Science.gov (United States)

tions, final noise-power spectral density measurements were made. These measurements of the noise-power spectral density were not the desired phase- noise ...

Energy Technology Data Exchange (ETDEWEB)

Increase in power utility loads in industrialized countries, as well as developing countries, demands a higher level of transmission line voltage. Radio interference (RI) problems have been determined to be a limiting factor in selecting the size of transmission line conductors. Transmission line noise is primarily caused by corona discharges in the immediate vicinity of the conductor. It has been observed that discharges occur during both half-cycles of the applied voltage, but positive corona is usually predominant at AM radio frequencies range with practical high-voltage and extra high-voltage transmission lines. The corona radio noise effect is highly dependent upon the presence of particles on the surface of the conductor and the increase of the electrical gradient beyond the breakdown value of the air. Therefore, corona radio noise ...

International Nuclear Information System (INIS)

Increase in power utility loads in industrialized countries, as well as developing countries, demands a higher level of transmission line voltage. Radio interference (RI) problems have been determined to be a limiting factor in selecting the size of transmission line conductors. Transmission line noise is primarily caused by corona discharges in the immediate vicinity of the conductor. It has been observed that discharges occur during both half-cycles of the applied voltage, but positive corona is usually predominant at AM radio frequencies range with practical high-voltage and extra high-voltage transmission lines. The corona radio noise effect is highly dependent upon the presence of particles on the surface of the conductor and the increase of the electrical gradient beyond the breakdown value of the air. Therefore, corona radio noise ...

Energy Technology Data Exchange (ETDEWEB)

The study of audible noise from high voltage transmission lines and a high voltage transformer station was conducted in three parts. Part 1 consisted of long-term measurement and statistical analysis by computer reduction of audible noise as a result of corona discharge from high voltage transmission lines and the associated weather conditions which contribute to this noise. Recommendations are given concerning further computer programming in order to improve the statistical reliability of corona noise presence and reduce the degree of background noise contamination of the present results. Part 2 consisted of categorizing and cataloguing of corona noise spectra from long-term measurements on 550, 735 and 765 kV transmission lines and to provide a library of such sounds on magnetic tape to be used in the ongoing study of corona ...

International Nuclear Information System (INIS)

Josephson effect heterodyne mixers with external local oscillators are very promising low noise mm-wave receivers for applications such as radio astronomy. Experiments at 36 GHz have shown that both the noise and the conversion efficiency of mixers made using Nb point contacts are in quantitative agreement with values calculated from the resistively shunted junction (RSJ) model. Preliminary measurements at 140 GHz suggest that this agreement extends to higher frequencies. In this paper the theoretical limits to the sensitivity of such receivers are explored as a function of the signal frequency. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

It is shown that de-noising a measured time signal by wavelet technique produces a rather good result in time domain, while it has unwanted consequences in spectrum estimation. Therefore it can be used for reconstruction of the picture of the physical process, but it should be avoided, when the aim is to reveal eigenfrequencies or transient behaviour of the spectra.

CERN Document Server

The PLL (Phase Locked Loop) has two modes: search mode and locking mode. The mode is determined by how far apart the internal frequency is from the external frequency. When the internal - and exter nal frequencies are close, the PLL is in locking mode. While locking on the external frequency, the PLL can largely be expressed as a linear term superimposed with a small "noise" term. We can t herefore calculate a transfer function that will completely describe the performance of the PLL apart from the precision, which is determined by the noise term. Two ideas are presented on how to re duce the noise term. The first idea is to compensate the noise term with an equal value of opposite sign. This completely removes the noise when the PLL locks on a steady frequency. Unfortunately it can not be used for the LEP Q-meter which is plagued by the presence of satellite frequencies. For other ...

CERN Document Server

We present the X-ray properties of a sample of 17 radio sources observed with the Chandra X-ray Observatory as part of a project aimed at studying the X-ray emission from their radio jets. In this paper, we concentrate on the X-ray properties of the unresolved cores. The sample includes 16 quasars (11 core-dominated and 5 lobe-dominated) in the redshift range z=0.30--1.96, and one low-power radio-galaxy at z=0.064. No diffuse X-ray emission is present around the cores of the quasars, except for the nearby low-power galaxy that has diffuse emission on a scale and with a luminosity consistent with other FRIs. No high-amplitude, short-term variability is detected within the relatively short Chandra exposures. However, 1510-089 shows low-amplitude flux changes with a timescale of $\\sim$25 minutes. The X-ray spectra of the quasar cores are generally well described by a single power law model with Galactic ...

British Library Electronic Table of Contents (United Kingdom)

A method to achieve NMR of dilute samples in the earth's magnetic field by applying para-hydrogen induced polarization is presented. Maximum achievable polarization enhancements were calculated by numerically simulating the experiment and compared to the experimental results and to the thermal equilibrium in the earth's magnetic field. Simultaneous 19F and 1H NMR detection on a sub-milliliter sample of a fluorinated alkyne at millimolar concentration (1018 nuclear spins) was realized with just one single scan. A highly resolved spectrum with a signal/noise ratio higher than 50:1 was obtained without using an auxiliary magnet or any form of radio frequency shielding.

CERN Document Server

We identify emission lines of post-iron peak elements in very high signal-to-noise spectra of a sample of planetary nebulae. Analysis of lines from ions of Kr and Xe reveals enhancements in most of the PNe, in agreement with the theories of s-process in AGB star. Surprisingly, we did not detect lines from Br even though s-process calculations indicate that it should be produced with Kr at detectable levels.

CERN Document Server

Previous work has shown the Orion Bar to be an interface between ionized and molecular gas, viewed roughly edge on, which is excited by the light from the Trapezium cluster. Much of the emission from any star-forming region will originate from such interfaces, so the Bar serves as a foundation test of any emission model. Here we combine X-ray, optical, IR and radio data sets to derive emission spectra along the transition from H+ to H0 to H2 regions. We then reproduce the spectra of these layers with a simulation that simultaneously accounts for the detailed microphysics of the gas, the grains, and molecules, especially H2 and CO. The magnetic field, observed to be the dominant pressure in another region of the Orion Nebula, is treated as a free parameter, along with the density of cosmic rays. Our model successfully accounts for the optical, IR and radio observations across the Bar by including a ...

Energy Technology Data Exchange (ETDEWEB)

Radio interference and TV interference are being a problem in urban and rural areas. This interference is generated by high voltage transmission lines as well as distribution lines. The radio noise can be produced by polluted or damaged insulators, and by metal parts of the distribution lines. The corona effect on the surface of the dielectric material produces high frequency electromagnetic fields during the ionization and during the recombination period. Fields of different intensity are produced by positive voltage and negative voltage. The insulator flashover (leaking current) also produces electromagnetic fields. A new technique to measure these fields was developed. This technique measures the radiated fields on time domain and on frequency domain. This permits us to characterize the radiated field and thus identify the type of the source. Several measurements were done varying the type of the RF generator, i.e., new ...

CERN Document Server

We present a dynamical spectral model for Large Eddy Simulation of the incompressible magnetohydrodynamic (MHD) equations based on the Eddy Damped Quasi Normal Markovian approximation. This model extends classical spectral Large Eddy Simulations for the Navier-Stokes equations to incorporate general (non Kolmogorovian) spectra as well as eddy noise. We derive the model for MHD and show that introducing a new eddy-damping time for the dynamics of spectral tensors in the absence of equipartition between the velocity and magnetic fields leads to better agreement with direct numerical simulations, an important point for dynamo computations.

CERN Document Server

Using a sample of 30,000 quasars from SDSS-DR7, we explore the range of properties exhibited by high-ionization, broad emission lines, such as CIV 1549. Specifically we investigate the anti-correlation between L_UV and emission line EQW (the Baldwin Effect) and the "blueshifting" of high-ionization emission lines. The blueshift of the CIV emission line is nearly ubiquitous, with a mean shift of 810 km/s for radio-quiet (RQ) quasars and 360 km/s for radio-loud (RL) quasars, and the Baldwin Effect is present in both RQ and RL samples. Composite spectra are constructed as a function of CIV emission line properties in attempt to reveal empirical relationships between different line species and the SED. Within a two-component disk+wind model of the broad emission line region (BELR), where the wind filters the continuum seen by the disk component, we find that RL quasars are consistent with being dominated by the disk component, ...

KoreaScience (Korea)

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CERN Document Server

We use UV/optical and X-ray observations of 272 radio-quiet Type 1 AGNs and quasars to investigate the CIV Baldwin Effect (BEff). The UV/optical spectra are drawn from the Hubble Space Telescope, International Ultraviolet Explorer and Sloan Digital Sky Survey archives. The X-ray spectra are from the Chandra and XMM-Newton archives. We apply correlation and partial-correlation analyses to the equivalent widths, continuum monochromatic luminosities, and alpha_ox, which characterizes the relative X-ray to UV brightness. The equivalent width of the CIV 1549 emission line is correlated with both alpha_ox and luminosity. We find that by regressing l_UV with EW(CIV) and alpha_ox, we can obtain tighter correlations than by regressing l_UV with only EW(CIV). Both correlation and regression analyses imply that l_UV is not the only factor controlling the changes of EW(CIV); alpha_ox (or, equivalently, the soft X-ray emission) plays a ...

CERN Document Server

The possibility of radio galaxies being random sample of otherwise normal elliptical galaxies is tested. Starting with the observed optical luminosity functions for elliptical galaxies, it is shown that the probability of an elliptical forming a radio source is a continuous, increasing function of optical luminosity, precisely proportional to square of the optical luminosity of the galaxy. Once the probability function is fixed, the luminosity function of normal elliptical galaxies is used as input for Monte Carlo simulations that reproduce the distribution of radio galaxies in the radio-optical luminosity plane. Our results show that radio galaxies are luminosity biased, but otherwise random sample of elliptical galaxies. This unified view of radio and non-radio ellipticals also explains the well known difference of 0.5 mag in average ...

Energy Technology Data Exchange (ETDEWEB)

Bluestein's Fast Fourier Transform (FFT), commonly called the Chirp-Z Transform (CZT), is a little-known algorithm that offers engineers a high-resolution FFT combined with the ability to specify bandwidth. In the field of digital signal processing, engineers are always challenged to detect tones, frequencies, signatures, or some telltale sign that signifies a condition that must be indicated, ignored, or controlled. One of these challenges is to detect specific frequencies, for instance when looking for tones from telephones or detecting 60-Hz noise on power lines. The Goertzel algorithm described in Embedded Systems Programming, September 2002, offered a powerful tool toward finding specific frequencies faster than the FFT.Another challenge involves analyzing a range of frequencies, such as recording frequency response measurements, matching voice patterns, or displaying spectrum information on the face of an amateur radio. To meet ...

International Nuclear Information System (INIS)

It is found that below 80 K o-TaS_3 demonstrates spontaneous resistance fluctuations growing when the temperature is decreasing. The average relaxation time, #tau#_0, obtained from the noise spectra demonstrates activated behavior, #tau#_0 #propor to# exp(W/T), W #approx# 1300 K for 50 < or #approx# T < or #approx# 70 K. In the vicinity of the threshold the average frequency of the fluctuations, f_0, grows with increasing the voltage, revealing onset of the Froehlich current. log(f_0) is found to be proportional to the increase of conductivity. We conclude that the main source of the resistance fluctuations are thermally-assisted jumps of dislocations of the charge-density waves. (orig.).

CERN Document Server

We present the results of a study on the 1.4 GHz kpc-scale radio emission in the complete flux density limited MOJAVE sample, comprising 135 radio-loud AGNs. While extended emission is detected in the majority of the sources, about 7% of the sources exhibit only radio core emission. Many BL Lacs exhibit extended radio power and kpc-scale morphology typical of powerful FRII jets, while a substantial number of quasars possess radio powers intermediate between FRIs and FRIIs. This poses challenges to the simple radio-loud unified scheme, which links BL Lacs to FRIs and quasars to FRIIs. We find a significant correlation between extended radio emission and pc-scale jet speeds: the more radio powerful sources possess faster jets. This indicates that the 1.4 GHz (or low frequency) radio emission is indeed ...

British Library Electronic Table of Contents (United Kingdom)

Abstract A method was developed to quantify the effect of scanner instability on functional MRI data by comparing the instability noise to endogenous noise present when scanning a human. The instability noise was computed from agar phantom data collected with two flip angles, allowing for a separation of the instability from the background noise. This method was used on human data collected at four 3 T scanners, allowing the physiological noise level to be extracted from the data. In a -well-operating- scanner, the instability noise is generally less than 10% of physiological noise in white matter and only about 2% of physiological noise in cortex. This indicates that instability in a well-operating scanner adds very little noise to functional MRI results. This new method allows researcher...

CERN Document Server

We discuss optimal detection of fast radio transients from astrophysical objects while taking into account the effects of propagation through intervening ionized media, including dispersion, scattering and scintillation.Our analysis applies to the giant-pulse phenomenon exhibited by some pulsars, for which we show examples, and to radio pulses from other astrophysical sources, such as prompt radio emission from gamma-ray burst sources and modulated signals from extra-terrestrial civilizations.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

CERN Document Server

We study the high-energy emission of the Galactic black hole candidate GX 339-4 using INTEGRAL/SPI and simultaneous RXTE/PCA data. By the end of January 2007, when it reached its peak luminosity in hard X-rays, the source was in a bright hard state. The SPI data from this period show a good signal to noise ratio, allowing a detailed study of the spectral energy distribution up to several hundred keV. As a main result, we report on the detection of a variable hard spectral feature (>150 keV) which represents a significant excess with respect to the cutoff power law shape of the spectrum. The SPI data suggest that the intensity of this feature is positively correlated with the 25 - 50 keV luminosity of the source and the associated variability time scale is shorter than 7 hours. The simultaneous PCA data, however, show no significant change in the spectral shape, indicating that the source is not undergoing a canonical state transition. We analyzed the broad band ...

CERN Document Server

In order to perform a detailed study of the stellar kinematics in the vertical axis of bars, we obtained high signal-to-noise spectra along the major and minor axes of the bars in a sample of 14 face-on galaxies, and used them to determine the line of sight stellar velocity distribution, parameterized as Gauss-Hermite series. With these data, we developed a diagnostic tool that allows one to distinguish between recently formed and evolved bars, as well as estimate their ages, assuming that bars form in vertically thin disks, recognizable by low values for the vertical velocity dispersion sigma_z. Through N-body realizations of bar unstable disk galaxies we could also check the time scales involved in the processes which give bars an important vertical structure. We show that sigma_z in evolved bars is roughly around 100 Km/s, which translates to a height scale of about 1.4 Kpc, giving support to scenarios in which bulges form through disk ...

UK PubMed Central (United Kingdom)

Parallel imaging reconstructions result in spatially varying noise amplification characterized by the g-factor, precluding conventional measurements of noise from the final...Full Text Available

International Nuclear Information System (INIS)

We use UV/optical and X-ray observations of 272 radio-quiet Type 1 active galactic nuclei and quasars to investigate the C IV Baldwin Effect (BEff). The UV/optical spectra are drawn from the Hubble Space Telescope, International Ultraviolet Explorer and Sloan Digital Sky Survey archives. The X-ray spectra are from the Chandra and XMM-Newton archives. We apply correlation and partial-correlation analyses to the equivalent widths (EWs), continuum monochromatic luminosities, and ?ox, which characterizes the relative X-ray to UV brightness. The EW of the C IV ?1549 emission line is correlated with both ?ox and luminosity. We find that by regressing l?(2500 A) with EW(C IV) and ?ox, we can obtain tighter correlations than by regressing l?(2500 A) with only EW(C IV). Both correlation and regression analyses imply that l?(2500 A) is not the only factor controlling the changes of EW(C IV); ?ox (or, equivalently, the soft X-ray ...

Science.gov (United States)

... 13 2.4 Inertial Navigation Error Model . . . . . ... sources such as electrical noise, thermal noise, etc. 2.4 Inertial Navigation Error Model ...

Science.gov (United States)

... Characterizing the Relative Contributions of Large Vessels to Total Ocean Noise Fields: A Case Study Using the Gerry E. ... ...

CERN Document Server

We present results of a study of large-scale neutral hydrogen (HI) gas in nearby radio galaxies. We find that the early-type host galaxies of different types of radio sources (compact, FR-I and FR-II) appear to contain fundamentally different large-scale HI properties: enormous regular rotating disks and rings are present around the host galaxies of a significant fraction of low power compact radio sources, while no large-scale HI is detected in low power, edge-darkened FR-I radio galaxies. Preliminary results of a study of nearby powerful, edge-brightened FR-II radio galaxies show that these systems generally contain significant amounts of large-scale HI, often distributed in tail- or bridge-like structures, indicative of a recent galaxy merger or collision. Our results suggest that different types of radio galaxies may have a different formation history, which ...

International Nuclear Information System (INIS)

High quality "3"1P MR spectra (signal to noise ratio (S/N) approximately 18, 15 min acquisition for each spectrum) were consistently obtained with surface coils over a period of 6-week RT. Both transient and steady state alterations in metabolites in response to RT were found in this case. The transient changes occurred during the first 3 hr immediately after the 3rd fractionated RT, these changes include the transient elevation of the PCr resonance, a decrease in PDE and an increase in intracellular pH. The monitoring showed that the metabolites approached steady state approximately 2 hr after the fractionated radiation intervention, suggesting that in vivo MRS can be useful for studying the dynamics of tumor response to RT such as repair of potential lethal damage, growth delay, and reoxygenation etc. The steady-state MR spectra showed the net response to each intervention and can clinically be useful for predicting and ...

KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Presentation of electromagnetic sources constituted by various radio transmitters contributing to different radio communication services in the environment. Results of a measures campaign to assess the electromagnetic field in the close neighbourhood of various stations. Analysis by frequency domains. (author)

Energy Technology Data Exchange (ETDEWEB)

Monolithic N-channel junction field effect transistors (NJFETs) dc characteristics, small signal parameters and noise have been studied from 300 K down to cryogenic temperatures before and after irradiation with {sup 60}Co {gamma}-rays and fast neutrons (1 MeV). Radiation induced effects on dc parameters and noise are reviewed. Noise spectral density measurements performed at various temperatures have shown that the radiation induces a noise increase which is temperature and frequency dependent. (orig.). 14 refs.

Science.gov (United States)

... small water or ice particles by impaction ... flight recording; principally the hydrometeor charge unit ... capability of directing aircraft movements by radio ...

International Nuclear Information System (INIS)

(Dec 1973). United Kingdom Stevenson, AC Medical Research Council, Oxford

International Nuclear Information System (INIS)

The effect of severe plastic deformation by cold high pressure torsion (HPT) on radio frequency (RF) plasma nitriding of pure iron, as well as St2K50 and X5CrNi1810 steels was investigated. Nitriding was carried out for 3 h in a nitrogen atmosphere at a pressure of 10"-"5 bar and temperatures of 350 and 400 deg. C. Nitrided specimens were analysed by scanning electron microscopy (SEM), X-ray diffraction and micro hardness measurements. It was found that HPT enhances the effect of nitriding leading almost to doubling of the thickness of the nitrided layer for pure iron and the high alloyed steel. The largest increase in hardness was observed when HPT was combined with RF plasma nitriding at 350 deg. C. In the case of pure iron, the X-ray diffraction spectra showed the formation of #epsilon# and #gamma#' nitrides in the compound layer, with a preferential formation of #gamma#' at the expense of the #alpha#-phase at the higher nitriding ...

International Nuclear Information System (INIS)

Active galactic nuclei (AGNs) and quasars (QSOs) appear to emit roughly equal energy per decade from radio to gamma-ray energies (e.g. Ramaty and Ligenfelter 1982). This argues strongly for a nonthermal radiation mechanism (see Rees 1984). In addition, statistical studies have indicated that the spectra of these objects in the IR-UV and 2 to 50 keV x-ray band, can be fitted very well with power laws of specific indices. These spectral indices do not seem to depend on the luminosity or morphology of the objects (Rothschild et al. 1983; Malkan 1984), and any theory should account for them in a basic and model independent way. If shocks accelerate relativistic protons via the first-order Fermi mechanism (e.g. Axfor 1981), the radiating electrons can be produced as secondaries throughout the source by proton-proton (p-p) collisions and pion decay, thus eliminating Compton losses (Protheroe and Kazanas 1983). As shown by Kazanas (1984), if ...

Science.gov (United States)

Language: English ...

International Nuclear Information System (INIS)

Point contact Josephson junctions can function as millimeter wave heterodyne mixers with conversion gain. The best results achieved thus far show a single sideband conversion gain of 1.3 and a mixer contribution to the system noise temperature of 54"0K. Both of these results are approximately 5 times better than the best published figures for cooled Schottky barrier diode mixers operated at the same frequency. The measured noise for a variety of junctions can be expressed as a universal function of the normalized rf frequency #OMEGA# = h#omega#/2eI/sub c/R. It is about a factor 2 larger than the calculated noise arising from the thermal noise in the junction shunt resistance, R. The noise calculation was done for the resistively shunted junction model using an analog junction simulator.

UK PubMed Central (United Kingdom)

Variability in motor performance decreases with practice but is never entirely eliminated, due in part to inherent motor noise. The present study develops a method that quantifies how performers...Full Text Available

UK PubMed Central (United Kingdom)

An examination of the noise of polycrystalline silicon thin film transistors, in the context of flat panel x-ray imager development, is reported. The study was conducted in the spirit of exploring...Full Text Available

UK PubMed Central (United Kingdom)

A new method of random data analysis has been developed with special implications for membrane noise. The integral spectrometer uses overlapping broad-band filters of simple design, whose bandwidth...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This paper presents calculations of the {sup 252}Cf-source-driven noise analysis measurements for subcritical highly enriched uranium metal cylinders using the Monte Carlo code MCNP-DSP. This code directly calculates the noise analysis data from the {sup 252}Cf- source-driven noise analysis method for both neutron and gamma ray detectors. Direct calculation of experimental observables by the Monte Carlo method allows for the benchmarking of the calculational model and the cross sections and for determining the bias in the calculation.

CERN Document Server

A method for simulating power law noise in clocks and oscillators is presented based on modification of the spectrum of white phase noise, then Fourier transforming to the time domain. Symmetric real matrices are introduced whose traces--the sums of their eigenvalues--are equal to the Allan variances, in overlapping or non-overlapping forms, as well as for the corresponding forms of the modified Allan variance. Diagonalization of these matrices leads to expressions for the probability distributions for observing a variance at an arbitrary value of the sampling or averaging interval $\\tau$, and hence for estimating confidence in the measurements. A number of applications are presented for the common power-law noises.

Science.gov (United States)

It is well known that laser oscillation is initiated by spontaneous radiation ''noise.'' Evidence for this is often based on the complete theory of laser oscillation, including the quantization of the electromagnetic field. In this article, the buildup of laser oscillation from quantum noise is demonstrated using the most elementary classical equation describing the amplification of laser intensity.

Energy Technology Data Exchange (ETDEWEB)

In the fall of 2003, the operators noticed that in the recently-refurbished Bruce A Shutdown System no. 1 (SDS1) the noise level in Log Rate signals were much larger than before. At the request of the Canadian Nuclear Safety Commission (CNSC), all Canadian CANDU reactors took action to characterize their Log Rate noise. Staff of the Inspection and Maintenance Services division of Ontario Power Generation (OPG) has collected high-speed high-accuracy noise data from nearly all 16 Ontario reactors, either as part of routine measurements before planned outages or as a dedicated noise recording. This paper gives the results of examining a suitable subset of this data, with respect to the characteristics and possible causes of Log Rate noise. The reactor and instrumentation design is different at each station: the locations of the moderator injection nozzles, the location of the ion ...

CERN Document Server

We report on the results of a simultaneous monitoring campaign employing eight Chandra X-ray (0.5-10 keV) and six VLA/EVLA (8.4 GHz) radio observations of NGC 4051 over seven months. Evidence for compact jets is observed in the 8.4 GHz radio band; This builds on mounting evidence that jet production may be prevalent even in radio-quiet Seyferts. Assuming comparatively negligible local diffuse emission in the nucleus, the results also demonstrate an inverse correlation of L_radio proportional to L_X-ray ^(-0.72+/-0.04) . Current research linking the mass of supermassive black holes and stellar-mass black holes in the "low/hard" state to X-ray luminosities and radio luminosities suggest a "fundamental plane of accretion onto black holes" that has a positive correlation of L_radio proportional to L_X-ray^(0.67+/-0.12) . Our simultaneous results differ from this ...

CERN Document Server

The detection of a stochastic background of gravitational waves could significantly impact our understanding of the physical processes that shaped the early Universe. The challenge lies in separating the cosmological signal from other stochastic processes such as instrument noise and astrophysical foregrounds. One approach is to build two or more detectors and cross correlate their output, thereby enhancing the common gravitational wave signal relative to the uncorrelated instrument noise. When only one detector is available, as will likely be the case with the Laser Interferometer Space Antenna (LISA), alternative analysis techniques must be developed. Here we show that models of the noise and signal transfer functions can be used to tease apart the gravitational and instrument noise contributions. We discuss the role of gravitational wave insensitive "null channels" formed from particular combinations ...

CERN Document Server

Motional heating of ions in micro-fabricated traps is a challenge hindering experimental realization of large-scale quantum processing devices. Recently a series of measurements of the heating rates in surface-electrode ion traps characterized their frequency, distance, and temperature dependencies, but our understanding of the microscopic origin of this noise is still vague. In this work we develop a theoretical model for the electric field noise which is associated with a random distribution of adsorbed atoms on the trap electrode surface. By using first principle calculations of the fluctuating dipole moments of the adsorbed atoms we evaluate the distance, frequency and temperature dependence of the resulting electric field fluctuation spectrum.Our theory calculates the noise spectrum beyond the standard scenario of two-level fluctuators, by incorporating all the relevant vibrational states. The $1/f$ ...

Energy Technology Data Exchange (ETDEWEB)

Contents include: index for 1970-1980; January 1981 data -- alert periods, daily solar indices, solar flares, solar radio emission, coronal holes, inferred interplanetary magnetic field polarities, mean solar magnetic field, spacecraft observations, December 1980 data -- daily solar-activity centers, sudden ionospheric disturbances, spacecraft observations, solar radio emission, cosmic rays, geomagnetic indices, radio-propagation indices; late data -- solar radio emission November, December 1980, spacecraft observations November 1980, cosmic rays, Huancayo Oct 1980 -- climax, alert, Deep River Nov 1980.

Science.gov (United States)

... of electronic systems (satellite terminals, radio and ... helps organizations investigate the stochastic nature of ... cycle time, maximum queue lengths, and ...

Science.gov (United States)

Briefly, 48 MOS microparticle sensors (essentially the same as those flown on .... at the Naval Research Lab to interpret the polarization of the incoming radio .... Adapter Satellite, to be published in Journal of Spacecraft and Rockets, 1994. ...

British Library Electronic Table of Contents (United Kingdom)

Abstract We have experimentally and theoretically investigated the equivalent magnetic noise in a magnetoelectric Metglas/ 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 laminate sensor unit by considering the constituent noise sources of dielectric loss (NDE) and DC leakage resistance (NR). In the low frequency range (f = 1 Hz), theory predicts that NR dominates the noise charge (1.6 times larger than NDE), with a 1 Hz noise of 9.1\\;{\\rm pt}/\\sqrt {\\rm Hz}. The experimental equivalent magnetic noise was 10.8\\;{\\rm pt}/\\sqrt {\\rm Hz}. This observed value is slightly higher than the predicted one, which might be due to an oversimplification of the theoretical model in terms of electrical charge amplifier and external vibration noise sources. ( 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Energy Technology Data Exchange (ETDEWEB)

The effect of severe plastic deformation by cold high pressure torsion (HPT) on radio frequency (RF) plasma nitriding of pure iron, as well as St2K50 and X5CrNi1810 steels was investigated. Nitriding was carried out for 3 h in a nitrogen atmosphere at a pressure of 10{sup -5} bar and temperatures of 350 and 400 deg. C. Nitrided specimens were analysed by scanning electron microscopy (SEM), X-ray diffraction and micro hardness measurements. It was found that HPT enhances the effect of nitriding leading almost to doubling of the thickness of the nitrided layer for pure iron and the high alloyed steel. The largest increase in hardness was observed when HPT was combined with RF plasma nitriding at 350 deg. C. In the case of pure iron, the X-ray diffraction spectra showed the formation of {epsilon} and {gamma}' nitrides in the compound layer, with a preferential formation of {gamma}' at the expense of the {alpha}-phase at the ...

Energy Technology Data Exchange (ETDEWEB)

Introduction: The goal of this study was to compare contrast-enhanced T1-weighted Flash and Turbo-Flash sequences with conventional spin-echo sequences as a basis for planning high-precision radiotherapy. Methods: A total of 25 consecutive patients with different intracranial tumors and a disrupted blood-brain barrier were studied. T1-weighted Flash, Turbo-Flash and conventional spin-echo images were evaluated after controlled 30-s infusion of 0.1 mmol/kg body weight of Gd-DTPA. The evaluation of the three sequences included the measurement of the signal- and contrast-to-noise ratios, the visual inspection of the tumors and artifacts, and the measurement of tumor size. Results: The signal- and contrast-to-noise ratios were significantly (P<0.05-0.01) lower for Flash and Turbo-Flash than for conventional spin-echo sequences. However, visual inspection of the contrast-enhancing tumors revealed in 23 and 24 of 25 lesions of Flash and ...

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...Explore - The Lab - Australian Broadcasting Corporation's Gateway to Science Radio TV Shop News Sport Local Children Science Environment more Topics help Science Home News in Science Features Explore TV & Radio Dr Karl Play Podcasts DNA - The discovery of the double helix structure of DNA completely changed biology and opened up the new field of genetics. The 'backbone of life' has given us the human genome, stem cell research, ...

Science.gov (United States)

Not Available

Science.gov (United States)

The gamma spectra and lifetimes of the Ta and W isotopes havimg mass numbers 173, 175, 177, and 179 are determined. (T.F.H.)

Energy Technology Data Exchange (ETDEWEB)

We reported the radio-protective effect of DTT. The treatment of DTT increased cell survival after gamma-irradiation, decreased in the frequencies of micronucleus, and reduction in DNA fragmentation and apoptotic cells. Induction of apoptosis after UV-C irradiation was revealed by the changes in the relative cell death, increase in the relative amount of apoptotic cells, and the induction of DNA fragmentation. About 100 medicinal plants were purchased and methanol extract samples were prepared. Radio-protective and radio-sensitizing activities of these samples were screened. Seven samples showed above 20% radio-protective activities: Salvia miltiorrhiza, Areca catechu, Cornus officinalis, Alpiniae officinari rhizoma, Meliae fructus, Alpiniae katsumadaii semen, Betulae cortex. Acanthopanax sessiliflous showed the highest radio-sensitizing effect and 10 other samples revealed moderate ...

International Nuclear Information System (INIS)

The Los Alamos FEL requires tight control of the amplitudes and phases of the fields in two linear accelerator tanks to obtain stable lasing. The accelerator control loops must establish constant, stable, repeatable amplitudes and phases of the rf fields and must have excellent bandwidth to control high-frequency noise components. A model of the feedback loops has been developed that agrees well with measurements and allows easy substitution of components and circuits, thus reducing breadboarding requirements. The model permits both frequency and time-domain analysis. This paper describes the accelerator control scheme and our model and discusses the control of noise in feedback loops, showing how low-frequency-noise components (errors) can be corrected, but high-frequency-noise components (errors) are actually amplified by the feedback circuit. Measurements of noise in both open- ...

Energy Technology Data Exchange (ETDEWEB)

Electrochemical noise generated during stress corrosion cracking (SCC) of type 304 stainless steel (UNS S30400) and {alpha}-brass were studied. Noise patterns showed common characteristics (i.e., a quick drop and slow recovery of the potential). The quick drop corresponded to the initiation of localized events where fresh metal was exposed. The slow recovery corresponded to the repassivation process of the exposed bare metal. The potential drop rate and recovery rate were almost constant during the SCC process for a given SCC system. For random noise, rates of potential rise and drop were similar. Frequency of the noise generated during SCC increased with an increase in applied stress. SCC initiation could be monitored and determined according to noise characteristics and distribution. Since the shift of background potentials had an obvious influence on characteristics of power ...

International Nuclear Information System (INIS)

... californium 252 fftf reactor mockup power density reactor cores reactor noise

Energy Technology Data Exchange (ETDEWEB)

During the present project the mechanisms of generation of low frequency noise (LFN) for upwind rotors has been investigated. A 3.6 MW turbine has been simulated with a noise prediction model from NASA in US. Running the model on this turbine a number of important turbine design parameters with influence on the LFN have been identified as well as other parameters not linked to the turbine design. Of important parameters can be mentioned 1) rotor rotational speed, 2) blade/tower clearance, 3) rotor configuration - upwind/downwind, 4) unsteadiness/turbulence in inflow. Further, the directivity characteristics of LFN has been computed as well as reduction in noise as function of distance from the turbine. In general low levels of LFN has been computed for the upwind rotor in standard configuration. (au)

Science.gov (United States)

... Voltage noise power spectral density measurements as a function of temperature, frequency, current, and magnetic field on DyBa2Cu3O7.x (DBCO ...

Science.gov (United States)

Not Available

CERN Document Server

According to empirical observations, some pattern formation phenomena in driven many-particle systems are more pronounced in the presence of a certain noise level. We investigate this phenomenon of fluctuation-driven ordering with a cellular automaton model of interactive motion in space and find an optimal noise strength, while order breaks down at high(er) fluctuation levels. Additionally, we discuss the phenomenon of noise- and drift-induced self-organization in systems that would show disorder in the absence of fluctuations. In the future, related studies may have applications to the control of many-particle systems such as the efficient separation of particles. The rather general formulation of our model in the spirit of game theory may allow to shed some light on several different kinds of noise-induced ordering phenomena observed in physical, chemical, biological, and socio-economic systems ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

... aurorae carbon dioxide emission spectra infrared radiation nitrogen nitrogen

Energy Technology Data Exchange (ETDEWEB)

A technique capable of measuring the electron energy fluence spectra in a scattering medium was designed. These measurements were performed by setting a bremsstrahlung conversion target on the surface of a phantom, at an intermediate depth, and at a depth equal to electron mean range. The bremsstrahlung produced by the deceleration of electrons in the target was passed through an air channel in the phantom and passed forward by a pinhole collimator into a Na(Tl) detector. The measured pulse height data were unfolded to correct for the distortion of the spectrometer system by using the FORIST unfolding code. The unfolded bremsstrahlung spectra represent the electron energy fluence spectra convolution with the bremsstrahlung produced in the target. To generate the electron energy fluence spectra, the unfolded bremsstrahlung spectra were deconvoluted by using the MAZE2 unfolding code. ...

CERN Document Server

We present a HST/STIS spectroscopic and optical/radio imaging study of the Seyfert NGC 2110 aiming to measure the dynamics and understand the nature of the nuclear outflow in the galaxy. Previous HST studies have revealed the presence of a linear structure in the Narrow-Line Region (NLR) aligned with the radio jet. We show that this structure is strongly accelerated, probably by the jet, but is unlikely to be entrained in the jet flow. The ionisation properties of this structure are consistent with photoionisation of dusty, dense gas by the active nucleus. We present a plausible geometrical model for the NLR, bringing together various components of the nuclear environment of the galaxy. We highlight the importance of the circum-nuclear disc in determining the appearance of the emission line gas and the morphology of the jet. From the dynamics of the emission line gas, we place constraints on the accelerating mechanism of the outflow and discuss ...

British Library Electronic Table of Contents (United Kingdom)

Over the past three decades, rising competition from television and other new media prompted the FCC to ease the responsibilities of radio stations to maintain extensive records of issues programming, while retaining the responsibility of stations to provide ready public access to records. This study investigated the availability of Issues-Programs Lists in nearly 100 Missouri radio station Public Files. One in five randomly sampled stations failed to produce access to Lists upon demand as required under federal law. Noncompliance themes include: Inability to access Public Files within 20 minutes of face-to-face requests; station personnel with limited or no knowledge of Files; denial of access to Files and Lists (i.e., verbal refusals, locked studio doors); and incomplete Files. The rate ...

CERN Document Server

Cyclic spectral analysis is a signal processing technique designed to deal with stochastic signals whose statistics vary periodically with time. Pulsar radio emission is a textbook example of this signal class, known as cyclostationary signals. In this paper, we discuss the application of cyclic spectral analysis methods to pulsar data, and compare the results with the traditional filterbank approaches used for almost all pulsar observations to date. In contrast to standard methods, the cyclic spectrum preserves phase information of the radio signal. This feature allows us to determine the impulse response of the interstellar medium and the intrinsic, unscattered pulse profile directly from a single observation. We illustrate these new analysis techniques using real data from an observation of the millisecond pulsar B1937+21.

Energy Technology Data Exchange (ETDEWEB)

A high-speed light-Diesel engine with direct injection has been developed by the Institute of Combustion Engines, Graz. Thanks to light construction throughout, exhaust gas supercharger and noise-reduced composition a Diesel engine could be built that is comparable to Otto-cycle engines as regards performance, weight, aggregate size and noise production but far superior to these with respect to fuel consumption and exhaust gas emission.

Science.gov (United States)

From nuclear science symposium; San Francisco, California, USA (14 Nov 1973). A digital Fourier analyzer was programmed to perform reactor neutron noise analysis measurements and on-line processing of the data to obtain the steady-state reactivity. The system is suitable for recovering cross spectral density with low correlatedsignal component and for repetitive measurements with efficient use of reactor time. (auth)

Energy Technology Data Exchange (ETDEWEB)

An automated surveillance and baseline noise signature acquisition system is being demonstrated at Sequoyah-1. A nonperturbing method is also being developed for monitoring the subcritical reactivity during initial core loading in LWRs, in fuel storage and processing facilities, and during postaccident recovery operations such as Three Mile Island-2. (DLC)

International Nuclear Information System (INIS)

Combustion noise, knock and ignition limits data are measured and presented for a dual fuel engine running on dual fuels of Diesel and three gaseous fuels separately. The gaseous fuels used are liquefied petroleum gas, pure methane and compressed natural gas mixture. The maximum pressure rise rate during combustion is presented as a measure of combustion noise, and the knocking and ignition limits are presented as torque output at the onset of knocking and ignition failure. Experimental investigation on the dual fuel engine revealed the noise generated from combustion, knocking and ignition limits for all gases at different design and operating conditions. A Ricardo E6 Diesel version engine is converted to run on dual fuel of Diesel and the tested gaseous fuel and is used throughout the work. The engine is fully computerized, and the cylinder pressure data, crank angle data and engine operating variables are stored in a PC ...

International Nuclear Information System (INIS)

The Moderator Temperature Coefficient of reactivity (MTC) was earlier proven to be properly determined via noise analysis when the neutron noise is measured locally and when the radial average of the moderator temperature noise is used. Nevertheless, measurements revealed that the MTC was correctly estimated on a much narrower frequency band (0.6 - 0.7 Hz) than expected (0.1 - 1.0 Hz). The present paper investigates the effect of the feedback on the MTC determination using this new MTC noise estimator (which could explain the deviation at low frequencies, i.e. between 0.1 - 0.5 Hz) and the effect of the detector time constants (which could explain the deviation at high frequencies, i.e. between 0.7 - 1.0 Hz). For that purpose, a coupled neutronic/thermalhydraulic model of the Ringhals-3 PWR is developed in the frequency-domain, based on a radial 2-dimensional heterogeneous representation of the core. ...

CERN Document Server

We present a Hubble Space Telescope image of the FRII radio galaxy 3C 401, obtained at 1.6 microns with the NICMOS camera in which we identify the infrared counterpart of the brightest region of the radio jet. The jet has a complex radio structure and brightens where bending occurs, most likely as a result of relativistic beaming. We analyze archival data in the radio, optical and X-ray bands and we derive its spectral energy distribution. Differently from all of the previously known optical extragalactic jets, the jet in 3C401 is not detected in the X-rays even in a long 48ksec X-ray Chandra exposure and the infrared emission dominates the overall SED. We propose that the dominant radiation mechanism of this jet is synchrotron. The low X-ray emission is then caused by two different effects: i) the lack of any strong external photon field and ii) the shape of the electron distribution. This affects the ...

Science.gov (United States)

We monitored PSR B0329+54 for one year using the Nanshan 25-m radio telescope, the scintillation velocity V ISS shows evidence of systematic variation with the day of the year. States of interstellar medium (ISM) are discussed.

Energy Technology Data Exchange (ETDEWEB)

A recent study reported the results of an exploratory study of alterations of the quantitative sleep profile due to the effects of a digital mobile radio telephone. Rapid eye movement (REM) was suppressed, and the spectral power density in the 8--13 Hz frequency range during REM sleep was altered. The aim of the present study was to illuminate the influence of digital mobile radio telephone on the awake electroencephalogram (EEG) of healthy subjects. For this purpose, the authors investigated 34 male subjects in a single-blind cross-over design experiment by measuring spontaneous EEGs under closed-eyes condition from scalp positions C{sub 3} and C{sub 4} and comparing the effects of an active and an inactive digital mobile radio telephone (GSM) system. During exposure of nearly 3.5 min to the 900 MHz electromagnetic field pulsed at a frequency of 217 Hz and with a pulse width of 580 {micro}s, the authors could not detect ...

CERN Document Server

The Westerbork Northern Sky Survey (WENSS) and the NRAO/VLA Sky Survey (NVSS) were used to determine an upper limit to the diffuse radio flux from the nearby cluster Abell 2199. For the entire cluster, this limit is <3.25 Jy at 327 MHz from WENSS; for the inner 15' radius, the limit is <168 mJy at 1.4 GHz. These limits are used to constrain the cluster magnetic field by requiring that the radio flux be consistent with the hard X-ray (HXR) flux observed by BeppoSAX, assuming that the observed HXR excess is due to inverse Compton (IC) scattering of cosmic microwave background photons by relativistic electrons in the intracluster gas. We find that the magnetic field must be very weak (<0.073 uG) in order to avoid producing an observable radio halo. We also consider the possibility that the HXR excess is due to nonthermal bremsstrahlung (NTB) by a population of suprathermal electrons which are being accelerated to ...

CERN Document Server

Unipolar induction (UI) is a fundamental physical process, which occurs when a conducting body transverses a magnetic field. It has been suggested that UI is operating in RX J0806+15 and RX J1914+24, which are believed to be ultra-compact binaries with orbital periods of 5.4 min and 9.6 min respectively. The UI model predicts that those two sources may be electron cyclotron maser sources at radio wavelengths. Other systems in which UI has been predicted to occur are short period extra-solar terrestrial planets with conducting cores. If UI is present, circularly polarised radio emission is predicted to be emitted. We have searched for this predicted radio emission from short period binaries using the VLA and ATCA. In one epoch we find evidence for a radio source, coincident in position with the optical position of RX J0806+15. Although we cannot completely exclude that this is a chance alignment between ...

International Nuclear Information System (INIS)

A sample of 41 radio-galaxies with 13.0<=msub(corr)<=15.5 has been analyzed to test the angular redshift anisotropy discovered on Sc I galaxies by Rubin, Rubin and Ford (1973). The sample does not present their anisotropy but contains an even more curious distribution of radial velocities which suggests that the Rubin-Ford effect results from an anomalous redshift of light when it travels through clusters of galaxies. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

On the 8 and 9 May 2002 representatives of the National Radiological Protection Board (NRPB) performed a radiofrequency electromagnetic field survey in the Cookridge area of Leeds in order to assess exposure to radio signals from transmitters mounted on a water tower/a lattice tower and a radio station tower. Guidelines on limiting exposure to radio signals have been published by NRPB and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). These guidelines are designed to prevent established adverse effects on human health. During this survey, the total exposures due to all radio signals from 30 MHz to 18000 MHz (18 GHz) were measured. This frequency range was chosen as it includes mobile phone base station transmissions, which are at around 900 and 1800 MHz and super high frequency (SHF) transmissions from most of the large microwave dish antennas mounted on the towers. In ...

Energy Technology Data Exchange (ETDEWEB)

Subsurface and surface coalfires are a serious problem in many coal-producing countries. Combustion can occur within the coal seams (underground or surface), in piles of stored coal, or in spoil dumps at the surface. While consuming a non renewable energy source, coalfires promote several environmental problems. Among all GHGs that are emitted from coalfires, CO2 is the most significant because of its high quantity. In connection to this environmental problem, the core aim of the present research is to develop a hyperspectral remote sensing and radiative transfer based model that is able to estimate CO2 concentration (ppmv) from coalfires. Since 1960s remote sensing is being used as a tool to detect and monitoring coalfires. With time, remote sensing has proven a reliable tool to identify and monitor coalfires. In the present study multi-temporal, multi-sensor and multi-spectral thermal remote sensing data are being used to detect and monitor coalfires. Unlike the earlier studies, the ...

Energy Technology Data Exchange (ETDEWEB)

Laser desorption (LD) and thermal desorption (TD) mass spectra of the metallofullerenes found in arc-produced primary soots have been studied for a large variety of alkaline earth and lanthanide elements. The metallofullerene ratios found in the LD spectra indicate that two distinct groups are observed: Sc, Y, La, Ce, Pr, Nd, Gd, Tb, Ho, Er, and Lu (group A) and Ca, Sr, Sm, Eu, and Yb (group B). The TD spectra of most of these same soots also separate into two groups that contain the same elements as groups A and B. Group A metallofullerenes show strong signals in both LD and TD spectra. Group B metallofullerenes are distinguished by their presence in the LD spectra but absence in the TD spectra. From the general ionic behavior of the elements of these groups, and recent studies of the endohedral oxidation states, we propose that the oxidation states are +3 for ...

Energy Technology Data Exchange (ETDEWEB)

Optical absorptance spectra of A-15 compounds were taken using a calorimetric technique in the range 0.2 eV to 4.0 eV. Thermomodulation spectra were taken on several A-15 sputtered films.

Energy Technology Data Exchange (ETDEWEB)

Delayed-neutron (DN) energy spectra following thermal neutron induced fission of /sup 239/Pu as a function of time after fission have been measured, using the beta-neutron time-of-flight (TOF) spectrometer at the University of Lowell. Thermal/epithermal neutrons were produced on the 5.5-MV Van de Graaff accelerator using the /sup 7/Li(p,n)/sup 7/Be reaction. Time spectra over the neutron energy range of 0.01-4.0 MeV were measured for seven different time intervals after fission, each interval containing varying contributions from the six delayed neutrons groups. The DN energy spectra following induced thermal fission of /sup 239/Pu are compared to those resulting from induced thermal fission of /sup 235/U for each of the seven delay time intervals. Decomposition of the measured spectra into six-group DN spectra was accomplished employing an iterative least-squares method, ...

International Nuclear Information System (INIS)

Full text: A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through de trending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality. (author)

Energy Technology Data Exchange (ETDEWEB)

There is a clear incentive, therefore, for early consideration of the measures required to meet noise and vibration standards. The platform or rig owner and the operator are jointly responsible for agreeing a noise and vibration control policy and approach at the conceptual design stage, and for then passing on their requirements to the engineering design teams. The engineering design teams and acoustic and vibration specialists for their part need to use all their skill and judgement to apply that policy to the intensely complex job of designing and fabricating topsides facilities. With these concerns as background, UEG started, and has nearly completed, a two-phase study to provide detailed guidance to project managers and designers to assist them to develop appropriate policy and procedures and to help them put those procedures into practice. This paper describes the development of UEG's study, its application and benefits.

Energy Technology Data Exchange (ETDEWEB)

A study has been conducted on the statistics of detected neutrons that leaked from four subcritical reflected, enriched-uranium assemblies, to explore the feasibility of developing a criticality warning system based on neutron noise analysis. Studies were conducted on three possible discriminators, i.e., three signatures that might be used to discriminate among assemblies of various multiplications. The noise analysis techniques studied performed well enough in deeply subcritical situations to deserve testing in an applications environment. They have a good chance of detecting changes in reactivity that are potentially dangerous. One can expect sharpest results when doing comparisons, i.e., when comparing two records, one taken in the past under circumstances known to be normal and one taken now to search for change.

Energy Technology Data Exchange (ETDEWEB)

Incomplete convergence in numerical simulation such as computational physics simulations and/or Monte Carlo simulations can enter into the calculation of the objective function in an optimization problem, producing noise, bias, and topo- graphical inaccuracy in the objective function. These affect accuracy and convergence rate in the optimization problem. This paper is concerned with global searching of a diverse parameter space, graduating to accelerated local convergence to a (hopefully) global optimum, in a framework that acknowledges convergence uncertainty and manages model resolu- tion to efficiently reduce uncertainty in the final optimum. In its own right, the global-to-local optimization engine employed here (devised for noise tolerance) performs better than other classical and contemporary optimization approaches tried individually and in combination on the "industrial" test problem to be presented.

Energy Technology Data Exchange (ETDEWEB)

The paper reports the results of the studies performed at the Electric Research Center of ENEL (Italian National Electricity Board) in the field of compacting high voltage transmission lines, from the point of view of dielectric and corona noise constraints. The results of switching impulse withstand voltage tests, performed on typical compact line insulation configurations, are given and optimization criteria of such insulation configurations in relation to switching impulse are outlined. The constraints regarding surface withstand voltage in polluted conditions of the above insulations are analyzed and the possibility of reducing their dimensions by using unconventional insulation materials is considered. Finally, evaluations of corona noise in the case of optimization of the line encumbrance from the point of view of dielectric constraints are given.

CERN Document Server

A possibility of geophysical measurements using the large scale laser interferometrical gravitational wave antenna is discussed. An interferometer with suspended mirrors can be used as a gradiometer measuring variations of an angle between gravity force vectors acting on the spatially separated suspensions. We analyze restrictions imposed by the atmospheric noises on feasibility of such measurements. Two models of the atmosphere are invoked: a quiet atmosphere with a hydrostatic coupling of pressure and density and a dynamic model of moving region of the density anomaly (cyclone). Both models lead to similar conclusions up to numerical factors. Besides the hydrostatic approximation, we use a model of turbulent atmosphere with the pressure fluctuation spectrum f^{-7/3} to explore the Newtonian noise in a higher frequency domain (up to 10 Hz) predicting the gravitational noise background for modern gravitational wave ...

International Nuclear Information System (INIS)

Short Communication.

International Nuclear Information System (INIS)

... electrophoresis fission products gamma radiation gamma spectra half-life

International Nuclear Information System (INIS)

This report provides a summary of theoretical and experimental studies of actinide spectra in condensed phases. Much of the work was accomplished at Argonne National Laboratory, but references to related investigations by others are included. Spectroscopic studies of the trivlent actinides are emphasized, as is the use of energy level parameters, evaluated from experimental data, to investigate systematic trends in electronic structure and other properties. Some reference is made to correlations with atomic spectra, as well as with spectra of the (II), (IV), and higher valence states. 207 refs., 39 figs., 38 tabs.

International Nuclear Information System (INIS)

Photoluminescence spectra for solutions containing Sm"3"+ isotope ions in heavy and normal water were studied in the wave length #lambda# = 500-700 nm and for absorption spectra and photoluminescence excitation spectra within the range of #lambda# = 260-600 nm. Differences in molar extinction coefficients for "1"4"4Sm"3"+ and "1"5"4Sm"3"+ were established both in the solutions with D_2O and by transition from the solutions with D_2O to the solutions with H_2O. New possible causes of the identified effects are discussed

International Nuclear Information System (INIS)

... coincidence spectrometry decay excited states gamma spectra half-life

International Nuclear Information System (INIS)

... coupling deformed nuclei gold 195 high spin states iridium 187 moment of

Energy Technology Data Exchange (ETDEWEB)

Tunneling spectroscopy of normal-insulator-superconductor junction is investigated theoretically. In anisotropic superconductors, differently from the case of isotropic superconductor, the effective pair potentials felt by quasiparticles depend on the direction of their motion. By taking this effect into account, it is shown that the conductance spectra strongly depend on the crystal orientation. Using Green`s function method, local density of states (LDOS) in superconductor is also calculated. The close relation between conductance spectra and LDOS is presented. The calculation is compared with experimental spectra of high-{Tc} superconductors.

Energy Technology Data Exchange (ETDEWEB)

The mass-energy spectra of the fragments of thermal fission of {sup 242m}Am are measured using the time-of-flight technique. The resulting mass-yield curve and peak-to-valley ratio agree with radiochemical data. The parameters of the kinetic energy distribution of the fragments are determined for the first time. Data on the fine structure of mass spectra in the region of cold fragmentation are presented. 15 refs., 4 figs.

International Nuclear Information System (INIS)

The Monte Carlo transport codes LAHET and MCNP were used to calculate energy fluence spectra at three neutron therapy facilities. The results compare very favourably with measured data. Kerma spectra and the ratio of ICRU muscle tissue kerma to A-150 kerma, along the carbon to oxygen kerma ratio, were determined. Absorbed dose rate calculations are in reasonable agreement with measured values. Use of these codes to study modifications to existing therapy beams is briefly discussed. (author).

UK PubMed Central (United Kingdom)

Synthetic gene networks can be used to control gene expression and cellular phenotypes in a variety of applications. In many instances, however, such networks can behave unreliably due to gene expression...Full Text Available

UK PubMed Central (United Kingdom)

Quartz has a dissipation factor of approximately 10(-4), which is an order of magnitude less than that of the best glasses previously used to fabricate patch pipettes; it's dielectric constant of 3.8...Full Text Available

UK PubMed Central (United Kingdom)

A robust technique for determining the principal axes of a 3D shape represented by a point set, possibly with noise, is presented. We use techniques from robust statistics to guide the classical...Full Text Available

DEFF Research Database (Denmark)

The sources of non-white noise in Blood Oxygenation Level Dependent (BOLD) functional magnetic resonance imaging (fMRI) are many. Familiar sources include low-frequency drift due to hardware imperfections, oscillatory noise due to respiration and cardiac pulsation and residual movement artefacts not accounted for by rigid body registration. These contributions give rise to temporal autocorrelation in the residuals of the fMRI signal and invalidate the statistical analysis as the errors are no longer independent. The low-frequency drift is often removed by high-pass filtering, and other effects are typically modelled as an autoregressive (AR) process. In this paper, we propose an alternative approach: Nuisance Variable Regression (NVR). By inclusion of confounding effects in a general linear model (GLM), we first confirm that the spatial distribution of the various fMRI noise sources is similar to what has already been ...

UK PubMed Central (United Kingdom)

The latest-generation cochlear implant devices provide many deaf patients with good speech recognition in quiet listening conditions. However, speech recognition deteriorates rapidly as the level of...Full Text Available

Science.gov (United States)

... Southall et al. 2007). However, based on preliminary simulation modeling that attempted to allow for various uncertainties in ... 1986. Behavioral responses of gray whales to industrial noise:

UK PubMed Central (United Kingdom)

Much public health research has been directed to studies of cancer risks due to chemical agents. Recently, increasing attention has been given to adverse reproductive outcomes as another, shorter-term...Full Text Available

UK PubMed Central (United Kingdom)

The temporal fine structure (TFS) of sound contributes significantly to the perception of music and speech in noise. The evaluation of new strategies to improve TFS delivery in cochlear implants (CIs)...Full Text Available

Science.gov (United States)

... to-noise density than the uplink budget has (74.2 ... in heav:, point-to-point link applications with ... 11.7 Expanded bands allocated (Ku band) (500 MHz ...

Energy Technology Data Exchange (ETDEWEB)

Air conditioning of urban electric cars by Peltier effect is simulated. Advantages (noise, simplicity of construction and of regulation, good heating performances...) and disadvantages (cooling performances lower than actual compressors, actual costs...) are presented. (A.B.). 8 refs., 5 figs.

International Nuclear Information System (INIS)

We report on a promising approach to high-sensitivity anisotropy measurements using a high-finesse cavity locked by optical feedback to a diode laser. We provide a simple and effective way to decouple the weak anisotropy of interest from the inherent mirror's birefringence whose drift may be identified as the key limiting parameter in cavity-based techniques. We demonstrate a shot-noise-limited phase shift resolution previously inaccessible in an optical cavity, readily achieving the state-of-the-art level of 3x10"-"1"3 rad.

Energy Technology Data Exchange (ETDEWEB)

This study deals with the application of wavelet analysis to detection and characterization of defects from eddy-current and ultrasonic testing signals of a low signal-to-noise ratio. Presented in this paper are the methods for processing eddy-current testing signals of heat exchanger tubes of a steam generator in a nuclear power plant. The results of processing eddy-current testing signals of tube test pieces with artificial flaws show that the flaw signals corrupted by noise and/or non-defect signals can be effectively detected and characterized by using the wavelet methods. (author)

International Nuclear Information System (INIS)

We have observed EUV spectra from the Large Helical Device (LHD) at the National Institute for Fusion Science (NIFS). We measured spectra of impurity ions; carbon, iron, xenon, tin and tungsten ions. In some cases, the plasma evolution was stable and a steady discharge was obtained, but sometimes the plasma underwent radiation collapse and rapid cooling. For carbon and iron spectra, we studied plasma diagnostics by intensity ratios of spectral lines. For other spectra of higher Z element, xenon, tin and tungsten, we studied mainly on line identifications comparing with theoretical calculations and experimental data. Related atomic data for these researches will be also discussed. (author)

Energy Technology Data Exchange (ETDEWEB)

For millions of people general noise and especially traffic noise are the main sources of environmental pollution. The increasingly stricter noise pollution abatement limiting values laid down by the law call for motor vehicle noise pollution abatement measures. Within the framework of today`s cost- and performance-oriented automobile and engine development developing engineers are required to reduce noise levels. The present state of the art is described and future possibilities of combustion engine structure-borne noise calculation and optimization are discussed from the point of view of K + P Computerunterstuetzte Strukturanalysen GmbH. (orig.) [Deutsch] Laerm allgemein und dabei speziell wiederum der Verkehrslaerm steht fuer Millionen von Menschen an allererster Stelle der persoenlichen Belastung durch die Umwelt. Zur Minderung der Laermbelastung werden vom ...

Science.gov (United States)

The study surveyed urban women's use of information media and drew attention to the implications for women in leadership positions and non-formal education. A questionnaire containing structured and unstructured items was administered to 300 women resident at Nsukka urban town Enugu State, Nigeria. One hundred and twenty-five usable copies were used for the data analysis. The findings show that oral media are the most popular among women irrespective of level of education and type of occupation. The level of education influenced the use of radio and television. Popular radio and television programmes among women include newscasts, socio-cultural programmes, music and drama. Problems hindering women's use of radio and television include time constraint, poor reception, poor condition of available sets and lack of money for repairs among others. Based on these findings the implication for the achievement of the Universal ...

Energy Technology Data Exchange (ETDEWEB)

To identify radio-protective agent candidate among medicinal plants and to elucidate the mechanism of action of the candidate material by using modern biochemical and molecular biological methods, we screened radio-protective activity among 48 medicinal plants. Seven samples showed above 20% protective activities against oxidative cell damage: Euryale ferox, Glycyrrhiza uralensis, Salvia miltiorrhiza, Eucomia ulmoides, Paeonia suffruticosa, Spirodela polyrrhiza, and Nelumbo nucifera. We also screened for oxidative stress sensitizing activity among other 51 medicinal plants. Among those samples, 11 samples showed good sensitizing effect; Melia azedarach, Agastache rugosa, Catalpa ovata, Prunus persica, Sinomenium acutum, Pulsatilla koreana, Oldenlandia diffusa, Anthriscus sylvestris, Schizandra chinensis, Gleditsia sinensis, and Cridium officinale. We also reported the radio-protective effect of DTT. The treatment of DTT ...

CERN Document Server

We present an analytical model for jets in Fanaroff & Riley Class I (FRI) radio galaxies, in which an initially laminar, relativistic flow is surrounded by a shear layer. We apply the appropriate conservation laws to constrain the jet parameters, starting the model where the radio emission is observed to brighten abruptly. We assume that the laminar flow fills the jet there and that pressure balance with the surroundings is maintained from that point outwards. Entrainment continuously injects new material into the jet and forms a shear layer, which contains material from both the environment and the laminar core. The shear layer expands rapidly with distance until finally the core disappears, and all of the material is mixed into the shear layer. Beyond this point, the shear layer expands in a cone and decelerates smoothly. We apply our model to the well-observed FRI source 3C31 and show that there is a self-consistent solution. We derive ...

International Nuclear Information System (INIS)

Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins is increasingly being used to treat recurrent or refractory atrial fibrillation that doesn't respond to pharmacologic therapy or cardioversion. Successful RFCA of atrial al fibrillation depends on the pre-procedural understanding of the complex anatomy of the distal pulmonary veins and the left atrium. Aim of this parer is to describe the technical main features that characterise the multidetector helical computed tomography in the evaluation of this anatomic region before and after RFCA procedure. The 3D post-processing techniques useful for pre-RFCA planning are straightforward.

CERN Document Server

The emission of the plerion G21.5-0.9 appears more extended in X rays than in radio. This is an unexpected result because it would imply that short-lived X-ray electrons may reach distances even larger than radio electrons. Applying an empirical relationship between dust scattering optical depth and photoelectric column density, the measured column density leads to a large optical depth at 1 keV, of about 1. Therefore we investigate the hypothesis that the detected halo be an effect of dust scattering, re-analyzing an Cal/PV XMM-Newton observation of G21.5-0.9 and critically examining it in terms of a dust scattering model. We also present a spectral analysis of a prominent extended feature in the northern sector of the halo.

Energy Technology Data Exchange (ETDEWEB)

The contents include: Detailed index for 1991; Data for November 1991--Solar-terrestrial environment, IUWDS alert periods (advance and worldwide), Solar activity indices, Solar flares, Solar radio emission, Stanford mean solar magnetic field; Data for October 1991--Solar active regions, Sudden ionospheric disturbances, Solar radio spectral observations, Cosmic ray measurements by neutron monitor, Geomagnetic indices; Late data--Cosmic ray measurements by neutron monitor (Climax February and May 1990, Deep River May-August 1991), Geomagnetic indices (Sudden commencements/Solar flare effects January-May 1991); Errata--August 1991 Geomagnetic activity indices.

International Nuclear Information System (INIS)

Nitriding of aluminium 2011 using a radio frequency plasma at higher power levels (500 and 700 W) and lower substrate temperature (500 deg. C) resulted in higher AlN/Al_2O_3 ratios than obtained at 100 W and 575 deg. C. AlN/Al_2O_3 ratios derived from X-ray photoelectron spectroscopic analysis (and corroborated by heavy ion elastic recoil time of flight spectrometry) for treatments preformed at 100 (575 deg. C), 500 (500 deg. C) and 700 W (500 deg. C) were 1.0, 1.5 and 3.3, respectively. Scanning electron microscopy revealed that plasma nitrided surfaces obtained at higher power levels exhibited much finer nodular morphology than obtained at 100 W.

Energy Technology Data Exchange (ETDEWEB)

Thin passive layers of uranium nitride were formed by nitriding pure metallic uranium in non-equilibrium, low pressure radio-frequency plasma of nitrogen. Plasma nitriding at low substrate temperature of 230 C-250 C was found to cause the formation of adherent layers of uranium sesquinitride ({alpha}-U{sub 2}N{sub 3}) which provide a considerable protection against hydrogen attack. The characteristics of these passivation layers were determined by X-ray diffraction and Auger electron spectroscopy. The incipient hydriding kinetics of the plasma-treated samples were compared with those of untreated and nitrogen-ion implantation ones, utilizing a hot-stage microscope that was monitored continuously with a TV camera and videotape. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Abstract In this paper, a Cognitive Radio Based Medium Access Control (CR-MAC) protocol for Wireless Sensor Body Area Networks (WSBAN) that utilizes cognitive radio transmission is proposed. In this proposal, the sensor nodes are classified into nodes of life-critical health information and nodes of non-critical health information. The CR-MAC protocol prioritizes the critical packets access to the transmission medium by transmitting them with higher power while transmitting lower priority packets using lower transmission power. At the receiver, a higher priority packet experiences collision only when there are more than one critical packet transmission at the same transmission slot while non critical packets experience collision when there are more than one transmission at the same transmi...

International Nuclear Information System (INIS)

We measured neutron time-of-flight spectra from 90 MeV protons and 140 MeV alpha particles bombarding thin targets of Al, Ni, Zr, and Bi at laboratory angles between 20_0 and 135_0. The low-energy (5 to 45 MeV) portions of the spectra were measured with 5 cm diameter by 5 cm deep NE-213 counters at 1 m flight paths with n-#betta# pulse-shape discrimination. The high-energy (35 to 150 MeV) portions of the spectra were measured with 12.7 cm diameter by 10.2 cm deep NE-102 counters at flight paths of 2.0 to 5.0 m. The proton-induced measured neutron spectra reveal three distinct energy regions: a low-energy evaporation region, a high-energy region dominated by the quasifree scattering process, and an intermediate-energy region dominated by multistep, preequilibrium processes. In the latter two regions, the spectra show strong angular dependence. The alpha-particle induced neutron ...

Science.gov (United States)

Surface wave tomography method based on analysis of ambient noise is widely used during the last decade. It is assumed that correlated component of noise is composed of surface waves generated by sources distributed over the Earth's surface more or less uniformly. In such a case the cross-correlation function (CCF) at two stations may be considered as the Green's function of surface wave. This function should be symmetric relatively to zero time. However analysis of CCF at the stations located at the East-European Platform shows that as a rule CCF is characterized with a strong asymmetry. Since "purered noise cannot be extracted from seismic records due to superposition of earthquake signals, the method for calculation of CCF includes amplitude normalization for suppression of earthquakes that reduces signals from earthquakes to a noise level. The parts of records containing waves from earthquakes are ...

Energy Technology Data Exchange (ETDEWEB)

Emission spectra obtained for three irradiated granular quartz samples under 1.43 eV excitation exhibited the 2.2 and 3.1 eV emission bands characteristic of feldspars. Excitation spectra of these same samples and several others show the 1.44 eV resonance typical of feldspars. This provides convincing evidence that the 2.2 and 3.1 eV infrared stimulated luminescence observed in these granular quartz samples arises from feldspar inclusions.

International Nuclear Information System (INIS)

Delayed neutron energy spectra have been measured for six delay-time intervals following the fast fission of "2"3"8U nuclei. The delay-time intervals span the range 0.17 to 10.2 seconds following initial fission while the measured spectra span neutron energies from 10 keV to 4 MeV. The experiment was performed utilizing the UMass/Lowell 5.5 MV Van de Graff accelerator to produce fast neutrons for inducing fission in a "2"3"8U lined fission chamber. The fission fragments were flushed via a helium jet stream to a well-shielded counting room where they were deposited onto a moving tape (magnetic audio tape) and transferred to a beta-neutron time-of-flight spectrometer. By adjusting the tape speed, composite delayed neutron time-of-flight spectra were measured for several different delay-time intervals. These measurements involved beta-neutron coincidences with "6Li-loaded glass scintillators for neutron energies from 10 keV to ...

Energy Technology Data Exchange (ETDEWEB)

The author gives an account of tests with the X-phone system. The aim of the tests was to establish the reliability and behaviour of the apparatus mounted on a winning machine and to investigate the possibility of setting up a radio link, without laying an extra wire, between the foot of the tubbing-lined roadway and the winning machine on a steep face. The author describes the face and the test conditions and presents details of the satisfactory test results.

International Nuclear Information System (INIS)

This paper focuses on potential effects of solar phenomena on communication systems used by the electric utility industry. It begins with a discussion of solar phenomena fundamentals and discussion of the interaction between solar emissions and the earth's ionosphere and magnetosphere. It continues with a discussion of the resulting impacts on communication systems including radio, satellite, wireline, fiber optic, and powerline systems and concludes with a discussion of mitigation techniques and a call for observers to report suspected solar impact experiencexperiences.

Energy Technology Data Exchange (ETDEWEB)

Various topics include: (1) direction finding, (2) range finding, (3) Doppler measurements, (4) construction of a receiver for radio interferometry, (5) mobile laser range finding system, (6) figure-and field parameter determination/geopotential, (7) dynamics of the Earth-Moon system, and (8) kinematics of geodetic point fields.

Science.gov (United States)

His talk was based on the suggestion that life on Earh has been a long but accelerating ..... a New Class of Submarine Hydrothermal System"; April 29, 2002 , ..... of media personnel, including radio, television, newspapers, and magazines. ...... "The Birth of Stars and Planets" (Denver Museum of Nature and Science ...

Energy Technology Data Exchange (ETDEWEB)

Today, highly frequent radio waves are regarded as undangerous to man. Diseases seen at radar-technicians during the 2nd World War, however, indicated that microwaves applied in radar systems were hazardous to health. The Russian work medicine has been knowing microwave-caused hazards in industry since the beginning of the thirties. Therefore in some East-European countries there are terms of protection and severe norms of safety for the staying of persons in the radiation sphere of microwaves.

Energy Technology Data Exchange (ETDEWEB)

This document defines the requirements for the GPRS (General Packet Radio Service) infrastructure as part of the Dutch Smart Meter Specification. In this document all requirements originating from the NTA 8130, or additionally surveyed by a delegation of the Dutch grid operators, are presented in tables. Each requirement is tightly connected to one or more business use cases presented in the document. The ultimate goal of this procedure is to reduce ambiguity of the requirements due to a better understanding of the requirements.

Energy Technology Data Exchange (ETDEWEB)

The chain of eddy current probes and a film cassette probe, which responds to radiation from a radio-active source in one of the heat exchanger pipes is examined. The probes are moved by nylon pipes on both ends of the chain through the pipe to be examined. The nylon pipes are bent off load. In this way the probes on the chain will adjust near to the plane of bending of the pipes to be tested.

Energy Technology Data Exchange (ETDEWEB)

This book presents the current knowledge about the effects of electromagnetic fields on living matter. The three-part format covers dielectric permittivity and electrical conductivity of biological materials; effects of direct current and low frequency fields; and effects of radio frequency (including microwave) fields. The parts are designed to be consulted independently or in sequence, depending upon the needs of the reader. Useful appendixes on measurement units and safety standards are also included.

International Nuclear Information System (INIS)

The uncertainty of the elemental analysis is one of the major factors governing the utility of on-line Prompt Gamma Neutron Activation Analysis (PGNAA) in the blending and sorting of bulk materials. In this paper, a general method applicable to Gamma spectra processing is presented and applied to PGNAA in mineral industry. Based on the Fourier transform of spectra and their de-correlation in the Fourier space (the improvement of the conditioning of the correlation matrix), processing of overlapping of characteristic peaks minimizes the propagation of random errors, which optimizes the accuracy and decreases the detection limits of elemental analyses. In comparison with classical methods based on the linear combinations of relevant regions of spectra the improvement may be considerable, especially when several elements are interfering. The method is applied to four case stories covering both borehole logging and on-line ...

International Nuclear Information System (INIS)

In recent years sufficient new spectra of actinides in their numerous valence states have been measured to encourage a broader scale analysis effort than was attempted in the past. Theoretical modelling in terms of effective operators has also undergone development. Well established electronic structure parameters for the trivalent actinides are being used as a basis for estimating parameters in other valence states and relationships to atomic spectra are being extended. Recent contributions to our understanding of the spectra of 4+ actinides have been particularly revealing and supportive of a developing general effort to progress beyond a preoccupation with modelling structure to consideration of the much broader area of structure-bonding relationships. We summarize here both the developments in modelling electronic structure and the interpretation of apparent trends in bonding. 60 refs., 9 figs., 1 tab.

International Nuclear Information System (INIS)

... alpha beams energy-level transitions gamma spectra iridium 187 iridium 189

International Nuclear Information System (INIS)

The report considers experimental and theoretical works on studying the energy spectra of prompt neutrons emitted in spontaneous fission and neutron induced fission of Minor Actinides. It is noted that neutron spectra investigations were done for only a small number of such nuclei, most measurements, except those of Cf-252, having been carried out long ago by obsolete methods and imperfectapparatus. The works have no detailed description of experiments, analysis of errors, detailed numerical information about results of experiments. A conclusion is made that the available data do not come up to modern requirements. It is necessary to make new measurements of fission prompt neutron spectra of transuranium nuclides important for the objectives of working out a conception of minor actinides transmutation by means of special reactors. (author).

Energy Technology Data Exchange (ETDEWEB)

The first application of optical Stark modulation has been applied to measure spatially precise Stark-modulated IR absorption spectra in a flame.

Science.gov (United States)

... and high-quality photospheric-phase Type II SN spectra to constrain core- collapse SN explosions, massive star evolution, and distances in the Universe ...

International Nuclear Information System (INIS)

... Thesis (Ph.D.). coincidence spectrometry excited states gamma spectra internal

International Nuclear Information System (INIS)

... levels excited states mev range 10-100 proton reactions proton spectra protons

Energy Technology Data Exchange (ETDEWEB)

A tunable diode laser is used to obtain infrared spectra of carbon dioxide in biological materials. The spectral resolution is sufficient to readily distinguish differing isotopic species. The technique may prove useful in clinical tests.

Energy Technology Data Exchange (ETDEWEB)

Of some interest is the comparison between the actinide nuclide burning up (fission) rates such as americium 241, americium 242, curium 244, and neptunium 237, in the reactors with fast or thermal neutron spectra.

Energy Technology Data Exchange (ETDEWEB)

The {sup 252}Cf-source-driven noise analysis method has been used in measurements for subcritical configurations of fissile systems for a variety of applications including a dynamic measurement that was the first step in applying this method to monitor fuel in a future reprocessing plant These measurements showed that this method has potential to monitor many dynamic situations in processing plants such as in a continuous dissolver or batch dissolvers either to obtain the neutron multiplication factor k or to be used as a signature to verify that various processes are occurring in a repeatable or bounded way. This verification of normal operation would be by comparing noise analysis signatures for the process with reference signatures. Abnormal operation could be ascertained if the signature deviates by some specified amount from the reference signatures from normal operation. The deviations from normal could be specified by measurement or by ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes recent measurements of the subcritical neutron multiplication factor using the /sup 252/Cf source-driven neutron noise analysis method. This work was supported by a program of collaboration between the United States Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan related to the development of fast breeder technology. The experiment reported consists of a configuration of two interacting tanks of uranyl nitrate aqueous solution with different uranium concentrations in each tank. The /sup 252/Cf-source-driven neutron noise analysis method obtains the subcriticality from the signals of three detectors: the first, a parallel plate ionization chamber with /sup 252/Cf electroplated on one of its plates that is located in or near the system containing the fissile material, and produces an electrical pulse for every spontaneous fission that occurs and thereby serves as a timed source of ...

Energy Technology Data Exchange (ETDEWEB)

One of the main goals in the determination of three-dimensional macromolecular structures from electron microscope images of individual molecules and complexes (single particles) is a sufficiently high spatial resolution, about 4 A, at which the interpretation with an atomic model becomes possible. To reach high resolution, an iterative refinement procedure using an expectation maximization algorithm is often used that leads to a more accurate alignment of the positional and orientational parameters for each particle. We show here the results of refinement algorithms that use a phase residual, a linear correlation coefficient, or a weighted correlation coefficient to align individual particles. The algorithms were applied to computer-generated data sets that contained projections from model structures, as well as noise. The algorithms show different degrees of over-fitting, especially at high resolution where the signal is weak. We demonstrate that the degree of ...

Science.gov (United States)

We report the growth and fabrication of midwave infrared InAs/GaSb strain layer superlattice (SLS) detectors. Growth of alternate interfaces leads to a reduced strain between the GaSb buffer and SLS ({delta}a{sub parallel}/a=-5x10{sup -4}), enabling the growth of active regions up to 3 {mu}m (625 periods). The structural, optical, and electrical properties of the active region were characterized using x-ray crystallography and photoluminescence, respectively. p-i-n detectors were grown using 625 periods of 8 ML (monolayer) InAs/8 ML GaSb as the active region. The {lambda}{sub cutoff} for the detectors was 4.6 {mu}m with a conversion efficiency of 32% at V{sub b}=-0.2 V. Detectivity was obtained using noise power spectral density measurements under 300 K 2{pi} field of view illumination and was equal to 5.2x10{sup 10} and 3x10{sup 10} cm Hz{sup 1/2}/W (V{sub b}=-0.02 V, T=80 K) in the white noise and 1/f noise limit (at 50 ...

Energy Technology Data Exchange (ETDEWEB)

Steam generator tubes in nuclear power plants are periodically checked by means of eddy current probes. The output of a probe is composed of three types of signals: known events (rolling zone, support plates, U-bend part), noise (mainly metallurgical noise) and possible flaws. The latter are random transients, both in arrival time and in shape: they have to be detected and then estimated, before to be fed to the high level stages of a diagnostics system. The objective of the study presented is to develop a semi-automatic system, which could manage and process more than 1 M-bytes of data per tube and provide an operator with reliable diagnostics proposals within a few minutes. This can be achieved only by cooperation of several digital signal processing techniques: detection, segmentation, estimation, noise subtraction, adaptive filtering, modelization, pattern recognition. The paper describes some of these items.

CERN Document Server

Probabilistic broadcast has been widely used as a flooding optimization mechanism to alleviate the effect of broadcast storm problem (BSP) in mobile ad hoc networks (MANETs). Many research studies have been carried-out to develop and evaluate the performance of this mechanism in an error-free (noiseless) environment. In reality, wireless communication channels in MANETs are an error-prone and suffer from high packet-loss due to presence of noise, i.e., noisy environment. In this paper, we propose a simulation model that can be used to evaluate the performance of probabilistic broadcast for flooding in noisy environment. In the proposed model, the noise-level is represented by a generic name, probability of reception (pc) (0<=pc<=1), where pc=1 for noiseless and <1 for noisy environment. The effect of noise is determined randomly by generating a random number \\zeta (0<=\\zeta<1); if \\zeta<=pc means the ...

British Library Electronic Table of Contents (United Kingdom)

The utilization of thermal fluctuations or Johnson/Nyquist noise as a spectroscopic method to determine transport properties in conductors or semiconductors is developed. The autocorrelation function is obtained from power spectral density measurements thus enabling electronic transport property calculation through the Green-Kubo formalism. This experimental approach is distinct from traditional numerical methods such as molecular dynamics simulations, which have been used to extract the autocorrelation function and directly related physics only. This work reports multi-transport property measurements consisting of the electronic relaxation time, resistivity, mobility, diffusion coefficient, electronic contribution to thermal conductivity and Lorenz number from experimental data. Double va...

Energy Technology Data Exchange (ETDEWEB)

The ability of the /sup 252/Cf-source-driven neutron noise analysis method to measure subcriticality has been demonstrated in a variety of experimental configurations of fissile materials. Calculations for an approximately 4-m-dia configuration of light water reactor (LWR) fuel elements indicated the feasibility of measuring the subcriticality of large, loosely coupled arrays of LWR fuel elements by this same method. These analysis suggested application to the initial loading of both pressurized and boiling water reactors, zero-power testing of reactors (such as shutdown margin measurements after initial loading), light water reactor refueling, and safe storage of LWR spent fuel. In the fuel storage application, direct measurement of subcriticality in the actual fuel storage facilities provides the parameter which is directly related to criticality safety.

DEFF Research Database (Denmark)

We examine moving average (MA) filters for estimating the integrated variance (IV) of a financial asset price in a framework where high-frequency price data are contaminated with market microstructure noise. We show that the sum of squared MA residuals must be scaled to enable a suitable estimator of IV. The scaled estimator is shown to be consistent, first-order efficient, and asymptotically Gaussian distributed about the integrated variance under restrictive assumptions. Under more plausible assumptions, such as time-varying volatility, the MA model is misspecified. This motivates an extensive simulation study of the merits of the MA-based estimator under misspecification. Specifically, we consider nonconstant volatility combined with rounding errors and various forms of dependence between the noise and efficient returns. We benchmark the scaled MA-based estimator to subsample and realized kernel estimators and find that the MA-based ...

Energy Technology Data Exchange (ETDEWEB)

In the international study of IEA Annex 27 `Demonstration and evaluation of domestic ventilation systems` a number of simple tools to gain insight into the characteristics of ventilation systems for dwellings are presented. The assessment is made with respect to e.g. indoor air quality, comfort, noise, energy, costs and reliability. In three articles the results of Annex 27 will be discussed. In the first article background information of IEA Annex 27 was given as well as applications in the Netherlands. In this second article attention is paid to the assessment models (`simplified tools`) for indoor air quality, thermal comfort and noise. 6 refs.

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation has been carried out to examine for the first time the performance and combustion noise of an indirect injection diesel engine running with new fuel derived from pure jojoba oil, jojoba methyl ester, and its blends with gas oil. A Ricardo E6 compression swirl diesel engine was fully instrumented for the measurement of combustion pressure and its rise rate and other operating parameters. Test parameters included the percentage of jojoba methyl ester in the blend, engine speed, load, injection timing and engine compression ratio. Results showed that the new fuel derived from jojoba is generally comparable and a good replacement to gas oil in diesel engine at most engine operating conditions, in terms of performance parameters and combustion noise produced. (author)

Science.gov (United States)

Readout integrated circuits (ROICs) for focal plane arrays (FPAs) have become increasingly complex to meet the needs of modern infrared systems. BAE Systems has pioneered a number of advanced signal processing architectures for FPA ROICs. Demonstrated signal processing capabilities of BAE Systems FPAs include analog-to-digital conversion, offset subtraction, individual pixel automatic gain compensation, transient noise suppression, on-FPA defect deselection, reconfigurable pixels, spatial neural network processing and subframe noise averaging. BAE Systems FPA advanced signal processing is not just for demonstrations, but is used in many of their deliverable FPAs, improving real system performance.

British Library Electronic Table of Contents (United Kingdom)

In this paper, a hybrid time-frequency method (HTM) based on the improved Morlet wavelet and auto terms window (ATW) is presented. The Morlet wavelet, for its shape is similar to the mechanical shock signals, is added two parameters which decide the shape of the mother wavelet. The added parameters and the appropriate scale parameter for continuous wavelet transformation (CWT) are calculated using the cross validation method (CVM) and the minimum Shannon entropy method. The useless noise in the original signal can be filtered by the CWT filter de-noising process. An ATW based on the Smoothed Pseudo Wigner-Ville Distribution (SPWVD) spectrum is designed as a window function to suppress the cross terms in Wigner-Ville Distribution (WVD). The gear fault diagnosis experiment results show that ...

Energy Technology Data Exchange (ETDEWEB)

In order to study nuclear criticality safety related to the development of fast breeder technology, /sup 252/Cf-source-driven neutron noise analysis measurements were performed with a Pu-U nitrate solution in a slab tank of various heights and thickness varying 11.43 cm to 19.05 cm. The results and conclusions of these experiments are (1) a capability to measure the subcriticality of a multiplying system of slab geometry to a k/sub eff/ as low as 0.7 was demonstrated, (2) calculated neutron multiplication factors agreed with those from the experiments within approx.0.02, and (3) the applicability of the method for plutonium solution systems was demonstrated. This paper describes measurements in which the height of the slab was varied for a fixed thickness and the thickness varied for a fixed height, which are the first applications of this measurement method to slab geometry.

Energy Technology Data Exchange (ETDEWEB)

In this paper para boson-fermion supersymmetry is exemplified in simple oscillator systems. The parasupercharge satisfies the ordinary supersymmetry algebra. The parabosonic and parafermionic oscillators do not commute and the energy spectra are non-trivial for even the one level system. The authors calculate the partition functions and compare with those for the non-supersymmetric systems.

International Nuclear Information System (INIS)

An original evaluating method of gain degradation has been found for neutron irradiated transistors. It establishes a correlation between degradation and the product of two coefficients: spectra factor and an electrical parameter which is measured or directly deduced from manufacturer's data. Equivalence for several type of spectra (fission, 14MeV and degradation sensitivity to electrical parameters values of individual components of a batch are obtained.

Energy Technology Data Exchange (ETDEWEB)

A method is provided for detecting pathological macromolecules in a patient. The method is comprised of the following: obtaining body fluid from the patient; pretreating the body fluid; subjecting the pretreated body fluid to size-exclusion chromatography to create an excluded fluid; and analyzing the excluded fluid to detect macromolecules having a predetermined molecular weight. The method also allows for comparing elution spectra with reference spectra of suspect pathologic proteins.

Energy Technology Data Exchange (ETDEWEB)

Intrinsic crossluminescence (CRL) of CsBr, CsCl, and of BaF{sub 2} was investigated with electron-beam and synchrotron radiation excitation. From the CRL spectra, the excitation spectra and the reflectivity, energy level schemes were deduced. Extrinsic CRL was observed changing either the initial (CsCl:Br{sup -}) or the final (RbCl:Cs{sup +}; KCl:Cs{sup +}) state of CRL by doping. (author).

Energy Technology Data Exchange (ETDEWEB)

Luminescence stimulated from feldspars using wavelengths in the infrared region can be applied to the dating of sedimentary grains. Reported stimulation spectra are very similar for a wide range of feldspars, but their emission spectra show greater variation. For accurate dating it is critical that unstable infrared-stimulated luminescence (IRSL) signals are removed from the laboratory-irradiated grains. Several approaches to isolate a thermally stable signal are described. (author).

Energy Technology Data Exchange (ETDEWEB)

Neutron time-of flight spectra were measured from 90 MeV protons and 140 MeV alpha-particle bombardment of Al, Ni, Zr, and Bi at laboratory angles between 20/sup 0/ and 130/sup 0/. The proton induced neutron spectra reveal three distinct energy regions; a low energy evaporation region, a high-energy region dominated by quasi-free scattering processes and an intermediate-energy region dominated by multi-step, pre-equilibrium processes. In the latter two regions, the spectra show strong angular dependence. The alpha-induced neutron spectra show these same distinct energy regions plus an exponential fall-off above the beam energy per nucleon. The high-energy portions of the forward-angle neutron and proton cross sections are in ratios consistent with the assumption that single nucleon-nucleon scattering dominates. For heavy-mass targets, the low-energy evaporation regions show neutron yields larger than ...

International Nuclear Information System (INIS)

The K"+- and K"-meson cumulative production cross sections are measured at 119"0 in the laboratory system on nuclei Be, Al, Cu and Ta bombarded by 10 GeV protons. Spectra of the K"-mesons consisting of only sea quarks show universal features characteristic of the spectra of cumulative particles, which contain valence quarks. Evidence is obtained for the fact that the energy density in a flucton can exceed the mean nuclear density by an order of magnitude.

International Nuclear Information System (INIS)

The electronic structure of UPd_3 has been determined by means of XPS and BIS experiments. The core level line shapes and the valence band spectra of occupied and empty states clearly reveal the localized character of the 5f electrons in this actinide compound. From these spectra their Coulomb correlation energy is found to be about 2 eV. (author).

Energy Technology Data Exchange (ETDEWEB)

Neutron and gamma ray energy spectra were measured using an NE-213 scintillator at depths of 7.2, 15.2, and 22.2 cm in a tissue-equivalent phantom which was uniformly irradiated on one face by deuterium--tritium (DT) neutrons. Coupled neutron--gamma ray multigroup discrete-ordinates calculations were performed using semi-infinite slab geometry. These calculations were used to supplement the measured spectra below 1 MeV. Similar calculations were performed to study the perturbation in the phantom due to the detector. The measured and calculated spectra were used to determine the kerma distributions for neutrons and gamma rays at each location. The gamma radiation was determined to contribute more than 10% of the total dose at each depth. The calculated kerma also reveals that a knowledge of the gamma ray spectra below 1 MeV is desirable. Key words: neutron--gamma spectra, ...

International Nuclear Information System (INIS)

Theoretical interpretation of fast-charged-particle spectra, observed in the #alpha#-particle-induced reactions on the s-d shell nuclei (A = 24-28), in terms of the Intranuclear Cascade Model and the GDH exciton model (ALICE) is presented. The de-excitation of the excited residual nuclei is accounted for by the evaporation process. The theoretically predicted fast-proton and #alpha#' spectral shapes compare reasonably well with the corresponding measured spectra. However, the magnitude depends critically (as expected) on the reaction cross section employed by the model. As a first step to improve the model predictability of the reaction products, a closer look at the calculation of the #alpha#-particle reaction cross sections was undertaken. A microscopic approach using the optical theorem of Glauber's theory was employed to estimate the #alpha#-induced reaction cross sections for the light target nuclei under consideration. The calculated ...

Energy Technology Data Exchange (ETDEWEB)

Plutonium-containing compounds vary widely in isotopic content, and as a result, the dose as function of isotopic content also varies considerably. Determination of the dose from neutrons, decay and capture gammas from plutonium in the form of compounds thus requires that the spontaneous fission and ({alpha},n) source and spectra from each individual isotope be known. To facilitate dose calculations from plutonium-containing compounds, we have calculated the spontaneous fission and ({alpha},n) sources and spectra for 1 g of each of the plutonium isotopes in the form of either PuF{sub 4} or PuO{sub 2}. As {sup 241}Am is often a component in a mixture of plutonium isotopic compounds, the source and spectra from 1 g of {sup 241}Am mixed with PuF{sub 4} or PuO{sub 2} has also been determined. Using these results, the neutron source and spectra may be determined for any sample composition. 2 refs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

The {sup 252}Cf-source-driven noise analysis method has been used in measurements for subcritical configurations of fissile systems for a variety of applications. Measurements of 25 fissile systems have been performed with a wide variety of materials and configurations. This method has been applied to measurements for (1) initial fuel loading of reactors, (2) quality assurance of reactor fuel elements, (3) fuel preparation facilities, (4) fuel processing facilities, (5) fuel storage facilities, (6) zero-power testing of reactors, and (7) verification of calculational methods for assemblies with the neutron k < l. These previous measurements, performed with a wide variety of multiplying systems, demonstrated the usefulness of the method. The high sensitivity of noise-measured parameters to small changes in fissile systems has been observed in several measurements. This high sensitivity has been evaluated using Monte Carlo neutron transport ...

International Nuclear Information System (INIS)

In order to understand the detail transient two-phase flow structure, more advanced two-phase flow instrumentation is required. One advanced technique for flow visualization is real-time neutron radiography. Reconstruction method of visualized radiographic image of liquid metal two-phase flow generated by the real-time neutron radiography system is proposed in this paper. Image processing techniques for noise reduction and image enhancement are discussed in detail. (author).

Energy Technology Data Exchange (ETDEWEB)

A method to deduce the 2 x 2 transport matrix for coupled heat and particle transport in Tokamaks is proposed. The method applies to perturbative experiments, and is based on a Fourier transform of the measured signals of temperature and density. By analyzing different linear combinations of temperature and density, the eigenvectors and eigenvalues of the transport matrix are determined. The method is tested for a number of illustrative cases using simulated data, and the sensitivity to noise on the signals is evaluated. (author).

CERN Document Server

We present a thorough analysis of single atom detection using optical cavities. The large set of parameters that influence the signal-to-noise ratio for cavity detection is considered, with an emphasis on detunings, probe power, cavity finesse and photon detection schemes. Real device operating restrictions for single photon counting modules and standard photodiodes are included in our discussion, with heterodyne detection emerging as the clearly favourable technique, particularly for detuned detection at high power.

International Nuclear Information System (INIS)

We discuss the use of active control to reduce mirror position fluctuations at the quantum level. We have shown in a recent experiment that it is possible to reduce the thermal noise of a mirror by measuring and controlling its motion with an optomechanical sensor based on a high-finesse optical cavity. This approach can be extended to lock the mirror motion at the quantum level, and to suppress the quantum effects of radiation pressure in interferometric measurements such as gravitational-wave detectors. The sensitivity improvement is furthermore independent of losses in the interferometer.

International Nuclear Information System (INIS)

Heterodyne detection with a point-contact Josephson junction has been investigated both experimentally and theoretically. The measured performance of the device at 36 GHz is in good agreement with the theory. By operating vanadium point contacts at 1.4 K, the authors have achieved a single-sideband (SSB) mixer noise temperature of 54 K with a conversion gain of 1.35 and a signal bandwidth on the order of 1 GHz. A potentially impressive performance for these devices at submillimeter wavelengths can be extrapolated from the results.

Energy Technology Data Exchange (ETDEWEB)

This book presents the papers given at a symposium on occupational safety in coal mines. Topics considered at the symposium included human factors, causes and prevention of personal injuries, remote sensing for ground control, respirable dust generation by continuous miners, accident analysis, hazard analysis of mining equipment, coal mine blasting accidents, coal mine respirable dust sampling, and noise in the mining industry.

CERN Document Server

We apply two variations of the principle of Minimum Cross Entropy (the Kullback information measure) to fit parameterized probability density models to observed data densities. For an array beamforming problem with P incident narrowband point sources, N > P sensors, and colored noise, both approaches yield eigenvector fitting methods similar to that of the MUSIC algorithm[1]. Furthermore, the corresponding cross-entropies are related to the MDL model order selection criterion[2].

DEFF Research Database (Denmark)

In this paper we present a modeling framework for analyzing computer models with two types of variations. The paper is based on a case study of an orthopedic surgical unit, which has both controllable and uncontrollable factors. Our results show that this structure of variation can be modeled effectively with linear mixed effects models and generalized additive models. Copyright (C) 2009 John Wiley & Sons, Ltd.

CERN Document Server

We have used the SINFONI integral field spectrograph to map the near-infrared K-band emission lines of molecular and ionised hydrogen in the central regions of two cool core galaxy clusters, Abell 2597 and Sersic 159-03. Gas is detected out to 20 kpc from the nuclei of the brightest cluster galaxies and found to be distributed in clumps and filaments around it. The ionised and molecular gas phases trace each other closely in extent and dynamical state. Both gas phases show signs of interaction with the active nucleus. Within the nuclear regions the kinetic luminosity of this gas is found to be somewhat smaller than the current radio luminosity. Outside the nuclear region the gas has a low velocity dispersion and shows smooth velocity gradients. There is no strong correlation between the intensity of the molecular and ionised gas emission and either the radio or X-ray emission. The molecular gas in Abell 2597 and Sersic 159-03 is well described ...

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Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti_2N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 #mu#m"2/s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to the high concentration of active nitrogen species in the plasma atmosphere and the formed microcracks near to the surface of the sample ...

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The Thomsen-Friedenreich (T) antigen, #betta#-D-Gal-(1->3)-#alpha#-D-GalNAc, is exposed in reactive form on many human adenocarcinomata, but not on corresponding benign tissues. Peanut lectin (PNA) has a strong binding affinity for the T antigen and reportedly binds preferentially to certain malignant tissues. We investigated the potential of radio-labelled PNA as a tumour localising agent in an animal model system using a mouse lymphoma (RI) shown to bind fluorescein-labelled PNA in vitro. The radio-iodinated lectin showed good tumour localisation and rapid blood clearance. Clear images of tumours were obtained, in serial scintigraphic imaging, by 24 and 48 h. No blood background subtraction was necessary. Biodistribution studies revealed tumour to blood ratios in mice were 6:1 (at 24 h) and 17:1 (at 48 h), and tumour to muscle ratios were 34:1 (at 24 h) and 40:1 (at 48 h). Rapid in vivo breakdown of _1_2_5I-PNA led to some localisation of ...

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Nitrogen ion implantation improves the wear resistance of Ti-6Al-4V alloys by forming a hard TiN superficial passivation layer. However, the thickness of the layer formed by traditional ion implantation is typically 100-200 nm and may not be adequate for many industrial applications. We propose to use radio-frequency (RF) plasma nitriding and nitrogen plasma immersion ion implantation (PIII) to increase the layer thickness. By using a newly designed inductively coupled RF plasma source and applying a series of negative high voltage pulses to the Ti-6Al-4V samples. RF plasma nitriding and nitrogen PIII can be achieved. Our process yields a substantially thicker modified layer exhibiting more superior wear resistance characteristics, as demonstrated by data from micro-hardness testing, pin-on-disc wear testing, scanning electron microscopy (SEM), as well as Auger electron spectroscopy (AES). The performance of our newly developed inductively coupled RF plasma source ...

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Zinc oxide thin films were obtained by laser ablation of a Zn target in oxygen reactive atmosphere, the oxygen being supplied either by a standard gas inlet valve or from a radio-frequency (rf) oxygen plasma. Pt-coated silicon and MgO were used as substrates. The influence of the deposition parameters as laser wavelength (266, 355, 1064 nm), laser fluence (1.5-20 J/cm2) and oxygen pressure (1-60 Pa) was studied. The influence of the rf plasma beam addition on the morphological proprieties of zinc oxide films was particularly investigated, simultaneously with several configurations of the direction of the ablation plasma, the rf plasma beam and the substrate. The obtained films, with thicknesses in the range of 50 nm to 1 ?m have been characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM).