In the framework of the planar restricted three body problem we study a considerable number of resonances associated to the Kuiper Belt dynamics and located between 30 and 48 a.u. Our study is based on the computation of resonant periodic orbits and their stability. Stable periodic orbits are surrounded by regular librations in phase space and in such domains the capture of trans-Neptunian object is possible. All the periodic orbits found are symmetric and there is evidence for the existence of asymmetric ones only in few cases. In the present work first, second and third order resonances are under consideration. In the planar circular case we found that most of the periodic orbits are stable. The families of periodic orbits are temporarily interrupted by collisions but they continue up to relatively large values of the Jacobi constant and highly eccentric regular motion exists for all cases. In the elliptic problem and for a particular eccentricity value of the primary bodies the periodic orbits are isolated. The corresponding families, where they belong to, bifurcate from specific periodic orbits of the circular problem and seem to continue up to the rectilinear problem. Both stable and unstable orbits are obtained for each case. In the elliptic problem the unstable orbits found are associated with narrow chaotic domains in phase space. The evolution of the orbits, which are located in such chaotic domains, seems to be practically regular and bounded for long time intervals.

George Voyatzis; Thomas Kotoulas

2005-02-28T23:59:59.000Z

223

Laser frequency stabilization to excited state transitions using electromagnetically induced transparency in a cascade system  

SciTech Connect

We demonstrate laser frequency stabilization to excited state transitions using cascade electromagnetically induced transparency. Using a room temperature Rb vapor cell as a reference, we stabilize a first diode laser to the D{sub 2} transition and a second laser to a transition from the intermediate 5P{sub 3/2} state to a highly excited state with principal quantum number n=19-70. A combined laser linewidth of 280{+-}50 kHz over a 100 {mu}s time period is achieved. This method may be applied generally to any cascade system and allows laser stabilization to an atomic reference in the absence of a direct absorption signal.

Abel, R. P.; Mohapatra, A. K.; Bason, M. G.; Pritchard, J. D.; Weatherill, K. J.; Raitzsch, U.; Adams, C. S. [Department of Physics, Durham University, Rochester Building, South Road, Durham DH1 3LE (United Kingdom)

2009-02-16T23:59:59.000Z

224

Frequency response of ice streams  

Science Journals Connector (OSTI)

...downstream strain rate is examined for...sub-decadal periods), penetration distances are tens...example would be penetration of melt to the bed...work on how the rate of melt supply controls...downstream strain rate is examined for...sub-decadal periods), penetration distances are tens...

2012-01-01T23:59:59.000Z

225

High-frequency conductivity of type-I superlattices  

Science Journals Connector (OSTI)

By using a method which employs a kinetic description and linear-response theory, we calculated the conductivity of electron-ion many-layer system (type-I superlattices) in the high-frequency and long-wavelength limits. Here electromagnetic radiation is taken to be a homogeneous, oscillating electric field. Our calculation takes into account all contributions in lowest order of the plasma parameter rs. Expressions for frequency-dependent scattering time and effective mass have been numerically obtained. Asymptotic limits for small and large frequencies are analytically derived.

Narkis Tzoar and Chao Zhang

1985-07-15T23:59:59.000Z

226

Photonic Radio-Frequency Phase Detector based on Radio-Frequency to Intermediate-Frequency Phase Mapping  

Science Journals Connector (OSTI)

A photonic radio-frequency phase detector based on radio-frequency (RF) to intermediate-frequency mapping is demonstrated, and the theoretical principle of the design is explained.

Sun, Dongning; Dong, Yi; Wang, Siwei; Xia, Zongyang; Xie, Weilin; Shi, Hongxiao; Yi, Lilin; Hu, Weisheng

227

STAR Teaching Program Application Period | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

STAR Teaching Program Application Period STAR Teaching Program Application Period STAR Teaching Program Application Period December 28, 2012 2:30PM EST to January 31, 2013 5:30PM EST Cal Poly The Science Teacher and Researcher (STAR) Researcher program, a collaborative project of California State University, provides pre-service and early career science teachers with eight week long paid mentor and research opportunities at a national research center. Applicants must have the following: A demonstrated interest in becoming a science or mathematics teacher at the secondary level (grades 6-12) Either a California State University (CSU) student OR NSF Noyce Scholar in the United States OR a STAR Alum with two or fewer years of participation AND two or fewer years of teaching experience (first time participants must be pre-service teachers, i.e., not yet teaching full-time

228

ASSOCIATING LONG-TERM {gamma}-RAY VARIABILITY WITH THE SUPERORBITAL PERIOD OF LS I +61 Degree-Sign 303  

SciTech Connect

Gamma-ray binaries are stellar systems for which the spectral energy distribution (discounting the thermal stellar emission) peaks at high energies. Detected from radio to TeV gamma rays, the {gamma}-ray binary LS I +61 Degree-Sign 303 is highly variable across all frequencies. One aspect of this system's variability is the modulation of its emission with the timescale set by the {approx}26.4960 day orbital period. Here we show that, during the time of our observations, the {gamma}-ray emission of LS I +61 Degree-Sign 303 also presents a sinusoidal variability consistent with the previously known superorbital period of 1667 days. This modulation is more prominently seen at orbital phases around apastron, whereas it does not introduce a visible change close to periastron. It is also found in the appearance and disappearance of variability at the orbital period in the power spectrum of the data. This behavior could be explained by a quasi-cyclical evolution of the equatorial outflow of the Be companion star, whose features influence the conditions for generating gamma rays. These findings open the possibility to use {gamma}-ray observations to study the outflows of massive stars in eccentric binary systems.

Ackermann, M.; Buehler, R. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Ajello, M. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Ballet, J.; Casandjian, J. M. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D.; Buson, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bonamente, E.; Cecchi, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brandt, T. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Brigida, M. [Dipartimento di Fisica ''M. Merlin'' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Caliandro, G. A. [Institute of Space Sciences (IEEE-CSIC), Campus UAB, E-08193 Barcelona (Spain); Cameron, R. A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Caraveo, P. A. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, I-20133 Milano (Italy); Cavazzuti, E. [Agenzia Spaziale Italiana (ASI) Science Data Center, I-00044 Frascati (Roma) (Italy); Chekhtman, A., E-mail: andrea.caliandro@ieec.uab.es, E-mail: hadasch@ieec.uab.es, E-mail: dtorres@ieec.uab.es [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); and others

2013-08-20T23:59:59.000Z

229

Polariton dispersion of periodic quantum well structures  

Science Journals Connector (OSTI)

We studied the polariton dispersion relations of a periodic quantum-well structure with a period in the vicinity of half the exciton resonance wavelength, i.e., the Bragg structure. We classified polariton mod...

A. V. Mintsev; L. V. Butov; C. Ell; S. Mosor…

2002-11-01T23:59:59.000Z

230

ARM - Field Campaign - 2001 Multi-Frequency Radar IOP  

NLE Websites -- All DOE Office Websites (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

231

Variable frequency microwave heating apparatus  

DOE Patents (OSTI)

A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN); Johnson, Arvid C. (Lake in the Hills, IL); Thigpen, Larry T. (Angier, NC)

1999-01-01T23:59:59.000Z

232

Periodic temperature-associated drought/flood drives locust plagues in China  

Science Journals Connector (OSTI)

...a multiple-variable-linked hypothesis...between every two variables. Using the same...other at both frequency and time spaces...components that drive locust dynamics...drought/flood drives locust plagues...effects of low-frequency climate variations...the different variables at different...

2009-01-01T23:59:59.000Z

233

High-frequency resonances in photorefractive crystals  

Science Journals Connector (OSTI)

Two-wave mixing in photorefractive materials is investigated for the case of applied dc electric fields and large detuning frequencies and for high-frequency alternating electric...

Grunnet-Jepsen, A; Aubrecht, I; Solymar, L

1995-01-01T23:59:59.000Z

234

Sum Frequency Generation for Surface Vibrational Spectroscopy...  

NLE Websites -- All DOE Office Websites (Extended Search)

Sum Frequency Generation for Surface Vibrational Spectroscopy Sum Frequency Generation for Surface Vibrational Spectroscopy This customized SFG-VS spectrometer incorporates unique...

235

Intelligent Radio Frequency (RF) Monitoring  

E-Print Network (OSTI)

? Intelligent Radio Frequency (RF) Monitoring ? 2009 Armstrong International, Inc. www.armstronginternational.com 2 ?Expect many enjoyable experiences!? David M. Armstrong Present Process Challenges ? Identifying a failure ? Procedure.... Armstrong Steam Trap Challenges ? Identifying a failure ? Manpower ? Location ? Magnitude of failure ? Energy loss ? Loss of heat transfer ? Justification for repair ? ?Speed of Implementation? ? Environmental concerns Manpower Location 4...

Kimbrough, B.

236

Quantum Revivals in Periodically Driven Systems close to nonlinear resonance  

E-Print Network (OSTI)

We calculate the quantum revival time for a wave-packet initially well localized in a one-dimensional potential in the presence of an external periodic modulating field. The dependence of the revival time on various parameters of the driven system is shown analytically. As an example of application of our approach, we compare the analytically obtained values of the revival time for various modulation strengths with the numerically computed ones in the case of a driven gravitational cavity. We show that they are in very good agreement.

Farhan Saif; Mauro Fortunato

2006-02-28T23:59:59.000Z

237

Dynamic frequency tuning of electric and magnetic metamaterial response  

DOE Patents (OSTI)

A geometrically modifiable resonator is comprised of a resonator disposed on a substrate, and a means for geometrically modifying the resonator. The geometrically modifiable resonator can achieve active optical and/or electronic control of the frequency response in metamaterials and/or frequency selective surfaces, potentially with sub-picosecond response times. Additionally, the methods taught here can be applied to discrete geometrically modifiable circuit components such as inductors and capacitors. Principally, controlled conductivity regions, using either reversible photodoping or voltage induced depletion activation, are used to modify the geometries of circuit components, thus allowing frequency tuning of resonators without otherwise affecting the bulk substrate electrical properties. The concept is valid over any frequency range in which metamaterials are designed to operate.

O'Hara, John F; Averitt, Richard; Padilla, Willie; Chen, Hou-Tong

2014-09-16T23:59:59.000Z

238

The US treasury market in August 1998: untangling the effects of Hong Kong and Russia with high frequency data  

E-Print Network (OSTI)

, Russia announced its default on sovereign bonds. This paper demonstrates that the HKMA interventions had a substantial impact on the outcomes for US Treasury markets during this period. Using a careful analysis of high frequency bond market data, both...

Dungey, Mardi; Goodheart, Charles; Tambakis, Demosthenes N

239

SES Probationary Period | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

SES Probationary Period SES Probationary Period SES Probationary Period An individual's initial appointment as an SES career appointee becomes final only after the individual has served a 1-year probationary period as a career appointee. That employee's rating official must perform an assessment of the new SES's performance during the probationary period. After the one year the selecting official must certify that the appointee performed at the level of excellence expected of a senior executive during the probationary period. When a career appointee's executive qualification have been certified by a Qualifications Review Board on the basis of special or unique qualities, as described in Sec. 317.502(c), the probationary assessment must address any executive development activities the agency identified in support of the

240

Periodic wave solutions of the Boussinesq equation  

Science Journals Connector (OSTI)

The Boussinesq equation usually arises in a physical problem as a long wave equation. The present work extends the search of periodic wave solutions for it. The Hirota bilinear method and Riemann theta function are employed in the process. We also analyse the asymptotic property of periodic waves in detail. Furthermore, it is of interest to note that well-known soliton solutions can be reduced from the periodic wave solutions.

Yi Zhang; Ling-ya Ye; Yi-neng Lv; Hai-qiong Zhao

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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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241

Variable frequency microwave furnace system  

DOE Patents (OSTI)

A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN)

1994-01-01T23:59:59.000Z

242

Variable frequency microwave furnace system  

DOE Patents (OSTI)

A variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity for testing or other selected applications. The variable frequency microwave furnace system includes a microwave signal generator or microwave voltage-controlled oscillator for generating a low-power microwave signal for input to the microwave furnace. A first amplifier may be provided to amplify the magnitude of the signal output from the microwave signal generator or the microwave voltage-controlled oscillator. A second amplifier is provided for processing the signal output by the first amplifier. The second amplifier outputs the microwave signal input to the furnace cavity. In the preferred embodiment, the second amplifier is a traveling-wave tube (TWT). A power supply is provided for operation of the second amplifier. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load. 5 figs.

Bible, D.W.; Lauf, R.J.

1994-06-14T23:59:59.000Z

243

Effects of radio frequency bias frequency and radio frequency bias pulsing on SiO{sub 2} feature etching in inductively coupled fluorocarbon plasmas  

SciTech Connect

The effect of radio frequency (rf) bias frequency on SiO{sub 2} feature etching using inductively coupled fluorocarbon plasmas is investigated. It is found that the rf bias frequency can have an important effect on SiO{sub 2} feature etch rate, microtrenching phenomena, and SiO{sub 2}-to-photoresist etch selectivity. In addition, the effect of rf bias pulsing on inductively coupled fluorocarbon plasma SiO{sub 2} etching has been studied and a model that describes the data well is presented. The model assumes that fluorocarbon deposition occurs while the rf bias is off, fluorocarbon etching occurs during the first part of time that the bias is on, and substrate etching occurs once the fluorocarbon material has been removed from the substrate. (c) 2000 American Vacuum Society.

Schaepkens, M. [Physics Department, University at Albany, Albany, New York 12222 (United States)] [Physics Department, University at Albany, Albany, New York 12222 (United States); Oehrlein, G. S. [Physics Department, University at Albany, Albany, New York 12222 (United States)] [Physics Department, University at Albany, Albany, New York 12222 (United States); Cook, J. M. [Lam Research Corporation, Fremont, California 94538-6470 (United States)] [Lam Research Corporation, Fremont, California 94538-6470 (United States)

2000-03-01T23:59:59.000Z

244

Saving Energy with Architectural and Frequency Adaptations for Multimedia Applications  

E-Print Network (OSTI)

Saving Energy with Architectural and Frequency Adaptations for Multimedia Applications will benefit DVS. Our adaptation control algorithm is effective in saving energy and exploits most. The existence of this idle time, called slack, implies that the processor can be slowed to save energy

Adve, Sarita

245

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

246

Transit time instabilities in an inverted fireball. II. Mode jumping and nonlinearities  

SciTech Connect

A fireball is formed inside a highly transparent spherical grid immersed in a dc discharge plasma. The ambient plasma acts as a cathode and the positively biased grid as an anode. A strong nearly current-free double layer separates the two plasmas. Electrons are accelerated into the fireball, ionize, and establish a discharge plasma with plasma potential near the grid potential. Ions are ejected from the fireball. Since electrons are lost at the same rate as ions, most electrons accelerated into the fireball just pass through it. Thus, the electron distribution contains radially counterstreaming electrons. High-frequency oscillations are excited with rf period given by the electron transit time through the fireball. Since the frequency is well below the electron plasma frequency, no eigenmodes other than a beam space-charge wave exists. The instability is an inertial transit-time instability similar to the sheath-plasma instability or the reflex vircator instability. In contrast to vircators, there is no electron reflection from a space-charge layer but counterstreaming arises from spherical convergence and divergence of electrons. While the basic instability properties have been presented in a companion paper [R. L. Stenzel et al., Phys. Plasmas 18, 012104 (2011)], the present paper focuses on observed mode jumping and nonlinear effects. The former produce frequency jumps and different potential profiles, the latter produce harmonics associated with electron bunching at large amplitudes. In situ probe measurements are presented and interpreted.

Stenzel, R. L. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States); Gruenwald, J.; Fonda, B.; Ionita, C.; Schrittwieser, R. [Institute for Ion Physics and Applied Physics, Leopold-Franzens University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria)

2011-01-15T23:59:59.000Z

247

A double-frequency dwarf nova oscillation  

E-Print Network (OSTI)

We have detected coherent oscillations (``dwarf nova oscillations'') in Hubble Space Telescope spectra of the dwarf nova OY Car. The oscillations were seen towards the end of a superoutburst of OY Car. The oscillations are extraordinary compared to the many other examples in the literature for two reasons. First, their amplitude is large, with a peak-to-peak variation of 8 to 20% of the total flux over the range 1100 to 2500A. However, most remarkably we find that there are two components present simultaneously. Both have periods close to 18sec (equivalent to 4800 cycles/day) but they are separated by 57.7+/-0.5 cycles/day. The lower frequency component of the pair has a strong second harmonic while its companion, which has about twice its amplitude, does not. The oscillation spectra appear hotter than the mean spectrum and approximately follow the continuum distribution of a black-body with a temperature in the range 30,000 to 50,000K. We tentatively suggest that the weaker non-sinusoidal component could represent the rotation of the white dwarf, although we have been unable to recover any such signal in quiescent data.

T. R. Marsh; Keith Horne

1998-06-02T23:59:59.000Z

248

Frequency stabilization of an InGaAsP distributed feedback laser to an NH/sub 3/ absorption line at 15137 A with an external frequency modulator  

SciTech Connect

The oscillation frequency of a 1.5-..mu..m InGaAsP distributed feedback laser is stabilized to an NH/sub 3/ linear absorption line at 15137 A. A LiNbO/sub 3/ external frequency modulator is used instead of direct frequency modulation of the laser to extract error signals. An effective bandwidth of 100 kHz for the feedback loop is obtained through this external modulation scheme. Frequency stability of sigma(2,tau) = 4 x 10/sup -11/ is achieved for an averaging time of 1 s< or =tau< or =100 s.

Yanagawa, T.; Saito, S.; Machida, S.; Yamamoto, Y.; Noguchi, Y.

1985-11-15T23:59:59.000Z

249

Unidirectional Invisibility Induced by PT-Symmetric Periodic Structures  

SciTech Connect

Parity-time (PT) symmetric periodic structures, near the spontaneous PT-symmetry breaking point, can act as unidirectional invisible media. In this regime, the reflection from one end is diminished while it is enhanced from the other. Furthermore, the transmission coefficient and phase are indistinguishable from those expected in the absence of a grating. The phenomenon is robust even in the presence of Kerr nonlinearities, and it can also effectively suppress optical bistabilities.

Lin Zin; Ramezani, Hamidreza; Kottos, Tsampikos [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States); Eichelkraut, Toni; Christodoulides, Demetrios N. [College of Optics and Photonics-CREOL, University of Central Florida, Orlando, Florida 32816 (United States); Cao Hui [Department of Applied Physics, Yale University, New Haven, Connecticut 06520 (United States)

2011-05-27T23:59:59.000Z

250

Architecture, implementation and parallelization of the software to search for periodic gravitational wave signals  

E-Print Network (OSTI)

The parallelization, design and scalability of the \\sky code to search for periodic gravitational waves from rotating neutron stars is discussed. The code is based on an efficient implementation of the F-statistic using the Fast Fourier Transform algorithm. To perform an analysis of data from the advanced LIGO and Virgo gravitational wave detectors' network, which will start operating in 2015, hundreds of millions of CPU hours will be required - the code utilizing the potential of massively parallel supercomputers is therefore mandatory. We have parallelized the code using the Message Passing Interface standard, implemented a mechanism for combining the searches at different sky-positions and frequency bands into one extremely scalable program. The parallel I/O interface is used to escape bottlenecks, when writing the generated data into file system. This allowed to develop a highly scalable computation code, which would enable the data analysis at large scales on acceptable time scales. Benchmarking of the code on a Cray XE6 system was performed to show efficiency of our parallelization concept and to demonstrate scaling up to 50 thousand cores in parallel.

Gevorg Poghosyan; Sanchit Matta; Achim Streit; Micha? Bejger; Andrzej Królak

2014-10-14T23:59:59.000Z

251

Sound Waves in the Atmosphere at Infrasonic Frequencies  

Science Journals Connector (OSTI)

Various geophysical processes generate sound waves in the atmosphere. Some typical sources are auroral discharges in the upper atmosphere tornadoes and severe storms surface waves on the oceans volcanic explosions earthquakes and atmospheric oscillations arising from unstable wind flow at the tropopause. Man?made sources include powerful explosions and the shock waves from vehicles moving at supersonic speeds at altitudes below about 125 km. The components of sound?wave energy at infrasonic frequencies (oscillation periods >1.0 sec) are propagated for large distances (thousands of kilometers) over the earth's surface with very little loss of energy from absorption by viscosity and heat conduction. But the propagation depends strongly on (a) the horizontally stratified temperature structure of the atmosphere (b) the influence of gravity at oscillation periods greater than the atmospheric resonance period ?300 sec and (c) the nonuniform distribution of atmospheric winds. The microphones and electroacoustical apparatus at an infrasonics observation station e.g. the one at Washington D. C. measure (1) the amplitude and waveform of incident sound pressure (2) the direction of local propagation of the wave (3) the horizontal trace velocity and (4) the distribution of sound wave energy at various oscillation frequencies. Researches on propagation require observational data from a network of stations separated geographically by large distances coupled with theoretical analysis of sound propagation to arrive at useful results on the acoustics of the atmosphere.

Richard K. Cook

1972-01-01T23:59:59.000Z

252

Pressure-induced OH frequency downshift in brucite: frequency-distance and frequency-field correlations  

Science Journals Connector (OSTI)

The ordered Mg(OH)2 crystal structure has been optimized for different pressures in the pressure range 0-21 GPa, within the trigonal P m1 space group. Anharmonic frequencies for the Raman-active OH vibrational mode were calculated from potential energy curves obtained by B3LYP and PW91 calculations with the CRYSTAL06 program. We find that an external pressure leads to an OH frequency downshift, in agreement with experiment, but there are no hydrogen bonds involved. The frequency downshift depends linearly on the electric field exerted on the OH ions from its neighbours in the 'opposite' layer. In agreement with experiment we also find that the pressure-induced 'v(OH) vs. interlayer R(O - - - O)' curve deviates from the well established correlation curves for hydrogen-bonded systems in the literature; the ?v/?R slope for high pressure conditions is much smaller. We also point out the merits of reporting both v(OH) and ?vgas-to-solid for comparison with experiment.

K Hermansson; G Gajewski; P D Mitev

2008-01-01T23:59:59.000Z

253

Complexity of hierarchically and 1-dimensional periodically specified problems  

SciTech Connect

We study the complexity of various combinatorial and satisfiability problems when instances are specified using one of the following specifications: (1) the 1-dimensional finite periodic narrow specifications of Wanke and Ford et al. (2) the 1-dimensional finite periodic narrow specifications with explicit boundary conditions of Gale (3) the 2-way infinite1-dimensional narrow periodic specifications of Orlin et al. and (4) the hierarchical specifications of Lengauer et al. we obtain three general types of results. First, we prove that there is a polynomial time algorithm that given a 1-FPN- or 1-FPN(BC)specification of a graph (or a C N F formula) constructs a level-restricted L-specification of an isomorphic graph (or formula). This theorem along with the hardness results proved here provides alternative and unified proofs of many hardness results proved in the past either by Lengauer and Wagner or by Orlin. Second, we study the complexity of generalized CNF satisfiability problems of Schaefer. Assuming P {ne} PSPACE, we characterize completely the polynomial time solvability of these problems, when instances are specified as in (1), (2),(3) or (4). As applications of our first two types of results, we obtain a number of new PSPACE-hardness and polynomial time algorithms for problems specified as in (1), (2), (3) or(4). Many of our results also hold for O(log N) bandwidth bounded planar instances.

Marathe, M.V.; Hunt, H.B. III; Stearns, R.E.; Radhakrishnan, V.

1995-08-23T23:59:59.000Z

254

Variable-Period Undulators for Synchrotron Radiation  

SciTech Connect

A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

2005-02-22T23:59:59.000Z

255

Occupational and residential 60-Hz electromagnetic fields and high-frequency electric transients: exposure assessment using a new dosimeter  

SciTech Connect

One problem that has limited past epidemiologic studies of cancer and exposure to extremely low-frequency (0-100 Hz) electric and magnetic fields has been the lack of adequate methods for assessing personal exposure to these fields. A new 60-Hz electromagnetic field dosimeter was tested to assess occupational and residential exposures of a group of electrical utility workers and a comparison background group over a 7-day period. Comparing work periods only, utility workers' exposures were significantly higher than background levels by a factor of about 10 for electric (E) and magnetic (B) fields and by a factor of 171 for high-frequency transient electric (HFTE) fields. When overall weekly time-weighted averages combining work and nonwork exposures were compared, ratios of the exposed to background groups were lower. B and HFTE exposure ratios remained statistically significant, with values of 3.5 and 58, respectively, whereas the electric field exposure ratio was no longer significant, with a value of 1.7. E-field exposures of the background group were the highest during the nonwork period, probably reflecting the use of electrical appliances at home. Residential E- and B-field exposures were in the same range as published results from other surveys, whereas occupational E-field exposures tended to be lower than exposures reported in other studies. The high variability associated with occupational exposures probably accounts for the latter discrepancy. Worker acceptance of wearing the dosimeter was good: 95% of participants found it to be of little or no inconvenience while at work. At home, 37% found the device to be inconvenient in its present form but would not object to wearing a slightly smaller and lighter dosimeter.

Deadman, J.E.; Camus, M.; Armstrong, B.G.; Heroux, P.; Cyr, D.; Plante, M.; Theriault, G.

1988-08-01T23:59:59.000Z

256

Public Comment Period Re-Opened for the Uranium Leasing Program PEIS |  

NLE Websites -- All DOE Office Websites (Extended Search)

Public Comment Period Re-Opened for the Uranium Leasing Program Public Comment Period Re-Opened for the Uranium Leasing Program PEIS Public Comment Period Re-Opened for the Uranium Leasing Program PEIS May 28, 2013 - 5:37pm Addthis Public Comment Period Re-Opened for the Uranium Leasing Program PEIS The U.S. Department of Energy is re-opening the public comment period for the Draft Uranium Leasing Program Programmatic Environmental Impact Statement (Draft ULP PEIS, DOE/EIS-0472D). DOE made the Draft ULP PEIS available for public comment on March 15, 2013 (78 FR 16500). The public comment period for the Draft ULP PEIS originally was to end on May 16, 2013, and an extension to May 31, 2013 was announced on April 23, 2013 (78 FR 23926). In response to a public request for additional review time, DOE re-opens the public comment period, which will now close on July 1,

257

Non-Abelian Geometric Phase, Floquet Theory, and Periodic Dynamical Invariants  

E-Print Network (OSTI)

For a periodic Hamiltonian, periodic dynamical invariants may be used to obtain non-degenerate cyclic states. This observation is generalized to the degenerate cyclic states, and the relation between the periodic dynamical invariants and the Floquet decompositions of the time-evolution operator is elucidated. In particular, a necessary condition for the occurrence of cyclic non-adiabatic non-Abelian geometrical phase is derived. Degenerate cyclic states are obtained for a magnetic dipole interacting with a precessing magnetic field.

Ali Mostafazadeh

1998-10-22T23:59:59.000Z

258

Non-Abelian Geometric Phase, Floquet Theory, and Periodic Dynamical Invariants  

E-Print Network (OSTI)

For a periodic Hamiltonian, periodic dynamical invariants may be used to obtain non-degenerate cyclic states. This observation is generalized to the degenerate cyclic states, and the relation between the periodic dynamical invariants and the Floquet decompositions of the time-evolution operator is elucidated. In particular, a necessary condition for the occurrence of cyclic non-adiabatic non-Abelian geometrical phase is derived. Degenerate cyclic states are obtained for a magnetic dipole interacting with a precessing magnetic field.

Mostafazadeh, A

1998-01-01T23:59:59.000Z

259

Sample Observations from the 2001.Multi-Frequency Radar IOP  

NLE Websites -- All DOE Office Websites (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

260

Watching an uniformly moving source of light using a telescope and a frequency-meter  

E-Print Network (OSTI)

We propose a scenario that involves a stationary observer who detects a point like source of light moving with constant velocity at a constant altitude, using a telescope and a frequency-meter. We derive a formula for the angular velocity at which we should rotate the axis of the telescope and a formula that relates the proper period at which the source emits successive wave crests and the proper period at which the stationary observer receives them

Bernhard Rothenstein; Ioan Damian

2005-04-04T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Frequency Synthesis in Wireless and Wireline Systems  

E-Print Network (OSTI)

First, a frequency synthesizer for IEEE 802.15.4 / ZigBee transceiver applications that employs dynamic True Single Phase Clocking (TSPC) circuits in its frequency dividers is presented and through the analysis and measurement results...

Turker, Didem 1981-

2010-12-06T23:59:59.000Z

262

Frequency domain design of interval controller  

E-Print Network (OSTI)

significant role in the analysis and design of interval systems. Its external properties are also discussed. The image set approach & frequency domain criteria can be used to calculate the IP stability margin. The frequency domain criteria are used...

Park, Wunyong

1993-01-01T23:59:59.000Z

263

PARS II Process Document – DOE Period Close  

Energy.gov (U.S. Department of Energy (DOE))

This document details the process adopted by the Office of Acquisition and Project Management to prepare APM DepSec Monthly Status Report, finalize DOE close period package, and perform reporting...

264

EIS-0504: Notice of Extension of Scoping Period | Department...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Extension of Scoping Period EIS-0504: Notice of Extension of Scoping Period Gulf LNG Liquefaction Project, Jackson County, Mississippi FERC extended the scoping period to September...

265

QUASI-PERIODIC WIGGLES OF MICROWAVE ZEBRA STRUCTURES IN A SOLAR FLARE  

SciTech Connect

Quasi-periodic wiggles of microwave zebra pattern (ZP) structures with periods ranging from about 0.5 s to 1.5 s are found in an X-class solar flare on 2006 December 13 at the 2.6-3.8 GHz with the Chinese Solar Broadband Radio Spectrometer (SBRS/Huairou). Periodogram and correlation analysis show that the wiggles have two to three significant periodicities and are almost in phase between stripes at different frequencies. The Alfvén speed estimated from the ZP structures is about 700 km s{sup –1}. We find the spatial size of the wave-guiding plasma structure to be about 1 Mm with a detected period of about 1 s. This suggests that the ZP wiggles can be associated with the fast magnetoacoustic oscillations in the flaring active region. The lack of a significant phase shift between wiggles of different stripes suggests that the ZP wiggles are caused by a standing sausage oscillation.

Yu, Sijie; Tan, Baolin; Yan, Yihua [Key Laboratory of Solar Activity, National Astronomical Observatories Chinese Academy of Sciences, Beijing 100012 (China); Nakariakov, V. M.; Selzer, L. A., E-mail: sjyu@nao.cas.cn [Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom)

2013-11-10T23:59:59.000Z

266

Lengthening the Storage Period of Cucumbers.  

E-Print Network (OSTI)

TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS BULLETIN NO. 576 AUGUST 1939 DIVISION OF RURAL HOME RESEARCH AND DIVISION OF HORTICULTURE 1NGTHENING THE STORAGE PERIOD OF CUCUMBERS..., in common storage. Consid- ering only loss of weight the period of common storage was increased from 1 to 7 weeks. When other factors such as palatability are taken into account, M. T. Cellophane wrapped cucumbers remained in good condition only about 10...

Hawthorn, L. R. (Leslie Rushton); Whitacre, Jessie (Jessie Opal); Yarnell, S. H. (Sidney Howe)

1939-01-01T23:59:59.000Z

267

ENOC 2014, July 6-11, 2014, Vienna, Austria Periodic motions of coupled impact oscillators  

E-Print Network (OSTI)

the latter case concerns thin oscillating mechanical structures (a string under tension or a clamped beamENOC 2014, July 6-11, 2014, Vienna, Austria Periodic motions of coupled impact oscillators Vincent. Summary. We study existence of time-periodic oscillations in a chain of coupled impact oscillators

268

METHODS OF RADIO-FREQUENCY CURRENT DRIVE  

E-Print Network (OSTI)

METHODS OF RADIO-FREQUENCY CURRENT DRIVE N. J. FISCH* Princeton Plasma Physics Laboratory-670 Radio-frequency waves can penetrate thermonuclear plasmas, depositing momentum and energy with great. INTRODUCTION Using radio-frequency (rf) waves to drive the toroidal current in tokamak reactors is attractive

269

Heterodyne laser instantaneous frequency measurement system  

DOE Patents (OSTI)

A heterodyne laser instantaneous frequency measurement system is disclosed. The system utilizes heterodyning of a pulsed laser beam with a continuous wave laser beam to form a beat signal. The beat signal is processed by a controller or computer which determines both the average frequency of the laser pulse and any changes or chirp of th frequency during the pulse.

Wyeth, Richard W. (Livermore, CA); Johnson, Michael A. (Pleasanton, CA); Globig, Michael A. (Livermore, CA)

1989-01-01T23:59:59.000Z

270

Frequency–dependent numerical dynamics in mosquitofish  

Science Journals Connector (OSTI)

...can invade, but not drive the others extinct...equilibrium of genotype frequencies and total numbers...replication in the low-frequency treatment because the...treatment to be more variable. Mesocosms were established...from throw-trap data Frequency-dependent numerical...

2002-01-01T23:59:59.000Z

271

High resolution time interval meter  

DOE Patents (OSTI)

Method and apparatus are provided for measuring the time interval between two events to a higher resolution than reliability available from conventional circuits and component. An internal clock pulse is provided at a frequency compatible with conventional component operating frequencies for reliable operation. Lumped constant delay circuits are provided for generating outputs at delay intervals corresponding to the desired high resolution. An initiation START pulse is input to generate first high resolution data. A termination STOP pulse is input to generate second high resolution data. Internal counters count at the low frequency internal clock pulse rate between the START and STOP pulses. The first and second high resolution data are logically combined to directly provide high resolution data to one counter and correct the count in the low resolution counter to obtain a high resolution time interval measurement.

Martin, A.D.

1986-05-09T23:59:59.000Z

272

3 GHz Yb-fiber laser based femtosecond sources and frequency comb  

E-Print Network (OSTI)

Many applications require femtosecond lasers of high repetition rate. In the time domain, a higher repetition rate means more pulses in a fixed time period. For nonlinear bio-optical imaging in which photo-induced damage ...

Chen, Hung-Wen, Ph. D. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

273

Real-Time Measurement of Material Elastic Properties in a High Gamma Irradiation Environment  

SciTech Connect

This paper describes the first noncontact elastic vibration measurements of an object in a high gamma radiation field. Using a laser-coupled resonant ultrasound technique, the vibration modes of an Inconel hollow capped cylinder were measured as the gamma radiation field was increased to 104 Gy/h. This measurement technique allowed shifts in the resonant frequency of the sample’s vibration modes to be tracked over a 170-h period. The vibration mode frequencies changed in a manner consistent with the temperature dependence of the elastic stiffness coefficients of the material. These results demonstrate the efficacy of the laser approach for real-time resonant ultrasound measurements in this severely hostile nuclear environment.

Ken Telschow; Rob Schley; Dave Cottle

2006-05-01T23:59:59.000Z

274

Real-Time Measurement of Material Elastic Properties in a High Gamma Irradiation Environment  

SciTech Connect

This paper describes the first noncontact elastic vibration measurements of an object in a high gamma radiation field. Using a laser-coupled resonant ultrasound technique, the vibration modes of an Inconel hollow capped cylinder were measured as the gamma radiation field was increased to 104 Gy/h. This measurement technique allowed shifts in the resonant frequency of the sample's vibration modes to be tracked over a 170 h period. The vibration mode frequencies changed in a manner consistent with the temperature dependence of the elastic stiffness coefficients of the material. These results demonstrate the efficacy of the laser approach for real-time resonant ultrasound measurements in this severely hostile nuclear environment.

Robert S. Schley; Kenneth L. Telschow; John B. Walter; David L. Cottle

2007-08-01T23:59:59.000Z

275

Theoretical modeling and analysis of mechanical impact driven and frequency up-converted piezoelectric energy harvester for low-frequency and wide-bandwidth operation  

Science Journals Connector (OSTI)

Abstract Vibration energy harvesters are capable of generating significant amount of power at higher frequencies rather than generating at low frequencies. Moreover, as low frequency vibrations (1–30 Hz) around the ambient environment are discursive in nature, resonance based power generators are limited to use within this low frequency range. In this paper, a mechanical impact driven and frequency up-converted wide-bandwidth piezoelectric vibration energy harvester has been proposed and demonstrated theoretically and experimentally. It converts low frequency environmental vibrations into high frequency vibration by mechanical impact. A low frequency flexible driving beam with horizontally extended tip mass, upon excitation, hits two high frequency rigid piezoelectric generating beams at the same time causing a change in the driving beam's effective stiffness that allows the device to offer approximately 180% increased ?3 dB bandwidth and more than 62% of the maximum power generation within the remaining operating frequency range as well. The overall bandwidth is 7.5 Hz within 7–14.5 Hz frequency range generating a minimum peak power of 233 ?W. A maximum of 378 ?W peak power from one generating beam is achieved under 6 ms?2 acceleration at the resonant frequency of 14.5 Hz. Output of both generating beams connected in series produces 734 ?W peak power under the same operating condition with the corresponding power density 38.8 ?W cm?3. The experimental results show some discrepancy with the theoretical results due to mechanical loss during impact and the process variations in the beam formation and assembling. The theoretical and experimental results reveal that the proposed configuration has the potential of powering small portable, handheld wireless smart devices from low frequency, specially human motion related vibrations.

Miah A. Halim; Jae Y. Park

2014-01-01T23:59:59.000Z

276

Multi-period design of heat exchanger networks  

Science Journals Connector (OSTI)

Heat exchanger networks are an integral part of chemical processes as they recover available heat and reduce utility consumption, thereby improving the overall economics of an industrial plant. This paper focuses on heat exchanger network design for multi-period operation wherein the operating conditions of a process may vary with time. A typical example is the hydrotreating process in petroleum refineries where the operators increase reactor temperature to compensate for catalyst deactivation. Superstructure based multi-period models for heat exchanger network design have been proposed previously employing deterministic optimisation algorithms, e.g. (Aaltola, 2002; Verheyen and Zhang, 2006). Stochastic optimisation algorithms have also been applied for the design of flexible heat exchanger networks recently (Ma et al., 2007, 2008). The present work develops an optimisation approach using simulated annealing for design of heat exchanger networks for multi-period operation. A comparison of the new optimisation approach with previous deterministic optimisation based design approaches is presented to illustrate the utilisation of simulated annealing in design of optimal heat exchanger network configurations for multi-period operation.

Muhammad Imran Ahmad; Nan Zhang; Megan Jobson; Lu Chen

2012-01-01T23:59:59.000Z

277

"Magic" radio-frequency dressing for trapped atomic microwave clocks  

E-Print Network (OSTI)

It has been proposed to use magnetically trapped atomic ensembles to enhance the interrogation time in microwave clocks. To mitigate the perturbing effects of the magnetic trap, "near-magic field" configurations are employed, where the involved clock transition becomes independent of the atoms potential energy to first order. Still, higher order effects are a dominating source for dephasing, limiting the perfomance of this approach. Here we propose a simple method to cancel the energy dependence to both, first and second order, using weak radio-frequency dressing. We give values for dressing frequencies, amplitudes, and trapping fields for 87Rb atoms and investigate quantitatively the robustness of these "second-order magic" conditions to variations of the system parameters. We conclude that radio-frequency dressing can suppress field-induced dephasing by at least one order of magnitude for typical experimental parameters.

Kazakov, Georgy A

2014-01-01T23:59:59.000Z

278

Visualization and Classification of Power System Frequency Data Streams  

SciTech Connect

Two challenges in the realization of the smart grid technology are the ability to visualize the deluge of expected data streams for global situational awareness and the ability to detect disruptive and classify events from spatially-distributed high-speed power system frequency measurements while minimizing false alarms and eliminating missed detection. This paper presents an interactive visualization model for high speed power system frequency data streams that presents both local and global views of the data streams for decision making process. It also presents a K-Median for clustering and identifying disruptive events in spatially-distributed data streams. The results from experimental evaluation on a variety of datasets show that K-Median achieve better performance and empowers analysts with the ability to make sense of a deluge of frequency measurements in a real-time situation.

Bank, Jason N [ORNL; Omitaomu, Olufemi A [ORNL; Fernandez, Steven J [ORNL; Liu, Yilu [ORNL

2009-01-01T23:59:59.000Z

279

Rate of DNA replication in the DNA synthetic period of the barley chromosomes  

Science Journals Connector (OSTI)

The rate of DNA replication, as judged by H3-thymidine incorporation, at the specific time of the S-period in chromosomes of barley (Hakata No. 2) is studied by means of autoradiography.

Akio Kusanagi

280

Long-Term Cycles in the History of Life: Periodic Biodiversity in the Paleobiology Database  

E-Print Network (OSTI)

Time series analysis of fossil biodiversity of marine invertebrates in the Paleobiology Database (PBDB) shows a significant periodicity at approximately 63 My, in agreement with previous analyses based on the Sepkoski database. I discuss how...

Melott, Adrian L.

2008-12-24T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Automatic tuning of continuous-time filters  

E-Print Network (OSTI)

Integrated high-Q continuous-time filters require adaptive tuning circuits that will correct the filter parameters such as center frequency and quality factor (Q). Three different automatic tuning techniques are introduced. In all of the proposed...

Sumesaglam, Taner

2004-11-15T23:59:59.000Z

282

Real time cosmology - A direct measure of the expansion rate of the Universe  

E-Print Network (OSTI)

In recent years cosmology has undergone a revolution, with precise measurements of the microwave background radiation, large galaxy redshift surveys, and the discovery of the recent accelerated expansion of the Universe using observations of distant supernovae. In this light, the SKA enables us to do an ultimate test in cosmology by measuring the expansion rate of the Universe in real time. This can be done by a rather simple experiment of observing the neutral hydrogen (HI) signal of galaxies at two different epochs. The signal will encounter a change in frequency imprinted as the Universe expands over time and thus monitoring the drift in frequencies will provide a real time measure of the cosmic acceleration. Over a period of 12 years one would expected a frequency shift of the order of 0.1 Hz assuming a standard Lambda-CDM cosmology. Based on the sensitivity estimates of the SKA and the number counts of the expected HI galaxies, it is shown that the number counts are sufficiently high to compensate for th...

Klöckner, H -R; Martins, C; Raccanelli, A; Champion, D; Roy, A; Lobanov, A; Wagner, J; Keller, R

2015-01-01T23:59:59.000Z

283

Multiple frequency method for operating electrochemical sensors  

DOE Patents (OSTI)

A multiple frequency method for the operation of a sensor to measure a parameter of interest using calibration information including the steps of exciting the sensor at a first frequency providing a first sensor response, exciting the sensor at a second frequency providing a second sensor response, using the second sensor response at the second frequency and the calibration information to produce a calculated concentration of the interfering parameters, using the first sensor response at the first frequency, the calculated concentration of the interfering parameters, and the calibration information to measure the parameter of interest.

Martin, Louis P. (San Ramon, CA)

2012-05-15T23:59:59.000Z

284

Effect of Microwave Frequency on Hydrothermal Synthesis of Nanocrystalline Tetragonal Barium Titanate  

E-Print Network (OSTI)

Effect of Microwave Frequency on Hydrothermal Synthesis of Nanocrystalline Tetragonal Barium) with particle sizes ranging from 30 to 100 nm were synthesized via microwave-hydrothermal routes at various, but increased gradually with extended aging time in variable frequency (3-5.5 GHz to 1 s) processing

Dutta, Prabir K.

285

Hydrogen atom in crossed electric and magnetic fields: Phase space topology and torus quantization via periodic orbits  

E-Print Network (OSTI)

A hierarchical ordering is demonstrated for the periodic orbits in a strongly coupled multidimensional Hamiltonian system, namely the hydrogen atom in crossed electric and magnetic fields. It mirrors the hierarchy of broken resonant tori and thereby allows one to characterize the periodic orbits by a set of winding numbers. With this knowledge, we construct the action variables as functions of the frequency ratios and carry out a semiclassical torus quantization. The semiclassical energy levels thus obtained agree well with exact quantum calculations.

Stephan Gekle; Jörg Main; Thomas Bartsch; T. Uzer

2006-10-02T23:59:59.000Z

286

Efficient periodic band diagram computation using a finite element method, Arnoldi eigensolver and sparse linear system solver  

E-Print Network (OSTI)

We present here a Finite Element Method devoted to the simulation of 3D periodic structures of arbitrary geometry. The numerical method based on ARPACK and PARDISO libraries, is discussed with the aim of extracting the eigenmodes of periodical structures and thus establishing their frequency band gaps. Simulation parameters and the computational optimization are the focus. Resolution will be used to characterize EBG (Electromagnetic Band Gap) structures, such as plasma rods and metallic cubes.

Garnier, Romain; Pascal, Olivier

2014-01-01T23:59:59.000Z

287

Analytical formulation of 3D dynamic homogenization for periodic elastic systems  

E-Print Network (OSTI)

Homogenization of the equations of motion for a three dimensional periodic elastic system is considered. Expressions are obtained for the fully dynamic effective material parameters governing the spatially averaged fields by using the plane wave expansion (PWE) method. The effective equations are of Willis form (Willis 1997) with coupling between momentum and stress and tensorial inertia. The formulation demonstrates that the Willis equations of elastodynamics are closed under homogenization. The effective material parameters are obtained for arbitrary frequency and wavenumber combinations, including but not restricted to Bloch wave branches for wave propagation in the periodic medium. Numerical examples for a 1D system illustrate the frequency dependence of the parameters on Bloch wave branches and provide a comparison with an alternative dynamic effective medium theory (Shuvalov 2011) which also reduces to Willis form but with different effective moduli.

A. N. Norris; A. L. Shuvalov; A. A. Kutsenko

2012-01-13T23:59:59.000Z

288

Under consideration for publication in J. Fluid Mech. 1 Double-frequency noise generation by  

E-Print Network (OSTI)

Under consideration for publication in J. Fluid Mech. 1 Double-frequency noise generation ?; accepted ?. - To be entered by editorial office) Oceanic observations, even in very deep water, and atmospheric pressure or seismic records, from anywhere on Earth, contain noise with dominant periods between 3

289

Frequency-domain multiscale quantum mechanics/electromagnetics simulation method  

SciTech Connect

A frequency-domain quantum mechanics and electromagnetics (QM/EM) method is developed. Compared with the time-domain QM/EM method [Meng et al., J. Chem. Theory Comput. 8, 1190–1199 (2012)], the newly developed frequency-domain QM/EM method could effectively capture the dynamic properties of electronic devices over a broader range of operating frequencies. The system is divided into QM and EM regions and solved in a self-consistent manner via updating the boundary conditions at the QM and EM interface. The calculated potential distributions and current densities at the interface are taken as the boundary conditions for the QM and EM calculations, respectively, which facilitate the information exchange between the QM and EM calculations and ensure that the potential, charge, and current distributions are continuous across the QM/EM interface. Via Fourier transformation, the dynamic admittance calculated from the time-domain and frequency-domain QM/EM methods is compared for a carbon nanotube based molecular device.

Meng, Lingyi; Yin, Zhenyu; Yam, ChiYung, E-mail: yamcy@yangtze.hku.hk, E-mail: ghc@everest.hku.hk; Koo, SiuKong; Chen, GuanHua, E-mail: yamcy@yangtze.hku.hk, E-mail: ghc@everest.hku.hk [Department of Chemistry, The University of Hong Kong, Pokfulam Road (Hong Kong)] [Department of Chemistry, The University of Hong Kong, Pokfulam Road (Hong Kong); Chen, Quan; Wong, Ngai [Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)] [Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)

2013-12-28T23:59:59.000Z

290

Casimir Effect under Quasi-Periodic Boundary Condition Inspired by Nanotubes  

E-Print Network (OSTI)

When one studies the Casimir effect, the periodic (anti-periodic) boundary condition is usually taken to mimic a periodic (anti-periodic) structure for a scalar field living in a flat space with a non-Euclidean topology. However, there could be an arbitrary phase difference between the value of the scalar field on one endpoint of the unit structure and that on the other endpoint, such as the structure of nanotubes. Then, in this paper, a periodic condition on the ends of the system with an additional phase factor, which is called the ``quasi-periodic" condition, is imposed to investigate the corresponding Casimir effect. And an attractive or repulsive Casimir force is found, whose properties depend on the phase angle value. Especially, the Casimir effect disappears when the phase angle takes a particular value. High dimensional space-time case is also investigated.

Feng, Chao-Jun; Zhai, Xiang-Hua

2014-01-01T23:59:59.000Z

291

Casimir Effect under Quasi-Periodic Boundary Condition Inspired by Nanotubes  

E-Print Network (OSTI)

When one studies the Casimir effect, the periodic (anti-periodic) boundary condition is usually taken to mimic a periodic (anti-periodic) structure for a scalar field living in a flat space with a non-Euclidean topology. However, there could be an arbitrary phase difference between the value of the scalar field on one endpoint of the unit structure and that on the other endpoint, such as the structure of nanotubes. Then, in this paper, a periodic condition on the ends of the system with an additional phase factor, which is called the ``quasi-periodic" condition, is imposed to investigate the corresponding Casimir effect. And an attractive or repulsive Casimir force is found, whose properties depend on the phase angle value. Especially, the Casimir effect disappears when the phase angle takes a particular value. High dimensional space-time case is also investigated.

Chao-Jun Feng; Xin-Zhou Li; Xiang-Hua Zhai

2013-12-06T23:59:59.000Z

292

QUASI-PERIODIC OSCILLATIONS AND BROADBAND VARIABILITY IN SHORT MAGNETAR BURSTS  

SciTech Connect

The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. However, with only three giant flares ever recorded, and only two with data of sufficient quality to search for QPOs, such analysis is seriously data limited. We set out a procedure for doing QPO searches in the far more numerous, short, less energetic magnetar bursts. The short, transient nature of these bursts requires the implementation of sophisticated statistical techniques to make reliable inferences. Using Bayesian statistics, we model the periodogram as a combination of red noise at low frequencies and white noise at high frequencies, which we show is a conservative approach to the problem. We use empirical models to make inferences about the potential signature of periodic and QPOs at these frequencies. We compare our method with previously used techniques and find that although it is on the whole more conservative, it is also more reliable in ruling out false positives. We illustrate our Bayesian method by applying it to a sample of 27 bursts from the magnetar SGR J0501+4516 observed by the Fermi Gamma-ray Burst Monitor, and we find no evidence for the presence of QPOs in any of the bursts in the unbinned spectra, but do find a candidate detection in the binned spectra of one burst. However, whether this signal is due to a genuine quasi-periodic process, or can be attributed to unmodeled effects in the noise is at this point a matter of interpretation.

Huppenkothen, Daniela; Watts, Anna L.; Uttley, Phil; Van der Horst, Alexander J.; Van der Klis, Michiel [Astronomical Institute ''Anton Pannekoek'', University of Amsterdam, Postbus 94249, 1090-GE Amsterdam (Netherlands); Kouveliotou, Chryssa [Office of Science and Technology, ZP12, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Goegues, Ersin [Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul 34956 (Turkey); Granot, Jonathan [The Open University of Israel, 1 University Road, P.O. Box 808, Ra'anana 43537 (Israel); Vaughan, Simon [X-Ray and Observational Astronomy Group, University of Leicester, Leicester LE1 7RH (United Kingdom); Finger, Mark H., E-mail: D.Huppenkothen@uva.nl [Universities Space Research Association, Huntsville, AL 35805 (United States)

2013-05-01T23:59:59.000Z

293

High-frequency-modulation spectroscopy with a lead-salt diode laser  

Science Journals Connector (OSTI)

For the first reported time, high-frequency optical heterodyne spectroscopy has been performed with tunable lead-salt diode lasers. N2O transitions at 1259.2 cm?1...

Gehrtz, Manfred; Young, Anthony T; Johnston, Harold S; Lenth, Wilfried

1986-01-01T23:59:59.000Z

294

Current mode integrators and their applications in low-voltage high frequency CMOS signal processing  

E-Print Network (OSTI)

Low voltage CMOS fully differential integrators for high frequency continuous-time filters using current-mode techniques are presented.. Current mode techniques are employed to avoid the use of the floating differential pair, in order to achieve...

Smith, Sterling Lane

2012-06-07T23:59:59.000Z

295

Interactions between frequency–dependent and vertical transmission in host–parasite systems  

Science Journals Connector (OSTI)

...frequency-dependent transmission to the total number...population over time. Solid line represents susceptible...fected via horizontal route and dot-dash-dot line is hosts infected via...coexistence when ver- tical transmission is possible. Including...

1997-01-01T23:59:59.000Z

296

Period Changes in Ultra-compact Double White Dwarfs  

E-Print Network (OSTI)

In recent years there has been much interest in the nature of two stars, V407 Vul and RXJ0806+1527, which are widely thought to be binary white dwarfs of very short orbital period, 570 and 321 seconds respectively. As such they should be strong sources of gravitational waves and possible ancestors of the accreting AM CVn stars. Monitoring at X-ray and optical wavelengths has established that the period of each star is decreasing, at rates compatible with that expected from gravitational radiation. This has been taken to support the ``unipolar inductor'' model in which the white dwarfs are detached and the X-rays produced by the dissipation of magnetically-induced electric currents. In this paper we show that this interpretation is incorrect because it ignores associated torques which transfer angular momentum between the spin of the magnetic white dwarf and the orbit. We show that this torque is 10^5 times larger than the GR term in the case of V407 Vul, and 10 times larger for RXJ0806+1527. For V407 Vul, the unipolar inductor model can only survive if the white dwarf spins 100 times faster than the orbit. Since this could only come about through accretion, the validity of the unipolar inductor appears questionable for this star. We also consider whether accretion models can fit the observed spin-up, concluding that they can, provided that a mechanism exists for driving the mass transfer rate away from its equilibrium value.

T. R. Marsh; G. Nelemans

2005-08-10T23:59:59.000Z

297

High-frequency acoustic modes in an ionic liquid  

Science Journals Connector (OSTI)

High-frequency collective dynamics of the ionic liquid 1-hexyl-3-methylimidazolium bromide [C6C1im]Br has been investigated by molecular dynamics simulations. Time correlation functions of mass current fluctuations were calculated for several wavevectors and the dispersion curves of excitations ?(k) for longitudinal and transverse acoustic sound modes were obtained at different temperatures and pressures. Two different thermodynamic states have the same high-frequency sound velocity irrespective of the temperature provided that both have the same density. Partial time correlation functions of mass currents were calculated for the atoms belonging to the polar or the non-polar domains resulting from the heterogeneous structure of [C6C1im]Br. The partial correlation functions indicate that the polar domains are stiffer than the non-polar domains of the simulated ionic liquid.

Mauro C. C. Ribeiro

2013-01-01T23:59:59.000Z

298

The periodic spectroscopic variability of FU Orionis  

Science Journals Connector (OSTI)

......the emergence of the energy liberated by accretion...of the central star in solar masses. The maximum...is the stellar mass in solar masses. Even in the...this could represent an economical solution to the two period...Associations and the Solar Vicinity. Kluwer, Dordrecht......

Stacie L. Powell; Mike Irwin; Jerome Bouvier; Cathie J. Clarke

2012-11-11T23:59:59.000Z

299

Coherency saturation in periodic structures with randomization  

E-Print Network (OSTI)

,28 or multicascade stimulated Raman scattering.29­31 A major example of naturally occurring spatially periodic with very reasonable precision. In the specific case of x ray transition radiation of low layers can generate resonantly enhanced radiation in the hard x ray domain with almost unhampered

Kaplan, Alexander

300

Broadband solar absorption enhancement via periodic  

E-Print Network (OSTI)

Broadband solar absorption enhancement via periodic nanostructuring of electrodes Michael M. Adachi Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada, 2 Province, 230009, P. R. China. Solution processed colloidal quantum dot (CQD) solar cells have great

Note: This page contains sample records for the topic "frequency time period" 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

Cryogenic sapphire oscillator with exceptionally high long-term frequency stability  

E-Print Network (OSTI)

We report on the development of a sapphire cryogenic microwave resonator oscillator long-term fractional frequency stability of 2x10^-17Sqrt[\\tau] for integration times \\tau>10^3 s and negative drift of about 2.2x10^-15/day. The short-term frequency instability of the oscillator is highly reproducible and also state-of-the-art: 5.6x10^-16 for an integration time of \\tau ~ 20 s.

J. G. Hartnett; C. R. Locke; E. N. Ivanov; M. E. Tobar; P. L. Stanwix

2006-08-11T23:59:59.000Z

302

Quantum theory of optical coherence of nonstationary light in the space-frequency domain  

SciTech Connect

Classical theories of coherence for statistically stationary, as well as, nonstationary optical fields are frequently discussed both in the space-time and in the space-frequency domains. However, the quantum treatment of coherence theory is generally carried out in the space-time domain. In this paper, we present a quantum-mechanical theory of first-order coherence for statistically nonstationary light in the space-frequency domain.

Lahiri, Mayukh [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Wolf, Emil [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

2010-10-15T23:59:59.000Z

303

On frequency dependence of pulsar linear polarization  

E-Print Network (OSTI)

Frequency dependence of pulsar linear polarization is investigated by simulations of emission and propagation processes. Linearly polarized waves are generated through curvature radiation by relativistic particles streaming along curved magnetic field lines, which have ordinary mode (O-mode) and extra-ordinary mode (X-mode) components. As emitted waves propagate outwards, two mode components are separated due to re- fraction of the O mode, and their polarization states are also modified. According to the radius to frequency mapping, low frequency emission is generated from higher magnetosphere, where significant rotation effect leads the X and O modes to be sepa- rated. Hence, the low frequency radiation has a large fraction of linear polarization. As the frequency increases, emission is generated from lower heights, where the rotation effect becomes weaker and the distribution regions of two modes are more overlapped. Hence, more significant depolarization appears for emission at higher frequencies. In addit...

Wang, P F; Han, J L

2015-01-01T23:59:59.000Z

304

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

305

10 microsecond time resolution studies of Cygnus X-1  

SciTech Connect

Time variability analyses have been applied to data composed of event times of X-rays emitted from the binary system Cygnus X-1 to search for unique black hole signatures. The X-ray data analyzed was collected at ten microsecond time resolution or better from two instruments, the High Energy Astrophysical Observatory (HEAO) A-1 detector and the Rossi X-ray Timing Explorer (XTE) Proportional Counter Array (PCA). HEAO A-1 and RXTE/PCA collected data from 1977--79 and from 1996 on with energy sensitivity from 1--25 keV and 2--60 keV, respectively. Variability characteristics predicted by various models of an accretion disk around a black hole have been searched for in the data. Drop-offs or quasi-periodic oscillations (QPOs) in the Fourier power spectra are expected from some of these models. The Fourier spectral technique was applied to the HEAO A-1 and RXTE/PCA data with careful consideration given for correcting the Poisson noise floor for instrumental effects. Evidence for a drop-off may be interpreted from the faster fall off in variability at frequencies greater than the observed breaks. Both breaks occur within the range of Keplerian frequencies associated with the inner edge radii of advection-dominated accretion disks predicted for Cyg X-1. The break between 10--20 Hz is also near the sharp rollover predicted by Nowak and Wagoner`s model of accretion disk turbulence. No QPOs were observed in the data for quality factors Q > 9 with a 95% confidence level upper limit for the fractional rms amplitude at 1.2% for a 16 M{sub {circle_dot}} black hole.

Wen, H.C.

1997-06-01T23:59:59.000Z

306

Frequency modulation drive for a piezoelectric motor  

DOE Patents (OSTI)

A piezoelectric motor has peak performance at a specific frequency f.sub.1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source connected to power the motor, the ac source repeatedly generating a frequency over a range from f.sub.1 -.DELTA.x to f.sub.1 +.DELTA.y.

Mittas, Anthony (Albuquerque, NM)

2001-01-01T23:59:59.000Z

307

Property:Maximum Wave Height(m) at Wave Period(s) | Open Energy Information  

Open Energy Info (EERE)

Wave Height(m) at Wave Period(s) Wave Height(m) at Wave Period(s) Jump to: navigation, search Property Name Maximum Wave Height(m) at Wave Period(s) Property Type String Pages using the property "Maximum Wave Height(m) at Wave Period(s)" Showing 25 pages using this property. (previous 25) (next 25) 1 1.5-ft Wave Flume Facility + 10.0 + 10-ft Wave Flume Facility + 10.0 + 11-ft Wave Flume Facility + 10.0 + 2 2-ft Flume Facility + 10.0 + 3 3-ft Wave Flume Facility + 10.0 + 5 5-ft Wave Flume Facility + 10.0 + 6 6-ft Wave Flume Facility + 10.0 + A Alden Large Flume + 0.0 + Alden Wave Basin + 1.0 + C Chase Tow Tank + 3.1 + Coastal Harbors Modeling Facility + 2.3 + Coastal Inlet Model Facility + 2.3 + D Davidson Laboratory Tow Tank + 4.0 + DeFrees Large Wave Basin + 3.0 + DeFrees Small Wave Basin + 3.0 +

308

Frequencies Studies Applied to Photovoltaic Modules.  

E-Print Network (OSTI)

?? This master thesis proposes to study applications of frequencies studies to the case of photovoltaic modules and photovoltaic plants. Such studies are little used… (more)

Miquel, Clément

2011-01-01T23:59:59.000Z

309

High-Frequency Electrostatic Plasma Instabilities  

Science Journals Connector (OSTI)

A description of the stability properties of a plasma under the influence of an external electric field oscillating near the plasma frequency is presented.

J. P. Freidberg and B. M. Marder

1971-10-01T23:59:59.000Z

310

High-frequency, high-intensity photoionization  

Science Journals Connector (OSTI)

Two analytical methods for computing ionization by high-frequency fields are compared. Predicted ionization rates compare well, but energy predictions for the onset of ionization...

Reiss, H R

1996-01-01T23:59:59.000Z

311

Explosives detection with a frequency modulation spectrometer  

Science Journals Connector (OSTI)

An explosives detection instrument was designed and tested at SRI International. The instrument uses frequency modulation spectroscopy with midinfrared lead-salt diode lasers to...

Riris, H; Carlisle, C B; McMillen, D F; Cooper, D E

1996-01-01T23:59:59.000Z

312

Topology and Design of Wide-Band 3D Metamaterials made of Periodically Loaded Transmission Line Arrays  

E-Print Network (OSTI)

Topology and Design of Wide-Band 3D Metamaterials made of Periodically Loaded Transmission Line index over a wide frequency band. These metamaterials consist of a three- dimensional transmission line and permeability. The cubic-cell transmission line host network is a physical realization of the 3D distributed

Tentzeris, Manos

313

Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids  

SciTech Connect

In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C{sub 2}H{sub 5}OH) and water (H{sub 2}O) using linearly polarized Ti:sapphire fs laser pulses of ?110 fs pulse duration and ?800?nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620?nm and high spatial frequency LIPSS which spectacles a periodicity less than 100?nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

Kuladeep, Rajamudili; Dar, Mudasir H.; Rao, D. Narayana, E-mail: dnrsp@uohyd.ac.in, E-mail: dnr-laserlab@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Deepak, K. L. N. [Department of Physics and Center for Research in Photonics, University of Ottawa, 150 Louis Pasteur, Ottawa K1N6N5, Ontario (Canada)

2014-09-21T23:59:59.000Z

314

A time-resolved laser induced fluorescence study on the ion velocity distribution function in a Hall thruster after a fast current disruption  

SciTech Connect

The temporal characteristics of the Xe{sup +} ion axial velocity distribution function (VDF) were recorded in the course of low-frequency discharge current oscillations ({approx}14 kHz) of the 5 kW class PPS X000 Hall thruster. The evolution in time of the ion axial velocity component is monitored by means of a laser induced fluorescence diagnostic tool with a time resolution of 100 ns. As the number of fluorescence photons is very low during such a short time period, a homemade pulse-counting lock-in system was used to perform real-time discrimination between background photons and fluorescence photons. The evolution in time of the ion VDF was observed at three locations along the thruster channel axis after a fast shutdown of the thruster power. The anode discharge current is switched off at 2 kHz during 5 {mu}s without any synchronization with the current oscillation cycle. This approach allows to examine the temporal behavior of the ion VDF during decay and ignition of the discharge as well as during forced and natural plasma oscillations. Measurements show that the distribution function of the axial component of the Xe{sup +} ion does change periodically in time with a frequency close to the current oscillation frequency in both forced and natural cases. The ion density and the mean velocity are found to oscillate, whereas the velocity dispersion stays constant, which indicates that ionization and acceleration layers have identical dynamics. Finally, variations over time in the electric field are for the first time experimentally evidenced in a crossed-field discharge.

Mazouffre, S.; Gawron, D. [ICARE, CNRS, 1C avenue de la Recherche Scientifique, 45071 Orleans (France); Sadeghi, N. [LSP, Joseph Fourier University, CNRS, 140 Av. de la Physique, 38402 St. Martin d'Hueres (France)

2009-04-15T23:59:59.000Z

315

REAL-TIME IN-SITU MEASUREMENT OF MATERIAL ELASTIC PROPERTIES IN A HIGH GAMMA IRRADIATION ENVIRONMENT  

SciTech Connect

The first measurements of elastic vibrations of an object in-situ to a high gamma irradiation field using a laser coupled resonant ultrasound method are described. A vibration mode of an Inconel hollow capped cylinder was measured throughout a period of 170 hours as the gamma radiation field was increased to 104 Gray/hour. The vibration mode frequency was observed to change in a manner consistent with the temperature dependence of the elastic stiffness coefficients of the material. These results illustrate the efficacy of the laser approach for real-time resonant ultrasound measurements in this severely hostile nuclear environment.

Ken Telschow; Rob Schley; Dave Cottle

2006-05-01T23:59:59.000Z

316

Demonstration of Real-time Spectrum Sensing for Cognitive Radio  

E-Print Network (OSTI)

Demonstration of Real-time Spectrum Sensing for Cognitive Radio Zhe Chen, Nan Guo, and Robert C sensing detects the availability of the radio frequency spectrum in a real-time fashion, which is essen Cognitive radio (CR) has been put forward to make effi- cient use of scarce radio frequency spectrum

Qiu, Robert Caiming

317

Investigation of effect of excitation frequency on electron energy distribution functions in low pressure radio frequency bounded plasmas  

SciTech Connect

Particle in cell (PIC) simulations are employed to investigate the effect of excitation frequency {omega} on electron energy distribution functions (EEDFs) in a low pressure radio frequency (rf) discharge. The discharge is maintained over a length of 0.10 m, bounded by two infinite parallel plates, with the coherent heating field localized at the center of the discharge over a distance of 0.05 m and applied perpendicularly along the y and z directions. On varying the excitation frequency f (={omega}/2{pi}) in the range 0.01-50 MHz, it is observed that for f {<=} 5 MHz the EEDF shows a trend toward a convex (Druyvesteyn-like) distribution. For f > 5 MHz, the distribution resembles more like a Maxwellian with the familiar break energy visible in most of the distributions. A prominent ''hot tail'' is observed at f{>=} 20 MHz and the temperature of the tail is seen to decrease with further increase in frequency (e.g., at 30 MHz and 50 MHz). The mechanism for the generation of the ''hot tail'' is considered to be due to preferential transit time heating of energetic electrons as a function of {omega}, in the antenna heating field. There exists an optimum frequency for which high energy electrons are maximally heated. The occurrence of the Druyvesteyn-like distributions at lower {omega} may be explained by a balance between the heating of the electrons in the effective electric field and elastic cooling due to electron neutral collision frequency {nu}{sub en}; the transition being dictated by {omega} {approx} 2{pi}{nu}{sub en}.

Bhattacharjee, Sudeep [Space plasma, Power and Propulsion, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Department of Physics, Indian Institute of Technology, Kanpur 208 016 (India); Lafleur, Trevor; Charles, Christine; Boswell, Rod [Space plasma, Power and Propulsion, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

2011-07-15T23:59:59.000Z

318

Word length and frequency as determinants of stuttering  

Science Journals Connector (OSTI)

Word length and Frequency were independently varied to assess their effect on stuttering frequency. The list of test words contained ... low, medium of high frequency of occurrence. Stuttering frequency of 31 you...

I. M. Schlesinger; Rachel Melkman; Ron Levy

1966-06-01T23:59:59.000Z

319

MASS-ANGULAR-MOMENTUM RELATIONS IMPLIED BY MODELS OF TWIN PEAK QUASI-PERIODIC OSCILLATIONS  

SciTech Connect

Twin peak quasi-periodic oscillations (QPOs) appear in the X-ray power-density spectra of several accreting low-mass neutron star (NS) binaries. Observations of the peculiar Z-source Circinus X-1 display unusually low QPO frequencies. Using these observations, we have previously considered the relativistic precession (RP) twin peak QPO model to estimate the mass of the central NS in Circinus X-1. We have shown that such an estimate results in a specific mass-angular-momentum (M - j) relation rather than a single preferred combination of M and j. Here we confront our previous results with another binary, the atoll source 4U 1636-53 that displays the twin peak QPOs at very high frequencies, and extend the consideration to various twin peak QPO models. In analogy to the RP model, we find that these imply their own specific M - j relations. We explore these relations for both sources and note differences in the {chi}{sup 2} behavior that represent a dichotomy between high- and low-frequency sources. Based on the RP model, we demonstrate that this dichotomy is related to a strong variability of the model predictive power across the frequency plane. This variability naturally comes from the radial dependence of characteristic frequencies of orbital motion. As a consequence, the restrictions on the models resulting from observations of low-frequency sources are weaker than those in the case of high-frequency sources. Finally we also discuss the need for a correction to the RP model and consider the removing of M - j degeneracies, based on the twin peak QPO-independent angular momentum estimates.

Toeroek, Gabriel; Bakala, Pavel; Sramkova, Eva; Stuchlik, Zdenek; Urbanec, Martin; Goluchova, Katerina, E-mail: pavel.bakala@fpf.slu.cz, E-mail: martin.urbanec@fpf.slu.cz, E-mail: zdenek.stuchlik@fpf.slu.cz, E-mail: terek@volny.cz, E-mail: sram_eva@centrum.cz [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezrucovo nam. 13, CZ-746 01 Opava (Czech Republic)

2012-12-01T23:59:59.000Z

320

Microwave coupling of frequency-locked Josephson junction arrays  

SciTech Connect

A high temperature superconducting YBa{sub 2}Cu{sub 3}O{sub y} array of five Josephson junctions designed with additional coupling lines has been developed to demonstrate the effects of frequency locking and impedance matching for applications such as oscillators, mixers, and detectors. The Josephson self-radiation power was directly detected by a superheterodyne receiver, and Shapiro steps were also measured. The Josephson self-radiation properties reveal good quality of phase locking and microwave coupling with external circuits. The maximum self-radiation power of our array is about 50 pW which is several ten times higher than that of a single Josephson junction, and its peak point exactly satisfies the Josephson current-voltage relation. The Shapiro-step measurements show that the behavior of current-voltage curve depends on the effective inductance of coupling lines which affects the total impedance of Josephson junction array and microwave coupling. The Josephson oscillation frequency was obtained up to about 880 GHz which is 73{percent} of the maximum available frequency calculated from the characteristic voltage of the Josephson junctions. Experimental results show that this type of Josephson junction array can improve the Josephson self-radiation power and increase the maximum detectable frequency. {copyright} {ital 1997 American Institute of Physics.}

Song, I.; Eom, Y.; Park, G. [Department of Physics, Sogang University, Seoul 100-611 (Korea)] [Department of Physics, Sogang University, Seoul 100-611 (Korea); Lee, E.; Park, S. [Electronic Materials Laboratory, Samsung Advanced Institute of Technology, Suwon (Korea)] [Electronic Materials Laboratory, Samsung Advanced Institute of Technology, Suwon (Korea)

1997-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" from the National Library of EnergyBeta (NLEBeta).
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321

Generation of Electron Bunches at Low Repetition Rates Using a Beat-Frequency Technique  

SciTech Connect

Even at a continuous wave facility such as CEBAF at Jefferson Lab, an electron beam with long time intervals (tens of ns) between individual bunches can be useful, for example to isolate sources of background via time of flight detection or to measure the energy of neutral particles that cannot be separated with a magnetic field. This paper describes a demonstrated method to quickly and easily deliver bunches with repetition rates of 20 to 100 MHz corresponding to time intervals between 10 to 50 ns (respectively). This is accomplished by changing the ON/OFF frequency of the RF-pulsed drive laser by a small amount (?f/f < 20%), resulting in a bunch frequency equal to the beat frequency between the radio frequencies of the drive laser and the photoinjector chopper system.

Matt Poelker; Joseph Grames; John Hansknecht; Reza Kazimi; John Musson

2007-05-01T23:59:59.000Z

322

Digital video analysis of nonequilibrium periodic patterns induced in nematics by magnetic reorientation  

Science Journals Connector (OSTI)

Early-time dynamics of transient periodic structures in reorienting lyotropic nematics are analyzed via digital video microscopy. Measurements of the time dependence of the pattern power spectrum and critical wave number are presented. The data are compared to the results of a simple linear theory.

J. P. McClymer; M. M. Labes; M. R. Kuzma

1988-02-15T23:59:59.000Z

323

Periodically Intermittent Stabilization of Delayed Neural Networks Based on Piecewise Lyapunov Functions/Functionals  

Science Journals Connector (OSTI)

This paper is concerned with the stabilization problem of delayed neural networks via a periodically intermittent controller. Two cases of time-varying bounded delays are considered: one is the time-varying delay without any constraints on the delay ... Keywords: Delayed neural networks, Intermittent control, Linear matrix inequalities, Piecewise Lyapunov functions/functionals

Wu-Hua Chen, Jiacheng Zhong, Zhiyong Jiang, Xiaomei Lu

2014-12-01T23:59:59.000Z

324

Reaction of plaice (Pleuronectes platessa) and cod (Gadus morhua) to low?frequency sound in an experimental tank  

Science Journals Connector (OSTI)

Anthropogenic sound in the sea is an increasing problem and more knowledge on the influence of sound on fish needs to be collected. For this reason experiments are carried out in an experimental tank 10 m in diameter to examine the reaction of juvenile and adult cod and plaice to sound. Pure tones from the frequency range of offshore wind turbines are artificially emitted in typical wind turbinesound levels of 130 and 140 dB re 1 Pa. A sound gradient in the tank enables the fish to avoid highest sound levels. The number of fish in the vicinity of the sound source is determined in regular time intervals before during and after the 24?h period of sound exposure. Changes in numbers of fish can be seen in the periods with and without sound in many experiments. Reactions of plaice are ambiguous pointing to both avoidance of or attraction to the sound. In the majority of the experiments carried out on cod avoidance behavior to the sound can be seen with strongest reactions at 25 60 and 90 Hz. The results indicate potential avoidance behavior of cod to the operational noise of offshore wind farms.

2006-01-01T23:59:59.000Z

325

1 Pitch, Frequency, Musical Scales 1 1.1 Pitch and Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  

E-Print Network (OSTI)

Contents ix 1 Pitch, Frequency, Musical Scales 1 1.1 Pitch and Frequency.2 Overtones, Pitch Equivalence, and Musical Scales . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2.1 Pitch Equivalence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1

Walker, James S.

326

HF heating of a plasma column at frequencies below the electron cyclotron frequency  

Science Journals Connector (OSTI)

Dispersion of waves, excited by the helical structure in a plasma column and the heating of a tail of the electron distribution ... frequencies below the electron plasma and the electron cyclotron frequency.

J. ?atlov; V. Kopecký; J. Musil; F. Žá?ek; K. Novik

1978-01-01T23:59:59.000Z

327

ION HEATING BY A SPECTRUM OF OBLIQUELY PROPAGATING LOW-FREQUENCY ALFVEN WAVES  

SciTech Connect

Ion stochastic heating by a monochromatic Alfven wave, which propagates obliquely to the background magnetic field, has been studied by Chen et al. It is shown that ions can be resonantly heated at frequencies a fraction of the ion cyclotron frequency when the wave amplitude is sufficiently large. In this paper, the monochromatic wave is extended to a spectrum of left-hand polarized Alfven waves. When the amplitude of the waves is small, the components of the ion velocity have several distinct frequencies, and their motions are quasi-periodic. However, when the amplitude of the waves is sufficiently large, the components of the ion velocity have a spectrum of continuous frequencies near the ion cyclotron frequency due to the nonlinear coupling between the Alfven waves and the ion gyromotion, and the ion motions are stochastic. Compared with the case of a monochromatic Alfven wave, the threshold of the ion stochastic heating by a spectrum of Alfven waves is much lower. Even when their frequencies are only several percent of the ion cyclotron frequency, the ions can also be stochastically heated. The relevance of this heating mechanism to solar corona is also discussed.

Lu Quanming [CAS Laboratory of Basic Plasma Physics, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Chen Liu [Institute for Fusion and Simulation, Zhejiang University, Hangzhou 310027 (China)

2009-10-10T23:59:59.000Z

328

Definition: Frequency Response | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Frequency Response Jump to: navigation, search Dictionary.png Frequency Response (Equipment) The ability of a system or elements of the system to react or respond to a change in system frequency. (System) The sum of the change in demand, plus the change in generation, divided by the change in frequency, expressed in megawatts per 0.1 Hertz (MW/0.1 Hz).[1] View on Wikipedia Wikipedia Definition Related Terms system, smart grid References ↑ Glossary of Terms Used in Reliability Standards An i LikeLike UnlikeLike You like this.Sign Up to see what your friends like. nline Glossary Definition Retrieved from "http://en.openei.org/w/index.php?title=Definition:Frequency_Response&oldid=502580"

329

Transition Period High Water Marks - May 2009.indd  

NLE Websites -- All DOE Office Websites (Extended Search)

Period High Water Marks (THWMs) and Above-Rate-Period High Water Mark (Above-RHWM) load data for the transition period for all customers with a CHWM contract. The transition...

330

A Dual Tone Multiple Frequency receiver using a multiplexed OTA-C filter frequency detection architecture  

E-Print Network (OSTI)

A DUAL TONE MULTIPLE FREQUENCY RECEIVER USING A MULTIPLEXED OTA-C FILTER FREQUENCY DETECTION ARCHITECTURE A Thesis by GERALD WILLIAM GARCIA Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 1988 Major Subject: Electrical Engineering A DUAL TONE MULTIPLE FREQUENCY RECEIVER USING A MULTIPLEXED OTA-C FILTER FREQUENCY DETECTION ARCHITECTURE A Thesis by GERALD WILLIAM GARCIA Approved as to style...

Garcia, Gerald William

2012-06-07T23:59:59.000Z

331

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine  

E-Print Network (OSTI)

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine-Frequency Control (LFC) is gradually shifted to Variable Speed Wind Turbines (VSWTs). In order to equip VSWT@et.aau.dk Abstract--In near future, with high penetration of Wind Energy (WE) in power system, the burden of Load

Silva, Filipe Faria Da

332

Phase-stabilized 167 MHz Repetition Frequency Carbon Nanotube Fiber Laser Frequency Comb  

E-Print Network (OSTI)

Phase-stabilized 167 MHz Repetition Frequency Carbon Nanotube Fiber Laser Frequency Comb Jinkang [2, 3]. Mode-locked fiber lasers using single-walled carbon nanotubes as a saturable absorber have-referenced frequency comb from a fiber laser passively modelocked by single walled carbon nanotubes. The carbon

Washburn, Brian

333

Low-frequency variability and heat transport in a low-order nonlinear coupled ocean-atmosphere model  

E-Print Network (OSTI)

We formulate and study a low-order nonlinear coupled ocean-atmosphere model with an emphasis on the impact of radiative and heat fluxes and of the frictional coupling between the two components. This model version extends a previous 24-variable version by adding a dynamical equation for the passive advection of temperature in the ocean, together with an energy balance model. The bifurcation analysis and the numerical integration of the model reveal the presence of low-frequency variability (LFV) concentrated on and near a long-periodic, attracting orbit. This orbit combines atmospheric and oceanic modes, and it arises for large values of the meridional gradient of radiative input and of frictional coupling. Chaotic behavior develops around this orbit as it loses its stability; this behavior is still dominated by the LFV on decadal and multi-decadal time scales that is typical of oceanic processes. Atmospheric diagnostics also reveals the presence of predominant low- and high-pressure zones, as well as of a subtropical jet; these features recall realistic climatological properties of the oceanic atmosphere. Finally, a predictability analysis is performed. Once the decadal-scale periodic orbits develop, the coupled system's short-term instabilities --- as measured by its Lyapunov exponents --- are drastically reduced, indicating the ocean's stabilizing role on the atmospheric dynamics. On decadal time scales, the recurrence of the solution in a certain region of the invariant subspace associated with slow modes displays some extended predictability, as reflected by the oscillatory behavior of the error for the atmospheric variables at long lead times.

Stéphane Vannitsem; Jonathan Demaeyer; Lesley De Cruz; Michael Ghil

2014-12-01T23:59:59.000Z

334

EIS-0380: Notice to Extend Comment Period on the Draft Site-Wide  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

to Extend Comment Period on the Draft Site-Wide to Extend Comment Period on the Draft Site-Wide Environmental Impact Statement EIS-0380: Notice to Extend Comment Period on the Draft Site-Wide Environmental Impact Statement Continued Operation of Los Alamos National Laboratory, Los Alamos, New Mexico In response to requests for additional time to review and comment on the document, NNSA is extending the public comment period until September 20, 2006. DOE/EIS-0380, Department of Energy, National Nuclear Security Administration, Extension of Comment Period on the Draft Site-Wide Environmental Impact Statement for Continued Operation of Los Alamos National Laboratory, Los Alamos, New Mexico, 76 FR 40352 (August 2006) More Documents & Publications EIS-0380: DOE Notice of Availability of the Draft Site-Wide Environmental

335

Digestion time  

NLE Websites -- All DOE Office Websites (Extended Search)

Digestion time Digestion time Name: Don Mancosh Location: N/A Country: N/A Date: N/A Question: I have always given the rule of thumb in class that material we eat is with us for about 24 hours before exiting the body. The question arises about the time value of liquids. Getting a big coke prior to a 3 hour drive generally means that there will be a stop along the way. Is there a generalization made about liquids in the body similar to the one for solid food? Replies: A physician would give a better answer, but I hazard this: the only liquids which people consume (deliberately) in significant quantities are water, ethyl alcohol and various oils. Water and alcohol are absorbed on a time scale of seconds to minutes through the mouth, stomach and digestive tract. The oils are huge molecules, so I'd guess like any other greasy food they get absorbed in the upper digestive tract. Some of them, perhaps the longest and most nonpolar, are not absorbed at all --- cf. the old-time remedy of mineral oil for constipation --- so there should be some average time-before-what's-left-is-excreted such as you're looking for, and my (wild) guess is that it would not differ substantially from that for food. You can define an average lifetime in the body for alcohol, since the natural level is zero. Rough guidelines are widespread in the context of drunk driving laws. But this is not really possible for water. One's body is normally full up to the brim with water, and there's no way for the body to distinguish between water molecules recently absorbed and molecules that've been moping around since the Beatles split up. Thus the water entering the toilet bowl after the pit stop is not in general the same water as was in the big coke. If you were to consider for water just the average time between drinking and peeing, it would seem to depend strongly on how well hydrated the body was before the drink, and how much was drunk. During sustained heavy exertion in the sun and dry air one can easily drink a pint of water an hour without peeing at all. On the other hand, if one is willing to drink enough water fast enough, so as to establish a high excess of body water one can pee 8 ounces 15 minutes or less after drinking 8 ounces.

336

EIS-0403: Notice to Extend Public Comment Period | Department...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

to Extend Public Comment Period EIS-0403: Notice to Extend Public Comment Period Solar Energy Development in Six Southwestern States The Department of Energy and the Bureau of...

337

EA-1566: Notice of Comment Period Extension | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

EA-1566: Notice of Comment Period Extension Proposed Infrastructure Improvements for the Yucca Mountain Project, Nevada DOE is extending the public comment period for the Yucca...

338

EA-1919: Notice of Public Comment Period Extension | Department...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

of Public Comment Period Extension EA-1919: Notice of Public Comment Period Extension Recycling of Scrap Metals Originating from Radiological Areas DOE has extended the public...

339

PARS II Process Document - DOE Period Close | Department of Energy  

Office of Environmental Management (EM)

by the Office of Acquisition and Project Management to prepare APM DepSec Monthly Status Report, finalize DOE close period package, and perform reporting period close...

340

An ubiquitous ~62 Myr periodic fluctuation superimposed on general trends in fossil biodiversity: Part I, Documentation  

E-Print Network (OSTI)

We use Fourier Analysis and related techniques to investigate the question of periodicities in fossil biodiversity. These techniques are able to identify cycles superimposed on the long-term trends of the Phanerozoic. We review prior results and analyze data previously reduced and published. Joint time series analysis of various reductions of the Sepkoski Data, Paleobiology Database, and Fossil Record 2 indicate the same periodicity in biodiversity of marine animals at 62 Myr. We have not found this periodicity in the terrestrial fossil record. We have found that the signal strength decreases with time because of the accumulation of apparently "resistant" long-lived genera. The existence of a 62 Myr periodicity despite very different treatment of systematic error, particularly sampling-strength biases, in all three major databases strongly argues for its reality in the fossil record.

Melott, Adrian L

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Time-Dependent Nonlinear Hadley Circulation  

Science Journals Connector (OSTI)

The time-dependent Hadley circulation is studied numerically in a nonlinear, nearly inviscid, axially symmetric primitive equation model, with the heating varying periodically on an annual cycle. The annual average of the Hadley circulation ...

Ming Fang; Ka Kit Tung

1999-06-01T23:59:59.000Z

342

Prime power subgroups in certain periodic groups  

E-Print Network (OSTI)

P$38E POlfRR SU89%(UPS IM CENPTAI? PERIODIC QROU1'8 A Thee1 ~ ~Ra Paalllae kxeendaria Lpptoved aa to style and oontent by& 6. P. Chairaen of Coaalttee C. c. aden visor a of epee teen t The author wishes to express his gratitude... groups will serve as a starting point. LENMA 1. 1. Let 0 be a group not the 1dentity alone. Then 0 has no proper subgroups 1f and only if 0 is s finite oyolio group of prime order. Suppose that 0 is a finite oyolio group of prime order p...

Armendariz, Efraim Pacillas

2012-06-07T23:59:59.000Z

343

Chapter 6 - Case Study–Renewable Integration: Flexibility Requirement, Potential Overgeneration, and Frequency Response Challenges  

Science Journals Connector (OSTI)

Abstract The ISO analysis has shown that variability and uncertainty of predicting renewable production do pose some operational challenges. The output from renewable production can increase and drop-off dramatically by hundreds of megawatts in just a matter of 30 minutes, which would require more flexible resources into the ISO’s generation mix. This need is compounded as California policy on once-through-cooling resources may result in the shutting-down of approximately 12,000 MW of conventional resources over the next 7 years. Managing a more complex grid during this transitional period, ensuring the right mix of resource are available in real-time to maintain reliability and meeting mandatory control performance standards become more of a challenge. As a result of this fleet evolution, there are real opportunities to design the fleet make up and incentivize new capability from a broad range of source including 1) demand response, 2) the variable resources themselves, 3) regional coordination, 4) storage and 5) hydro, in addition to the conventional resources to optimize meeting the policy objectives while ensuring basic grid reliability is maintained. On some days during the spring months, the ISO’s net-load is expected to drop to levels that encroach on non-dispatchable production levels when solar and wind production is high and system demand is low. Thus, in the middle of the day when the sun is shining there would be less need for additional supply resources. As time progresses to the evening hours towards sunset, there is an immediate need to replace the solar generation in addition to meeting increase in consumer demand. A complicating factor is that many of the conventional resources that could replace the solar generation must start prior to this significant ramp. These resources often require several hours to a day or more to fully come on line, which can cause more generation to be on line than consumer demand causing over generation conditions. Under existing arrangement solar (and wind) resources have limited provisions to be curtailed. Therefore as most conventional generators require this "start-up" time to reach their minimum load levels, at times the minimum energy on conventional resources may not be needed but the units cannot be shut down because the resources are needed later on during the day. There is little that a grid operator can do to accommodate this excess generation condition as supply and demand must match instantaneously. As over generation condition increase there would be a need to increase regional coordination by forming an Energy Imbalance Market to help mitigate the potential for over-generation conditions. Other solutions such as advanced demand response and storage may also be innovative solutions in the future to help balance the system during range of expected daily imbalance conditions. In addition, incentivizing the renewable resources to be flexible themselves may also be part of the solution. To reliably operate the system, the ISO is advocating for resource flexibility that can start up and provide its maximum energy quickly. An additional condition requiring flexible resources is the intra-hour variability of passing clouds or storm conditions that can interrupt the output of the wind and solar generation resources. Another operational condition that must be met in real-time is the need to ensure sufficient inertia and frequency response exists in the system. Today, conventional resources because of their rotating mass and ability to respond to changes in frequency provide a reliable shock absorber to disturbance events. As such resources are displaced by renewable resources, it will be important to ensure the system is able to respond to dynamic events in a stable manner. Again in this area, opportunities exist that would allow renewable resources to be part of the solution. There are also opportunities to make wider use of demand response and smart technologies to provide this primary frequency response capability.

Mark Rothleder; Clyde Loutan

2014-01-01T23:59:59.000Z

344

Two-Phase Reaction Turbine. Technical progress report for the period July-December 1999  

SciTech Connect

During the initial part of this period the concentrated effort was placed on getting comprehensive analysis and design of the turbine prototype. This was in order to be able to initiate its fabrication as needed for its building, assembling and timely testing. In the second part of this period the effort was placed on design and other considerations needed to acquire the test rig within the limited budget based on subsequent grant from the DOE.

NONE

1999-12-31T23:59:59.000Z

345

Comparison of quantization of charge transport in periodic and open pumps  

E-Print Network (OSTI)

We compare the charges transported in two systems, a spatially periodic and an open quantum pump, both depending periodically and adiabatically on time. The charge transported in a cycle was computed by Thouless, respectively by Buttiker et al. in the two cases. We show that the results agree in the limit where the two physical situations become the same, i.e., that of a large open pump.

Gian Michele Graf; Gregorio Ortelli

2007-09-19T23:59:59.000Z

346

Self-seeded single-frequency laser peening method  

DOE Patents (OSTI)

A method of operating a laser to obtain an output pulse having a single wavelength, comprises inducing an intracavity loss into a laser resonator having an amount that prevents oscillation during a time that energy from the pump source is being stored in the gain medium. Gain is built up in the gain medium with energy from the pump source until formation of a single-frequency relaxation oscillation pulse in the resonator. Upon detection of the onset of the relaxation oscillation pulse, the intracavity loss is reduced, such as by Q-switching, so that the built-up gain stored in the gain medium is output from the resonator in the form of an output pulse at a single frequency. An electronically controllable output coupler is controlled to affect output pulse characteristics. The laser acts a master oscillator in a master oscillator power amplifier configuration. The laser is used for laser peening.

DAne, C.Brent; Hackey, Lloyd A.; Harris, Fritz B.

2012-06-26T23:59:59.000Z

347

IUPAC Periodic Table of Isotopes for the Educational Community  

SciTech Connect

John Dalton first proposed the concept of atomic weights of the elements in the first decade of the nineteenth century. These atomic weights of the chemical elements were thought of as constants of nature, similar to the speed of light. Dmitri Mendeleev arranged the atomic weights of the elements in ascending order of value and used the systematic variation of their chemical properties to produce his Periodic Table of the Elements in 1869. Measurement of atomic weight values became an important chemical activity for a century and a half. Theodore Richards received a Noble Prize for his work in this area. In 1913, Fredrick Soddy found a species of radium, which had an atomic weight value of 228, compared to the familiar radium gas value of 226. Soddy coined the term 'isotope' (Greek for 'in the same place') to account for this second atomic weight value in the radium position of the Periodic Table. Both of these isotopes of radium are radioactive. Radioactive isotopes are energetically unstable and will decay (disintegrate) over time. The time it takes for one half of a sample of a given radioactive isotope to decay is the half-life of that isotope. In addition to having different atomic weight values, radium-226 and radium-228 also have different half-life values. Around the same time as Soddy's work, J.J. Thomson (discoverer of the electron) identified two stable (non-radioactive) isotopes of the same element, neon. Over the next 40 years, the majority of the known chemical elements were found to have two or more stable (or long-lived radioactive isotopes that contribute significantly to the determination of the atomic weights of the elements).

Holden N. E.; Holden,N.E.; Coplen,T.B.

2012-07-15T23:59:59.000Z

348

Reconstruction of spatial patterns of climatic anomalies during the medieval warm period (AD 900-1300)  

SciTech Connect

The workshop will focus on climatic variations during the Medieval Warm Period or Little Climatic Optimum. The nominal time interval assigned to this period is AD 900--1300, but climate information available during the century or two preceding and following this episode is welcome. The aims of the workshop will be to: examine the available evidence for the existence of this episode; assess the spatial and temporal synchronicity of the climatic signals; discuss possible forcing mechanisms; and identify areas and paleoenvironmental records where additional research efforts are needed to improve our knowledge of this period. This document consists of abstracts of eighteen papers presented at the meeting.

Diaz, H.F. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Environmental Research Labs.; Hughes, M.K. [Arizona Univ., Tucson, AZ (United States). Lab. of Tree-Ring Research

1992-12-31T23:59:59.000Z

349

Connection between the period and the amplitude of the Blazhko effect  

E-Print Network (OSTI)

We found a possible relationship between the modulation period and the amplitude of the Blazhko RR Lyrae stars: long modulation period generally implies high modulation amplitude while the short modulation period results in small amplitude. Although this effect is much more a tendency than a strict rule, it can be detected easily in the space-born time series data produced by Kepler and CoRoT. Good quality ground-based data show this relation, too. This phenomenon could give us constraints for the physics of the Blazhko effect.

Benk?, J M

2014-01-01T23:59:59.000Z

350

Dynamic Response of a Rotor-air Bearing System Due to Base Induced Periodic Motions  

E-Print Network (OSTI)

.............................................................. 20 Typical base motion induced accelerations..................................... 20 Rotor speed coast down tests .......................................................... 22... ............................................................. 16 6 Photograph of connection of shaker to test rig base plate.......................... 17 7 Typical measured base acceleration in time domain. Shaker excitation frequency: 6 Hz. Rotor speed = 34 krpm (567 Hz...

Niu, Yaying

2010-01-14T23:59:59.000Z

351

Electromagnetic Siegert states for periodic dielectric structures  

E-Print Network (OSTI)

The formalism of Siegert states to describe the resonant scattering in quantum theory is extended to the resonant scattering of electromagnetic waves on periodic dielectric arrays. The excitation of electromagnetic Siegert states by an incident wave packet and their decay is studied. The formalism is applied to develop a theory of coupled electromagnetic resonances arising in the electromagnetic scattering problem for two such arrays separated by a distance 2h (or, generally, when the physical properties of the scattering array depend on a real coupling parameter h). Analytic properties of Siegert states as functions of the coupling parameter h are established by the Regular Perturbation Theorem which is an extension the Kato-Rellich theorem to the present case. By means of this theorem, it is proved that if the scattering structure admits a bound state in the radiation continuum at a certain value of the coupling parameter h, then there always exist regions within the structure in which the near field can be amplified as much as desired by adjusting the value of h. This establishes a rather general mechanism to control and amplify optical nonlinear effects in periodically structured planar structures possessing a nonlinear dielectric susceptibility.

Friends R. Ndangali; Sergei V. Shabanov

2011-08-09T23:59:59.000Z

352

Turbine bucket natural frequency tuning rib  

DOE Patents (OSTI)

A tuning rib is added preferably in the aft cavity of a cored turbine bucket to alter the bucket's natural frequencies. The tuning rib may be a solid rib or a segmented rib and is particularly suited for altering high order frequency modes such as 2T, 4F and 1-3S. As such, detrimental crossings of natural bucket frequencies and gas turbine stimuli can be avoided to thereby improve the reliability of a gas turbine without impacting other features of the bucket that are important to the performance of the gas turbine.

Wang, John Zhiqiang (Greenville, SC); Norton, Paul Francis (Greenville, SC); Barb, Kevin Joseph (Halfmoon, NY); Jacala, Ariel Caesar-Prepena (Simpsonville, SC)

2002-01-01T23:59:59.000Z

353

High power radio frequency attenuation device  

DOE Patents (OSTI)

A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

Kerns, Quentin A. (Bloomingdale, IL); Miller, Harold W. (Winfield, IL)

1984-01-01T23:59:59.000Z

354

Robust Inventory Routing with Flexible Time Window Allocation  

E-Print Network (OSTI)

Jan 15, 2015 ... ... time buffers are spread among deliveries and consecutive deliveries at a port are separated by at least some minimum number of periods.

Chengliang Zhang

2015-01-15T23:59:59.000Z

355

Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time  

E-Print Network (OSTI)

Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Amy:56:27.6 Deborah Mc Eligot Deborah Storrings Male Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Macon Fessenden 20 1 5:42.2 2 0:26.9 1 34:29.7 3:23 1 0:12.8 1 17:41.1 3

Suzuki, Masatsugu

356

REPORT NAME (CLICK FOR A SAMPLE) DESCRIPTION FREQUENCY KEY FIELDS Budget Allocation & Transfer Report Provides a line detail view of budget allocation and transfer  

E-Print Network (OSTI)

REPORT NAME (CLICK FOR A SAMPLE) DESCRIPTION FREQUENCY KEY FIELDS Budget Allocation & Transfer Report Provides a line detail view of budget allocation and transfer transactions by department as of a specific mid-month or month-end period (i.e. accounting period). Report can be sorted by Account, Fund

de Lijser, Peter

357

Parametric Instability in Long Optical Cavities and Suppression by Dynamic Transverse Mode Frequency Modulation  

E-Print Network (OSTI)

Three mode parametric instability has been predicted in Advanced gravitational wave detectors. Here we present the first observation of this phenomenon in a large scale suspended optical cavity designed to be comparable to those of advanced gravitational wave detectors. Our results show that previous modelling assumptions that transverse optical modes are stable in frequency except for frequency drifts on a thermal deformation time scale is unlikely to be valid for suspended mass optical cavities. We demonstrate that mirror figure errors cause a dependence of transverse mode offset frequency on spot position. Combined with low frequency residual motion of suspended mirrors, this leads to transverse mode frequency modulation which suppresses the effective parametric gain. We show that this gain suppression mechanism can be enhanced by laser spot dithering or fast thermal modulation. Using Advanced LIGO test mass data and thermal modelling we show that gain suppression factors of 10-20 could be achieved for ind...

Zhao, Chunnong; Fang, Qi; Blair, Carl; Qin, Jiayi; Blair, David; Degallaix, Jerome; Yamamoto, Hiroaki

2015-01-01T23:59:59.000Z

358

Data Compression for Nearly-Periodic Data  

Science Journals Connector (OSTI)

Shape from shade and Hartmann sensing require plenty of pixels for measurement, but many fewer can be analyzed, saving space and time. We found a method to compress large-format camera...

Talmi, Amos; Ribak, Erez N

359

Time-specific measurements of energy deposition from radiation fields in simulated sub-micron tissue volumes  

SciTech Connect

A tissue-equivalent spherical proportional counter is used with a modified amplifier system to measure specific energy deposited from a uniform radiation field for short periods of time ({approximately}1 {micro}s to seconds) in order to extrapolate to dose in sub-micron tissue volumes. The energy deposited during these time intervals is compared to biological repair processes occurring within the same intervals after the initial energy deposition. The signal is integrated over a variable collection time which is adjusted with a square-wave pulse. Charge from particle passages is collected on the anode during the period in which the integrator is triggered, and the signal decays quickly to zero after the integrator feedback switch resets; the process repeats for every triggering pulse. Measurements of energy deposited from x rays, {sup 137}Cs gamma rays, and electrons from a {sup 90}Sr/{sup 90}Y source for various time intervals are taken. Spectral characteristics as a function of charge collection time are observed and frequency plots of specific energy and collection time-interval are presented. In addition, a threshold energy flux is selected for each radiation type at which the formation of radicals (based on current measurements) in mammalian cells equals the rate at which radicals are repaired.

Famiano, M.A.

1997-07-07T23:59:59.000Z

360

Characterization of arcs in frequency domain  

SciTech Connect

Arc detection systems are developed for ICRH on ITER to prevent arcs from damaging the RF components. One of the detectors, the Sub-Harmonic Arc Detector (SHAD) is based on the detection of the frequencies emitted in the MHz range by arcs [R1]. To ensure the high level of reliability required for this safety system, it is necessary to demonstrate that these frequencies present a signal with a Signal to Noise Ratio high enough to be detected under the wide range of operational conditions (frequency, power, configuration) and for the different types of arcs that can appear in the feeding lines and on the antennas (vacuum arc, glow discharge, multipactor-induced discharge). For each type of arc, we analyze the evolution of the frequency spectrum relative to the evolution of other electrical parameters (reflected power, voltage)

D'Inca, R.; Siegl, G.; Faugel, H.; Braun, F.; Eckert, B.; Bobkov, V. [Max Planck Institut fuer Plasmaphysik, Garching, Germany, EURATOM Association (Germany); El Khaldi, M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Noterdaeme, J.-M. [Max Planck Institut fuer Plasmaphysik, Garching, Germany, EURATOM Association (Germany); Gent University, EESA Department (Belgium)

2009-11-26T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Spatial Frequency Filtering Using Nondelineated Thin Films  

Science Journals Connector (OSTI)

We present a new approach for achieving spatial frequency filtering in the analog domain. Our device, the Thin Film Spatial Filter, is a hybrid structure which combines the strengths of analog VLSI technology with the simplicity of a continuous sheet ...

J. Mcelvain; J. Langan; A. J. Heeger

1997-10-01T23:59:59.000Z

362

Laser Doppler vibrometer employing active frequency feedback  

SciTech Connect

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

363

Radio Frequency Identification : regulating information privacy protection  

E-Print Network (OSTI)

As applications of Radio Frequency Identification (RFID) become more profuse, the technology itself is stirring up some controversy. Due to its potential for amassing large amounts of information about both people and ...

Laufer, Deanna (Deanna Raquel)

2007-01-01T23:59:59.000Z

364

Developing high-frequency equities trading models  

E-Print Network (OSTI)

The purpose of this paper is to show evidence that there are opportunities to generate alpha in the high frequency environment of the US equity market, using Principal Component Analysis (PCA hereafter) as a basis for short ...

Infantino, Leandro Rafael

2010-01-01T23:59:59.000Z

365

Calibration for Frequencies of Stellar Spectral Lines  

E-Print Network (OSTI)

When studying the expansion of the universe, a significant problem is measuring the red shifts of stellar absorption lines with sufficiently high accuracy; this requires extremely accurate reference frequencies for calibration. An important recent...

Gomez, Juana

2010-07-14T23:59:59.000Z

366

Plasma Paramagnetism in Radio-Frequency Fields  

Science Journals Connector (OSTI)

A study by experiment, simulation, and theory has found that a plasma responds paramagnetically to the external rf magnetic field applied perpendicular to the static magnetic field with frequency ?frequency. This effect can be exploited in the rf plugging and heating of plasmas; it explains the earlier rf plugging experiment (type-3 coil) of Watari et al. at Nagoya and possibly the rf heating experiment of Dikii et al. on the Uragan stellarator.

Y. Ohsawa; M. Inutake; T. Tajima; T. Hatori; T. Kamimura

1979-10-22T23:59:59.000Z

367

IAA: Interference Aware Anticipatory Algorithm for Scheduling and Routing Periodic Real-time Streams  

E-Print Network (OSTI)

, cabling is expensive, and can cost as much as $2000 per foot in highly controlled environments such as nuclear power plants [3]. Cabling systems do not scale easily to large geographic areas, and can reliability and increase maintenance costs. Wireless communication is a cheaper and more scalable alternative

Whitehouse, Kamin

368

STEADY MODES IN RELAY CONTROL SYSTEMS WITH TIME DELAY AND PERIODIC  

E-Print Network (OSTI)

, Ramat- Aviv, 69978 Tel Aviv, Israel. E-mail: emilia@eng.tau.ac.il Chihuahua Institute of Technology, Av. Technologica 2909, A.P. 2-1549, Chihuahua, Chi, C.P. 31160, Mexico E-mail: lfridman@platon.itch.edu.mx School

Fridman, Emilia

369

Determining articulator configuration in voiced stop consonants by matching time-domain patterns in pitch periods  

E-Print Network (OSTI)

In this thesis I will be concerned with linking the observed speechsignal to the configuration of articulators.Due to the potentially rapid motion of the articulators, the speechsignal can be highly non-stationary. The ...

Kondacs, Attila

2005-01-28T23:59:59.000Z

370

Systems for optimizing the condition of beef carcasses for distribution over extended time periods  

E-Print Network (OSTI)

of simulated nitrogen gas atmospheres in comparison to normal air atmospheres for beef storage. Eighty beef sides were divided into quarters and subjected to one of eight treatments 48 hr postmortem. Two kinds of surface protection (unprotected vs. PVC film... wrapping), two rinsing treat- ments (200 ppm chlorine vs. no chlorine rinse), two types of atmos- phere (air vs. nitrogen gas) and two storage intervals (14 vs. 21 days) were compared. Analysis of variance revealed that wrapping in PVC film, rinsing...

Simmons, Ronald Douglas

1974-01-01T23:59:59.000Z

371

Quality factor tuning of high-frequency high-Q filter biquads using adaptive signal processing  

E-Print Network (OSTI)

A quality factor (Q) tuning technique for high-frequency and high-Q continuous-time filter biquads is proposed. The method is based on the existing magnitude locked loop Q-tuning technique, but it utilizes the continuous-time adaptive LMS algorithm...

Stevenson, Jan-Michael

2012-06-07T23:59:59.000Z

372

Mo Year Report Period: EIA ID NUMBER:  

U.S. Energy Information Administration (EIA) Indexed Site

Version No: 2013.01 Mo Year Report Period: EIA ID NUMBER: http://www.eia.gov/survey/form/eia_14/instructions.pdf Mailing Address: Secure File Transfer option available at: (e.g., PO Box, RR) https://signon.eia.doe.gov/upload/noticeoog.jsp Electronic Transmission: The PC Electronic Zip Code - Data Reporting Option (PEDRO) is available. If interested in software, call (202) 586-9659. Email form to: OOG.SURVEYS@eia.doe.gov - - - - Fax form to: (202) 586-9772 Mail form to: Oil & Gas Survey Email address: U.S. Department of Energy Ben Franklin Station PO Box 279 Washington, DC 20044-0279 Questions? Call toll free: 1-800-638-8812 PADD 4 Type of Report (Check One ): (Thousands of dollars) (Thousands of barrels) PADD 2 PADD 3 PAD DISTRICT (a) Revision to Report:

373

Steady periodic gravity waves with surface tension  

E-Print Network (OSTI)

In this paper we consider two-dimensional, stratified, steady water waves propagating over an impermeable flat bed and with a free surface. The motion is assumed to be driven by capillarity (that is, surface tension) on the surface and a gravitational force acting on the body of the fluid. We prove the existence of global continua of classical solutions that are periodic and traveling. This is accomplished by first constructing a 1-parameter family of laminar flow solutions, $\\mathcal{T}$, then applying bifurcation theory methods to obtain local curves of small amplitude solutions branching from $\\mathcal{T}$ at an eigenvalue of the linearized problem. Each solution curve is then continued globally by means of a degree theoretic theorem in the spirit of Rabinowitz. Finally, we complement the degree theoretic picture by proving an alternate global bifurcation theorem via the analytic continuation method of Dancer.

Samuel Walsh

2009-11-06T23:59:59.000Z

374

Extremely high frequency RF effects on electronics.  

SciTech Connect

The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

2012-01-01T23:59:59.000Z

375

Theory of parametric frequency down conversion of light  

Science Journals Connector (OSTI)

A theoretical study is made of the process in which incident pump photons that interact with a nonlinear medium (such as a crystal lacking inversion symmetry) are spontaneously split into lower-frequency signal and idler photons. The down-converted fields are quantized and described by a continuum of modes, a subset of which interacts with each photodetector. It is shown that when two ideal photodetectors are appropriately located so that they receive the conjugate signal and idler photons, then the joint probability of two-photon detection by the two detectors can equal the single-photon detection probability. The time correlation between the two detected photons is shown to be limited either by the resolving time of the detectors, or by the bandwidth of the down-converted light, and to be independent of the coherence time of the pump field or of the length of the nonlinear medium. These conclusions are compared with the results of recent experiments.

C. K. Hong and L. Mandel

1985-04-01T23:59:59.000Z

376

Sound attenuation in ducts using locally resonant periodic flush mounted flexible silicon aerogel patches  

Science Journals Connector (OSTI)

In recent years low frequency noise has become an important factor especially in the Aircraft HVAC and Automotive industries. In order to reduce this low frequency noise noise attenuation by the classical Helmholtz resonators has size limitations due to the large wavelengths. Promising noise reductions with flush mounted Silicon Aerogel patches can be obtained implementing attenuation due to local resonance and that too without any size constraints. The objective of the current paper is to introduce locally resonant Silicon Aerogel patches flush mounted to an acoustic duct walls aiming at creating frequency stop bands at the low frequency zone (below 500 Hz). Green’s Function is used under the framework of interface response theory to predict the degree of attenuation of the local resonant patches. Realistic techniques for expanding the stop bandwidth have been introduced and difference between the Bragg scattering and the locally resonant mechanism was demonstrated using mathematical models. The effect of the arrays of patches on the effective dynamic density and bulk modulus has also been investigated. It is also shown that the numbers and periodicity of these local resonators also plays role in determining the depth and width of the acoustic band gap.

Maaz Farooqui; Wael Akl

2013-01-01T23:59:59.000Z

377

Radial Velocity Planets De-aliased: A New, Short Period for Super-Earth 55 Cnc e  

Science Journals Connector (OSTI)

Radial velocity measurements of stellar reflex motion have revealed many extrasolar planets, but gaps in the observations produce aliases, spurious frequencies that are frequently confused with the planets' orbital frequencies. In the case of Gl 581 d, the distinction between an alias and the true frequency was the distinction between a frozen, dead planet and a planet possibly hospitable to life. To improve the characterization of planetary systems, we describe how aliases originate and present a new approach for distinguishing between orbital frequencies and their aliases. Our approach harnesses features in the spectral window function to compare the amplitude and phase of predicted aliases with peaks present in the data. We apply it to confirm prior alias distinctions for the planets GJ 876 d and HD 75898 b. We find that the true periods of Gl 581 d and HD 73526 b/c remain ambiguous. We revise the periods of HD 156668 b and 55 Cnc e, which were afflicted by daily aliases. For HD 156668 b, the correct period is 1.2699 days and the minimum mass is (3.1 ± 0.4) M ?. For 55 Cnc e, the correct period is 0.7365 days—the shortest of any known planet—and the minimum mass is (8.3 ± 0.3) M ?. This revision produces a significantly improved five-planet Keplerian fit for 55 Cnc, and a self-consistent dynamical fit describes the data just as well. As radial velocity techniques push to ever-smaller planets, often found in systems of multiple planets, distinguishing true periods from aliases will become increasingly important.

Rebekah I. Dawson; Daniel C. Fabrycky

2010-01-01T23:59:59.000Z

378

"Stokes' Second Problem in High Frequency Limit. Application to Micro (Nano)- Resonators  

E-Print Network (OSTI)

Using kinetic equation in the relaxation approximation (RTA), we investigate a flow generated by an infinite plate oscillating with frequency $\\omega$. Geometrical simplicity of the problem allows a solution in the entire range of dimensionless frequency variation $0\\leq \\omega \\tau\\leq \\infty$, where $\\tau$ is a properly defined relaxation time. A transition from viscoelastic behavior of Newtonian fluid ($\\omega\\tau\\to 0$) to purely elastic dynamics in the limit $\\omega\\tau\\to \\infty$ is discovered. The relation of the derived solutions to microfluidics (high-frequency micro-resonators) is demonstrated on an example of a "plane oscillator .

V. Yakhot; C. Colosqui

2007-03-26T23:59:59.000Z

379

Evaluation of fossil plants versus hydro plants for load frequency control  

SciTech Connect

The economics of using hydroplants with Francis turbines or fossil plants for load frequency control are evaluated. Using data from the TVA Gallatin steam plant and the TVA Cherokee, Wilson, and Fontana hydroplants, a cost comparison of different modes of operation for load frequency control was performed considering two plants at a time. The results showed that when the fossil plant was used for load frequency control instead of a hydro plant a lower system generation cost was incurred. Dynamic responses of fossil and hydro units, improved controls for fossil plants, and maneuvering costs of the Gallatin plant are also considered.

Broadwater, R.P.; Johnson, R.L.; Duckett, F.E.; Boston, W.T.

1985-01-01T23:59:59.000Z

380

Observation of audio-frequency edge magnetoplasmons in the classical two-dimensional electron gas  

Science Journals Connector (OSTI)

The electric admittance of a two-dimensional electron gas on liquid helium measured at audio frequencies ? is observed to oscillate as a function of magnetic field at strong magnetic fields. The oscillations can be attributed to the propagation of very-low-frequency (???10-6, ? scattering time; ?/?c?10-8, ?c cyclotron frequency) edge magnetoplasmons. The directly determined dispersion relation agrees with theory and quantitatively with measurements in the collisionless regime (???1). The attenuation, theoretically obtained by incorporating the screening in a simple local-capacitance model, agrees well with experiments.

P. J. M. Peters; M. J. Lea; A. M. L. Janssen; A. O. Stone; W. P. N. M. Jacobs; P. Fozooni; R. W. van der Heijden

1991-10-14T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Time Brightness  

NLE Websites -- All DOE Office Websites (Extended Search)

Perlmutter, et al., in Thermonuclear Supernovae, NATO ASI, v. 486 (1997) Perlmutter, et al., in Thermonuclear Supernovae, NATO ASI, v. 486 (1997) Cosmology from . . . Time Brightness ... . . . 50-100 Fields Lunar Calendar Scheduled Follow-Up Imaging at Hubble, Cerro Tololo, WIYN, Isaac Newton Scheduled Follow-Up Spectroscopy at Keck Almost 1000 Galaxies per Field RESULT: ~24 Type Ia supernovae discovered while still brightening, at new moon Berkeley Lab Keck WIYN Cerro Tololo Isaac Newton Hubble Strategy We developed a strategy to guarantee a group of supernova discoveries on a certain date. Just after a new moon, we observe some 50 to 100 high-galactic lattitute fields-each containing almost a thousand high-redshift galaxies-in two nights on the Cerro Tololo 4-meter telescope with Tyson & Bernstein's wide-field camera. We return three weeks later to observe the same

382

An ultra-capacitor for frequency stability enhancement in small-isolated power systems: Models, simulation and field tests  

Science Journals Connector (OSTI)

Abstract The most relevant issue in operation of isolated power systems is frequency stability. Frequency stability is concerned with the ability of generators to supply the loads at an acceptable frequency after a disturbance. Frequency stability is governed by the kinetic energy stored in the generator-prime mover rotating masses and the prime mover frequency primary regulation. If frequency excursions are not within +/?2.5 Hz range, cascade tripping of the remaining generators can occur because of generator over/under frequency protections tripping. Energy storage systems can contribute to frequency stability enhancement if their discharging is governed by a frequency controller. Endesa is leading a research project on testing the state of the art of energy storage systems for several applications (peak-shaving, voltage control, frequency control) in several isolated power systems of the Canary Islands. Several applications are being investigated. One of them consists on the application of a 4 MW–5 s ultracapacitor (UC) for frequency stability enhancement of the La Palma power system. This paper reports the dynamic model developed for time domain simulation and controller design of frequency stability, and field tests undertaken to validate models and the controller settings. A simple but still accurate model is presented. The proposed model takes into account the UC’s state of charge (SoC) and it represents the dynamics of the power electronics by means of a non-linear first-order model. The frequency control consists of droop control and inertia emulation. Ramp rate limits, power limits and SoC are also taken into account in the frequency control. In comparison with the recorded field tests, the proposed model is able to accurately represent the response of the UC for the purpose of frequency stability analysis.

I. Egido; L. Sigrist; E. Lobato; L. Rouco; A. Barrado

2015-01-01T23:59:59.000Z

383

Systems for controlling the intensity variations in a laser beam and for frequency conversion thereof  

DOE Patents (OSTI)

In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the frequency components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and frequency converted (doubled, tripled or quadrupled in frequency) with nonlinear optical elements (birefringent crystals). The spectral variation across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the frequency converter may be used to recollimate the beam. The frequency converted beam is recombined so that portions of different frequency interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temoral oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral variation.

Skupsky, Stanley (Rochester, NY); Craxton, R. Stephen (Rochester, NY); Soures, John (Pittsford, NY)

1990-01-01T23:59:59.000Z

384

Optimal Tariff Period Determination Cost of electricity generation is closely related to system demand. In general, the  

E-Print Network (OSTI)

Optimal Tariff Period Determination Cost of electricity generation is closely related to system setting is giving signal to customers the time variant cost of supplying electricity. Since the costs demand. In general, the generation cost is higher during system peak period, and vice versa. In Hong Kong

385

Vacuum electron acceleration by using two variable frequency laser pulses  

SciTech Connect

A method is proposed for producing a relativistic electron bunch in vacuum via direct acceleration by using two frequency-chirped laser pulses. We consider the linearly polarized frequency-chiped Hermit-Gaussian 0, 0 mode lasers with linear chirp in which the local frequency varies linearly in time and space. Electron motion is investigated through a numerical simulation using a three-dimensional particle trajectory code in which the relativistic Newton's equations of motion with corresponding Lorentz force are solved. Two oblique laser pulses with proper chirp parameters and propagation angles are used for the electron acceleration along the z-axis. In this way, an electron initially at rest located at the origin could achieve high energy, ?=319 with the scattering angle of 1.02{sup ?} with respect to the z-axis. Moreover, the acceleration of an electron in different initial positions on each coordinate axis is investigated. It was found that this mechanism has the capability of producing high energy electron microbunches with low scattering angles. The energy gain of an electron initially located at some regions on each axis could be greatly enhanced compared to the single pulse acceleration. Furthermore, the scattering angle will be lowered compared to the acceleration by using laser pulses propagating along the z-axis.

Saberi, H.; Maraghechi, B. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

2013-12-15T23:59:59.000Z

386

THz laser based on quasi-periodic AlGaAs superlattices  

SciTech Connect

The use of quasi-periodic AlGaAs superlattices as an active element of a quantum cascade laser of terahertz range is proposed and theoretically investigated. A multi-colour emission, having from three to six peaks of optical gain, is found in Fibonacci, Thue-Morse, and figurate superlattices in electric fields of intensity F = 11 - 13 kV cm{sup -1} in the frequency range f = 2 - 4 THz. The peaks depend linearly on the electric field, retain the height of 20 cm{sup -1}, and strongly depend on the thickness of the AlGaAs-layers. (lasers)

Malyshev, K V [N.E. Bauman Moscow State Technical University, Moscow (Russian Federation)

2013-06-30T23:59:59.000Z

387

Atmospheric glow discharges from the high-frequency to very high-frequency bands  

Science Journals Connector (OSTI)

This letter reports an experimental investigation of an atmospheric glow discharge in both the high-frequency (HF) band of 3–30 MHz and the very high frequency band of 30–300 MHz. At constant input power increased frequency is found to change little the electron density and to reduce slightly the electron excitation temperature. Significantly an eightfold frequency increase from 20 to 80 MHz leads to a 20-fold increase in the maximum plasma power without plasma constriction. The maximum power density of 355 ? W / cm 3 achieved at 80 MHz is far greater than those reported in the HF band.

J. L. Walsh; F. Iza; M. G. Kong

2008-01-01T23:59:59.000Z

388

Influence of excitation frequency on plasma parameters and etching characteristics of radio-frequency discharges  

Science Journals Connector (OSTI)

Abstract Plasma parameters such as electron density, electron-collision rate, resonance frequency and the bias voltage were shown to be important for the characterization of radio-frequency (RF) plasmas. By means of self-excited electron resonance spectroscopy (SEERS), the plasma parameters were compared at two different frequencies, 13.56 \\{MHz\\} and 40.68 MHz, in argon, oxygen, fluorine and their mixtures at low pressure. Upon increasing the generator frequency, more RF power has to be applied to achieve the same bias voltage. At the lower pressure, the bias voltage indicates the mean energy of the ions impacting on the substrate and causing damage at the surface. The experimental results show that generally more power was dissipated in the plasma instead of the sheath if the frequency of the substrate generator was decreased. This results in a significantly higher electron density at the higher frequency. The increase of mean ion energy, owing to lower sheath thickness, has to be taken into account as a second-order effect. In order to show the influence of frequency for process applications, the etch rate of SiO2 on silicon was determined in CF4. For the same generator power, there is no well-pronounced dependence of the etch rate of SiO2 on silicon (CF4) on the frequency. For the same bias voltage, the etch rate of SiO2 increases roughly with the frequency.

M. Klick; L. Eichhorn; W. Rehak; M. Kammeyer; H. Mischke

1999-01-01T23:59:59.000Z

389

Atmospheric glow discharges from the high-frequency to very high-frequency bands  

SciTech Connect

This letter reports an experimental investigation of an atmospheric glow discharge in both the high-frequency (HF) band of 3-30 MHz and the very high frequency band of 30-300 MHz. At constant input power, increased frequency is found to change little the electron density and to reduce slightly the electron excitation temperature. Significantly, an eightfold frequency increase from 20 to 80 MHz leads to a 20-fold increase in the maximum plasma power without plasma constriction. The maximum power density of 355 W/cm{sup 3} achieved at 80 MHz is far greater than those reported in the HF band.

Walsh, J. L.; Iza, F.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

2008-12-22T23:59:59.000Z

390

Performance Period Total Fee Paid FY2001  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

01 01 $4,547,400 FY2002 $4,871,000 FY2003 $6,177,902 FY2004 $8,743,007 FY2005 $13,134,189 FY2006 $7,489,704 FY2007 $9,090,924 FY2008 $10,045,072 FY2009 $12,504,247 FY2010 $17,590,414 FY2011 $17,558,710 FY2012 $14,528,770 Cumulative Fee Paid $126,281,339 Cost Plus Award Fee DE-AC29-01AL66444 Washington TRU Solutions LLC Contractor: Contract Number: Contract Type: $8,743,007 Contract Period: $1,813,482,000 Fee Information Maximum Fee $131,691,744 Total Estimated Contract Cost: $4,547,400 $4,871,000 $6,177,902 October 2000 - September 2012 Minimum Fee $0 Fee Available EM Contractor Fee Site: Carlsbad Field Office - Carlsbad, NM Contract Name: Waste Isolation Pilot Plant Operations March 2013 $13,196,690 $9,262,042 $10,064,940 $14,828,770 $12,348,558 $12,204,247 $17,590,414 $17,856,774

391

Effects of periodic matter in kaon regeneration  

E-Print Network (OSTI)

We study the effects of periodic matter in kaon regeneration, motivated by the possibility of parametric resonance in neutrino oscillations. The large imaginary parts of the forward kaon-nucleon scattering amplitudes and the decay width difference $\\Delta\\Gamma$ prevent a sizable enhancement of the $K_L\\to K_S$ transition probability. However, some interesting effects can be produced using regenerators made of alternating layers of two different materials. Despite the fact that the regenerator has a fixed length one can obtain different values for the probability distribution of the $K_L$ decay into a final state. Using a two-arm regenerator set up it is possible to measure the imaginary parts of the $K^0(\\bar{K}^0)$-nucleon scattering amplitudes in the correlated decays of the $\\phi$-resonance. Combining the data of the single-arm regenerator experiments with direct and reverse orders of the matter layers in the regenerator one can independently measure the CP violating parameter $\\delta$.

Evgeny Akhmedov; Augusto Barroso; Petteri Keränen

2001-07-23T23:59:59.000Z

392

Time Dependent Density Functional Theory Application to Extended Systems  

E-Print Network (OSTI)

Time Dependent Density Functional Theory Application to Extended Systems Francesco Sottile Facility (ETSF) Donostia, 25 July 2007 Time Dependent Density Functional Theory Francesco Sottile #12 Density Functional Theory Francesco Sottile #12;Linear Periodic systems ALDA The Quest for the Holy

Botti, Silvana

393

Study of the OCS6 Lattice Using Frequency Maps  

E-Print Network (OSTI)

Frequency maps for the OCS5 and OCS6Frequency maps for the OCS6 lattice for a tune of Q x =tunes. . . . . . . . . Frequency maps for the OCS6 lattice

Reichel, Ina

2007-01-01T23:59:59.000Z

394

Diversity–disturbance relationships: frequency and intensity interact  

Science Journals Connector (OSTI)

...relationship depended on the frequency of disturbances by the...diversity as the response variable and frequency and intensity as factors...unequivocally that the frequency-intensity interaction drives the coexistence of ecologically...

2012-01-01T23:59:59.000Z

395

Superconvergence of period doubling cascade in trapezoid maps  

E-Print Network (OSTI)

In the symmetric and the asymmetric trapezoid maps, as a slope of the trapezoid is increased, the period doubling cascade occurs and the symbolic sequence of periodic points is the Metropolis-Stein-Stein sequence and the convergence of the onset point of the period 2^m solution to the accumulation point is exponentially fast. We reported these results previously. In this paper, we give the detailed description of the proof on the results. Further, we study the period doubling cascade starting from period p solution and show the superconvergence of the period doubling cascade.

T. Uezu

2000-01-12T23:59:59.000Z

396

Search for periodicities in the B8 solar neutrino flux measured by the Sudbury Neutrino Observatory  

Science Journals Connector (OSTI)

A search has been made for sinusoidal periodic variations in the B8 solar neutrino flux using data collected by the Sudbury Neutrino Observatory over a 4-year time interval. The variation at a period of 1 yr is consistent with modulation of the B8 neutrino flux by the Earth’s orbital eccentricity. No significant sinusoidal periodicities are found with periods between 1 d and 10 years with either an unbinned maximum likelihood analysis or a Lomb-Scargle periodogram analysis. The data are inconsistent with the hypothesis that the results of the recent analysis by Sturrock et al., based on elastic scattering events in Super-Kamiokande, can be attributed to a 7% sinusoidal modulation of the total B8 neutrino flux.

B. Aharmim et al. (SNO Collaboration)

2005-09-30T23:59:59.000Z

397

Properties of Fourier spectrum of the signal, generated at the accumulation point of period-tripling bifurcations  

E-Print Network (OSTI)

Universal regularities of the Fourier spectrum of signal, generated by complex analytic map at the period-tripling bifurcations accumulation point are considered. The difference between intensities of the subharmonics at the values of frequency corresponding to the neighbor hierarchical levels of the spectrum is characterized by a constant $\\gamma=21.9$ dB?, which is an analogue of the known value $\\gamma_F=13.4$ dB, intrinsic to the Feigenbaum critical point. Data of the physical experiment, directed to the observation of the spectrum at period-tripling accumulation point, are represented.

O. B. Isaeva

2005-07-11T23:59:59.000Z

398

THE DISCOVERY OF PERIODIC MODULATIONS IN THE OPTICAL SPECTRA OF GALAXIES, POSSIBLY DUE TO ULTRARAPID LIGHT BURSTS FROM THEIR MASSIVE CENTRAL BLACK HOLES  

SciTech Connect

A Fourier transform analysis of 2.5 million spectra in the SDSS survey was carried out to detect periodic modulations contained in the intensity versus frequency spectrum. A statistically significant signal was found for 223 galaxies, while the spectra of 0.9 million galaxies were observed. A plot of the periods as a function of redshift clearly shows that the effect is real without any doubt, because the modulations are quantized at two base periods that increase with redshift in two very tight parallel linear relations. We suggest that this result could be caused by light bursts separated by times on the order of 10{sup -13} s, but other causes may be possible. We investigate the hypothesis that the modulation is generated by the Fourier transform of spectral lines, but conclude that this hypothesis is not valid. Although the light burst suggestion implies absurdly high temperatures, it is supported by the fact that the Crab pulsar also has extremely short unresolved pulses (<0.5 ns) that imply similarly high temperatures. Furthermore, the radio spectrum of the Crab pulsar also has spectral bands similar to those that have been detected. Finally, decreasing the signal-to-noise threshold of detection gives results consistent with beamed signals having a small beam divergence, as expected from non-thermal sources that send a jet, like those seen in pulsars. Considering that galaxy centers contain massive black holes, exotic black hole physics may be responsible for the spectral modulation. However, at this stage, this idea is only a hypothesis to be confirmed with further work.

Borra, Ermanno F., E-mail: borra@phy.ulaval.ca [Centre d'Optique, Photonique et Laser, Departement de Physique, Universite Laval, Quebec, G1K 7P4 Quebec (Canada)

2013-09-10T23:59:59.000Z

399

Frequency Instability Problems in North American Interconnections  

NLE Websites -- All DOE Office Websites (Extended Search)

Frequency Instability Problems in Frequency Instability Problems in North American Interconnections May 1, 2011 DOE/NETL-2011/1473 Frequency Instability Problems in North American Interconnections Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement,

400

Frequency dependence of the Chiral Vortical Effect  

E-Print Network (OSTI)

We study the frequency dependence of all the chiral vortical and magnetic conductivities for a relativistic gas of free chiral fermions and for a strongly coupled conformal field theory with holographic dual in four dimensions. Both systems have gauge and gravitational anomalies, and we compute their contribution to the conductivities. The chiral vortical conductivities and the chiral magnetic conductivity in the energy current show a frequency dependence in the form of a delta centered at zero frequency. This highly discontinuous behavior is a natural consequence of the Ward identities that include the energy momentum tensor. We discuss the physical interpretation of this result and its possible implications for the quark gluon plasma as created in heavy ion collisions. In the Appendix we discuss why the chiral magnetic effect seems to vanish in the consistent current for a particular implementation of the axial chemical potential.

Karl Landsteiner; Eugenio Megias; Francisco Peña Benítez

2014-09-18T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

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

402

Determination of the superhump period of the dwarf nova V701 Tau during the 2005 December superoutburst  

E-Print Network (OSTI)

We report new measurements of the superhump period of the UGSU-type dwarf nova V701 Tau during the 2005 December superoutburst. Using unfiltered time series CCD observations on 3 nights, we determine a probable superhump period Psh = 0.0690, plus or minus 0.0002d, but note that our data also permit a possible shorter period of 0.0663, plus or minus 0.0002d. The longer period agrees with the value measured during the first recorded superoutburst in 1995.

Jeremy Shears; David Boyd

2006-08-03T23:59:59.000Z

403

INSTALLATION, COMMISSIONING AND TROUBLE SHOOTING OF VARIABLE FREQUENCY DRIVE.  

E-Print Network (OSTI)

??In this thesis, the installation of variable frequency drive on board a ship is introduced briefly. In this particular study the variable frequency drive was… (more)

Kuituniemi, Santtu

2013-01-01T23:59:59.000Z

404

LOFAR, a new low frequency radio telescope  

E-Print Network (OSTI)

LOFAR, the Low Frequency Array, is a large radio telescope consisting of approximately 100 soccer-field sized antenna stations spread over a region of 400 km in diameter. It will operate at frequencies from ~10 to 240 MHz, with a resolution at 240 MHz of better than an arcsecond. Its superb sensitivity will allow for studies of a broad range of astrophysical topics, including reionisation, transient radio sources and cosmic rays, distant galaxies and AGNs. In this contribution a status rapport of the LOFAR project and an overview of the science case is presented.

H. J. A. Rottgering

2003-09-19T23:59:59.000Z

405

Seismic isolation systems with distinct multiple frequencies  

DOE Patents (OSTI)

A method and apparatus for isolating a building or other structure from smic vibratory motion which provides increased assurance that large horizontal motion of the structure will not occur than is provided by other isolation systems. Increased assurance that large horizontal motion will not occur is achieved by providing for change of the natural frequency of the support and structure system in response to displacement of the structure beyond a predetermined value. The natural frequency of the support and structure system may be achieved by providing for engaging and disengaging of the structure and some supporting members in response to motion of the supported structure.

Wu, Ting-shu (Downers Grove, IL); Seidensticker, Ralph W. (Wheaton, IL)

1990-01-01T23:59:59.000Z

406

Undulations from amplified low frequency surface waves  

SciTech Connect

We study the linear scattering of gravity waves in longitudinal inhomogeneous stationary flows. When the flow becomes supercritical, it is known that counterflow propagating shallow waves are blocked and converted into deep waves. Here we show that in the zero-frequency limit, the reflected waves are amplified in such a way that the free surface develops an undulation, i.e., a zero-frequency wave of large amplitude with nodes located at specific places. This amplification involves negative energy waves and implies that flat surfaces are unstable against incoming perturbations of arbitrary small amplitude. The relation between this instability and black hole radiation (the Hawking effect) is established.

Coutant, Antonin, E-mail: antonin.coutant@aei.mpg.de [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Muhlenberg 1, 14476 Golm (Germany)] [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Muhlenberg 1, 14476 Golm (Germany); Parentani, Renaud, E-mail: renaud.parentani@th.u-psud.fr [Laboratoire de Physique Théorique, CNRS UMR 8627, Bâtiment 210, Université Paris-Sud 11, 91405 Orsay Cedex (France)] [Laboratoire de Physique Théorique, CNRS UMR 8627, Bâtiment 210, Université Paris-Sud 11, 91405 Orsay Cedex (France)

2014-04-15T23:59:59.000Z

407

Two-frequency excitation of hydrogen atoms  

Science Journals Connector (OSTI)

When a hydrogen atom in a state with principal quantum number ni is irradiated simultaneously with light of frequency ?L, nearly that required to produce a transition to a higher state with principal quantum number nf and with microwave radiation of frequency ?, the transition is very probable when the resonance condition ?L+k?=Ef-Ei is satisfied, the emission or absorption of the net number k of microwave photons just compensating for the detuning of the light from the resonance. This process is analyzed with the use of a forward scattering method and the results are used to discuss the experiments of Bayfield et al. on the excitation of hydrogen.

P. Stehle

1982-11-01T23:59:59.000Z

408

Periodic thermodynamics of laser-driven molecular motor  

Science Journals Connector (OSTI)

Operation of a laser-driven nano-motor inevitably generates a non-trivial amount of heat, which can possibly lead to instability or even hinder the motor's continual running. This work quantitatively examines the overheating problem for a recently proposed laser-operated molecular locomotive. We present a single-molecule cooling theory, in which molecular details of the locomotive system are explicitly treated. This theory is able to quantitatively predict cooling efficiency for various candidates of molecular systems for the locomotive, and also suggests concrete strategies for improving the locomotive's cooling. It is found that water environment is able to cool the hot locomotive down to room temperature within 100 picoseconds after photon absorption. This cooling time is a few orders of magnitude shorter than the typical time for laser operation, effectively preventing any overheating for the nano-locomotive. However, when the cooling is less effective in non-aqueous environment, residual heat may build up. A continuous running of the motor will then lead to a periodic thermodynamics, which is a common character of many laser-operated nano-devices.

Li Dan; Zheng Wen-Wei; Wang Zhi-Song

2008-01-01T23:59:59.000Z

409

Frequency locking in an injection-locked frequency divider Michele V. Bartuccelli  

E-Print Network (OSTI)

experimentally, and the devil's staircase structure of the lockings is measured: when the ratio of the frequency of the driving frequency. We provide explicit formulae for the width of the plateaux appearing in the devil's staircase structure of the lockings, and in particular show that the largest plateaux correspond to even

Gentile, Guido

410

Frequency locking in the injection-locked frequency divider Michele V. Bartuccelli  

E-Print Network (OSTI)

- tally, and the devil's staircase structure of the lockings is measured: when the ratio of the frequency of the driving frequency. We provide explicit formulae for the width of the plateaux appearing in the devil's staircase structure of the lockings, and in particular show that the largest plateaux correspond to even

Roma "La Sapienza", Università di

411

Long period oscillations and tidal level in the Port of Ferrol  

Science Journals Connector (OSTI)

ABSTRACT A new container terminal will soon be inaugurated in the Port of Ferrol (Spain). Sea level observations show the occurrence of seiche events in the basin. The objective of this work is to investigate the long wave oscillations and their dependence on the tidal level. Two analysis techniques, fast Fourier transform (FFT) and short time Fourier transform (STFT), are applied. Time-averaged spectra corresponding to different tidal levels are obtained with the FFT, whereas seiche events are identified on spectrograms computed with the STFT. The time-averaged power density spectra features eleven well-marked peaks, with moderate to high amplification. A clear influence of the tide on the spectral peaks is found, with most peaks presenting higher frequencies and greater power densities at high tide. The analysis of the individual seiche events shows that the behavior of long wave energy in the basin varies across the spectrum; on these grounds, three frequency bands are proposed: LF (low frequency), VLF (very low frequency), and ULF (ultra low frequency). The LF band exhibits a high correlation with the offshore swell energy, both outside and inside the harbor. At the other end of the long wave spectrum, the ULF band is only weakly correlated with the swell; it responds to a different forcing, possibly related to atmospheric disturbances. Finally, the intermediate VLF band presents a mixed character, with influences both from the swell and the other driving agent. The contributions of the paper are as follows. First, the long wave behavior at the Port of Ferrol, a major port in Spain, is characterized for the first time. Second, two contrasting behaviors affecting different frequency ranges are identified—one is proven to be swell-driven, whereas the other is proven, on the contrary, to not be swell-related. And, finally, the tidal oscillation is found to be relevant to the long wave behavior within the port, for it affects both the frequencies and power densities of the spectral peaks—but not to the generation of long waves outside the harbor.

M. López; G. Iglesias; N. Kobayashi

2012-01-01T23:59:59.000Z

412

EIS-0403: Public Comment Period Extension | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

403: Public Comment Period Extension 403: Public Comment Period Extension EIS-0403: Public Comment Period Extension Solar Energy Development in Six Southwestern States The Bureau of Land Management (BLM) announced a two-week extension of the public comment period for the Draft Solar Programmatic Environmental Impact Statement (Draft Solar PEIS), a joint effort with the Department of Energy. The agencies had previously provided for a 120-day public comment period on the Draft Solar PEIS. Because of numerous requests, the agencies extended the comment period by an additional two weeks beyond April 16, 2011. The comment period ran (with extension) until May 2, 2011. EIS-0403-DEIS_Second_Comment_Extension-2011.pdf More Documents & Publications EIS-0403: Notice to Extend Public Comment Period

413

An Investigation into Solar Wind Plasma Periodicities Karolen I. Paularena  

E-Print Network (OSTI)

An Investigation into Solar Wind Plasma Periodicities Karolen I. Paularena Center for Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts Received ; accepted To be submitted to Journal of Geophysical Research, 1996. Short title: SOLAR WIND PLASMA PERIODICITIES #12

Richardson, John

414

Recommendation 186: Option Periods in Prime Contract Language  

Energy.gov (U.S. Department of Energy (DOE))

The inclusion of option periods in the language of all future DOE Request for Proposals for prime contracts when appropriate.

415

Micromachined low frequency rocking accelerometer with capacitive pickoff  

DOE Patents (OSTI)

A micro electro mechanical sensor that uses capacitive readout electronics. The sensor involves a micromachined low frequency rocking accelerometer with capacitive pickoff fabricated by deep reactive ion etching. The accelerometer includes a central silicon proof mass, is suspended by a thin polysilicon tether, and has a moving electrode (capacitor plate or interdigitated fingers) located at each end the proof mass. During movement (acceleration), the tethered mass moves relative to the surrounding packaging, for example, and this defection is measured capacitively by a plate capacitor or interdigitated finger capacitor, having the cooperating fixed electrode (capacitor plate or interdigitated fingers) positioned on the packaging, for example. The micromachined rocking accelerometer has a low frequency (<500 Hz), high sensitivity (.mu.G), with minimal power usage. The capacitors are connected to a power supply (battery) and to sensor interface electronics, which may include an analog to digital (A/D) converter, logic, RF communication link, antenna, etc. The sensor (accelerometer) may be, for example, packaged along with the interface electronics and a communication system in a 2".times.2".times.2" cube. The proof mass may be asymmetric or symmetric. Additional actuating capacitive plates may be used for feedback control which gives a greater dynamic range.

Lee, Abraham P. (Arlington, VA); Simon, Jonathon N. (San Leandro, CA); McConaghy, Charles F. (Livermore, CA)

2001-01-01T23:59:59.000Z

416

Periodic Broadcast and Patching Services Implementation, Measurement, and Analysis in an Internet  

E-Print Network (OSTI)

Periodic Broadcast and Patching Services ­ Implementation, Measurement, and Analysis in an Internet time al- lowing asynchronous access to multimedia steams by a large number of clients. Current research, and explore the issues that arise when implementing these algorithms. We present measurements detailing

Massachusetts at Amherst, University of

417

Small angle neutron scattering on periodically deformed polymers A. R. Rennie  

E-Print Network (OSTI)

765 Small angle neutron scattering on periodically deformed polymers A. R. Rennie Institut für Phys-768 SEPTEMBRE 1984, 1. Introduction. Neutron scattering has proved a useful tool for the investigation of a wide time for a small angle neutron scattering spectrum is several minutes. Obser- vation on rapidly

Boyer, Edmond

418

The evolution of circular loops of a cosmic string with periodic tension  

E-Print Network (OSTI)

In this paper the equation of circular loops of cosmic string with periodic tension is investigated in the Minkowski spacetime and Robertson-Walker universe respectively. We find that the cosmic string loops possessing this kind of time-varying tension will evolve to oscillate instead of collapsing to form a black hole if their initial radii are not small enough.

Wang, Leilin

2012-01-01T23:59:59.000Z

419

Detection of signals in the ion cyclotron frequency range at the edge during ICRF heating on ASDEX Upgrade  

SciTech Connect

The ICRF system on ASDEX Upgrade is equipped with an arc detector based on the observation of frequencies between 5 and 25 MHz in the RF feeding line [R1]. On some shots, the detector was triggered in an anomalous way: tenths of detections over several hundreds of milliseconds on detectors of all antennas at the same time [R2]. It was suggested that these frequencies were not excited by arcs but came from the plasma. We installed a RF probe inside the vacuum vessel and connected it to a fast acquisition system. We indeed observed frequencies during ICRF heating of several shots. We present here the features of these frequencies, their possible conditions of existence in terms of plasma and RF parameters (magnetic field, density, temperature, RF frequency, power injected) and we compare the source of these frequencies with known phenomena like ICE, CAE and surface waves.

D'Inca, R.; Assas, S.; Bobkov, V. [Max Planck Institut fuer Plasmaphysik, Garching (Germany); EURATOM Association (Germany); Noterdaeme, J.-M. [Max Planck Institut fuer Plasmaphysik, Garching, Germany, EURATOM Association (Germany); Gent University, EESA Department (Belgium)

2009-11-26T23:59:59.000Z

420

Cascaded multilevel converter based superconducting magnetic energy storage system for frequency control  

Science Journals Connector (OSTI)

Abstract The Super conducting magnetic energy storage (SMES), owing to high energy density and capacity, has been widely applied in different stages of power systems. One of these applications is the frequency control of the electric power systems. Frequency of a power system depends on the balance of produced and demanded energy in any instant of time. Subsequent to a sudden change in the system, which causes produced and demanded energy mismatch, frequency oscillates. According to standards, the permissible variation band of the frequency is very restricted. Larger swings of frequency may result in instability and undesirable trips. As a result, suitable frequency control mechanisms should be implemented in the system. SMES is well-suited for this application because of high energy density and fast response. SMES is attached to system by a power conditioning system (PCS) which include power electronic converters, mainly a dc–dc chopper and an inverter. This paper, studies the application of a cascaded H-bridge (CHB) multilevel converter for frequency control. As far as the authors' knowledge, such a study has not been done before. The design procedure of the converter is presented. Simulation results on a sample system are presented to verify the performance of the proposed PCS.

Mohammad Farhadi Kangarlu; Mohammad Reza Alizadeh Pahlavani

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Science with the Frequency Agile Solar Radiotelescope  

E-Print Network (OSTI)

of Technology #12;EGU Meeting 2004 April 29 NJIT Center for Solar Terrestrial Research 2 / 30 #12;EGU MeetingScience with the Frequency Agile Solar Radiotelescope Dale E. Gary New Jersey Institute 2004 April 29 NJIT Center for Solar Terrestrial Research 3 / 30 FASR Instrument (Antennas) Three arrays

422

High-Frequency Conductivity of Degenerate Semiconductors  

Science Journals Connector (OSTI)

The problem of high-frequency conductivity of a degenerate semiconductor is investigated by a kinetic description. The finite duration of encounters is taken into account in a self-consistent fashion which properly includes collective effects. This treatment is an extension for quantum plasmas of the Dawson-Oberman method given for classical plasmas.

Amiram Ron and Narkis Tzoar

1963-09-01T23:59:59.000Z

423

Fiber type, meal frequency and colonic cytokinetics  

E-Print Network (OSTI)

The effects of dietary fiber type (cellulose, pectin or oat bran) and meal frequency (gorge or nibble) on colonic short chain fatty acids (SCFAs), in vivo colonic pH and epithelial cell proliferation were examined in male Sprague-Dawley rats...

Zhang, Jianhu

1993-01-01T23:59:59.000Z

424

Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e  

E-Print Network (OSTI)

Radial velocity measurements of stellar reflex motion have revealed many extra-solar planets, but gaps in the observations produce aliases, spurious frequencies that are frequently confused with the planets' orbital frequencies. In the case of Gl 581d, the distinction between an alias and the true frequency was the distinction between a dead, frozen planet and a planet likely hospitable to life (Udry et al. 2007; Mayor et al. 2009). To improve the characterization of planetary systems, we describe how aliases originate and present a new approach for distinguishing between orbital frequencies and their aliases. Our approach harnesses features in the spectral window function to compare the amplitude and phase of predicted aliases with peaks present in the data. We apply it to confirm prior alias distinctions for the planets GJ 876d and HD 75898b. We find that the true periods of Gl 581c and HD 73526b/c remain ambiguous. We revise the periods of HD 156668b and 55 Cnc e, which were afflicted by daily aliases. For...

Dawson, Rebekah I

2010-01-01T23:59:59.000Z

425

The level crossing analysis of German stock market index (DAX) and daily oil price time series  

E-Print Network (OSTI)

The level crossing analysis of DAX and oil price time series are given. We determine the average frequency of positive-slope crossings, $\

Shayeganfar, F; Peinke, J; Tabar, M Reza Rahimi

2010-01-01T23:59:59.000Z

426

Real-Time Particulate Mass Measurements Pre and Post Diesel Particulat...  

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

2005deeranderson.pdf More Documents & Publications Advanced Radio Frequency-Based Sensors for Monitoring Diesel Particulate Filter Loading and Regeneration Real-Time...

427

Long-term cycles in the history of life: Periodic biodiversity in the Paleobiology Database  

E-Print Network (OSTI)

Time series analysis of fossil biodiversity of marine invertebrates in the Paleobiology Database (PBDB) shows a significant periodicity at approximately 63 My, in agreement with previous analyses based on the Sepkoski database. I discuss how this result did not appear in a previous analysis of the PBDB. The existence of the 63 My periodicity, despite very different treatment of systematic error in both PBDB and Sepkoski databases strongly argues for consideration of its reality in the fossil record. Cross-spectral analysis of the two datasets finds that a 62 My periodicity coincides in phase by 1.6 My, equivalent to better than the errors in either measurement. Consequently, the two data sets not only contain the same strong periodicity, but its peaks and valleys closely correspond in time. Two other spectral peaks appear in the PBDB analysis, but appear to be artifacts associated with detrending and with the increased interval length. Sampling-standardization procedures implemented by the PBDB collaboration suggest that the signal is not an artifact of sampling bias. Further work should focus on finding the cause of the 62 My periodicity.

Adrian L. Melott

2008-12-24T23:59:59.000Z

428

The Frequency Ratio Method for the seismic modelling of gamma Doradus stars. II The role of rotation  

E-Print Network (OSTI)

The effect of rotation on the Frequency Ratio Method (Moya et al. 2005) is examined. Its applicability to observed frequencies of rotating gamma Doradus stars is discussed taking into account the following aspects: the use of a perturbative approach to compute adiabatic oscillation frequencies; the effect of rotation on the observational Brunt-Vaisala integral determination and finally, the problem of disentangling multiplet-like structures from frequency patterns due to the period spacing expected for high-order gravity modes in asymptotic regime. This analysis reveals that the FRM produces reliable results for objects with rotational velocities up to 70 kms/s, for which the FRM intrinsic error increases one order of magnitude with respect to the typical FRM errors given in Moya et al. (2005). Our computations suggest that, given the spherical degree "l" identification, the FRM may be discriminating for m = 0 modes, in the sense that the method avoids any misinterpretation induced by the presence of rotation...

Suárez, J C; Martin-Ruiz, S; Amado, P J; Garrido, A G R

2005-01-01T23:59:59.000Z

429

Correlation analysis for wind speed and failure rate of wind turbines using time series approach  

Science Journals Connector (OSTI)

The correlation between wind speed and failure rate (FR) of wind turbines is analyzed with time series approach. The time series of power index (PI) and FR of wind turbines are established based on historical data which are pretreated by singularity processing stationarity processing and wavelet de-noising. The trend variations of the time series are analyzed from both time domain and frequency domain by extracting the indicator functions including auto-correlation function cross-correlation function and spectral density function. A case study is given out to verify the validity of the model and the method which is based on the wind speed and failure data from January 1995 to December of 2002 in Nordjylland Denmark. Auto-correlation function and spectral density function show that time series of PI and FR have strong seasonal characteristics and quite similar periodicity while the cross-correlation function shows they keep high consistency and strong correlation. The results indicate that by calculating and monitoring PI the failure rule of wind turbines can be forecast which provides theoretical basis for preventive maintenance of wind turbines.

Chun Su; Quan Jin; Yequn Fu

2012-01-01T23:59:59.000Z

430

Laser Frequency Stabilization with Optical Cavities Anya M. Davis  

E-Print Network (OSTI)

Laser Frequency Stabilization with Optical Cavities Anya M. Davis Walla Walla University University Effective laser cooling requires the laser's frequency to be precise, with a frequency drift of no more than lasers for correcting frequency drift. In the University of Washington Quantum Computing with Trapped

Blinov, Boris

431

A detached double degenerate with a 1.4 hr orbital period  

E-Print Network (OSTI)

We have discovered that the detached double degenerate binary WD 0957-666 has an orbital period of 1.46 hours, rather than the 1.15 day orbital period reported earlier. This is the shortest period example of such a system yet discovered. We obtain a unique period, which fits both our and earlier data. At this period the emission of gravitational radiation will cause the binary to merge within approximately 2.0 x 10*8 years. This system represents a population of short orbital period binaries which will merge within a Hubble time, and so could account for type Ia supernovae, although due to the low mass of both stars (0.3 to 0.4 solar masses), it is unlikely to become a supernova itself. We have detected the companion star and have measured a mass ratio of q = 1.15. This is the third double degenerate for which q has been measured and all three have q close to 1, which is in conflict with the predicted mass ratio distribution which peaks at 0.7. This system is viewed close to edge on, and we estimate that the probability of this system undergoing eclipses is 15 %.

C. Moran; T. R. Marsh; A. Bragaglia

1997-04-24T23:59:59.000Z

432

Silicon nanoparticle synthesis by short-period thermal anneals at atmospheric pressure in argon  

SciTech Connect

Silicon nanoparticles have been studied for a wide variety of applications including nanoelectronic, photovoltaic, and optoelectronic devices. In this work, silicon nanoparticles were synthesized by short-period annealing of silicon-on-insulator substrates to temperatures ranging between 600 and 900 deg. C in argon gas at atmospheric pressure. Two different top silicon layers were deposited by ion-beam sputtering onto oxidized substrates. The thinner 6 nm top layer samples were annealed to temperatures for 30 s periods while thicker 15 nm top layer samples were annealed for 60 s periods. For both sets of samples, nanoparticles were observed to form at all the anneal temperatures through imaging by AFM. One long-period UHV anneal study, with 30-min anneal times, observed nanoparticle formation at temperatures similar to the current work while another similar long-period UHV anneal reported nanoparticle formation only above well-defined formation temperatures that depended upon the starting top layer thickness. In the current work, the average nanoparticle radius was found to increase both with the final anneal temperature and anneal period. For the highest anneal temperatures of the 6 nm top layer samples, a changing surface topography indicated that the thinner Si source layer was becoming depleted and the nanoparticle formation process was nearing completion. No such changes were observed for the thicker 15 nm samples at the same temperatures.

Spencer, Gregory; Anyamesem-Mensah, Benedict; Galloway, Heather C.; Bandyopadhyay, Anup; Frasier, Daniel [Department of Physics, Texas State University-San Marcos, San Marcos, Texas 78666 (United States); Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76207 (United States); Department of Physics, Texas State University-San Marcos, San Marcos, Texas 78666 (United States)

2011-09-15T23:59:59.000Z

433

Radio frequency ion source operated with field effect transistor based radio frequency system  

SciTech Connect

Characteristics of radio frequency (RF) plasma production are investigated using a field effect transistor inverter power supply as an RF wave source. With the frequency of around 0.3 MHz, an electron density over 10{sup 18} m{sup -3} is produced in argon plasma. Although lower densities are obtained in hydrogen plasma, it drastically increased up to 5x10{sup 18} m{sup -3} with an axial magnetic field of around 100 G applied in the driver region. Effects of the magnetic field and gas pressure are investigated in the RF produced plasma with the frequency of several hundred kilohertz.

Ando, A.; Komuro, A.; Matsuno, T. [Department of Electrical Engineering, Tohoku University, Sendai 980-8759 (Japan); Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)

2010-02-15T23:59:59.000Z

434

The cellular basis for parallel neural transmission of a high-frequency stimulus and its low-frequency envelope  

Science Journals Connector (OSTI)

...a sinusoidal electric organ discharge (EOD) that produces an electric field around...individual A. leptorhynchus maintain a stable EOD frequency (13), the species has a frequency...1,000 Hz. Two fish with widely spaced EOD frequencies will generate a high-frequency...

Jason W. Middleton; André Longtin; Jan Benda; Leonard Maler

2006-01-01T23:59:59.000Z

435

Micro-scale piezoelectric vibration energy harvesting: from fixed-frequency to adaptable-frequency devices  

E-Print Network (OSTI)

Chen, Paul K Wright, and James Evans. Resonance frequency21] Christine C Ho, James W Evans, and Paul K Wright. Direct22] Christine C Ho, James W Evans, and Paul K Wright. Direct

Miller, Lindsay Margaret

2012-01-01T23:59:59.000Z

436

Do High-Frequency Eddies Contribute to Low-Frequency Teleconnection Tendencies?  

Science Journals Connector (OSTI)

An isentropic potential vorticity (PV) budget analysis is employed to examine the role of synoptic transients, advection, and nonconservative processes as forcings for the evolution of the low-frequency PV anomalies locally and those associated ...

Panos J. Athanasiadis; Maarten H. P. Ambaum

2010-02-01T23:59:59.000Z

437

Frequency-dependent conductivity of electron glasses  

Science Journals Connector (OSTI)

Results of dc and frequency-dependent conductivity in the quantum limit—i.e., ??>kBT—for a broad range of dopant concentrations in nominally uncompensated, crystalline phosphorous-doped silicon and amorphous niobium-silicon alloys are reported. These materials fall under the general category of disordered insulating systems, which are referred to as electron glasses. Using microwave resonant cavities and quasioptical millimeter-wave spectroscopy we are able to study the frequency-dependent response on the insulating side of the metal-insulator transition. We identify a quantum critical regime, a Fermi glass regime, and a Coulomb glass regime. Our phenomenological results lead to a phase diagram description, or taxonomy, of the electrodynamic response of electron glass systems.

E. Helgren; N. P. Armitage; G. Grüner

2004-01-13T23:59:59.000Z

438

High frequency fast wave current drive for DEMO  

SciTech Connect

A steady-state tokamak reactor (SSTR) requires a high efficiency current drive system, from plug to driven mega-amps. RF systems working in the ion-cyclotron range of frequencies (ICRF) have high efficiency from plug to antenna but a limited current drive (CD) efficiency and centrally peaked CD profiles. The latter feature is not adequate for a SSTR where the current should be sufficiently broad to keep the central safety factor (possibly significantly) above 1. In addition, the fact that the fast wave (FW) is evanescent at the edge limits coupling, requiring high voltage operation, which makes the system dependent on plasma edge properties and prone to arcing, reducing its reliability. A possible way to overcome these weaknesses is to operate at higher frequency (10 times or more the cyclotron frequency). The advantages are: (1) The coupling can be much better (waves propagate in vacuum) if the parallel refractive index n{sub ||} is kept below one, (2) The FW group velocity tends to align to the magnetic field, so the power circumnavigates the magnetic axis and can drive off-axis current, (3) Due to the latter property, n{sub ||} can be upshifted along the wave propagation path, allowing low n{sub ||} launch (hence good coupling, large CD efficiency) with ultimately good electron absorption (which requires higher n{sub ||}. Note however that the n{sub ||} upshift is a self-organized feature, that electron absorption is in competition with {alpha}-particle absorption and that uncoupling of the FW from the lower hybrid resonance at the edge requires n{sub ||} slightly above one. The latter possibly counterproductive features might complicate the picture. The different aspects of this potentially attractive off-axis FWCD scheme are discussed.

Koch, R.; Lerche, E.; Van Eester, D. [LPP/ERM-KMS, Association 'EURATOM-Belgian State', 1000 Brussels, TEC Partner (Belgium); Nightingale, M. [Culham Centre for Fusion Energy, Abingdon OX14 3DB (United Kingdom)

2011-12-23T23:59:59.000Z

439

Radio frequency (RF) heated supersonic flow laboratory  

SciTech Connect

A unique supersonic flow apparatus which employs an inductively-coupled, radio frequency (RF) torch to supply high enthalpy source gas to the nozzle inlet is described. The main features of this system are the plasma tube, a cooled nozzle assembly, and a combustion/expansion chamber with a heat exchanger. A description of these components with current test data is presented. In addition, a discussion of anticipated experiments utilizing this system is included.

Wantuck, P.; Watanabe, H.

1990-01-01T23:59:59.000Z

440

Hawking spectrum and high frequency dispersion  

Science Journals Connector (OSTI)

We study the spectrum of created particles in two-dimensional black hole geometries for a linear, Hermitian scalar field satisfying a Lorentz noninvariant field equation with higher spatial derivative terms that are suppressed by powers of a fundamental momentum scale k0. The preferred frame is the "free-fall frame" of the black hole. This model is a variation of Unruh's sonic black hole analogy. We find that there are two qualitatively different types of particle production in this model: a thermal Hawking flux generated by "mode conversion" at the black hole horizon, and a nonthermal spectrum generated via scattering off the background into negative free-fall frequency modes. This second process has nothing to do with black holes and does not occur for the ordinary wave equation because such modes do not propagate outside the horizon with positive Killing frequency. The horizon component of the radiation is astonishingly close to a perfect thermal spectrum: for the smoothest metric studied, with Hawking temperature TH?0.0008k0, agreement is of order (THk0)3 at frequency ?=TH, and agreement to order THk0 persists out to ?TH?45 where the thermal number flux is ?10-20. The flux from scattering dominates at large ? and becomes many orders of magnitude larger than the horizon component for metrics with a "kink," i.e., a region of high curvature localized on a static world line outside the horizon. This nonthermal flux amounts to roughly 10% of the total luminosity for the kinkier metrics considered. The flux exhibits oscillations as a function of frequency which can be explained by interference between the various contributions to the flux.

Steven Corley and Ted Jacobson

1996-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Systematic calculations of plasma transport coefficients for the Periodic Table  

Science Journals Connector (OSTI)

Theoretical results are given for the ionization state, electrical conductivity, thermal conductivity, and thermoelectric coefficient for the entire Periodic Table over extreme ranges of temperature and density. A spherical average ion embedded in a uniform plasma background is used as a model to evaluate the electron densities of states, elastic scattering cross sections, and ionization states. These are then combined with one-component plasma structure factors to compute mean relaxation times and electrical resistivities according to an extended Ziman formula. The method of Lampe is used to compute thermal conductivities and thermoelectric coefficients from these values. Some experimental comparisons are made. The transport coefficients appear to be accurate for weakly and moderately correlated plasmas, but not for strongly correlated liquids or crystalline materials. The coefficients are tabulated as numerical functions of temperature and density. The tables extend in temperature from 10-2 to 104 eV. Density ranges depend upon atomic mass; lower limits range from 10-4 to 10-2 g/cm3, and upper limits range from 105 to 107 g/cm3. Indications are given of the regions of validity of the results.

George A. Rinker

1988-02-15T23:59:59.000Z

442

THE DECAYING LONG-PERIOD OSCILLATION OF A STELLAR MEGAFLARE  

SciTech Connect

We analyze and interpret the oscillatory signal in the decay phase of the U-band light curve of a stellar megaflare observed on 2009 January 16 on the dM4.5e star YZ CMi. The oscillation is well approximated by an exponentially decaying harmonic function. The period of the oscillation is found to be 32 minutes, the decay time about 46 minutes, and the relative amplitude 15%. As this observational signature is typical of the longitudinal oscillations observed in solar flares at extreme ultraviolet and radio wavelengths, associated with standing slow magnetoacoustic waves, we suggest that this megaflare may be of a similar nature. In this scenario, macroscopic variations of the plasma parameters in the oscillations modulate the ejection of non-thermal electrons. The phase speed of the longitudinal (slow magnetoacoustic) waves in the flaring loop or arcade, the tube speed, of about 230 km s{sup -1} would require a loop length of about 200 Mm. Other mechanisms, such as standing kink oscillations, are also considered.

Anfinogentov, S. [Institute of Solar Terrestrial Physics, Irkutsk (Russian Federation); Nakariakov, V. M. [Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Mathioudakis, M. [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN (United Kingdom); Van Doorsselaere, T. [Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Kowalski, A. F., E-mail: anfinogentov@iszf.irk.ru [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)

2013-08-20T23:59:59.000Z

443

Discovery and application of Frequency Ratio Method to the new multiperiodic gamma Dor star HD 218427  

E-Print Network (OSTI)

gamma Dor-type oscillations have been discovered in the star HD218427 through simultaneous uvby photometric observations carried out in the year 2003. A few Hbeta-Crawford measurements were also collected for calibration purposes which place this star well-located inside the gamma Dor instability region. Deficiency in metal content, similar to other well-defined gamma Dor stars, is found in HD218427 and the possibility of a lambda Boo nature is discussed. Frequency analysis was carried out for different filters, the combined "vby" filter was also used and five frequencies were found as significant with periods ranging between 0.3 and 0.8 days. The recently developed Frequency Ratio Method is used in order to perform an identification of the excited modes. The results are consistent with an l=2 identification for all the modes and high radial quantum numbers (n~40) for the three main observed periodicities. The possibility of multiplet structures is also discussed. However, no consistency is found when the Tim...

Rodríguez, E; Suárez, J C; Moya, A; Dupret, M A; Poretti, E; Grigahcene, A; Costa, V; Lopez-Gonzalez, M J

2006-01-01T23:59:59.000Z

444

EIS-0463: Extension of Scoping Period | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Extension of Scoping Period Extension of Scoping Period EIS-0463: Extension of Scoping Period Presidential Permit Application for Northern Pass Transmission, New Hampshire The U.S. Department of Energy (DOE) is reopening the public scoping period for the Northern Pass Transmission Line Project Environmental Impact Statement (EIS) (DOE/EIS-0463). In anticipation of additional alternative route information being provided by Northern Pass, DOE is reopening the scoping period. DOE will determine the close of the scoping period once the additional routing information is received from Northern Pass, and DOE will provide at least 45 days for public review and scoping comments on any such routing information. EIS-0463-ScopingExtension-2011.pdf More Documents & Publications Application for presidential permit OE Docket No. PP-371 Northern Pass

445

EIS-0463: Reopening of Scoping Period for the Environmental Impact  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reopening of Scoping Period for the Environmental Impact Reopening of Scoping Period for the Environmental Impact Statement EIS-0463: Reopening of Scoping Period for the Environmental Impact Statement Northern Pass Transmission Line Project The U.S. Department of Energy (DOE) is reopening the public scoping period for the Northern Pass Transmission Line Project Environmental Impact Statement (EIS) (DOE/EIS-0463). The scoping period now ends on June 14, 2011. Reopening of Scoping Period for the Northern Pass Transmission Line Project Environmental Impact Statement, EIS-0463 (April 2011) (76 FR 21338) More Documents & Publications EIS-0385: EPA Notice of Availability of the Final Environmental Impact Statement EIS-0425: EPA Notice of Availability of Draft Environmental Impact Statement EIS-0448: Notice of Adoption of an Environmental Impact Statement

446

EIS-0463: Reopening of Scoping Period for the Environmental Impact  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

463: Reopening of Scoping Period for the Environmental Impact 463: Reopening of Scoping Period for the Environmental Impact Statement EIS-0463: Reopening of Scoping Period for the Environmental Impact Statement Northern Pass Transmission Line Project The U.S. Department of Energy (DOE) is reopening the public scoping period for the Northern Pass Transmission Line Project Environmental Impact Statement (EIS) (DOE/EIS-0463). The scoping period now ends on June 14, 2011. Reopening of Scoping Period for the Northern Pass Transmission Line Project Environmental Impact Statement, EIS-0463 (April 2011) (76 FR 21338) More Documents & Publications EIS-0385: EPA Notice of Availability of the Final Environmental Impact Statement EIS-0408: DOE Notice of Availability of a Programmatic Draft Environmental Impact Statement EIS-0469: Notice of Intent To Prepare an Environmental Impact Statement and

447

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"

448

Joint-Frequency Bins versus Conventional Bin Weather Data in Analysis of HVAC System Operation  

E-Print Network (OSTI)

Often in simplified energy analysis the use of bin weather data is employed for a more time efficient and better organized analysis than using the full 8760-hour annual weather data. It has been suggested that joint-frequency bins be used instead...

Jones, A.; Baltazar, J. C.; Claridge, D. E.

449

CNV amplitude as a neural correlate for stuttering frequency: A case report of acquired stuttering  

Science Journals Connector (OSTI)

Abstract A neural hallmark of developmental stuttering is abnormal articulatory programming. One of the neurophysiological substrates of articulatory preparation is the contingent negative variation (CNV). Unfortunately, CNV tasks are rarely performed in persons who stutter and mainly focus on the effect of task variation rather than on interindividual variation in stutter related variables. However, variations in motor programming seem to be related to variation in stuttering frequency. The current study presents a case report of acquired stuttering following stroke and stroke related surgery in the left superior temporal gyrus. A speech related CNV task was administered at four points in time with differences in stuttering severity and frequency. Unexpectedly, CNV amplitudes at electrode sites approximating bilateral motor and left inferior frontal gyrus appeared to be inversely proportional to stuttering frequency. The higher the stuttering frequency, the lower the activity for articulatory preparation. Thus, the amount of disturbance in motor programming seems to determine stuttering frequency. At right frontal electrodes, a relative increase in CNV amplitude was seen at the test session with most severe stuttering. Right frontal overactivation is cautiously suggested to be a compensation strategy. In conclusion, late CNV amplitude elicited by a relatively simple speech task seems to be able to provide an objective, neural correlate of stuttering frequency. The present case report supports the hypothesis that motor preparation has an important role in stuttering.

Sarah Vanhoutte; John Van Borsel; Marjan Cosyns; Katja Batens; Pieter van Mierlo; Dimitri Hemelsoet; Dirk Van Roost; Paul Corthals; Miet De Letter; Patrick Santens

2014-01-01T23:59:59.000Z

450

Metric assessment of subjective annoyance due to low frequency aircraft noise  

Science Journals Connector (OSTI)

A low frequency noise study was conducted at the Pennsylvania State University to investigate human response to the low frequency content of aviation noise. Metric assessment included level based and loudness metrics including time?varying loudness. Current predictive noise models and metrics may underestimate the impact of low?frequency noise produced by aviation noise. Assessing the role of low frequency noise on human response will facilitate understanding how this type of noise can impact communities. Indoor recordings of aircraft arrivals and departures at Washington Dulles International Airport made in 2004 were used to assess subjective noise annoyance. These recordings and low?frequency variants of these recordings were reproduced for subjects through the Gulfstream Supersonic Acoustic Signature Simulator II (SASS II); the signatures were then rated for annoyance. Subjective judgments were statistically analyzed and compared against objective metrics that were calculated for each signature. Results are shown that all things being equal higher levels of low?frequency content in aircraft noise can result in increased annoyance in subjects. The C?weighted sound exposure level was found to correlate well with the subjective annoyance response.

Kathleen Hodgdon; Matthew L. Nickerson; Anthony A. Atchley; Thomas Gabrielson

2008-01-01T23:59:59.000Z

451

EIS-0489: Notice of Comment Period Extension and Additional Scoping...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Meetings EIS-0489: Notice of Comment Period Extension and Additional Scoping Meetings Jordan Cove Liquefaction Project (Coos County, OR) and Pacific Connector Pipeline Project...

452

Guidance on the Required Period for Grantees to Obligate Funds...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

on the Required Period for Grantees to Obligate Funds and the Procedures for Reporting of Obligated Funds for the Energy Efficiency Conservation Block Grant (EECBG) Program...

453

EIS-0369: Notice of Public Comment Period Extension and Additional...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Notice of Public Comment Period Extension and Additional Public Meeting Supplemental Yucca Mountain Rail Corridor and Rail Alignment The Department of Energy is now announcing...

454

Green's function analysis of periodic structures in computational electromagnetics  

E-Print Network (OSTI)

the two-dimensional periodic Green's function," IEEE Trans.evaluation of the Green's function for the Helmholtzrepresentations of certain Green's functions," J. Comp.

Van Orden, Derek

2011-01-01T23:59:59.000Z

455

Microsoft Word - PARS II Process Document - Close Period 2013...  

Office of Environmental Management (EM)

the process of preparing the APM Deputy Secretary Monthly Report and closing the DOE Reporting Period in PARS II. SCOPE This process applies to the Headquarters Office of...

456

Periodic Boundary Conditions in the ALEGRA Finite Element Code  

SciTech Connect

This document describes the implementation of periodic boundary conditions in the ALEGRA finite element code. ALEGRA is an arbitrary Lagrangian-Eulerian multi-physics code with both explicit and implicit numerical algorithms. The periodic boundary implementation requires a consistent set of boundary input sets which are used to describe virtual periodic regions. The implementation is noninvasive to the majority of the ALEGRA coding and is based on the distributed memory parallel framework in ALEGRA. The technique involves extending the ghost element concept for interprocessor boundary communications in ALEGRA to additionally support on- and off-processor periodic boundary communications. The user interface, algorithmic details and sample computations are given.

AIDUN,JOHN B.; ROBINSON,ALLEN C.; WEATHERBY,JOE R.

1999-11-01T23:59:59.000Z

457

S&TR | April 2007: A New Block on the Periodic Table  

NLE Websites -- All DOE Office Websites (Extended Search)

Article title: A New Block on the Periodic Table; photo of Dawn Shaughnessy. Livermore chemist Dawn Shaughnessy adds the most recently created element to the periodic table. SCIENTISTS from Lawrence Livermore working in collaboration with a team from the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, have discovered element 118, the newest block on the periodic table. Lasting less than a millisecond before decaying and ultimately fissioning, element 118 is the latest element to be synthesized artificially. Why do scientists work so hard to create new elements that last for such a short time? According to chemist Dawn Shaughnessy from Livermore's Chemistry, Materials, and Life Sciences Directorate, "Each new element we discover provides more knowledge about the forces that bind nuclei and what

458

Three-Dimensional Electromagnetic High Frequency Axisymmetric Cavity Scars.  

SciTech Connect

This report examines the localization of high frequency electromagnetic fi elds in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This report treats both the case where the opposing sides, or mirrors, are convex, where there are no interior foci, and the case where they are concave, leading to interior foci. The scalar problem is treated fi rst but the approximations required to treat the vector fi eld components are also examined. Particular att ention is focused on the normalization through the electromagnetic energy theorem. Both projections of the fi eld along the scarred orbit as well as point statistics are examined. Statistical comparisons are m ade with a numerical calculation of the scars run with an axisymmetric simulation. This axisymmetric cas eformstheoppositeextreme(wherethetwomirror radii at each end of the ray orbit are equal) from the two -dimensional solution examined previously (where one mirror radius is vastly di ff erent from the other). The enhancement of the fi eldontheorbitaxiscanbe larger here than in the two-dimensional case. Intentionally Left Blank

Warne, Larry K.; Jorgenson, Roy E.

2014-10-01T23:59:59.000Z

459

Frequency-feedback tuning for single-cell cavity under rf heating  

SciTech Connect

A tuning system is described that is being used to match the source frequency of a high-power klystron on the resonant frequency of the prototype single-cell cavity for the 7-GeV Advance Photon Source (APS) storage ring. Typically a water-cooled piston tuner is required to adjust the reactive component of the cavity`s impedance to minimize reflected power back to the RF drive source. As the cavity watts expand due to RF heating, the resonant frequency decreases. Adjusting the source frequency to follow the cavity resonant frequency is a convenient method used to condition the cavity (for vacuum) at high power levels, in this case, 1 MV gap voltage at 100 kW power level. The tuning system consists of two coupling ports, a phase detector, a digitizing I/O system, and a DC coupled FM-modulated RF source. Proportional Integral Derivative (PID) loop parameters for the Experimental Physics and Industrial Control System (EPICS) software are calculated, and data is presented showing the damped response to peturbations on the loop. The timing system presented here does not need water-cooling, has no moving parts to wear out, and has an inherently faster response time. Its one limitation is the digitizing sampling rate. The only limitation in tuning range is the bandwidth of the RF source.

Stepp, J.D.; Bridges, J.F.

1993-08-01T23:59:59.000Z

460

Sequentially firing neurons confer flexible timing in neural pattern generators  

Science Journals Connector (OSTI)

Neuronal networks exhibit a variety of complex spatiotemporal patterns that include sequential activity, synchrony, and wavelike dynamics. Inhibition is the primary means through which such patterns are implemented. This behavior is dependent on both the intrinsic dynamics of the individual neurons as well as the connectivity patterns. Many neural circuits consist of networks of smaller subcircuits (motifs) that are coupled together to form the larger system. In this paper, we consider a particularly simple motif, comprising purely inhibitory interactions, which generates sequential periodic dynamics. We first describe the dynamics of the single motif both for general balanced coupling (all cells receive the same number and strength of inputs) and then for a specific class of balanced networks: circulant systems. We couple these motifs together to form larger networks. We use the theory of weak coupling to derive phase models which, themselves, have a certain structure and symmetry. We show that this structure endows the coupled system with the ability to produce arbitrary timing relationships between symmetrically coupled motifs and that the phase relationships are robust over a wide range of frequencies. The theory is applicable to many other systems in biology and physics.

Alexander Urban and Bard Ermentrout

2011-05-16T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

Radio-frequency probes of Antarctic ice at South Pole  

E-Print Network (OSTI)

System Sciences O p e n A cce ss Discussions Radio-frequency probes of Antarctic ice at South Pole D. Besson1 and I. Kravchenko2 1University of Kansas, Department of Physics and Astronomy, Lawrence, KS 66045-7582, USA 2University of Nebraska – Lincoln... to successive waveforms. Each 0.5 meter division horizontally corresponds to approximately 5 ns. -20 -10 0 10 20 Rx v ol ta ge ( V, a ft er s ca li ng ; of fs e Time (ns, relative) 6 us echo (Vx1) 9.6 us echo (Vx1.3) 13.9 us echo (Vx3.5) 17.2 us echo (Vx10...

Besson, David Zeke; Kravchenko, I.

2013-05-16T23:59:59.000Z

462

Oil price and financial markets: Multivariate dynamic frequency analysis  

Science Journals Connector (OSTI)

Abstract The aim of this paper is to study the degree of interdependence between oil price and stock market index into two groups of countries: oil-importers and oil-exporters. To this end, we propose a new empirical methodology allowing a time-varying dynamic correlation measure between the stock market index and the oil price series. We use the frequency approach proposed by Priestley and Tong (1973), that is the evolutionary co-spectral analysis. This method allows us to distinguish between short-run and medium-run dependence. In order to complete our study by analysing long-run dependence, we use the cointegration procedure developed by Engle and Granger (1987). We find that interdependence between the oil price and the stock market is stronger in exporters? markets than in the importers? ones.

Anna Creti; Zied Ftiti; Khaled Guesmi

2014-01-01T23:59:59.000Z

463

Method for imaging with low frequency electromagnetic fields  

DOE Patents (OSTI)

A method is described for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The travel times corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter [alpha] for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography. 13 figures.

Lee, K.H.; Xie, G.Q.

1994-12-13T23:59:59.000Z

464

High-frequency shear-horizontal surface acoustic wave sensor  

DOE Patents (OSTI)

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

Branch, Darren W

2014-03-11T23:59:59.000Z

465

Effect of Pressure Transmission Lines on the Frequency Response of Pressure Transducers  

SciTech Connect

It is well known that the length and diameter of the transmission lines between a pressure transducer and the pressure source can significantly affect the dynamic frequency response of the transducer. A new lumped parameter model has been developed to predict the time and frequency response of any number of different transducers connected in parallel in a manifold. While the model is simple to apply, it can provide quantitative information given the transducer and transmission line characteristic parameters. More importantly, the model can be used to evaluate the measured, in-situ response. this provides the natural frequency and the effective damping which can then be used to generate a frequency response curve. The model is also useful for designing a new pressure transmission system, which will have the required frequency response. The model was qualified by comparison to measurements of the step-function pressure response of a number of different transducers and test installations. With the aid of the model, the system resonant frequency and damping can be determined. Additional damping can be added if necessary to prevent ringing of the signal and to assure an accurate pressure measurement with a flat frequency response. For all of the experimental systems evaluated in this work, the response at the natural frequency was significantly underdamped and ringing was observed. This means that to perform accurate measurements damping needs to be added to the system. It was observed that the use of flexible pressure lines versus hard lines does increase the damping and may therefore be useful in certain situations. Equations were developed to permit sizing an orifice to be added to the system to provide the necessary damping.

G.J. Kirouac

2000-11-13T23:59:59.000Z

466

Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models  

SciTech Connect

Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present 4 sets of lightcurves from the Kepler spacecraft, which each show multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems architectures, even in cases for which high-precision Doppler follow-up is impractical.

Fabrycky, Daniel C.; /UC, Santa Cruz; Ford, Eric B.; /Florida U.; Steffen, Jason H.; /Fermilab; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Moorhead, Althea V.; /Florida U.; Batalha, Natalie M.; /San Jose State U.; Borucki, William J.; /NASA, Ames; Bryson, Steve; /NASA, Ames; Buchhave, Lars A.; /Bohr Inst. /Copenhagen U.; Christiansen, Jessie L.; /SETI Inst., Mtn. View /NASA, Ames /Caltech

2012-01-01T23:59:59.000Z

467

Monitoring based on time-frequency tracking of estimated harmonic series and modulation sidebands  

E-Print Network (OSTI)

machine (e.g., on a wind turbine) aims to reduce the operating costs by applying a predictive maintenance for simulating a wind turbine operation and for which the inner race of the main bearing has been damaged. Above

Paris-Sud XI, Université de

468

Optimizing symbol timing, frequency spacing, and SNR estimation for communication systems  

E-Print Network (OSTI)

normal- ized unit energy constellation with M constellationa zero mean, unit energy constellation with equiprobablethe constellations are normalized to have unit energy. Table

Das, Aniruddha

469

MRS signal quantitation: a review of time-and frequency-domain methods  

E-Print Network (OSTI)

-PRO HLSVD with partial reorthogonalization [12] HSVD Hankel singular value decomposition [13] HTLS Hankel total least squares [14] HTLS-PK Hankel total least squares using prior knowledge [15] ICA independent

470

Combining frequency and time domain approaches to systems with multiple spike train input and output  

E-Print Network (OSTI)

between neuronal spike trains. Prog Biophys Mol Biol Vapnikto systems with multiple spike train input and output D. R.Keywords Multiple spike trains · Neural coding · Maximum

Brillinger, D. R.; Lindsay, K. A.; Rosenberg, J. R.

2009-01-01T23:59:59.000Z

471

Harvesting time-frequency-space diversity with coded modulation for underwater acoustic communications  

E-Print Network (OSTI)

The goal of this thesis is to design a low-complexity, high data-rate acoustic communications system with robust performance under various channel conditions. The need for robust performance emerges because underwater ...

Pelekanakis, Konstantinos

2009-01-01T23:59:59.000Z

472

High frequency continuous-time circuits and built-in-self-test using CMOS RMS detector  

E-Print Network (OSTI)

it is connected 2.2.2 Basic Architecture Using Current Mirror as a Rectifier The two most important elements needed for a simple RMS detector would be a rectifier and a filter to extract the DC level of the rectified signal. The simplest rectifier that can... it is connected 2.2.2 Basic Architecture Using Current Mirror as a Rectifier The two most important elements needed for a simple RMS detector would be a rectifier and a filter to extract the DC level of the rectified signal. The simplest rectifier that can...

Venkatasubramanian, Radhika

2007-04-25T23:59:59.000Z

473

Histogram of gradients of Time-Frequency Representations for Audio Scene Detection  

E-Print Network (OSTI)

is of primary importance in the domain of machine listening since it is strongly related to the context in which the acquisition device capturing the audio scene lives. Typically, in order to get some context awareness, a machine, say a smart-phone or any mobile electronic device, should be able to predict the environment

Paris-Sud XI, Université de

474

Histogram of Gradients of Time-Frequency Representations for Audio Scene Detection  

E-Print Network (OSTI)

is of primary importance in the domain of machine listening since it is strongly related to the context in which the acquisition device capturing the audio scene lives. Typically, in order to get some context awareness, a machine, say a smart-phone or any mobile electronic device, should be able to predict the environment

Paris-Sud XI, Université de

475

The time-frequency characteristics of quarry blasts and calibration explosions recorded in Kazakhstan, USSR  

Science Journals Connector (OSTI)

......T. J., Jr & Orcutt, J. A., 1985b. Synthesis of realistic oceanic Pn wave trains, J. geophys. Res., 90, 12755-12776. Sharpe, J. A., 1942. The production of elastic waves by explosion pressures, I. Theory and empirical field observations......

Michael A. H. Hedlin; J. Bernard Minster; John A. Orcutt

1989-10-01T23:59:59.000Z

476

Mitigating container security risk using real-time monitoring with active Radio Frequency Identification and sensors  

E-Print Network (OSTI)

The global village in which we live enables increased trade and commerce across regions but also brings a complicated new set of challenges such as terrorist activity, human and drug smuggling and theft in foreign or ...

Schlesinger, Adam Ian

2005-01-01T23:59:59.000Z

477

A Time-frequency application with the Stokes-Woodward Technique  

E-Print Network (OSTI)

coupling without calling for higher-order statistics. Two power spectra are detected; the first is related signals from the ocean surface [3]. We gen- eralized this theorem in [1] to include joint amplitude'Oc´eanographie Spatiale, IFREMER, France D. Vandemark is with Univ. of New Hampshire, Ocean Process Analysis Laboratory

Paris-Sud XI, Université de

478

Periodic forcing of a model sensory neuron Carlo R. Laing*  

E-Print Network (OSTI)

continuously generate a weak electrical field known as the electric organ discharge EOD . The field permeates the periphery to the brain of the fish. The amplitude of the EOD is approximately sinusoidal and the frequency

Laing, Carlo R.

479

Investigation of the delay time distribution of high power microwave surface flashover  

SciTech Connect

Characterizing and modeling the statistics associated with the initiation of gas breakdown has proven to be difficult due to a variety of rather unexplored phenomena involved. Experimental conditions for high power microwave window breakdown for pressures on the order of 100 to several 100 torr are complex: there are little to no naturally occurring free electrons in the breakdown region. The initial electron generation rate, from an external source, for example, is time dependent and so is the charge carrier amplification in the increasing radio frequency (RF) field amplitude with a rise time of 50 ns, which can be on the same order as the breakdown delay time. The probability of reaching a critical electron density within a given time period is composed of the statistical waiting time for the appearance of initiating electrons in the high-field region and the build-up of an avalanche with an inherent statistical distribution of the electron number. High power microwave breakdown and its delay time is of critical importance, since it limits the transmission through necessary windows, especially for high power, high altitude, low pressure applications. The delay time distribution of pulsed high power microwave surface flashover has been examined for nitrogen and argon as test gases for pressures ranging from 60 to 400 torr, with and without external UV illumination. A model has been developed for predicting the discharge delay time for these conditions. The results provide indications that field induced electron generation, other than standard field emission, plays a dominant role, which might be valid for other gas discharge types as well.

Foster, J.; Krompholz, H.; Neuber, A. [Department of Electrical and Computer Engineering, Center for Pulsed Power and Power Electronics, Texas Tech University, Lubbock, Texas 79409-3102 (United States)

2011-01-15T23:59:59.000Z

480

Cross-spectrum Analyzer for Low Frequency Noise Analysis  

E-Print Network (OSTI)

The design and performance of a sensitive and reliable cross-correlation spectrum analyzer for studying low frequency transport noise is described in detail. The design makes use of common PC-based data acquisition hardware and preamplifiers to acquire time-based data, along with software we have developed to compute the cross-correlation and noise spectral density. The impedance of device under test may cover four decades from ${100\\,{\\Omega}}$ to ${1\\,{\\mathrm{M}\\Omega}}$. By utilizing a custom developed signal processing program, this system is tested to be accurate and efficient for measuring voltage noise as low as $\\sim\\!10^{-19}\\,\\mathrm{V}^2/\\mathrm{Hz}$ from ${0.001\\,}$Hz to ${100\\,}$kHz within one day's averaging time, comparable with more expensive hardware solutions (bandwidth in real measurements may be limited by the sample impedance and stray capacitance). The time dependence of measurement sensitivity is discussed theoretically and characterized experimentally to optimize between measuring tim...

Zhong, Xing; Jones, Josh; Mewes, Claudia; LeClair, Patrick R

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency time period" 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

The Fermi blazars' divide based on the diagnostic of the SEDs peak frequencies  

E-Print Network (OSTI)

We have studied the quasi-simultaneous Spectral Energy Distributions (SED) of 48 LBAS blazars, detected within the three months of the LAT Bright AGN Sample (LBAS) data taking period, combining Fermi and Swift data with radio NIR-Optical and hard-X/gamma-ray data. Using these quasi-simultaneous SEDs, sampling both the low and the high energy peak of the blazars broad band emission, we were able to apply a diagnostic tool based on the estimate of the peak frequencies of the synchrotron (S) and Inverse Compton (IC) components. Our analysis shows a Fermi blazars' divide based on the peak frequencies of the SED. The robust result is that the Synchrotron Self Compton (SSC) region divides in two the plane were we plot the peak frequency of the synchrotron SED vs the typical Lorentz factor of the electrons most contributing to the synchrotron emission and to the inverse Compton process. Objects within or below this region, radiating likely via the SSC process, are high-frequency-peaked BL Lac object (HBL), or low/in...

Tramacere, A; Giommi, P; Mazziotta, N; Monte, C

2010-01-01T23:59:59.000Z

482

The periodic variations of a white-light flare observed with ULTRACAM  

E-Print Network (OSTI)

High time resolution observations of a white--light flare on the active star EQ PegB show evidence of intensity variations with a period of approximately 10 s. The period drifts to longer values during the decay phase of the flare. If the oscillation is interpreted as an impulsively--excited, standing--acoustic wave in a flare loop, the period implies a loop length of 1.7 Mm and 3.4 Mm for the case of the fundamental mode and the second harmonic, respectively. However, the small loop lengths imply a very high modulation depth making the acoustic interpretation unlikely. A more realistic interpretation may be that of a fast--MHD wave, with the modulation of the emission being due to the magnetic field. Alternatively, the variations could be due to a series of reconnection events. The periodic signature may then arise as a result of the lateral separation of individual flare loops or current sheets with oscillatory dynamics (i.e. periodic reconnection).

M. Mathioudakis; D. S. Bloomfield; D. B. Jess; V. S. Dhillon; T. R. Marsh

2006-05-08T23:59:59.000Z

483

Beat-Frequency Models of Kilohertz QPOs  

E-Print Network (OSTI)

Kilohertz QPO sources are reasonably well-characterized observationally, but many questions remain about the theoretical framework for these sources and the consequent implications of the observations for disk physics, strong gravity, and dense matter. We contrast the predictions and implications of the most extensively studied class of kilohertz QPO models, the beat-frequency models, with those of alternative classes of models. We also discuss the expected impact of new observations of these sources with satellites such as Chandra, XMM, and Constellation-X.

M. Coleman Miller

2000-07-19T23:59:59.000Z

484

Nonlinear optical protection against frequency agile lasers  

SciTech Connect

An eye-protection or equipment-filter device for protection from laser energy is disclosed. The device may be in the form of a telescope, binoculars, goggles, constructed as part of equipment such as image intensifiers or range designators. Optical elements focus the waist of the beam within a nonlinear frequency-doubling crystal or nonlinear optical element or fiber. The nonlinear elements produce a harmonic outside the visible spectrum in the case of crystals, or absorb the laser energy in the case of nonlinear fibers. Embodiments include protectors for the human eye as well as filters for sensitive machinery such as TV cameras, FLIR systems or other imaging equipment.

McDowell, V.P.

1988-08-04T23:59:59.000Z

485

Efficiency optimization for atomic frequency comb storage  

SciTech Connect

We study the efficiency of the atomic frequency comb storage protocol. We show that for a given optical depth, the preparation procedure can be optimize to significantly improve the retrieval. Our prediction is well supported by the experimental implementation of the protocol in a Tm{sup 3+}:YAG crystal. We observe a net gain in efficiency from 10 to 17% by applying the optimized preparation procedure. In the perspective of high bandwidth storage, we investigate the protocol under different magnetic fields. We analyze the effect of the Zeeman and superhyperfine interaction.

Bonarota, M.; Ruggiero, J.; Le Goueet, J.-L.; Chaneliere, T. [Laboratoire Aime Cotton, CNRS-UPR 3321, Univ. Paris-Sud, Bat. 505, F-91405 Orsay Cedex (France)

2010-03-15T23:59:59.000Z

486

Self isolating high frequency saturable reactor  

DOE Patents (OSTI)

The present invention discloses a saturable reactor and a method for decoupling the interwinding capacitance from the frequency limitations of the reactor so that the equivalent electrical circuit of the saturable reactor comprises a variable inductor. The saturable reactor comprises a plurality of physically symmetrical magnetic cores with closed loop magnetic paths and a novel method of wiring a control winding and a RF winding. The present invention additionally discloses a matching network and method for matching the impedances of a RF generator to a load. The matching network comprises a matching transformer and a saturable reactor.

Moore, James A. (Powell, TN)

1998-06-23T23:59:59.000Z

487

Characterization of the reactive flow field dynamics in a gas turbine injector using high frequency PIV  

E-Print Network (OSTI)

The present work details the analysis of the aerodynamics of an experimental swirl stabilized burner representative of gas turbine combustors. This analysis is carried out using High Frequency PIV (HFPIV) measurements in a reactive situation. While this information is usually available at a rather low rate, temporally resolved PIV measurements are necessary to better understand highly turbulent swirled flows, which are unsteady by nature. Thanks to recent technical improvements, a PIV system working at 12 kHz has been developed to study this experimental combustor flow field. Statistical quantities of the burner are first obtained and analyzed, and the measurement quality is checked, then a temporal analysis of the velocity field is carried out, indicating that large coherent structures periodically appear in the combustion chamber. The frequency of these structures is very close to the quarter wave mode of the chamber, giving a possible explanation for combustion instability coupling.

Barbosa, Séverine; Ducruix, Sébastien

2008-01-01T23:59:59.000Z

488

Black Bear Prep plant replaces high-frequency screens with fine wire sieves  

SciTech Connect

At the Black Bear prep plant (near Wharncliffe, WV, USA) the clean coal from the spirals traditionally reported to high-frequency screens, which removed high-ash clay fines. Screens have inherent inefficiencies that allow clean coal to report to the screen underflow. The goal of this project was to capture the maximum amount of spiral clean coal while still removing the high-ash clay material found in the spiral product. The reduction of the circulating load and plant downtime for unscheduled maintenance were projected as additional benefits. After the plant upgrade, the maintenance related to the high frequency screens was eliminated and an additional 2.27 tons per hour (tph) of fine coal was recovered, which resulted in a payback period of less than one year. The article was adapted from a paper presented at Coal Prep 2007 in April 2007, Lexington, KY, USA. 1 ref., 1 fig., 1 tab.

Barbee, C.J.; Nottingham, J.

2007-12-15T23:59:59.000Z

489

Dual periodicities in the rotational modulation of Saturn narrowband emissions  

E-Print Network (OSTI)

Dual periodicities in the rotational modulation of Saturn narrowband emissions S.Y. Ye,1 D. A emissions is examined, restricting the spacecraft location to either the northern or the southern hemisphere of Saturn. It is found that in both hemispheres, the modulation period of 5 kHz narrowband emissions has two

Gurnett, Donald A.

490

Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities  

DOE Patents (OSTI)

A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

Harrison, Neil (Santa Fe, NM); Singleton, John (Los Alamos, NM); Migliori, Albert (Santa Fe, NM)

2008-08-05T23:59:59.000Z

491

Another look at periodic wavelets Brody Dylan Johnson  

E-Print Network (OSTI)

Another look at periodic wavelets Brody Dylan Johnson St. Louis University 16 May 2009 Brody Dylan Johnson (St. Louis University) Another look at periodic wavelets 16 May 2009 1 / 31 #12;Overview Overview. (see, e.g., the texts of Meyer and Daubechies) Brody Dylan Johnson (St. Louis University) Another look

Johnson, Brody Dylan

492

Photonic bandgaps of periodic multilayers with diffuse interfaces  

E-Print Network (OSTI)

of the locations and widths of the forbidden bandgaps is standard [1­3]. However, generally the interfaces betweenPhotonic bandgaps of periodic multilayers with diffuse interfaces Jean-Michel André* , Philippe-michel.andre1@upmc.fr The photonic bandgap of periodic multil