Science.gov

Sample records for power line harmonic

  1. Generation mechanism of power line harmonic radiation

    NASA Astrophysics Data System (ADS)

    Kostrov, Alexander; Gushchin, Mikhail; Korobkov, Sergei

    The questions concerning the generation of power line harmonic radiation (PLHR) and magne-tospheric line radiation (MLR) are discussed, including the effective source of high harmonics of 50/60 Hz, and fine dynamic structure of the frequency spectrum of PLHR and MLR. It is shown, that thyristor-based power regulators used by large electrical power consumers produce the periodic sequences of current pulses with duration of about 10 microseconds in a power line. The repetition rate of these pulses is typically 100/120 Hz; the bandwidth is as broad as 100 kHz. For high harmonics of 50/60 Hz, the power line represents an effective traveling-wave (or Beverage) antenna, especially in a frequency range of several kHz corresponding to VLF whistler band in Earth ionosphere and magnetosphere. For the fixed length of the power line, which acts as antenna, radiation directivity diagram in relation to horizon depends of frequency. Hence the spatial separation of whistlers emitted at various frequencies (1-10 kHz in a consid-ered case) is possible, with subsequent propagation of whistlers with different frequencies along different L-shells. Estimations show that the efficiency of power line as travelling-wave antenna can be changed by variations of its load, but not more than twice ("weekend effect"). Since the PLHR can represent the sequence of short electromagnetic bursts, then careful se-lection of frequency-time resolution of the data acquisition equipment is needed. Typically, the time constant of the data recording and processing is too large, and the spectra of PLHR or MLR are characterized by a well-known line structure. At the same time, original bursty structure of PLHR can not be defined. Fine structure of MLR is also discussed. Frequency drift of MLR can be explained by the perturbations of the magnetospheric plasma by intense ULF waves and particle flows affecting the propagation of PLHR. Hence the physical nature of PLHR and MLR is the same, excepting the

  2. Satellite observations of power line harmonic radiation

    NASA Astrophysics Data System (ADS)

    Bullough, K.

    1983-06-01

    Observations of the spheric wavefield over North America, the adjacent North Atlantic, and their Southern-Hemisphere geomagnetic conjugates made with Ariel 4 are analyzed in terms of the relative influence of power-line harmonic radiation (PLHR) on wave-particle interactions affecting the earth's radiation belts. Inconsistencies in previous reports on the Sunday effect, on the starting frequencies of chorus emissions, and on the global distribution of PLHR are reviewed, and the validity of Ariel-3 and Ariel-4 findings of increased PLHR-induced emissions over the industrial areas of the US is asserted. At 9.6 kHz, the emissions over North America and the North Atlantic are characterized by almost identical spherical wavefields, while the whistler-mode signal in the Atlantic conjugate zone was found to be weaker than that in the North American conjugate; at 3.2 kHz, the sea-conjugate signal was weakened, but the land-conjugate signal was found to be identical to the land signal. It is inferred that multihop propagation permanently present over the mainland but rare over the sea is the result of duct structures which can be supported by PLHR.

  3. Power line harmonic radiation: A systematic study using DEMETER spacecraft

    NASA Astrophysics Data System (ADS)

    Němec, F.; Santolík, O.; Parrot, M.; Berthelier, J. J.

    We present results of a systematic survey of Power line harmonic radiation (PLHR) observed by the DEMETER spacecraft. DEMETER is a French micro-satellite launched in June, 2004 with an altitude of orbit of about 700 km. It is designed specifically to study electromagnetic effects connected with seismic and man-made activity. All available high-resolution burst-mode electromagnetic data measured since the beginning of the mission till July 2006 (altogether about 1650 h of data) have been analyzed using an automatic identification procedure. This procedure was specially developed to search for emissions of PLHR type. It is running in DEMETER control center in Orléans, France. 49 PLHR events with frequency spacing of 50/100 or 60/120 Hz have been found, allowing us to perform a statistical study of properties of PLHR. It is shown that for all the events, the observed frequency spacing corresponds well to the power system frequency at anticipated source locations. Moreover, the frequency of the observed lines often (80%) corresponds to the exact harmonics of the power system base frequency. Finally, the most intense events are observed at lower frequencies and no weak events are observed under geomagnetically disturbed conditions.

  4. Effect of Power Line Interference on Microphone Calibration Measurements Made at or Near Harmonics of the Power Line Frequency.

    PubMed

    Wagner, Randall P; Nedzelnitsky, Victor

    2007-01-01

    The electrical measurements required during the primary calibrations of laboratory standard microphones by the reciprocity method can be influenced by power line interference. Because of this influence, the protocols of international inter-laboratory key comparisons of microphone calibrations usually have not included measurements at power line frequencies. Such interference has been observed in microphone output voltage measurements made with a microphone pressure reciprocity calibration system under development at NIST. This system was configured for a particular type of standard microphone in such a way that measurements of relatively small signal levels, which are more susceptible to the effect of power line interference, were required. This effect was investigated by acquiring microphone output voltage measurement data with the power line frequency adjusted to move the frequency of the interference relative to the center frequency of the measurement system passband. These data showed that the effect of power line interference for this system configuration can be more than one percent at test frequencies harmonically related to the power line frequency. These data also showed that adjusting the power line frequency to separate the interference and test frequencies by as little as 1.0 Hz can reduce the effect of the interference by at least an order of magnitude. Adjustment of the power line frequency could enable accurate measurements at test frequencies that otherwise might be avoided.

  5. Power-Line Harmonic Radiation: Can It Significantly Affect the Earth's Radiation Belts?

    PubMed

    Thorne, R M; Tsurutani, B T

    1979-05-25

    It has been suggested that harmonic radiation from the earth's 50- and 60-hertz power transmission lines might significantly influence the distribution of electrons in the radiation belts. On the basis of observations presented here, it seems advisable to accept such a hypothesis with caution. New evidence suggests that power-line radiation does not play any major role in the nonadiabatic dynamics of radiation belt electrons.

  6. Power-line harmonic radiation - Can it significantly affect the earth's radiation belts

    NASA Technical Reports Server (NTRS)

    Thorne, R. M.; Tsurutani, B. T.

    1979-01-01

    It has been suggested that harmonic radiation from the earth's 50- and 60-hertz power transmission lines might significantly influence the distribution of electrons in the radiation belts. On the basis of observations presented here, it seems advisable to accept such a hypothesis with caution. New evidence suggests that power-line radiation does not play any major role in the nonadiabatic dynamics of radiation belt electrons.

  7. A novel modular approach to active power-line harmonic filtering in distribution systems

    NASA Astrophysics Data System (ADS)

    El Shatshat, Ramadan A.

    The objective of this research is to develop an efficient and reliable modular active harmonic filter system to realize a cost-effective solution to the harmonic problem. The proposed filter system consists of a number CSC modules, each dedicated to filter a specific harmonic of choice (Frequency-Splitting Approach). The power rating of the modules will decrease and their switching frequency will increase as the order of the harmonic to be filtered is increased. The overall switching losses are minimized due to the selected harmonic elimination and balanced a "power rating"-"switching frequency" product. Two ADALINEs are proposed as a part of the filter controller for processing the signals obtained from the power-line. One ADALINE (the Current ADALINE) extracts the fundamental and harmonic components of the distorted current. The other ADALINE (the Voltage ADALINE) estimates the line voltage. The outputs of both ADALINEs are used to construct the modulating signals of the filter modules. The proposed controller decides which CSC filter module(s) is connected to the electric grid. The automated connection of the corresponding filter module(s) is based on decision-making rules in such a way that the IEEE 519-1992 limits are not violated. The information available on the magnitude of each harmonic component allows us to select the active filter bandwidth (i.e., the highest harmonic to be suppressed). This will result in more efficiency and higher performance. The proposed controller adjusts the I dc in each CSC module according to the present magnitude of the corresponding harmonic current. This results in optimum dc-side current value and minimal converter losses. The comparison of the proposed modular active filter scheme and the conventional one converter scheme on practical use in industry is presented. This comparison shows that the proposed solution is more economical, reliable and flexible compared to conventional one. High speed and accuracy of ADALINE, self

  8. Extremum seeking x-ray position feedback using power line harmonic leakage as the perturbation

    NASA Astrophysics Data System (ADS)

    Zohar, S.; Kissick, D. J.; Venugopalan, N.; Ogata, C. M.; Makarov, O.; Stepanov, S.; Fischetti, R. F.

    2016-09-01

    Small x-ray beam sizes necessary for probing nanoscale phenomena require exquisite stability to prevent data corruption by noise. One source of instability at synchrotron radiation x-ray beamlines is the slow detuning of x-ray optics to marginal alignment where the onset of clipping increases the beam's susceptibility to higher frequency position oscillations. In this article, we show that a 1 μ m amplitude horizontal x-ray beam oscillation driven by power line harmonic leakage into the electron storage ring can be used as perturbation for horizontal position extremum seeking feedback. Feedback performance is characterized by convergence to 1.5% away from maximum intensity at optimal alignment.

  9. High-harmonic fast-wave power flow along magnetic field lines in the scrape-off layer of NSTX.

    PubMed

    Perkins, R J; Hosea, J C; Kramer, G J; Ahn, J-W; Bell, R E; Diallo, A; Gerhardt, S; Gray, T K; Green, D L; Jaeger, E F; Jaworski, M A; LeBlanc, B P; McLean, A; Maingi, R; Phillips, C K; Roquemore, L; Ryan, P M; Sabbagh, S; Taylor, G; Wilson, J R

    2012-07-27

    A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

  10. Observations of power line harmonic radiation by the low-altitude AUREOL 3 satellite

    SciTech Connect

    Parrot, M.

    1994-03-01

    This paper presents observations of very low frequency radiation in the lower part of the ionosphere from a polar orbiting satellite at low latitudes. It was able to record several observation of low frequency radiation which is very close to a harmonic of the 50 Hz line frequency. The frequency is observed to drift in time, from 1 to 8 Hz/sec. They are not sure how to account for this apparent non-linear coupling of these very low frequency waves into the ionosphere.

  11. Fetal ECG Extraction from Abdominal Signals: A Review on Suppression of Fundamental Power Line Interference Component and Its Harmonics

    PubMed Central

    Ţarălungă, Dragoş-Daniel; Ungureanu, Georgeta-Mihaela; Gussi, Ilinca; Strungaru, Rodica; Wolf, Werner

    2014-01-01

    Interference of power line (PLI) (fundamental frequency and its harmonics) is usually present in biopotential measurements. Despite all countermeasures, the PLI still corrupts physiological signals, for example, electromyograms (EMG), electroencephalograms (EEG), and electrocardiograms (ECG). When analyzing the fetal ECG (fECG) recorded on the maternal abdomen, the PLI represents a particular strong noise component, being sometimes 10 times greater than the fECG signal, and thus impairing the extraction of any useful information regarding the fetal health state. Many signal processing methods for cancelling the PLI from biopotentials are available in the literature. In this review study, six different principles are analyzed and discussed, and their performance is evaluated on simulated data (three different scenarios), based on five quantitative performance indices. PMID:24660020

  12. Living with power system harmonics

    SciTech Connect

    Palko, E.

    1992-06-18

    This paper reports the effect of harmonics on electronic equipment in manufacturing plants which was essentially a nonproblem as recently as nine years ago. In years past, harmonics were essentially a problem experienced by electric utility companies, with a relatively few types of industries impressing a serous degree of harmonics onto the utility system. Utilities typically solved their harmonic problems by imposing limits on the amount of harmonics that a customer was permitted to reflect onto the utility system, and assessing heavy financial penalties for noncompliance. Today's electronic equipment creates a problem that feeds on itself: solid-state electronic equipment is a flagrant generator of harmonics, and solid-state equipment is, itself, intolerant of harmonics and is susceptible to malfunction and failure when served from a harmonic-laden power source.

  13. High Power Amplifier Harmonic Output Level Measurement

    NASA Technical Reports Server (NTRS)

    Perez, R. M.; Hoppe, D. J.; Khan, A. R.

    1995-01-01

    A method is presented for the measurement of the harmonic output power of high power klystron amplifiers, involving coherent hemispherical radiation pattern measurements of the radiated klystron output. Results are discussed for the operation in saturated and unsaturated conditions, and with a waveguide harmonic filter included.

  14. Harmonic resonance on parallel high voltage transmission lines

    SciTech Connect

    Harries, J.R.; Randall, J.L.

    1997-01-01

    The Bonneville Power Administration (BPA) has received complaints of telephone interference over a wide area of northwestern Washington State for several years. However, until 1995 investigations had proved inconclusive as either the source of the harmonics or the operating conditions changed whenever investigators arrived. The 2,100 Hz interference had been noticed at several optically isolated telephone exchanges. The area of complaint corresponded to electric service areas near the transmission line corridors of the BPA Custer-Monroe 500-kV lines. High 2,100 Hz field strength was measured near the 500-kV lines and also under lower voltage lines served from stations along the transmission line corridor. Tests and studies made with the Alternative Transients Program version of the Electromagnetic Transients Program (EMTP) were able to define the phenomena and isolate the source. Harmonic resonance has been observed, measured and modeled on parallel 500-kV lines that are about one wavelength at 2,100 Hz, the 35th harmonic. A seemingly small harmonic injection at one location on the system causes significant problems some distance away such as telephone interference.

  15. Power Factor Correction to Mitigate Harmonic Distortion

    NASA Astrophysics Data System (ADS)

    Kochetkov, Gary

    Many direct current (DC) devices must receive their power from the alternating current (AC) grid. Rectifiers use diodes to create DC for these devices. Due to diodes' non-linear nature however, harmonics are created and these travel back into the grid. A significant presence of harmonics causes component heating and possible malfunction. A harmonic mitigation procedure is needed. With the correct usage of transistors, the current drawn by a rectifier can be manipulated to remove almost all harmonics. This process is called power factor correction (PFC), and formally acts to reduce the total harmonic distortion (THD) of the current. To investigate this, a three phase active rectifier was computer simulated and a controller was designed to provide switching signals for the transistors. Finally, the device was constructed in the laboratory to drive a DC motor, verifying its operating principle outside of the idealities of simulation.

  16. Power Divider for Harmonically Rich Waveforms

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III (Inventor)

    2001-01-01

    A power divider divides an RF signal into two output signals having a phase difference of 180 deg. or a multiple thereof. When the RF signal is a square wave or another harmonically rich signal. the phases of the fundamental and the harmonics have the proper relationship. The divider can be implemented in the form of microstrips on a board, with one of the output microstrips having several bends to provide a different electrical length from the other.

  17. Harmonics in a Wind Power Plant: Preprint

    SciTech Connect

    Preciado, V.; Madrigal, M.; Muljadi, E.; Gevorgian, V.

    2015-04-02

    Wind power generation has been growing at a very fast pace for the past decade, and its influence and impact on the electric power grid is significant. As in a conventional power plant, a wind power plant (WPP) must ensure that the quality of the power being delivered to the grid is excellent. At the same time, the wind turbine should be able to operate immune to small disturbances coming from the grid. Harmonics are one of the more common power quality issues presented by large WPPs because of the high switching frequency of the power converters and the possible nonlinear behavior from electric machines (generator, transformer, reactors) within a power plant. This paper presents a summary of the most important issues related to harmonics in WPPs and discusses practical experiences with actual Type 1 and Type 3 wind turbines in two WPPs.

  18. Power Divider for Waveforms Rich in Harmonics

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III

    2005-01-01

    A method for dividing the power of an electronic signal rich in harmonics involves the use of an improved divider topology. A divider designed with this topology could be used, for example, to propagate a square-wave signal in an amplifier designed with a push-pull configuration to enable the generation of more power than could be generated in another configuration.

  19. Power System Harmonic Elimination to Improve Power Quality

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, K.; Ramachandaramurthy, V. K.

    2015-06-01

    An improvised RLC interface filter for a Dynamic Voltage Restorer (DVR) is proposed. The RLC filter is connected in the front end between the IGBT based Voltage Source Inverter (VSI) and the injection transformer and is able to eliminate voltage harmonics in the system and also switching harmonics generated from VSI. The voltage at the sensitive load end is pure sinusoidal. In this method, the DVR produced Pulse Width Modulation (PWM) voltage with voltage harmonic canceling the voltage harmonic generated from the supply main. The VSI handles harmonic power. The low order switching harmonics generated by the IGBT based VSI is suppressed. The DVR has greater voltage injection capability. Good dynamic and transient results recorded and Total Harmonic Distortion (THD) at the sensitive load end is minimized. The voltage at the sensitive load is sinusoidal and at 1.0 pu. PSCAD/EMTDC is used to validate the performance of the interface filter and the DVR. Simulated results are presented.

  20. Analysis of Even Harmonics Generation in an Isolated Electric Power System

    NASA Astrophysics Data System (ADS)

    Kanao, Norikazu; Hayashi, Yasuhiro; Matsuki, Junya

    Harmonics bred from loads are mainly odd order because the current waveform has half-wave symmetry. Since the even harmonics are negligibly small, those are not generally measured in electric power systems. However, even harmonics were measured at a 500/275/154kV substation in Hokuriku Electric Power Company after removal of a transmission line fault. The even harmonics caused malfunctions of protective digital relays because the relays used 4th harmonics at the input filter as automatic supervisory signal. This paper describes the mechanism of generation of the even harmonics by comparing measured waveforms with ATP-EMTP simulation results. As a result of analysis, it is cleared that even harmonics are generated by three causes. The first cause is a magnetizing current of transformers due to flux deviation by DC component of a fault current. The second one is due to harmonic conversion of a synchronous machine which generates even harmonics when direct current component or even harmonic current flow into the machine. The third one is that increase of harmonic impedance due to an isolated power system produces harmonic voltages. The design of the input filter of protective digital relays should consider even harmonics generation in an isolated power system.

  1. Power line detection system

    DOEpatents

    Latorre, Victor R.; Watwood, Donald B.

    1994-01-01

    A short-range, radio frequency (RF) transmitting-receiving system that provides both visual and audio warnings to the pilot of a helicopter or light aircraft of an up-coming power transmission line complex. Small, milliwatt-level narrowband transmitters, powered by the transmission line itself, are installed on top of selected transmission line support towers or within existing warning balls, and provide a continuous RF signal to approaching aircraft. The on-board receiver can be either a separate unit or a portion of the existing avionics, and can also share an existing antenna with another airborne system. Upon receipt of a warning signal, the receiver will trigger a visual and an audio alarm to alert the pilot to the potential power line hazard.

  2. Power line detection system

    DOEpatents

    Latorre, V.R.; Watwood, D.B.

    1994-09-27

    A short-range, radio frequency (RF) transmitting-receiving system that provides both visual and audio warnings to the pilot of a helicopter or light aircraft of an up-coming power transmission line complex. Small, milliwatt-level narrowband transmitters, powered by the transmission line itself, are installed on top of selected transmission line support towers or within existing warning balls, and provide a continuous RF signal to approaching aircraft. The on-board receiver can be either a separate unit or a portion of the existing avionics, and can also share an existing antenna with another airborne system. Upon receipt of a warning signal, the receiver will trigger a visual and an audio alarm to alert the pilot to the potential power line hazard. 4 figs.

  3. Harmonic analysis of spacecraft power systems using a personal computer

    NASA Technical Reports Server (NTRS)

    Williamson, Frank; Sheble, Gerald B.

    1989-01-01

    The effects that nonlinear devices such as ac/dc converters, HVDC transmission links, and motor drives have on spacecraft power systems are discussed. The nonsinusoidal currents, along with the corresponding voltages, are calculated by a harmonic power flow which decouples and solves for each harmonic component individually using an iterative Newton-Raphson algorithm. The sparsity of the harmonic equations and the overall Jacobian matrix is used to an advantage in terms of saving computer memory space and in terms of reducing computation time. The algorithm could also be modified to analyze each harmonic separately instead of all at the same time.

  4. High average power second harmonic generation in air

    SciTech Connect

    Beresna, Martynas; Kazansky, Peter G.; Svirko, Yuri; Barkauskas, Martynas; Danielius, Romas

    2009-09-21

    We demonstrate second harmonic vortex generation in atmospheric pressure air using tightly focused femtosecond laser beam. The circularly polarized ring-shaped beam of the second harmonic is generated in the air by fundamental beam of the same circular polarization, while the linear polarized beam produces two-lobe beam at the second harmonic frequency. The achieved normalized conversion efficiency and average second harmonic power are two orders of magnitude higher compared to those previously reported and can be increased up to 20 times by external gas flow. We demonstrate that the frequency doubling originates from the gradient of photoexcited free electrons created by pondermotive force.

  5. Efficient millimeter wave 1140 GHz/ diode for harmonic power generation

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Epitaxial gallium arsenide diode junction formed in a crossed waveguide structure operates as a variable reactance harmonic generator. This varactor diode can generate power efficiently in the low-millimeter wavelength.

  6. Development of a control and acquisition module for the harmonic detection of multiple spectral lines

    NASA Astrophysics Data System (ADS)

    Ataíde de Lima, Ricardo; Fontana, Eduardo

    2017-03-01

    This paper describes development of a control and acquisition module—CAM—capable of driving multiple DFB lasers and performing data acquisition of harmonic detection signals of gas spectral lines for applications in the electric power industry. The system comprises a novel approach to set the operating parameters of several distributed feedback—DFB—lasers, by means of a single OEM driver with solid-state relays and auxiliary circuits. A preliminary performance analysis is reported with respect to laser polarization/modulation and temperature control, harmonic distortion, as well as optical power output and emission wavelength, for the case of two DFB lasers. Paired experiments directed to the harmonic detection of carbon monoxide further demonstrate the dependability of the module.

  7. Digital Filter Design with Harmonics Estimation for Power Supplies

    NASA Astrophysics Data System (ADS)

    Shah, P. J.; Saxena, R.; Chawla, M. P. S.

    2012-06-01

    The quality of voltage waveforms is nowadays an issue of the utmost importance for power utilities and electronic equipment. Modern frequency power converters generate a wide spectrum of harmonic components, which deteriorate the quality of the delivered energy, increase the energy losses as well as decrease their liability of a power supplies. In large converters systems not only harmonics, but also considerable interharmonics strongly deteriorate the quality of the power supply voltage. The estimation of the components parameters is very important for control and protection tasks. Digital low pass filter overcome the voltage drift, temperature drift and time drift problems and can be used for harmonic detection for better utilization in real-time. Real-time detection of harmonics can be implemented using MATLAB software and developing simulation circuit set up. With the appropriate cutoff frequency f c and nth order of filter, low pass filter and band-pass filter for real-time harmonic detection can be analyzed. In this paper the aim is to design filters using different methods including Prony analysis. The monitoring of power system harmonics an important issue in the frame of modern power system management and control can be achieved easily using digital filters.

  8. Extremal harmonic active control of power for a monocylinder hybrid powertrain

    NASA Astrophysics Data System (ADS)

    Gauthier, Jean-Philippe; Micheau, Philippe; Cauet, Sébastien; Coirault, Patrick; Martin, Pascal

    2011-11-01

    This article presents a real-life application for the extremal harmonic active control of power [1] applied on a hybrid engine setup. The active control was adapted for a hybrid powertrain constituted of a one-cylinder diesel engine coupled with a permanent magnet synchronous machine. The problem was formulated in the harmonic domain and the control objective was to extremalize energetic criterions. Three criterions were considered: minimizing the speed ripple of the engine, maximizing the mechanical reactive power (mechanical impedance adaptation) and maximizing the active electric power for energy harvesting. The results show that, for the first and second orders of the ripple, speed oscillations can be completely cancelled and reactive power and active power can be optimized on-line. The implicit extremal controller converged rapidly, remaining stable even when the mean engine speed changed abruptly. These results confirm the robustness and the applicability of the extremal harmonic active control for industrial applications.

  9. Systematic harmonic power laws inter-relating multiple fundamental constants

    NASA Astrophysics Data System (ADS)

    Chakeres, Donald; Buckhanan, Wayne; Andrianarijaona, Vola

    2017-01-01

    Power laws and harmonic systems are ubiquitous in physics. We hypothesize that 2, π, the electron, Bohr radius, Rydberg constant, neutron, fine structure constant, Higgs boson, top quark, kaons, pions, muon, Tau, W, and Z when scaled in a common single unit are all inter-related by systematic harmonic powers laws. This implies that if the power law is known it is possible to derive a fundamental constant's scale in the absence of any direct experimental data of that constant. This is true for the case of the hydrogen constants. We created a power law search engine computer program that randomly generated possible positive or negative powers searching when the product of logical groups of constants equals 1, confirming they are physically valid. For 2, π, and the hydrogen constants the search engine found Planck's constant, Coulomb's energy law, and the kinetic energy law. The product of ratios defined by two constants each was the standard general format. The search engine found systematic resonant power laws based on partial harmonic fraction powers of the neutron for all of the constants with products near 1, within their known experimental precision, when utilized with appropriate hydrogen constants. We conclude that multiple fundamental constants are inter-related within a harmonic power law system.

  10. Power transmission line monitoring system

    SciTech Connect

    Seppa, T.O.

    1993-08-17

    A method for monitoring the sag of an overhead power transmission line comprising the steps of: measuring the tension of the power line; producing an electrical signal representative of the tension measurement; processing said electrical signal in accordance with a predetermined tension-sag relationship to produce a second signal which is a function of sag of the power line; transmitting said second electrical signal to a distant location in a predetermined transmission mode; receiving the second signal at the distant location whereby current in the power line is adjusted in accordance with the received second signal.

  11. Analysis of dc harmonics using the three-pulse model for the intermountain power project HVDC transmission

    SciTech Connect

    Dickmander, D.L.; Peterson, K.J.

    1989-04-01

    The harmonic analysis of the dc-side of an HVDC line transmission requires realistic models of the converters, the dc line, and other relevant equipment. These models must include all important paths for harmonic current, and appropriate sources of harmonic voltage generation. The classical converter modeling technique has been demonstrated to be insufficient in field measurements and analysis of the harmonic spectra found on recent HVDC line transmission. For this reason, a new model of the converter bridge which takes into account the major stray capacitances in the converter (the three-pulse model) has been developed, and is described in detail elsewhere. This paper presents comparisons between the classical and three-pulse calculations for the Intermountain Power Project (IPP) HVDC transmission. The calculation results from the three-pulse model agree favorably with the harmonics found in field measurements.

  12. Self-Excitation and Harmonics in Wind Power Generation

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Romanowitz, H.; Yinger, R.

    2005-11-01

    Traditional wind turbines are commonly equipped with induction generators because they are inexpensive, rugged, and require very little maintenance. Unfortunately, induction generators require reactive power from the grid to operate; capacitor compensation is often used. Because the level of required reactive power varies with the output power, the capacitor compensation must be adjusted as the output power varies. The interactions among the wind turbine, the power network, and the capacitor compensation are important aspects of wind generation that may result in self-excitation and higher harmonic content in the output current. This paper examines the factors that control these phenomena and gives some guidelines on how they can be controlled or eliminated.

  13. Identification and tracking of harmonic sources in a power system using a Kalman filter

    SciTech Connect

    Ma, H.; Girgis, A.A.

    1996-07-01

    In this paper, two problems have been addressed on harmonic sources identification: the optimal locations of a limited number of harmonic meters and the optimal dynamic estimates of harmonic source locations and their injections in unbalanced three-phase power systems. A Kalman filtering is used to attack these problems. System error covariance analysis by the Kalman filter associated with a harmonic injection estimate determines the optimal arrangement of limited harmonic meters. Based on the optimally-arranged harmonic metering locations, the Kalman filter then yields the optimal dynamic estimates of harmonic injections with a few noisy harmonic measurements. The method is dynamic and has the capability of identifying, analyzing and tracking each harmonic injection at all buses in unbalanced three-phase power systems. Actual recorded harmonic measurements and simulated data in a power distribution system are provided to prove the efficiency of this approach.

  14. High gain amplifiers: Power oscillations and harmonic generation

    SciTech Connect

    Dattoli, G.; Ottaviani, P. L.; Pagnutti, S.

    2007-08-01

    We discuss the power oscillations in saturated high gain free electron laser amplifiers and show that the relevant period can be written in terms of the gain length. We use simple arguments following from the solution of the pendulum equation in terms of Jacobi elliptic functions. Nontrivial effects due to nonlinear harmonic generation and inhomogeneous broadening are discussed too, as well as the saturated dynamics of short pulses.

  15. An improved adaptive power line interference canceller for electrocardiography.

    PubMed

    Martens, Suzanna M M; Mischi, Massimo; Oei, S Guid; Bergmans, Jan W M

    2006-11-01

    Power line interference may severely corrupt a biomedical recording. Notch filters and adaptive cancellers have been suggested to suppress this interference. We propose an improved adaptive canceller for the reduction of the fundamental power line interference component and harmonics in electrocardiogram (ECG) recordings. The method tracks. the amplitude, phase, and frequency of all the interference components for power line frequency deviations up to about 4 Hz. A comparison is made between the performance of our method, former adaptive cancellers, and a narrow and a wide notch filter in suppressing the fundamental power line interference component. For this purpose a real ECG signal is corrupted by an artificial power line interference signal. The cleaned signal after applying all methods is compared with the original ECG signal. Our improved adaptive canceller shows a signal-to-power-line-interference ratio for the fundamental component up to 30 dB higher than that produced by the other methods. Moreover, our method is also effective for the suppression of the harmonics of the power line interference.

  16. Operation of the unified power flow controller as harmonic isolator

    SciTech Connect

    Enslin, J.H.R.; Zhao, J.; Spee, R.

    1996-11-01

    The unified power flow controller (UPFC) is a tool in the implementation of Flexible AC Transmission Systems (FACTS). It provides for the equivalent of static VAr compensation and series injection using back-to-back force commutated converters. This paper proposes a control strategy to extend UPFC operation to allow for the isolation of harmonics due to nonlinear loads. Simulation results based on the Electromagnetic Transients Program (EMTP) are used to illustrate device performance in a power system environment. Experimental results based on a single phase laboratory implementation verify the proposed control algorithm.

  17. Reactive power and harmonic compensation based on the generalized instantaneous reactive power theory for three-phase power systems

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng

    1996-10-01

    A generalized theory of instantaneous reactive power for three-phase power systems is proposed in this paper. This theory gives a generalized definition of instantaneous reactive power, which is valid for sinusoidal or nonsinusoidal, balanced or unbalanced, three- phase power systems with or without zero-sequence currents and/or voltages. The properties and physical meanings of the newly defined instantaneous reactive power are discussed in detail. With this new reactive power theory, it is very easy to calculate and decompose all components, such as fundamental active/reactive power and current, harmonic current, etc. Reactive power and/or harmonic compensation systems for a three-phase distorted power system with and without zero-sequence components in the source voltage and/or load current are then used as examples to demonstrate the measurement, decomposition, and compensation of reactive power and harmonics.

  18. Multi-pulse Converters and Passive Filtering to Improve Power Harmonics in an Integrated Power System

    DTIC Science & Technology

    2007-05-07

    Conversion Module Ship Service Power Rect. 10 applied to a propulsion motor that is directly coupled to the propeller shaft. To enhance reliability ...Harmonic Analysis A periodic waveform ( )f t is one that functionally satisfies ( ) ( )f t T f t+ = Equation 1 where t is time and T is the...period in seconds. The fundamental frequency ω in radians/second is then found from 2 T π ω = Equation 2 A harmonic is defined as a component

  19. Power line carrier interference from HVDC converter terminals

    SciTech Connect

    Tatro, P.J.; Adamson, K.A. ); Eitzmann, M.A.; Smead, M. . Power Systems Engineering Dept.)

    1993-07-01

    Power line carrier (PLC) equipment typically operates in the frequency range from 25 kHz to 300 kHz. Interference studies for HVDC converters usually concentrate on interference from noise sources within this frequency range. However, operating experience at the Sandy Pond converter terminal has indicated that PLC equipment is also susceptible to interference from sources of power system harmonics below the PLC frequency range. Extensive field testing and analytical studies have shown that each PLC circuit has a resonant frequency below the operating frequency. If excited at this resonant frequency, high voltages may exist within the PLC circuit. The resulting saturation of PLC components leads to local generation of radio frequency (RF) noise that interferes with proper operation of PLC circuits. Sources of power system harmonics in the 3-10 kHz range, such as line commutated dc converters, are potential sources of this type of interference.

  20. Advanced configuration of hybrid passive filter for reactive power and harmonic compensation.

    PubMed

    Kececioglu, O Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

    2016-01-01

    Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. Simulation results show that performance of reactive power and harmonic compensation with advanced hybrid passive filter is better than conventional hybrid passive filters.

  1. Static third-harmonic lines in widely variable fiber continuum generation

    NASA Astrophysics Data System (ADS)

    Tu, Haohua; Zhao, Youbo; Liu, Yuan; Boppart, Stephen A.

    2014-01-01

    An intriguing phenomenon of third-harmonic generation under fiber continuum generation is the emission of an anharmonic signal. One popular interpretation of this effect has developed into a general theory of fiber third-harmonic generation. Here we produce "static" third-harmonic lines dictated fully by fiber properties independent of pump parameters, in contrast to the signals of all known phase-matched nonlinear optical processes that vary dynamically with these parameters. We argue that the anharmonic signal is an illusion of the continuum generation, that it is in fact harmonic, and that this theory should be reevaluated.

  2. In-line sensor for accurate rf power measurements

    NASA Astrophysics Data System (ADS)

    Gahan, D.; Hopkins, M. B.

    2005-10-01

    An in-line sensor has been constructed with 50Ω characteristic impedance to accurately measure rf power dissipated in a matched or unmatched load with a view to being implemented as a rf discharge diagnostic. The physical construction and calibration technique are presented. The design is a wide band, hybrid directional coupler/current-voltage sensor suitable for fundamental and harmonic power measurements. A comparison with a standard wattmeter using dummy load impedances shows that this in-line sensor is significantly more accurate in mismatched conditions.

  3. In-line sensor for accurate rf power measurements

    SciTech Connect

    Gahan, D.; Hopkins, M.B.

    2005-10-15

    An in-line sensor has been constructed with 50 {omega} characteristic impedance to accurately measure rf power dissipated in a matched or unmatched load with a view to being implemented as a rf discharge diagnostic. The physical construction and calibration technique are presented. The design is a wide band, hybrid directional coupler/current-voltage sensor suitable for fundamental and harmonic power measurements. A comparison with a standard wattmeter using dummy load impedances shows that this in-line sensor is significantly more accurate in mismatched conditions.

  4. Compensation for Harmonic Currents and Reactive Power in Wind Power Generation System using PWM Inverter

    NASA Astrophysics Data System (ADS)

    Shinohara, Katsuji; Shinhatsubo, Kurato; Iimori, Kenichi; Yamamoto, Kichiro; Saruban, Takamichi; Yamaemori, Takahiro

    In recent year, consciousness of environmental problems is enhancing, and the price of the electric power purchased by an electric power company is established expensive for the power plant utilizing the natural energy. So, the introduction of the wind power generation is promoted in Japan. Generally, squirrel-cage induction machines are widely used as a generator in wind power generation system because of its small size, lightweight and low-cost. However, the induction machines do not have a source of excitation. Thus, it causes the inrush currents and the instantaneous voltage drop when the generator is directly connected to a power grid. To reduce the inrush currents, an AC power regulator is used. Wind power generations are frequently connected to and disconnected from the power grid. However, when the inrush currents are reduced, harmonic currents are caused by phase control of the AC power regulator. And the phase control of AC power regulator cannot control the power factor. Therefore, we propose the use of the AC power regulator to compensate for the harmonic currents and reactive power in the wind power generation system, and demonstrate the validity of its system by simulated and experimental results.

  5. Thermal optimization of second harmonic generation at high pump powers.

    PubMed

    Sahm, Alexander; Uebernickel, Mirko; Paschke, Katrin; Erbert, Götz; Tränkle, Günther

    2011-11-07

    We measure the temperature distribution of a 3 cm long periodically poled LiNbO₃ crystal in a single-pass second harmonic generation (SHG) setup at 488 nm. By means of three resistance heaters and directly mounted Pt100 sensors the crystal is subdivided in three sections. 9.4 W infrared pump light and 1.3 W of SHG light cause a de-homogenized temperature distribution of 0.2 K between the middle and back section. A sectional offset heating is used to homogenize the temperature in those two sections and thus increasing the conversion efficiency. A 15% higher SHG output power matching the prediction of our theoretical model is achieved.

  6. High harmonic generation in ZnO with a high-power mid-IR OPA

    NASA Astrophysics Data System (ADS)

    Gholam-Mirzaei, Shima; Beetar, John; Chini, Michael

    2017-02-01

    We generate high-order harmonics in a-cut (11-20) ZnO at a high repetition rate of 50 kHz, using the tunable mid-infrared pulses (3-4 μm wavelength) from a high-power optical parametric amplifier. For driving laser pulses with 3.8 μm central wavelength, we observe nonperturbative harmonic spectra that well exceed the material band gap. The harmonic spectra depend strongly on the orientation of the crystal with respect to the laser polarization, with odd harmonics exhibiting periodicities of π/2 for a polarization within the (11-20) crystal plane. Energy conversion efficiencies of ˜10-6 per harmonic are measured for the 9th-13th harmonics, yielding an average power of more than 0.2 μW for the 13th harmonic.

  7. National Maglev initiative: California line electric utility power system requirements

    NASA Technical Reports Server (NTRS)

    Save, Phil

    1994-01-01

    The electrical utility power system requirements were determined for a Maglev line from San Diego to San Francisco and Sacramento with a maximum capacity of 12,000 passengers an hour in each direction at a speed of 300 miles per hour, or one train every 30 seconds in each direction. Basically the Maglev line requires one 50-MVA substation every 12.5 miles. The need for new power lines to serve these substations and their voltage levels are based not only on equipment loading criteria but also on limitations due to voltage flicker and harmonics created by the Maglev system. The resulting power system requirements and their costs depend mostly on the geographical area, urban or suburban with 'strong' power systems, or mountains and rural areas with 'weak' power systems. A reliability evaluation indicated that emergency power sources, such as a 10-MW battery at each substation, were not justified if sufficient redundancy is provided in the design of the substations and the power lines serving them. With a cost of $5.6 M per mile, the power system requirements, including the 12-kV DC cables and the inverters along the Maglev line, were found to be the second largest cost component of the Maglev system, after the cost of the guideway system ($9.1 M per mile), out of a total cost of $23 M per mile.

  8. A Perturbation of the Dunkl Harmonic Oscillator on the Line

    NASA Astrophysics Data System (ADS)

    Álvarez López, Jesús A.; Calaza, Manuel

    2015-07-01

    Let J_σ be the Dunkl harmonic oscillator on R (σ>-1/2). For 00, it is proved that, if σ>u-1/2, then the operator U=J_σ+ξ|x|^{-2u}, with appropriate domain, is essentially self-adjoint in L^2({R},|x|^{2σ} dx), the Schwartz space S is a core of overline U^{1/2}, and overline U has a discrete spectrum, which is estimated in terms of the spectrum of overline{J_σ}. A generalization J_{σ,τ} of J_σ is also considered by taking different parameters σ and τ on even and odd functions. Then extensions of the above result are proved for J_{σ,τ}, where the perturbation has an additional term involving, either the factor x^{-1} on odd functions, or the factor x on even functions. Versions of these results on R_+ are derived.

  9. Measurement of Oxygen A Band Line Parameters by Using Modulation Spectroscopy with Higher Harmonic Detection

    NASA Technical Reports Server (NTRS)

    Dharamsi, Amin

    1999-01-01

    Wavelength modulation spectroscopy is used to demonstrate that extremely weak absorption lines can be measured even when these lines suffer from interference from the wings of adjacent stronger lines. It is shown that the use of detection at several harmonics allows such interference to be examined clearly and conveniently. The results of experimental measurements on a weak magnetic dipole driven, spin-forbidden line in the oxygen A band, which experiences interference from the wings of a pair of adjacent lines towards the blue and red regions of line center, are presented. A comparison of the experimental results to theory is given.

  10. Higher-order harmonic transmission-line RF coil design for MR applications.

    PubMed

    Zhang, Xiaoliang; Zhu, Xiao-Hong; Chen, Wei

    2005-05-01

    A novel concept based on the use of higher-order harmonic resonances in a transmission-line resonator is introduced for the design of high-frequency RF coils at high and ultrahigh fields, where conventional RF coil designs present difficulties and limitations. To demonstrate this concept, we successfully designed and fabricated a 400-MHz RF coil for rat imaging using a second-harmonic resonant microstrip transmission line. This coil has a high Q-factor, reduces coil-cable interactions without the use of a matching balun, and has a broad range for tuning the coil's resonant frequency at the loaded condition. This work demonstrates that the use of higher-order harmonics in a transmission-line resonator provides an alternative, efficient approach to the design of large and high-frequency RF coils.

  11. New hybrid active power filter for harmonic current suppression and reactive power compensation

    NASA Astrophysics Data System (ADS)

    Biricik, Samet; Cemal Ozerdem, Ozgur; Redif, Soydan; Sezai Dincer, Mustafa

    2016-08-01

    In the case of undistorted and balanced grid voltages, low ratio shunt active power filters (APFs) can give unity power factors and achieve current harmonic cancellation. However, this is not possible when source voltages are distorted and unbalanced. In this study, the cost-effective hybrid active power filter (HAPF) topology for satisfying the requirements of harmonic current suppression and non-active power compensation for industry is presented. An effective strategy is developed to observe the effect of the placement of power capacitors and LC filters with the shunt APF. A new method for alleviating the negative effects of a nonideal grid voltage is proposed that uses a self-tuning filter algorithm with instantaneous reactive power theory. The real-time control of the studied system was achieved with a field-programmable gate array (FPGA) architecture, which was developed using the OPAL-RT system. The performance result of the proposed HAPF system is tested and presented under nonideal supply voltage conditions.

  12. A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.; Simons, Rainee N.

    2014-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

  13. Low-power continuous-wave generation of visible harmonics in silicon photonic crystal nanocavities.

    PubMed

    Galli, Matteo; Gerace, Dario; Welna, Karl; Krauss, Thomas F; O'Faolain, Liam; Guizzetti, Giorgio; Andreani, Lucio Claudio

    2010-12-06

    We present the first demonstration of frequency conversion by simultaneous second- and third-harmonic generation in a silicon photonic crystal nanocavity using continuous-wave optical excitation. We observe a bright dual wavelength emission in the blue/green (450-525 nm) and red (675-790 nm) visible windows with pump powers as low as few microwatts in the telecom bands, with conversion efficiencies of ∼ 10 (-5) /W and ∼ 10/ W(2) for the second- and third-harmonic, respectively. Scaling behaviors as a function of pump power and cavity quality-factor are demonstrated for both second- and third order processes. Successful comparison of measured and calculated emission patterns indicates that third-harmonic is a bulk effect while second-harmonic is a surface-related effect at the sidewall holes boundaries. Our results are promising for obtaining practical low-power, continuous-wave and widely tunable multiple harmonic generation on a silicon chip.

  14. A Portable Low-Power Harmonic Radar System and Conformal Tag for Insect Tracking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harmonic radar systems provide an effective modality for tracking insect behavior. This paper presents a harmonic radar system proposed to track the migration of the Emerald Ash Borer (EAB). The system offers a unique combination of portability, low power and small tag design. It is comprised of a...

  15. A harmonic cancellation technique for an ultrasound transducer excited by a switched-mode power converter.

    PubMed

    Tang, Sai Chun; Clement, Gregory T

    2008-02-01

    The aim of this study is to evaluate the feasibility of using harmonic cancellation for a therapeutic ultrasound transducer excited by a switched-mode power converter without an additional output filter. A switching waveform without the third harmonic was created by cascading two switched-mode power inverter modules at which their output waveforms were pi/3 phase shifted from each other. A PSPICE simulation model for the power converter output stage was developed. The simulated results were in good agreement with the measurement. The waveform and harmonic contents of the acoustic pressure generated by a 1-MHz, self-focused piezoelectric transducer with and without harmonic cancellation have been evaluated. Measured results indicated that the acoustic third harmonicto- fundamental ratio at the focus was small (-48 dB) with harmonic cancellation, compared to that without harmonic cancellation (-20 dB). The measured acoustic levels of the fifth harmonic for both cases with and without harmonic cancellation also were small (-46 dB) compared to the fundamental. This study shows that it is viable to drive a piezoelectric ultrasound transducer using a switched-mode power converter without the requirement of an additional output filter in many high-intensity focused ultrasound (HIFU) applications.

  16. Ames Lab 101: Next Generation Power Lines

    SciTech Connect

    Russell, Alan

    2010-01-01

    Ames Laboratory scientist Alan Russell discusses the need to develop new power lines that are stronger and more conductive as a way to address the problem of the nation's aging and inadequate power grid.

  17. Ames Lab 101: Next Generation Power Lines

    ScienceCinema

    Russell, Alan

    2016-07-12

    Ames Laboratory scientist Alan Russell discusses the need to develop new power lines that are stronger and more conductive as a way to address the problem of the nation's aging and inadequate power grid.

  18. Fast wave power flow along SOL field lines in NSTX

    NASA Astrophysics Data System (ADS)

    Perkins, R. J.; Bell, R. E.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; Leblanc, B. P.; Kramer, G. J.; Phillips, C. K.; Roquemore, L.; Taylor, G.; Wilson, J. R.; Ahn, J.-W.; Gray, T. K.; Green, D. L.; McLean, A.; Maingi, R.; Ryan, P. M.; Jaeger, E. F.; Sabbagh, S.

    2012-10-01

    On NSTX, a major loss of high-harmonic fast wave (HHFW) power can occur along open field lines passing in front of the antenna over the width of the scrape-off layer (SOL). Up to 60% of the RF power can be lost and at least partially deposited in bright spirals on the divertor floor and ceiling [1,2]. The flow of HHFW power from the antenna region to the divertor is mostly aligned along the SOL magnetic field [3], which explains the pattern of heat deposition as measured with infrared (IR) cameras. By tracing field lines from the divertor back to the midplane, the IR data can be used to estimate the profile of HHFW power coupled to SOL field lines. We hypothesize that surface waves are being excited in the SOL, and these results should benchmark advanced simulations of the RF power deposition in the SOL (e.g., [4]). Minimizing this loss is critical optimal high-power long-pulse ICRF heating on ITER while guarding against excessive divertor erosion.[4pt] [1] J.C. Hosea et al., AIP Conf Proceedings 1187 (2009) 105. [0pt] [2] G. Taylor et al., Phys. Plasmas 17 (2010) 056114. [0pt] [3] R.J. Perkins et al., to appear in Phys. Rev. Lett. [0pt] [4] D.L. Green et al., Phys. Rev. Lett. 107 (2011) 145001.

  19. Correlation of the earth's rotation rate and the secular change of the geomagnetic field. [power spectra/harmonic analysis

    NASA Technical Reports Server (NTRS)

    Jin, R. S.

    1975-01-01

    Power spectral density analysis using Burg's maximum entropy method was applied to the geomagnetic dipole field and its rate of change for the years 1901 to 1969. Both spectra indicate relative maxima at 0.015 cycles/year and its harmonics. These maxima correspond approximately to 66, 33, 22, 17, 13, 11, and 9-year spectral lines. The application of the same analysis techniques to the length-of-day (l.o.d) fluctuations for the period 1865 to 1961 reveal similar spectral characteristics. Although peaks were observed at higher harmonics of the fundamental frequency, the 22-year and 11-year lines are not attributed unambiguously to the solar magnetic cycle and the solar cycle. It is suggested that the similarity in the l.o.d fluctuations and the dipole field variations is related to the motion within the earth's fluid core during the past one hundred years.

  20. Third-Harmonic Envelope Feedback Method for High-Efficiency Linear Power Amplifiers

    NASA Astrophysics Data System (ADS)

    Oshima, Shoichi; Ugajin, Mamoru; Harada, Mitsuru

    A new low-power feedback structure for a power amplifier (PA) reduces signal distortion while keeping the power efficiency of the PA high. The feedback structure injects the envelope of the third-order harmonics into the input signal. In adopting this method for a class-A amplifier, we obtain over 10% higher efficiency while maintaining the same adjacent channel power ratio (ACPR). The power consumption of additional circuit is 200µW.

  1. ULTRA HIGH POWER TRANSMISSION LINE TECHNIQUES

    DTIC Science & Technology

    The ultra-high power transmission line techniques including both failure mechanisms and component design are discussed. Failures resulting from...a waveguide. In view of the many advantages of the low loss mode in circular waveguide for ultra-high power levels, a mode transducer and a two...percent of the peak power of a standard rectangular wave guide. Water cooling is provided for high average power operation. Analysis of mode sup pression

  2. RF design and processing of a power coupler for third harmonic superconducting cavities

    SciTech Connect

    Li, Jianjian; Harms, Elvin; Kubicki, Tom; Nicklaus, Dennis; Olis, Daniel; Prieto, Peter; Reid, John; Solyak, Nikolay; Wong, Thomas; /IIT, Chicago

    2007-06-01

    The FLASH user facility providing free electron laser radiation is built based on the TTF project at DESY. Fermilab has the responsibility for the design and processing of a third harmonic, 3.9 GHz, superconducting cavity which is powered via a coaxial power coupler. Six power couplers have been manufactured at CPI after successful design of the power coupler including RF simulation, multipacting calculation, and thermal analysis. The power couplers are being tested and processed with high pulsed power in an elaborate test stand at Fermilab now. This paper presents the RF design and processing work of the power coupler.

  3. Phase protection system for ac power lines

    NASA Technical Reports Server (NTRS)

    Wong, W. J. (Inventor)

    1974-01-01

    The system described provides protection for phase sensitive loads from being or remaining connected to ac power lines whenever a phase reversal occurs. It comprises a solid state phase detection circuit, a dc power relay circuit, an ac-to-dc converter for energizing the relay circuit, and a bistable four terminal transducer coupled between the phase detection circuit and the power relay circuit, for controlling both circuits.

  4. Transmission Line Adapted Analytical Power Charts Solution

    NASA Astrophysics Data System (ADS)

    Sakala, Japhet D.; Daka, James S. J.; Setlhaolo, Ditiro; Malichi, Alec Pulu

    2016-08-01

    The performance of a transmission line has been assessed over the years using power charts. These are graphical representations, drawn to scale, of the equations that describe the performance of transmission lines. Various quantities that describe the performance, such as sending end voltage, sending end power and compensation to give zero voltage regulation, may be deduced from the power charts. Usually required values are read off and then converted using the appropriate scales and known relationships. In this paper, the authors revisit this area of circle diagrams for transmission line performance. The work presented here formulates the mathematical model that analyses the transmission line performance from the power charts relationships and then uses them to calculate the transmission line performance. In this proposed approach, it is not necessary to draw the power charts for the solution. However the power charts may be drawn for the visual presentation. The method is based on applying derived equations and is simple to use since it does not require rigorous derivations.

  5. High average power coherent vuv generation at 10 MHz repetition frequency by intracavity high harmonic generation.

    PubMed

    Ozawa, Akira; Zhao, Zhigang; Kuwata-Gonokami, Makoto; Kobayashi, Yohei

    2015-06-15

    Intracavity high harmonic generation was utilized to generate high average-power coherent radiation at vacuum ultraviolet (vuv) wavelengths. A ytterbium-doped fiber-laser based master-oscillator power-amplifier (MOPA) system with a 10 MHz repetition frequency was developed and used as a driving laser for an external cavity. A series of odd-order harmonic radiations was generated extending down to ∼ 30 nm (41 eV in photon energy). The 7th harmonic radiation generated was centered at 149 nm and had an average output power of up to 0.5 mW. In this way, we developed a sub-mW coherent vuv-laser with a 10 MHz repetition frequency, which, if used as an excitation laser source for photo-electron spectroscopy, could improve the signal count-rate without deterioration of the spectral-resolution caused by space-charge effects.

  6. Self Excitation and Harmonics in Wind Power Generation: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Romanowitz, H.; Yinger, R.

    2004-11-01

    Traditional wind turbines are equipped with induction generators. Induction generators are preferred because they are inexpensive, rugged, and require very little maintenance. Unfortunately, induction generators require reactive power from the grid to operate. Because reactive power varies with the output power, the terminal voltage at the generator may become too low to compensate the induction generator. The interactions among the wind turbine, the power network, and the capacitor compensation, are important aspects of wind generation. In this paper, we will show the interactions among the induction generator, capacitor compensation, power system network, and magnetic saturations and examine the cause of resonance conditions and self-excitation.

  7. Power Doppler myocardial contrast echocardiography using an improved multiple frame triggered Harmonic Angio technique.

    PubMed

    Murthy, T H; Locricchio, E; Kuersten, B; Li, P; Baisch, C; Vannan, M A

    2001-04-01

    Although B-mode harmonic, intermittent-triggered myocardial contrast echocardiography (MCE) is a well-established technique, a variety of MCE techniques have been introduced recently to improve myocardial opacification. One such technique uses a power Doppler method in conjunction with multiple frame triggering (MFT), but has been limited by nonuniform microbubble destruction and blooming as well as motion artifacts. Utilizing two different contrast agents, Definity and Optison, we tested the feasibility of an improved version of Harmonic Angio MFT that utilizes a lower transmit frequency, reduced packet size, and more stringent wall filter in normal volunteers and in patients with known perfusion defects. The results showed that Harmonic Angio MFT produced fill frames with readily visible opacification and destruction frames with little visible opacification. The patterns of opacification also correlated with the expected perfusion patterns in both groups of subjects. Thus, Harmonic Angio MFT appears to be a promising new MCE technique.

  8. Photovoltaic power converter system with a controller configured to actively compensate load harmonics

    DOEpatents

    de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

    2008-12-16

    Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

  9. Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation.

    PubMed

    Chen, Chiun-Fan; Bikson, Marom; Chou, Li-Wei; Shan, Chunlei; Khadka, Niranjan; Chen, Wen-Shiang; Fregni, Felipe

    2017-03-03

    It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20-80 Hz (r = 0.4247, p = 0.0243), 100-180 Hz (r = 0.5894, p = 0.0001), 200-280 Hz (r = 0.7002, p < 0.0001), 300-380 Hz (r = 0.7449, p < 0.0001), 400-480 Hz (r = 0.7906, p < 0.0001), 500-600 Hz (r = 0.7717, p < 0.0001), indicating a trend of increasing correlation, specifically at higher order frequency power harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis.

  10. Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation

    PubMed Central

    Chen, Chiun-Fan; Bikson, Marom; Chou, Li-Wei; Shan, Chunlei; Khadka, Niranjan; Chen, Wen-Shiang; Fregni, Felipe

    2017-01-01

    It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20–80 Hz (r = 0.4247, p = 0.0243), 100–180 Hz (r = 0.5894, p = 0.0001), 200–280 Hz (r = 0.7002, p < 0.0001), 300–380 Hz (r = 0.7449, p < 0.0001), 400–480 Hz (r = 0.7906, p < 0.0001), 500–600 Hz (r = 0.7717, p < 0.0001), indicating a trend of increasing correlation, specifically at higher order frequency power harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis. PMID:28256638

  11. The harmonic impact of electric vehicle battery chargers on residential power distribution

    SciTech Connect

    Wang, Y.; O`Connell, R.M.; Brownfield, G.

    1999-11-01

    Electric vehicles (EV), which are powered by battery-driven electric motors, are becoming an ecologically attractive alternative to gasoline driven vehicles. One drawback to them is that the associated battery chargers are power electronic circuits which, because of their non-linear nature, can produce deleterious harmonic effects on the electric utility distribution system. To investigate the harmonic effects of widespread use of EV battery chargers, three different commercially available EV battery chargers are modeled using the injection current method to represent their current waveforms for simulation in a SPICE model of a particular distribution system.

  12. Circuit for Communication Over Power Lines

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J.; Prokop, Normal F.; Greer, Lawrence C., III; Nappier, Jennifer

    2011-01-01

    Many distributed systems share common sensors and instruments along with a common power line supplying current to the system. A communication technique and circuit has been developed that allows for the simple inclusion of an instrument, sensor, or actuator node within any system containing a common power bus. Wherever power is available, a node can be added, which can then draw power for itself, its associated sensors, and actuators from the power bus all while communicating with other nodes on the power bus. The technique modulates a DC power bus through capacitive coupling using on-off keying (OOK), and receives and demodulates the signal from the DC power bus through the same capacitive coupling. The circuit acts as serial modem for the physical power line communication. The circuit and technique can be made of commercially available components or included in an application specific integrated circuit (ASIC) design, which allows for the circuit to be included in current designs with additional circuitry or embedded into new designs. This device and technique moves computational, sensing, and actuation abilities closer to the source, and allows for the networking of multiple similar nodes to each other and to a central processor. This technique also allows for reconfigurable systems by adding or removing nodes at any time. It can do so using nothing more than the in situ power wiring of the system.

  13. Motor run-up system. [power lines

    NASA Technical Reports Server (NTRS)

    Daeges, J. J. (Inventor)

    1975-01-01

    A starting system is described for bringing a large synchronous motor up to speed to prevent large power line disturbances at the moment the motor is connected to the power line. The system includes (1) a digital counter which generates a count determined by the difference in frequency between the power line and a small current generated by the synchronous motor; (2) a latch which stores the count; and (3) a comparator which compares the stored count with a newly generated count to determine whether the synchronous motor is accelerating or decelerating. Signals generated by the counter and comparator control the current to a clutch that couples a starting motor to the large synchronous motor.

  14. Concurrent Wind Cooling in Power Transmission Lines

    SciTech Connect

    Jake P Gentle

    2012-08-01

    Idaho National Laboratory and the Idaho Power Company, with collaboration from Idaho State University, have been working on a project to monitor wind and other environmental data parameters along certain electrical transmission corridors. The combination of both real-time historical weather and environmental data is being used to model, validate, and recommend possibilities for dynamic operations of the transmission lines for power and energy carrying capacity. The planned results can also be used to influence decisions about proposed design criteria for or upgrades to certain sections of the transmission lines.

  15. 76 FR 71892 - Broadband Over Power Lines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-21

    ... COMMISSION 47 CFR Part 15 Broadband Over Power Lines AGENCY: Federal Communications Commission. ACTION: Final... public comment on those studies, and (3) provide a reasoned explanation of its choice of the... action addressing the court's concerns and its proposals in the RFC/FNPRM. It finds that the...

  16. High-frequency AC/DC converter with unity power factor and minimum harmonic distortion

    SciTech Connect

    Wernekinch, E.R.

    1987-01-01

    The power factor is controlled by adjusting the relative position of the fundamental component of an optimized PWM-type voltage with respect to the supply voltage. Current harmonic distortion is minimized by the use of optimized firing angles for the converter at a frequency where GTO's can be used. This feature makes this approach very attractive at power levels of 100 to 600 kW. To obtain the optimized PWM pattern, a steepest descent digital computer algorithm is used. Digital-computer simulations are performed and a low-power model is constructed and tested to verify the concepts and the behavior of the model. Experimental results show that unity power factor is achieved and that the distortion in the phase currents is 10.4% at 90% of full load. This is less than achievable with sinusoidal PWM, harmonic elimination, hysteresis control, and deadbeat control for the same switching frequency.

  17. Numerical study on a 0.4 THz second harmonic gyrotron with high power

    SciTech Connect

    Chaojun, Lei; Sheng, Yu; Hongfu, Li; Yinghui, Liu; Xinjian, Niu; Qixiang, Zhao

    2013-07-15

    Terahertz and sub-terahertz science and technology are promising topics today. However, it is difficult to obtain high power source of terahertz wave. In this paper, the mode competition and beam-wave interaction in a gradually tapered cavity are studied to achieve high efficiency of a 0.4THz second harmonic gyrotron in practice. In order to attain high power and stable radiation, the TE{sub 32,5} mode is selected as the operating mode of the desired gyrotron to realize single mode oscillation. The issues of studying on the high-order mode gyrotrons are solved effectively by transforming the generalized telegraphist's equations. The efficiency and output power of the gyrotron under different conditions have been calculated by the code, which is based on the transformed equations. Consequently, the results show that single mode second harmonic radiation with power of over 150 kW at frequency of 0.4 THz could be achieved.

  18. A high efficiency C-band internally-matched harmonic tuning GaN power amplifier

    NASA Astrophysics Data System (ADS)

    Lu, Y.; Zhao, B. C.; Zheng, J. X.; Zhang, H. S.; Zheng, X. F.; Ma, X. H.; Hao, Y.; Ma, P. J.

    2016-09-01

    In this paper, a high efficiency C-band gallium nitride (GaN) internally-matched power amplifier (PA) is presented. This amplifier consists of 2-chips of self-developed GaN high-electron mobility transistors (HEMTs) with 16 mm total gate width on SiC substrate. New harmonic manipulation circuits are induced both in the input and output matching networks for high efficiency matching at fundamental and 2nd-harmonic frequency, respectively. The developed amplifier has achieved 72.1% power added efficiency (PAE) with 107.4 W output power at 5 GHz. To the best of our knowledge, this amplifier exhibits the highest PAE in C-band GaN HEMT amplifiers with over 100 W output power. Additionally, 1000 hours' aging test reveals high reliability for practical applications.

  19. Harmonic analysis of Boolean networks: determinative power and perturbations

    PubMed Central

    2013-01-01

    Consider a large Boolean network with a feed forward structure. Given a probability distribution on the inputs, can one find, possibly small, collections of input nodes that determine the states of most other nodes in the network? To answer this question, a notion that quantifies the determinative power of an input over the states of the nodes in the network is needed. We argue that the mutual information (MI) between a given subset of the inputs X={X1,...,Xn} of some node i and its associated function fi(X) quantifies the determinative power of this set of inputs over node i. We compare the determinative power of a set of inputs to the sensitivity to perturbations to these inputs, and find that, maybe surprisingly, an input that has large sensitivity to perturbations does not necessarily have large determinative power. However, for unate functions, which play an important role in genetic regulatory networks, we find a direct relation between MI and sensitivity to perturbations. As an application of our results, we analyze the large-scale regulatory network of Escherichia coli. We identify the most determinative nodes and show that a small subset of those reduces the overall uncertainty of the network state significantly. Furthermore, the network is found to be tolerant to perturbations of its inputs. PMID:23642003

  20. Multimode harmonic power measurement of 40 MW pulsed S-band klystrons

    SciTech Connect

    Fowkes, W.R.; Wu, E.S.

    1984-08-01

    An array of 12 calibrated RF electric field probes on the waveguide walls are used to sample the complex field profile at the second and third harmonics where the fundamental power is in the 40 MW range at 2856 MHx. The measured amplitude and phase signals from these are Fourier analyzed to determine with good accuracy the power in each of the many possible propagating modes.

  1. Interaction of lightning with power distribution lines

    NASA Astrophysics Data System (ADS)

    Mata, Carlos Tomas

    Triggered-lightning experiments were conducted in 1996, 1999, and 2000 to study the responses of overhead power distribution lines to lightning at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. The lightning was artificially initiated (triggered) from natural thunderclouds using the rocket-and-wire technique, and its current was directed to a phase conductor at midspan or at a pole near the center of the line. Experimental results and associated EMTP modeling are presented in this dissertation for the following line configurations: (1)a two-conductor, 740-m overhead distribution line with 2 arrester stations in 1996; (2)a four- conductor, 245-m overhead distribution line with 2 arrester stations in 1999; and (3)a four-conductor, 829-m overhead distribution line with 6 arrester stations in 2000. The three-phase lines tested in 1999 and 2000 were standard designs of a major Florida power company. Lightning peak currents injected into the lines ranged from 7 to 57 kA. Voltages and currents were measured at various locations along the line. Video and photographic cameras were used to image lightning channels and detect line flashovers. The significant results of the research are (1)flashovers between conductors were observed, both accompanied and not accompanied by arrester failures, (2)an arrester failed on seven of eight direct lightning strikes to the line in 2000, (3)arcing between conductors may prevent failures of arresters connected to the struck phase, (4)the bulk of the lightning current flows from the struck phase to neutral through the arresters closest to the strike point, (5)the withstand energy of the arresters can be exceeded due to the contribution from multiple strokes and/or relatively low-level, long-lasting current components, (6)the distribution of charge transferred to ground among multiple neutral grounds, which is determined by low-frequency, low-current grounding resistances is different from the

  2. A zero power harmonic transponder sensor for ubiquitous wireless μL liquid-volume monitoring.

    PubMed

    Huang, Haiyu; Chen, Pai-Yen; Hung, Cheng-Hsien; Gharpurey, Ranjit; Akinwande, Deji

    2016-01-06

    Autonomous liquid-volume monitoring is crucial in ubiquitous healthcare. However, conventional approach is based on either human visual observation or expensive detectors, which are costly for future pervasive monitoring. Here we introduce a novel approach based on passive harmonic transponder antenna sensor and frequency hopping spread spectrum (FHSS) pattern analysis, to provide a very low cost wireless μL-resolution liquid-volume monitoring without battery or digital circuits. In our conceptual demonstration, the harmonic transponder comprises of a passive nonlinear frequency multiplier connected to a metamaterial-inspired 3-D antenna designed to be highly sensitive to the liquid-volume within a confined region. The transponder first receives some FHSS signal from an interrogator, then converts such signal to its harmonic band and re-radiates through the antenna sensor. The harmonic signal is picked up by a sniffer receiver and decoded through pattern analysis of the high dimensional FHSS signal strength data. A robust, zero power, absolute accuracy wireless liquid-volume monitoring is realized in the presence of strong direct coupling, background scatters, distance variance as well as near-field human-body interference. The concepts of passive harmonic transponder sensor, metamaterial-inspired antenna sensor, and FHSS pattern analysis based sensor decoding may help establishing cost-effective, energy-efficient and intelligent wireless pervasive healthcare monitoring platforms.

  3. A zero power harmonic transponder sensor for ubiquitous wireless μL liquid-volume monitoring

    NASA Astrophysics Data System (ADS)

    Huang, Haiyu; Chen, Pai-Yen; Hung, Cheng-Hsien; Gharpurey, Ranjit; Akinwande, Deji

    2016-01-01

    Autonomous liquid-volume monitoring is crucial in ubiquitous healthcare. However, conventional approach is based on either human visual observation or expensive detectors, which are costly for future pervasive monitoring. Here we introduce a novel approach based on passive harmonic transponder antenna sensor and frequency hopping spread spectrum (FHSS) pattern analysis, to provide a very low cost wireless μL-resolution liquid-volume monitoring without battery or digital circuits. In our conceptual demonstration, the harmonic transponder comprises of a passive nonlinear frequency multiplier connected to a metamaterial-inspired 3-D antenna designed to be highly sensitive to the liquid-volume within a confined region. The transponder first receives some FHSS signal from an interrogator, then converts such signal to its harmonic band and re-radiates through the antenna sensor. The harmonic signal is picked up by a sniffer receiver and decoded through pattern analysis of the high dimensional FHSS signal strength data. A robust, zero power, absolute accuracy wireless liquid-volume monitoring is realized in the presence of strong direct coupling, background scatters, distance variance as well as near-field human-body interference. The concepts of passive harmonic transponder sensor, metamaterial-inspired antenna sensor, and FHSS pattern analysis based sensor decoding may help establishing cost-effective, energy-efficient and intelligent wireless pervasive healthcare monitoring platforms.

  4. A zero power harmonic transponder sensor for ubiquitous wireless μL liquid-volume monitoring

    PubMed Central

    Huang, Haiyu; Chen, Pai-Yen; Hung, Cheng-Hsien; Gharpurey, Ranjit; Akinwande, Deji

    2016-01-01

    Autonomous liquid-volume monitoring is crucial in ubiquitous healthcare. However, conventional approach is based on either human visual observation or expensive detectors, which are costly for future pervasive monitoring. Here we introduce a novel approach based on passive harmonic transponder antenna sensor and frequency hopping spread spectrum (FHSS) pattern analysis, to provide a very low cost wireless μL-resolution liquid-volume monitoring without battery or digital circuits. In our conceptual demonstration, the harmonic transponder comprises of a passive nonlinear frequency multiplier connected to a metamaterial-inspired 3-D antenna designed to be highly sensitive to the liquid-volume within a confined region. The transponder first receives some FHSS signal from an interrogator, then converts such signal to its harmonic band and re-radiates through the antenna sensor. The harmonic signal is picked up by a sniffer receiver and decoded through pattern analysis of the high dimensional FHSS signal strength data. A robust, zero power, absolute accuracy wireless liquid-volume monitoring is realized in the presence of strong direct coupling, background scatters, distance variance as well as near-field human-body interference. The concepts of passive harmonic transponder sensor, metamaterial-inspired antenna sensor, and FHSS pattern analysis based sensor decoding may help establishing cost-effective, energy-efficient and intelligent wireless pervasive healthcare monitoring platforms. PMID:26732251

  5. 29 CFR 1926.1411 - Power line safety-while traveling under or near power lines with no load.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... equipment traveling under or near a power line on a construction site with no load. Equipment traveling on a... 29 Labor 8 2014-07-01 2014-07-01 false Power line safety-while traveling under or near power lines... CONSTRUCTION Cranes and Derricks in Construction § 1926.1411 Power line safety—while traveling under or...

  6. 29 CFR 1926.1411 - Power line safety-while traveling under or near power lines with no load.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... equipment traveling under or near a power line on a construction site with no load. Equipment traveling on a... 29 Labor 8 2011-07-01 2011-07-01 false Power line safety-while traveling under or near power lines... CONSTRUCTION Cranes and Derricks in Construction § 1926.1411 Power line safety—while traveling under or...

  7. Free power dissipation from functional line integration

    NASA Astrophysics Data System (ADS)

    Brader, Joseph M.; Schmidt, Matthias

    2015-09-01

    Power functional theory provides an exact generalisation of equilibrium density functional theory to non-equilibrium systems undergoing Brownian many-body dynamics. Practical implementation of this variational approach demands knowledge of an excess (over ideal gas) dissipation functional. Using functional line integration (i.e. the operation inverse to functional differentiation), we obtain an exact expression for the excess free power dissipation, which involves the pair interaction potential and the two-body, equal-time density correlator. This provides a basis for the development of approximation schemes.

  8. Reliability of IGBT in a STATCOM for Harmonic Compensation and Power Factor Correction

    SciTech Connect

    Gopi Reddy, Lakshmi Reddy; Tolbert, Leon M; Ozpineci, Burak; Xu, Yan; Rizy, D Tom

    2012-01-01

    With smart grid integration, there is a need to characterize reliability of a power system by including reliability of power semiconductors in grid related applications. In this paper, the reliability of IGBTs in a STATCOM application is presented for two different applications, power factor correction and harmonic elimination. The STATCOM model is developed in EMTP, and analytical equations for average conduction losses in an IGBT and a diode are derived and compared with experimental data. A commonly used reliability model is used to predict reliability of IGBT.

  9. Modified Perfect Harmonics Cancellation Control of a Grid Interfaced SPV Power Generation

    NASA Astrophysics Data System (ADS)

    Singh, B.; Shahani, D. T.; Verma, A. K.

    2015-03-01

    This paper deals with a grid interfaced solar photo voltaic (SPV) power generating system with modified perfect harmonic cancellation (MPHC) control for power quality improvement in terms of mitigation of the current harmonics, power factor correction, control of point of common coupling (PCC) voltage with reactive power compensation and load balancing in a three phase distribution system. The proposed grid interfaced SPV system consists of a SPV array, a dc-dc boost converter and a voltage source converter (VSC) used for the compensation of other connected linear and nonlinear loads at PCC. The reference grid currents are estimated using MPHC method and control signals are derived by using pulse width modulation (PWM) current controller of VSC. The SPV power is fed to the common dc bus of VSC and dc-dc boost converter using maximum power point tracking (MPPT). The dc link voltage of VSC is regulated by using dc voltage proportional integral (PI) controller. The analysis of the proposed SPV power generating system is carried out under dc/ac short circuit and severe SPV-SX and SPV-TX intrusion.

  10. HHFW Power Flow Along Magnetic Field Lines In The Scrape-off Layer of NSTX

    SciTech Connect

    Rory Perkins, et. al.

    2012-02-27

    A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast wave heating and current drive.

  11. Current transducers used in power line measurements

    NASA Astrophysics Data System (ADS)

    Milcarz, Sz.; Gołebiowski, J.

    2014-08-01

    There are many solutions used for current measurements in power lines. The study shows a transducer consisting of a ferromagnetic core, a beam placed in an air-gap and a sensor for optical readout. The beam is made of silicon with a thin 50%Ni50%Fe film. The material of the core is permalloy. A distribution of magnetic field depends on current supplying the power line. The beam is deflected due to magnetic field in the air-gap. A deflection of the beam is measured by the optical fibre sensor. Its advantage is simple design, high precision of processing, non-electric transmission, low costs and ability of a non-contact measurement. Comsol Multiphysics 4.4 and Magnetic Fields Module (mef) were used for modeling. An influence of magnetic circuit's materials and dimensions of the ferromagnetic core and the air-gap were tested in order to determine the most sufficient distribution of magnetic field in the air-gap. The study shows results of the modeling of the transducer compared to practical results for a similar construction scaled down to lower current values.

  12. Apparatus and Method for Communication over Power Lines

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J. (Inventor); Prokop, Norman F. (Inventor); Greer, Lawrence C., III (Inventor); Nappier, Jennifer M. (Inventor)

    2015-01-01

    An apparatus and method are provided for communicating over power lines. The apparatus includes a coupling modem that is situated between a power line and a device. The coupling modem is configured to demodulate a signal received from the power line into a sine signal and a cosine signal. The coupling modem is also configured to modulate a communicated bit stream received from the device into a transmitted signal in order to impose the transmitted signal onto the power line.

  13. U. H. F. Power Transistors and Lecher Line Oscillators.

    ERIC Educational Resources Information Center

    Howes, R. W.

    1980-01-01

    Describes the use of transistors instead of valves for Lecher line and radiation demonstrations. Two oscillator circuits which provide power for Lecher line use are described. Impedance of Lecher line is also discussed. (HM)

  14. 47 CFR 15.113 - Power line carrier systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Power line carrier systems. 15.113 Section 15.113 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unintentional Radiators § 15.113 Power line carrier systems. Power line carrier systems, as defined in § 15.3(t),...

  15. 47 CFR 15.113 - Power line carrier systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Power line carrier systems. 15.113 Section 15.113 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unintentional Radiators § 15.113 Power line carrier systems. Power line carrier systems, as defined in § 15.3(t),...

  16. 47 CFR 15.113 - Power line carrier systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Power line carrier systems. 15.113 Section 15.113 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unintentional Radiators § 15.113 Power line carrier systems. Power line carrier systems, as defined in § 15.3(t),...

  17. 47 CFR 15.113 - Power line carrier systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Power line carrier systems. 15.113 Section 15.113 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unintentional Radiators § 15.113 Power line carrier systems. Power line carrier systems, as defined in § 15.3(t),...

  18. 47 CFR 15.113 - Power line carrier systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Power line carrier systems. 15.113 Section 15.113 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unintentional Radiators § 15.113 Power line carrier systems. Power line carrier systems, as defined in § 15.3(t),...

  19. 32 CFR 644.431 - Power transmission lines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 4 2013-07-01 2013-07-01 false Power transmission lines. 644.431 Section 644... Power transmission lines. (a) Authority. Pursuant to the provisions of section 13(d) of the Surplus... power transmission line and the right of way acquired for its construction is needed for or adaptable...

  20. 32 CFR 644.431 - Power transmission lines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Power transmission lines. 644.431 Section 644... Power transmission lines. (a) Authority. Pursuant to the provisions of section 13(d) of the Surplus... power transmission line and the right of way acquired for its construction is needed for or adaptable...

  1. Generalized power-spectrum Larmor formula for an extended charged particle embedded in a harmonic oscillator

    NASA Astrophysics Data System (ADS)

    Marengo, Edwin A.; Khodja, Mohamed R.

    2006-09-01

    The nonrelativistic Larmor radiation formula, giving the power radiated by an accelerated charged point particle, is generalized for a spatially extended particle in the context of the classical charged harmonic oscillator. The particle is modeled as a spherically symmetric rigid charge distribution that possesses both translational and spinning degrees of freedom. The power spectrum obtained exhibits a structure that depends on the form factor of the particle, but reduces, in the limit of an infinitesimally small particle and for the charge distributions considered, to Larmor’s familiar result. It is found that for finite-duration small-enough accelerations as well as perpetual uniform accelerations the power spectrum of the spatially extended particle reduces to that of a point particle. It is also found that when the acceleration is violent or the size parameter of the particle is very large compared to the wavelength of the emitted radiation the power spectrum is highly suppressed. Possible applications are discussed.

  2. Bionic Vision-Based Intelligent Power Line Inspection System

    PubMed Central

    Ma, Yunpeng; He, Feijia; Xu, Jinxin

    2017-01-01

    Detecting the threats of the external obstacles to the power lines can ensure the stability of the power system. Inspired by the attention mechanism and binocular vision of human visual system, an intelligent power line inspection system is presented in this paper. Human visual attention mechanism in this intelligent inspection system is used to detect and track power lines in image sequences according to the shape information of power lines, and the binocular visual model is used to calculate the 3D coordinate information of obstacles and power lines. In order to improve the real time and accuracy of the system, we propose a new matching strategy based on the traditional SURF algorithm. The experimental results show that the system is able to accurately locate the position of the obstacles around power lines automatically, and the designed power line inspection system is effective in complex backgrounds, and there are no missing detection instances under different conditions. PMID:28203269

  3. Bionic Vision-Based Intelligent Power Line Inspection System.

    PubMed

    Li, Qingwu; Ma, Yunpeng; He, Feijia; Xi, Shuya; Xu, Jinxin

    2017-01-01

    Detecting the threats of the external obstacles to the power lines can ensure the stability of the power system. Inspired by the attention mechanism and binocular vision of human visual system, an intelligent power line inspection system is presented in this paper. Human visual attention mechanism in this intelligent inspection system is used to detect and track power lines in image sequences according to the shape information of power lines, and the binocular visual model is used to calculate the 3D coordinate information of obstacles and power lines. In order to improve the real time and accuracy of the system, we propose a new matching strategy based on the traditional SURF algorithm. The experimental results show that the system is able to accurately locate the position of the obstacles around power lines automatically, and the designed power line inspection system is effective in complex backgrounds, and there are no missing detection instances under different conditions.

  4. Observations of radiation from power lines in near-earth space

    NASA Astrophysics Data System (ADS)

    Korepanov, V. E.; Dudkin, F. L.; Pronenko, V. A.

    2015-09-01

    The possible effects of technogenic impacts on the ionosphere, with the continuing trend towards its sustainable growth, are unknown today. It is therefore very important and urgent task to conduct statistically valid research related to the study of variations of ionospheric parameters due to the influence of powerful technogenic factors, primarily due to a significant increase of the electromagnetic energy production. In this paper, we discuss new results of observations of electromagnetic fields in the ionosphere at the power lines main frequency of 50 (60) Hz and its harmonics onboard SICH-1M (2004) and CHIBIS-M (2012-2014) satellites. The spatial distribution of the observed phenomena and their connection with possible ground-based sources-powerful transmission lines is presented. It is concluded that organization of regular monitoring of technogenic fields may allow continuous control of energy consumption in both the local (within a country or even a powerful consumer) and global scales.

  5. Low-power analog processing for sensing applications: low-frequency harmonic signal classification.

    PubMed

    White, Daniel J; William, Peter E; Hoffman, Michael W; Balkir, Sina

    2013-07-25

    A low-power analog sensor front-end is described that reduces the energy required to extract environmental sensing spectral features without using Fast Fouriér Transform (FFT) or wavelet transforms. An Analog Harmonic Transform (AHT) allows selection of only the features needed by the back-end, in contrast to the FFT, where all coefficients must be calculated simultaneously. We also show that the FFT coefficients can be easily calculated from the AHT results by a simple back-substitution. The scheme is tailored for low-power, parallel analog implementation in an integrated circuit (IC). Two different applications are tested with an ideal front-end model and compared to existing studies with the same data sets. Results from the military vehicle classification and identification of machine-bearing fault applications shows that the front-end suits a wide range of harmonic signal sources. Analog-related errors are modeled to evaluate the feasibility of and to set design parameters for an IC implementation to maintain good system-level performance. Design of a preliminary transistor-level integrator circuit in a 0.13 µm complementary metal-oxide-silicon (CMOS) integrated circuit process showed the ability to use online self-calibration to reduce fabrication errors to a sufficiently low level. Estimated power dissipation is about three orders of magnitude less than similar vehicle classification systems that use commercially available FFT spectral extraction.

  6. Geomagnetic field-line resonant harmonics measured by the Viking and AMPTE/CCE magnetic field experiments

    NASA Technical Reports Server (NTRS)

    Zanetti, L. J.; Potemra, T. A.; Erlandson, R. E.; Engebretson, M. J.; Acuna, M. H.

    1987-01-01

    The first simultaneous observations of multiple harmonic, azimuthally polarized, ULF pulsations at two points along a geomagnetic flux tube in space are reported. In March 1986, the elliptically orbiting equatorial AMPTE/CCE satellite was oriented with the apogee near 0830 h MLT, and the orbital plane of the polar-orbiting Viking satellite was at 1000 MLT. The satellites were situated within approximately the same flux tube but with an effective separation of approximately 10 R(e) near L = 8 on the inbound pass of the AMPTE/CCE orbit. Structured harmonic pulsations were observed by the magnetic field experiments on both spacecraft, and they appeared to turn off and on simultaneously at both locations. Both the observations and the relative amplitudes along the magnetic field lines support recent ideas of multiple field-line resonances of Alfven waves.

  7. Cryogenic Yb:YAG picosecond laser with high average power visible and ultraviolet harmonic generation

    NASA Astrophysics Data System (ADS)

    Brown, D. C.; Kowalewski, K.; Envid, V.; Zembek, J.; Canale, B.; Kolis, J. W.; McMillen, C. D.; Geisber, H.

    2012-06-01

    Cryogenic Yb:YAG lasers operating at 1029 nm have been demonstrated at Snake Creek Lasers with high average power CW and ultrafast output powers, and provide near diffraction-limited output beams that are ideal for applications in harmonic generation. We describe experiments that have produced high average power green output power at 515 nm as well as preliminary experiments producing UV output power at 257.25 nm. Frequency doubling experiments used a 20 mm long non-critically phase-matched LBO crystal mounted in a constant temperature oven. A mode-locked Yb fiber laser operating at 50 MHz was used to drive a two Yb:YAG cryogenic amplifier system, producing hundreds of watts of average power output with a FWHM pulsewidth of 12 ps. Doubling efficiencies of > 50 % have been observed. For frequency quadrupling, we have used hydrothermally grown KTTP crystals grown at Clemson University and Advanced Photonic Crystals. KBBF offers unprecedented UV transmission down to 155 nm, and was used in a Type I phasematching configuration. The properties of KBBF will be discussed, as well as the experimental results observed and conversion efficiency.

  8. Acoustic power in non-uniform lined ducts

    NASA Astrophysics Data System (ADS)

    Eversman, Walter

    2008-06-01

    A definition of acoustic power in conservation form in lined infinitely long uniform ducts is extended to include axially symmetric non-uniform ducts with potential mean flow and finite length lining. The definition includes a contribution at the lined boundary. Benchmarking is accomplished by verification of acoustic power conservation in the case of a purely reactive lining. Calculations in the case of reactively lined ducts show that intense acoustic gradients near the lined surface can occur, and contributions to acoustic power from the boundary power term become relatively large. This observed behavior diminishes as the resistive component of lining impedance is increased. Power calculations for propagation and radiation from a typical turbo-fan inlet and equivalent calculations for an infinite duct propagation model of the same inlet contour are compared. Results are remarkably similar for the case considered, though it is noted that this conclusion is geometry dependent.

  9. Research of on-line monitoring method for insulation condition of power transformer bushing

    NASA Astrophysics Data System (ADS)

    Xia, Jiuyun; Qian, Zheng; Yu, Hao; Yao, Junda

    2016-01-01

    The power transformer is the key equipment of the power system; its insulation condition will directly influence the security and reliability of the power system. Thus, the on-line monitoring of power transformer is urgently required in order to guarantee the normal operation of the power system. Moreover, the dielectric loss factor is a significant parameter reflecting the condition of transformer bushing, so the on-line measurement of dielectric loss factor is really important. In this paper, the phase-to-phase comparison method is selected as the on-line monitoring method based on the overall analysis and discussion of the existing on-line monitoring methods. At first, the harmonic analysis method is utilized to calculate the dielectric loss of each phase of the three-phase transformer bushing, and then the differences of dielectric loss between every two phases are calculated and analyzed. So the insulation condition of each bushing could be achieved based on the careful analysis of different phase-to-phase dielectric loss. The simulation results of phase-to-phase comparison method are carried out in this paper, and the validity is verified. At last, this method is utilized in an actual equipment of on-line monitoring.

  10. Monitoring System of Power Line Icing Based on GPRS

    NASA Astrophysics Data System (ADS)

    Wancheng, Xie

    GPRS-based power line monitoring system for ice. The system is based on the images to monitor the power line monitoring device for ice. System through the use of simplified Sobel algorithm and Hough transform to image edge detection, with DSP high-speed computing performance and optimization of DSP code, and realized the power line ice thickness of the terminal identification and automatic alarm function; using the terminal identification means, is intelligent Monitoring of a new attempt.

  11. Resolution-Enhanced Harmonic and Interharmonic Measurement for Power Quality Analysis in Cyber-Physical Energy System

    PubMed Central

    Liu, Yanchi; Wang, Xue; Liu, Youda; Cui, Sujin

    2016-01-01

    Power quality analysis issues, especially the measurement of harmonic and interharmonic in cyber-physical energy systems, are addressed in this paper. As new situations are introduced to the power system, the impact of electric vehicles, distributed generation and renewable energy has introduced extra demands to distributed sensors, waveform-level information and power quality data analytics. Harmonics and interharmonics, as the most significant disturbances, require carefully designed detection methods for an accurate measurement of electric loads whose information is crucial to subsequent analyzing and control. This paper gives a detailed description of the power quality analysis framework in networked environment and presents a fast and resolution-enhanced method for harmonic and interharmonic measurement. The proposed method first extracts harmonic and interharmonic components efficiently using the single-channel version of Robust Independent Component Analysis (RobustICA), then estimates the high-resolution frequency from three discrete Fourier transform (DFT) samples with little additional computation, and finally computes the amplitudes and phases with the adaptive linear neuron network. The experiments show that the proposed method is time-efficient and leads to a better accuracy of the simulated and experimental signals in the presence of noise and fundamental frequency deviation, thus providing a deeper insight into the (inter)harmonic sources or even the whole system. PMID:27355946

  12. Resolution-Enhanced Harmonic and Interharmonic Measurement for Power Quality Analysis in Cyber-Physical Energy System.

    PubMed

    Liu, Yanchi; Wang, Xue; Liu, Youda; Cui, Sujin

    2016-06-27

    Power quality analysis issues, especially the measurement of harmonic and interharmonic in cyber-physical energy systems, are addressed in this paper. As new situations are introduced to the power system, the impact of electric vehicles, distributed generation and renewable energy has introduced extra demands to distributed sensors, waveform-level information and power quality data analytics. Harmonics and interharmonics, as the most significant disturbances, require carefully designed detection methods for an accurate measurement of electric loads whose information is crucial to subsequent analyzing and control. This paper gives a detailed description of the power quality analysis framework in networked environment and presents a fast and resolution-enhanced method for harmonic and interharmonic measurement. The proposed method first extracts harmonic and interharmonic components efficiently using the single-channel version of Robust Independent Component Analysis (RobustICA), then estimates the high-resolution frequency from three discrete Fourier transform (DFT) samples with little additional computation, and finally computes the amplitudes and phases with the adaptive linear neuron network. The experiments show that the proposed method is time-efficient and leads to a better accuracy of the simulated and experimental signals in the presence of noise and fundamental frequency deviation, thus providing a deeper insight into the (inter)harmonic sources or even the whole system.

  13. Life Cycle Greenhouse Gas Emissions of Utility-Scale Wind Power: Systematic Review and Harmonization

    SciTech Connect

    Dolan, S. L.; Heath, G. A.

    2012-04-01

    A systematic review and harmonization of life cycle assessment (LCA) literature of utility-scale wind power systems was performed to determine the causes of and, where possible, reduce variability in estimates of life cycle greenhouse gas (GHG) emissions. Screening of approximately 240 LCAs of onshore and offshore systems yielded 72 references meeting minimum thresholds for quality, transparency, and relevance. Of those, 49 references provided 126 estimates of life cycle GHG emissions. Published estimates ranged from 1.7 to 81 grams CO{sub 2}-equivalent per kilowatt-hour (g CO{sub 2}-eq/kWh), with median and interquartile range (IQR) both at 12 g CO{sub 2}-eq/kWh. After adjusting the published estimates to use consistent gross system boundaries and values for several important system parameters, the total range was reduced by 47% to 3.0 to 45 g CO{sub 2}-eq/kWh and the IQR was reduced by 14% to 10 g CO{sub 2}-eq/kWh, while the median remained relatively constant (11 g CO{sub 2}-eq/kWh). Harmonization of capacity factor resulted in the largest reduction in variability in life cycle GHG emission estimates. This study concludes that the large number of previously published life cycle GHG emission estimates of wind power systems and their tight distribution suggest that new process-based LCAs of similar wind turbine technologies are unlikely to differ greatly. However, additional consequential LCAs would enhance the understanding of true life cycle GHG emissions of wind power (e.g., changes to other generators operations when wind electricity is added to the grid), although even those are unlikely to fundamentally change the comparison of wind to other electricity generation sources.

  14. 2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ...

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

    2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ITS WAY TOWARD THE CEMENT MILL Photographer: Walter J. Lubken, November 19, 1907 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  15. Harmonic Resonance in Power Transmission Systems due to the Addition of Shunt Capacitors

    NASA Astrophysics Data System (ADS)

    Patil, Hardik U.

    Shunt capacitors are often added in transmission networks at suitable locations to improve the voltage profile. In this thesis, the transmission system in Arizona is considered as a test bed. Many shunt capacitors already exist in the Arizona transmission system and more are planned to be added. Addition of these shunt capacitors may create resonance conditions in response to harmonic voltages and currents. Such resonance, if it occurs, may create problematic issues in the system. It is main objective of this thesis to identify potential problematic effects that could occur after placing new shunt capacitors at selected buses in the Arizona network. Part of the objective is to create a systematic plan for avoidance of resonance issues. For this study, a method of capacitance scan is proposed. The bus admittance matrix is used as a model of the networked transmission system. The calculations on the admittance matrix were done using Matlab. The test bed is the actual transmission system in Arizona; however, for proprietary reasons, bus names are masked in the thesis copy intended for the public domain. The admittance matrix was obtained from data using the PowerWorld Simulator after equivalencing the 2016 summer peak load (planning case). The full Western Electricity Coordinating Council (WECC) system data were used. The equivalencing procedure retains only the Arizona portion of the WECC. The capacitor scan results for single capacitor placement and multiple capacitor placement cases are presented. Problematic cases are identified in the form of 'forbidden response. The harmonic voltage impact of known sources of harmonics, mainly large scale HVDC sources, is also presented. Specific key results for the study indicated include: (1) The forbidden zones obtained as per the IEEE 519 standard indicates the bus 10 to be the most problematic bus. (2) The forbidden zones also indicate that switching values for the switched shunt capacitor (if used) at bus 3 should be

  16. Introduction to macroscopic power scaling principles for high-order harmonic generation

    NASA Astrophysics Data System (ADS)

    Heyl, C. M.; Arnold, C. L.; Couairon, A.; L'Huillier, A.

    2017-01-01

    This tutorial presents an introduction to power scaling concepts for high-order harmonic generation (HHG) and attosecond pulse production. We present an overview of state-of-the-art HHG-based extreme ultraviolet (XUV) sources, followed by a brief introduction to basic principles underlying HHG and a detailed discussion of macroscopic effects and scaling principles. Particular emphasis is put on a general scaling model that allows the invariant scaling of the HHG process both, to μJ-level driving laser pulses and thus to multi-MHz repetition rates as well as to 100 mJ-or even Joule-level laser pulses, allowing new intensity regimes with attosecond XUV pulses.

  17. Development of a single-phase harmonic power flow program to study the 20 kHz AC power system for large spacecraft

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan; Kankam, M. David

    1991-01-01

    The development of software is described to aid in design and analysis of AC power systems for large spacecraft. The algorithm is an important version of harmonic power flow program, HARMFLO, used for the study of AC power quality. The new program is applicable to three-phase systems typified by terrestrial power systems, and single-phase systems characteristic of space power systems. The modified HARMFLO accommodates system operating frequencies ranging from terrestrial 60 Hz to and beyond aerospace 20 kHz, and can handle both source and load-end harmonic distortions. Comparison of simulation and test results of a representative spacecraft power system shows a satisfactory correlation. Recommendations are made for the direction of future improvements to the software, to enhance its usefulness to power system designer and analysts.

  18. 32 CFR 644.431 - Power transmission lines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 4 2012-07-01 2011-07-01 true Power transmission lines. 644.431 Section 644.431... transmission lines. (a) Authority. Pursuant to the provisions of section 13(d) of the Surplus Property Act of... transmission line and the right of way acquired for its construction is needed for or adaptable to...

  19. 32 CFR 644.431 - Power transmission lines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 4 2014-07-01 2013-07-01 true Power transmission lines. 644.431 Section 644.431... transmission lines. (a) Authority. Pursuant to the provisions of section 13(d) of the Surplus Property Act of... transmission line and the right of way acquired for its construction is needed for or adaptable to...

  20. 32 CFR 644.431 - Power transmission lines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Power transmission lines. 644.431 Section 644.431... transmission lines. (a) Authority. Pursuant to the provisions of section 13(d) of the Surplus Property Act of... transmission line and the right of way acquired for its construction is needed for or adaptable to...

  1. Definitions of non-stationary vibration power for time-frequency analysis and computational algorithms based upon harmonic wavelet transform

    NASA Astrophysics Data System (ADS)

    Heo, YongHwa; Kim, Kwang-joon

    2015-02-01

    While the vibration power for a set of harmonic force and velocity signals is well defined and known, it is not as popular yet for a set of stationary random force and velocity processes, although it can be found in some literatures. In this paper, the definition of the vibration power for a set of non-stationary random force and velocity signals will be derived for the purpose of a time-frequency analysis based on the definitions of the vibration power for the harmonic and stationary random signals. The non-stationary vibration power, defined as the short-time average of the product of the force and velocity over a given frequency range of interest, can be calculated by three methods: the Wigner-Ville distribution, the short-time Fourier transform, and the harmonic wavelet transform. The latter method is selected in this paper because band-pass filtering can be done without phase distortions, and the frequency ranges can be chosen very flexibly for the time-frequency analysis. Three algorithms for the time-frequency analysis of the non-stationary vibration power using the harmonic wavelet transform are discussed. The first is an algorithm for computation according to the full definition, while the others are approximate. Noting that the force and velocity decomposed into frequency ranges of interest by the harmonic wavelet transform are constructed with coefficients and basis functions, for the second algorithm, it is suggested to prepare a table of time integrals of the product of the basis functions in advance, which are independent of the signals under analysis. How to prepare and utilize the integral table are presented. The third algorithm is based on an evolutionary spectrum. Applications of the algorithms to the time-frequency analysis of the vibration power transmitted from an excitation source to a receiver structure in a simple mechanical system consisting of a cantilever beam and a reaction wheel are presented for illustration.

  2. Enhanced second-harmonic generation by means of high-power confinement in a photovoltaic soliton-induced waveguide.

    PubMed

    Lou, Cibo; Xu, Jingjun; Qiao, Haijun; Zhang, Xinzheng; Chen, Yunlin; Chen, Zhigang

    2004-05-01

    We present the first experimental demonstration of enhanced second-harmonic generation (SHG) by means of power confinement with a femtosecond laser in a photovoltaic soliton-induced waveguide. A dark spatial soliton created with a weak cw laser beam in a photovoltaic lithium niobate crystal induces an efficient waveguide for SHG, leading to a 60% enhancement of the conversion efficiency.

  3. A fast, robust algorithm for power line interference cancellation in neural recording

    NASA Astrophysics Data System (ADS)

    Keshtkaran, Mohammad Reza; Yang, Zhi

    2014-04-01

    Objective. Power line interference may severely corrupt neural recordings at 50/60 Hz and harmonic frequencies. The interference is usually non-stationary and can vary in frequency, amplitude and phase. To retrieve the gamma-band oscillations at the contaminated frequencies, it is desired to remove the interference without compromising the actual neural signals at the interference frequency bands. In this paper, we present a robust and computationally efficient algorithm for removing power line interference from neural recordings. Approach. The algorithm includes four steps. First, an adaptive notch filter is used to estimate the fundamental frequency of the interference. Subsequently, based on the estimated frequency, harmonics are generated by using discrete-time oscillators, and then the amplitude and phase of each harmonic are estimated by using a modified recursive least squares algorithm. Finally, the estimated interference is subtracted from the recorded data. Main results. The algorithm does not require any reference signal, and can track the frequency, phase and amplitude of each harmonic. When benchmarked with other popular approaches, our algorithm performs better in terms of noise immunity, convergence speed and output signal-to-noise ratio (SNR). While minimally affecting the signal bands of interest, the algorithm consistently yields fast convergence (<100 ms) and substantial interference rejection (output SNR >30 dB) in different conditions of interference strengths (input SNR from -30 to 30 dB), power line frequencies (45-65 Hz) and phase and amplitude drifts. In addition, the algorithm features a straightforward parameter adjustment since the parameters are independent of the input SNR, input signal power and the sampling rate. A hardware prototype was fabricated in a 65 nm CMOS process and tested. Software implementation of the algorithm has been made available for open access at https://github.com/mrezak/removePLI. Significance. The proposed

  4. Harmonic analysis of GaN-HEMTs at different temperatures and frequencies using Volterra power series

    NASA Astrophysics Data System (ADS)

    Yıldırım, Remzi; Karaarslan, Ahmet

    2015-02-01

    In this study, the detailed harmonic analysis of GaN high electron mobility transistor (HEMT) at different temperatures and frequencies is presented. Volterra power series and multi-dimensional Laplace transform are used as a method. The Volterra power series is also solved up to third degree, and the small signal transfer functions of kernels (H1, H2 and H3) are obtained. The relationship between drain inductance (Ld), gate-source voltage (Vgs), impedance (ZL) and the effect of frequency (Fr) to the output gain is identified. Besides, the nonlinear gains of H1, H2 and H3 kernels of the GaN-HEMT are obtained. The inverse relationship between the output gains of H1, H2 and H3 kernels are derived. An unsuitable situation has also been identified for sub-carrier inter-modulation systems. In addition, an asymmetric structure is also obtained between the output gain of H2 and side-band frequencies. The effects of other parameters are carried out for the output gain.

  5. Wireless power transfer and fault diagnosis of high-voltage power line via robotic bird

    NASA Astrophysics Data System (ADS)

    Liu, Chunhua; Chau, K. T.; Zhang, Zhen; Qiu, Chun; Li, Wenlong; Ching, T. W.

    2015-05-01

    This paper presents a new idea of wireless power transfer (WPT) and fault diagnosis (FD) of high-voltage power line via robotic bird. The key is to present the conceptual robotic bird with WPT coupling coil for detecting and capturing the energy from the high-voltage power line. If the power line works in normal condition, the robotic bird is able to stand on the power line and extract energy from it. If fault occurs on the power line, the corresponding magnetic field distribution will become different from that in the normal situation. By analyzing the magnetic field distribution of the power line, the WPT to the robotic bird and the FD by the robotic bird are performed and verified.

  6. Depolarization of radiation from high-power neodymium lasers and second harmonic generation of partly depolarized radiation

    SciTech Connect

    Arifzhanov, S.B.; Gulamov, A.A.; Redkorechev, V.I.; Usmanov, T.

    1985-07-01

    A theoretical analysis is made of two mechanisms (linear and nonlinear) of depolarization of radiation emitted by high-power solid-state glass lasers: these mechanisms are anisotropy-induced in the active elements and a nonlinear rotation of the polarization ellipse. In the cases of linear and circular polarization of practical interest, a qualitative and numerical analysis is made of the influence of depolarization of the radiation on second harmonic generation by the second type of interaction in KDP crystals. It is shown that in a field of partly depolarized radiation the second harmonic generation efficiency is limited mainly by depolarization of the radiation.

  7. Extraction of power lines from mobile laser scanning data

    NASA Astrophysics Data System (ADS)

    Xiang, Qing; Li, Jonathan; Wen, Chenglu; Huang, Pengdi

    2016-03-01

    Modern urban life is becoming increasingly more dependent on reliable electric power supply. Since power outages cause substantial financial losses to producers, distributors and consumers of electric power, it is in the common interest to minimize failures of power lines. In order to detect defects as early as possible and to plan efficiently the maintenance activities, distribution networks are regularly inspected. Carrying out foot patrols or climbing the structures to visually inspect transmission lines and aerial surveys (e.g., digital imaging or most recent airborne laser scanning (ALS) are the two most commonly used methods of power line inspection. Although much faster in comparison to the foot patrol inspection, aerial inspection is more expensive and usually less accurate, in complex urban areas particularly. This paper presents a scientific work that is done in the use of mobile laser scanning (MLS) point clouds for automated extraction of power lines. In the proposed method, 2D power lines are extracted using Hough transform in the projected XOY plane and the 3D power line points are visualized after the point searching. Filtering based on an elevation threshold is applied, which is combined with the vehicle's trajectory in the horizontal section.

  8. Integrating Residential Photovoltaics With Power Lines

    NASA Technical Reports Server (NTRS)

    Borden, C. S.

    1985-01-01

    Report finds rooftop solar-cell arrays feed excess power to electric-utility grid for fee are potentially attractive large-scale application of photovoltaic technology. Presents assessment of breakeven costs of these arrays under variety of technological and economic assumptions.

  9. Life Cycle Greenhouse Gas Emissions of Trough and Tower Concentrating Solar Power Electricity Generation: Systematic Review and Harmonization

    SciTech Connect

    Burkhardt, J. J.; Heath, G.; Cohen, E.

    2012-04-01

    In reviewing life cycle assessment (LCA) literature of utility-scale concentrating solar power (CSP) systems, this analysis focuses on reducing variability and clarifying the central tendency of published estimates of life cycle greenhouse gas (GHG) emissions through a meta-analytical process called harmonization. From 125 references reviewed, 10 produced 36 independent GHG emissions estimates passing screens for quality and relevance: 19 for parabolic trough (trough) technology and 17 for power tower (tower) technology. The interquartile range (IQR) of published estimates for troughs and towers were 83 and 20 grams of carbon dioxide equivalent per kilowatt-hour (g CO2-eq/kWh),1 respectively; median estimates were 26 and 38 g CO2-eq/kWh for trough and tower, respectively. Two levels of harmonization were applied. Light harmonization reduced variability in published estimates by using consistent values for key parameters pertaining to plant design and performance. The IQR and median were reduced by 87% and 17%, respectively, for troughs. For towers, the IQR and median decreased by 33% and 38%, respectively. Next, five trough LCAs reporting detailed life cycle inventories were identified. The variability and central tendency of their estimates are reduced by 91% and 81%, respectively, after light harmonization. By harmonizing these five estimates to consistent values for global warming intensities of materials and expanding system boundaries to consistently include electricity and auxiliary natural gas combustion, variability is reduced by an additional 32% while central tendency increases by 8%. These harmonized values provide useful starting points for policy makers in evaluating life cycle GHG emissions from CSP projects without the requirement to conduct a full LCA for each new project.

  10. 29. CROSSCUT FACILITY PROPERTY AND POWER LINE LOCATION, SHOWING INDIAN ...

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

    29. CROSSCUT FACILITY PROPERTY AND POWER LINE LOCATION, SHOWING INDIAN BEND POND LABELLED 'SETTLING BASIN,' STEAM/DIESEL PLANT AND OTHER FEATURES. 1951 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

  11. Passive optical sensor for lightning detection on overhead power lines

    NASA Astrophysics Data System (ADS)

    Rosolem, J. B.; Barbosa, C. F.; Florídia, C.; Bezerra, E. L.

    2009-10-01

    In this work we present the results of a passive optical sensor for monitoring lightning strikes on overhead power lines, which can also be used for several other applications. The optic sensor is very simple and cheap and basically consists in the use of an antenna connected directly to a semiconductor laser. No batteries and solar panels are necessary to implement this sensing system in power lines towers. It was tested in laboratory and showed a good performance.

  12. Brief communication: coaxial lines for multiphase power distribution.

    PubMed

    Barnes, F S; Harwick, P; Banerjee, A

    1996-01-01

    A coaxial cable can be used to reduce the magnetic and electric fields that extend into environments in the vicinity of transmission lines and distribution lines and in-house or building wiring for power distribution systems. The use of the coaxial geometry may prove useful in cases where there are environmental concerns with respect to health effects and in cases where there is a need to run high-speed data communications in close proximity to power distribution systems.

  13. Living and Working Safely Around High-Voltage Power Lines.

    SciTech Connect

    United States. Bonneville Power Administration.

    2001-06-01

    High-voltage transmission lines can be just as safe as the electrical wiring in the homes--or just as dangerous. The crucial factor is ourselves: they must learn to behave safely around them. This booklet is a basic safety guide for those who live and work around power lines. It deals primarily with nuisance shocks due to induced voltages, and with potential electric shock hazards from contact with high-voltage lines. References on possible long-term biological effects of transmission lines are shown. In preparing this booklet, the Bonneville Power Administration has drawn on more than 50 years of experience with high-voltage transmission. BPA operates one of the world`s largest networks of long-distance, high-voltage lines. This system has more than 400 substations and about 15,000 miles of transmission lines, almost 4,400 miles of which are operated at 500,000 volts.

  14. Energy harvesting from electric power lines employing the Halbach arrays.

    PubMed

    He, Wei; Li, Ping; Wen, Yumei; Zhang, Jitao; Lu, Caijiang; Yang, Aichao

    2013-10-01

    This paper proposes non-invasive energy harvesters to scavenge alternating magnetic field energy from electric power lines. The core body of a non-invasive energy harvester is a linear Halbach array, which is mounted on the free end of a piezoelectric cantilever beam. The Halbach array augments the magnetic flux density on the side of the array where the power line is placed and significantly lowers the magnetic field on the other side. Consequently, the magnetic coupling strength is enhanced and more alternating magnetic field energy from the current-carrying power line is converted into electrical energy. An analytical model is developed and the theoretical results verify the experimental results. A power of 566 μW across a 196 kΩ resistor is generated from a single wire, and a power of 897 μW across a 212 kΩ resistor is produced from a two-wire power cord carrying opposite currents at 10 A. The harvesters employing Halbach arrays for a single wire and a two-wire power cord, respectively, exhibit 3.9 and 3.2 times higher power densities than those of the harvesters employing conventional layouts of magnets. The proposed devices with strong response to the alternating currents are promising to be applied to electricity end-use environment in electric power systems.

  15. Noise characterization of mode-locked lasers by comparing the power spectra of the fundamental and second-harmonic pulses

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Chen, L. P.; Liu, J. M.

    1995-10-01

    By comparing the noise power spectra of the fundamental pulses and those of the second-harmonic pulses, the peak intensity fluctuation, the pulse-width fluctuation, the pulse timing jitter, and the cross correlation between the pulse width and the peak intensity fluctuations of a mode-locked pulse train can be separately quantified. The noise characteristics of an actively mode-locked Nd:YLF laser are presented to demonstrate this technique.

  16. Extended optical-emission-line gas in powerful radio galaxies

    SciTech Connect

    Baum, S.A.

    1987-01-01

    Results of a search for extended optical-emission-line gas in 43 powerful radio galaxies are presented. Spatially extended optical-emission-line gas is common in these galaxies. The extent and luminosity of the emission-line gas in powerful radio galaxies is an order of magnitude greater than in normal elliptical galaxies of similar optical magnitudes. The total emission-line luminosity is roughly half of the radio luminosity, and the radio luminosity correlates with the narrow-line luminosity over four decades. The near-nuclear emission-line gas is often distributed in a smooth, roughly elliptical feature, centered on and symmetric about the nucleus. The distribution of axial ratios found in these small emission-line nebulae (ELN) is inconsistent with them being disks seen from different orientations. The minor axes of the small regions of emission-line gas show only a weak tendency to align with the position angle of the extended radio source and the major axis of the stellar isophotes. The very extended emission line gas (d{sub neb} > 10 kpc) is filamentary and is found preferentially within the regions occupied by the radio source. The small (d{sub radio} < 100 kpc) radio sources with very extended ELN show evidence of interacting with their gas-rich environments; the large (d{sub radio} > 100 kpc) radio sources with very extended ELN show no signs that they have been disturbed by their surrounding media. Lower limits to the density of the emission line gas at distances of 10 kpc from the galaxy nucleus are {approximately}0.1 cm{sup {minus}3} and upper limits to the total mass in emission line gas are {approximately}10{sup 9} M {circle dot}. The optical nuclear continuum is strongly correlated with the narrow emission line luminosity and is sufficient to photoionize the ELN.

  17. "These Power Lines Make Me Ill": A Typology of Residents' Health Responses to a New High-Voltage Power Line.

    PubMed

    Porsius, Jarry T; Claassen, Liesbeth; Woudenberg, Fred; Smid, Tjabe; Timmermans, Danielle R M

    2017-03-17

    Little attention has been devoted to the potential diversity in residents' health responses when exposed to an uncertain environmental health risk. The present study explores whether subgroups of residents respond differently to a new high-voltage power line (HVPL) being put into operation. We used a quasi-experimental prospective field study design with two pretests during the construction of a new HVPL, and two posttests after it was put into operation. Residents living nearby (0-300 m, n = 229) filled out questionnaires about their health and their perception of the environment. We applied latent class growth models to investigate heterogeneity in the belief that health complaints were caused by a power line. Classes were compared on a wide range of variables relating to negative-oriented personality traits, perceived physical and mental health, and perceptions of the environment. We identified five distinct classes of residents, of which the largest (49%) could be described as emotionally stable and healthy with weak responses to the introduction of a new power line. A considerable minority (9%) responded more strongly to the new line being activated. Residents in this class had heard more about the health effects of power lines beforehand, were more aware of the activation of the new line, and reported a decrease in perceived health afterwards. Based on our findings we can conclude that there is a considerable heterogeneity in health responses to a new HVPL. Health risk perceptions appear to play an important role in this typology, which has implications for risk management.

  18. Minimum Power Requirements and Optimal Rotor Design for Conventional, Compound, and Coaxial Helicopters Using Higher Harmonic Control

    NASA Astrophysics Data System (ADS)

    Giovanetti, Eli B.

    This thesis presents a method for computing the optimal aerodynamic performance of conventional, compound, and coaxial helicopters in trimmed forward flight with a limited set of design variables, including the blade's radial twist and chord distributions and conventional and higher harmonic blade pitch control. The optimal design problem, which is cast as a variational statement, minimizes the sum of the induced and viscous power required to develop a prescribed lift and/or thrust. The variational statement is discretized and solved efficiently using a vortex-lattice technique. We present two variants of the analysis. In the first, the sectional blade aerodynamics are modeled using a linear lift curve and a quadratic drag polar, and flow angles are assumed to be small. The result is a quadratic programming problem that yields a linear set of equations to solve for the unknown optimal design variables. In the second approach, the problem is cast as a constrained nonlinear optimization problem, which is solved using Newton iteration. This approach, which accounts for realistic lift and drag coefficients including the effects of stall and the attendant increase in drag at high angles of attack, is capable of optimizing the blade planform in addition to the radial twist distribution and conventional and higher harmonic blade pitch control. We show that for conventional rotors, coaxial counterrotating rotors, and a wing-rotor compound, using radially varying twist and chord distributions and higher harmonic blade pitch control can produce significant reductions in required power, especially at high advance ratios.

  19. Development of on-line laser power monitoring system

    NASA Astrophysics Data System (ADS)

    Ding, Chien-Fang; Lee, Meng-Shiou; Li, Kuan-Ming

    2016-03-01

    Since the laser was invented, laser has been applied in many fields such as material processing, communication, measurement, biomedical engineering, defense industries and etc. Laser power is an important parameter in laser material processing, i.e. laser cutting, and laser drilling. However, the laser power is easily affected by the environment temperature, we tend to monitor the laser power status, ensuring there is an effective material processing. Besides, the response time of current laser power meters is too long, they cannot measure laser power accurately in a short time. To be more precisely, we can know the status of laser power and help us to achieve an effective material processing at the same time. To monitor the laser power, this study utilize a CMOS (Complementary metal-oxide-semiconductor) camera to develop an on-line laser power monitoring system. The CMOS camera captures images of incident laser beam after it is split and attenuated by beam splitter and neutral density filter. By comparing the average brightness of the beam spots and measurement results from laser power meter, laser power can be estimated. Under continuous measuring mode, the average measuring error is about 3%, and the response time is at least 3.6 second shorter than thermopile power meters; under trigger measuring mode which enables the CMOS camera to synchronize with intermittent laser output, the average measuring error is less than 3%, and the shortest response time is 20 millisecond.

  20. Life Cycle GHG Emissions from Conventional Natural Gas Power Generation: Systematic Review and Harmonization (Presentation)

    SciTech Connect

    Heath, G.; O'Donoughue, P.; Whitaker, M.

    2012-12-01

    This research provides a systematic review and harmonization of the life cycle assessment (LCA) literature of electricity generated from conventionally produced natural gas. We focus on estimates of greenhouse gases (GHGs) emitted in the life cycle of electricity generation from conventionally produced natural gas in combustion turbines (NGCT) and combined-cycle (NGCC) systems. A process we term "harmonization" was employed to align several common system performance parameters and assumptions to better allow for cross-study comparisons, with the goal of clarifying central tendency and reducing variability in estimates of life cycle GHG emissions. This presentation summarizes preliminary results.

  1. Line bisection task performance and resting EEG alpha power.

    PubMed

    Ciçek, Metehan; Nalçaci, Erhan; Kalaycioglu, Canan

    2003-06-01

    Neurologically normal subjects generally err to the left of veridical center when performing a line bisection task, a phenomenon termed "pseudoneglect." We hypothesized that resting electroencephalogram (EEG) alpha oscillations may show relationships with attentional mechanisms and give some clues about the underlying mechanisms of pseudoneglect. We recorded resting EEGs of 41 subjects and tested them with a paper-pencil line bisection task. Our results showed that line bisection scores of men (n=18) were less biased and their performance was higher compared to those of women (n=20), but these differences only approached significance. The eyes open resting EEG alpha power of women was significantly and positively correlated with their line bisection performance. In general, significant relationships were related to the left hand performance when the lines were presented in the left hemispace. Greater resting alpha power was correlated with lower absolute bisection score or, in other words, higher bisection performance. Greater alpha power also correlated with diminished leftward bisection bias (or reduced pseudo-neglect). The resting EEG alpha of men was weakly associated with bisection performance. Results discussed in terms of Kinsbourne's activation-orientation theory and Basar's view on brain oscillations.

  2. Some computational aspects of the hals (harmonic analysis of x-ray line shape) method

    SciTech Connect

    Moshkina, T.I.; Nakhmanson, M.S.

    1986-02-01

    This paper discusses the problem of distinguishing the analytical line from the background and approximates the background component. One of the constituent parts of the program package in the procedural-mathematical software for x-ray investigations of polycrystalline substances in application to the DRON-3, DRON-2 and ADP-1 diffractometers is the SSF system of programs, which is designed for determining the parameters of the substructure of materials. The SSF system is tailored not only to Unified Series (ES) computers, but also to the M-6000 and SM-1 minicomputers.

  3. Harmonization of initial estimates of shale gas life cycle greenhouse gas emissions for electric power generation.

    PubMed

    Heath, Garvin A; O'Donoughue, Patrick; Arent, Douglas J; Bazilian, Morgan

    2014-08-05

    Recent technological advances in the recovery of unconventional natural gas, particularly shale gas, have served to dramatically increase domestic production and reserve estimates for the United States and internationally. This trend has led to lowered prices and increased scrutiny on production practices. Questions have been raised as to how greenhouse gas (GHG) emissions from the life cycle of shale gas production and use compares with that of conventionally produced natural gas or other fuel sources such as coal. Recent literature has come to different conclusions on this point, largely due to differing assumptions, comparison baselines, and system boundaries. Through a meta-analytical procedure we call harmonization, we develop robust, analytically consistent, and updated comparisons of estimates of life cycle GHG emissions for electricity produced from shale gas, conventionally produced natural gas, and coal. On a per-unit electrical output basis, harmonization reveals that median estimates of GHG emissions from shale gas-generated electricity are similar to those for conventional natural gas, with both approximately half that of the central tendency of coal. Sensitivity analysis on the harmonized estimates indicates that assumptions regarding liquids unloading and estimated ultimate recovery (EUR) of wells have the greatest influence on life cycle GHG emissions, whereby shale gas life cycle GHG emissions could approach the range of best-performing coal-fired generation under certain scenarios. Despite clarification of published estimates through harmonization, these initial assessments should be confirmed through methane emissions measurements at components and in the atmosphere and through better characterization of EUR and practices.

  4. Remote sensing methods for power line corridor surveys

    NASA Astrophysics Data System (ADS)

    Matikainen, Leena; Lehtomäki, Matti; Ahokas, Eero; Hyyppä, Juha; Karjalainen, Mika; Jaakkola, Anttoni; Kukko, Antero; Heinonen, Tero

    2016-09-01

    To secure uninterrupted distribution of electricity, effective monitoring and maintenance of power lines are needed. This literature review article aims to give a wide overview of the possibilities provided by modern remote sensing sensors in power line corridor surveys and to discuss the potential and limitations of different approaches. Monitoring of both power line components and vegetation around them is included. Remotely sensed data sources discussed in the review include synthetic aperture radar (SAR) images, optical satellite and aerial images, thermal images, airborne laser scanner (ALS) data, land-based mobile mapping data, and unmanned aerial vehicle (UAV) data. The review shows that most previous studies have concentrated on the mapping and analysis of network components. In particular, automated extraction of power line conductors has achieved much attention, and promising results have been reported. For example, accuracy levels above 90% have been presented for the extraction of conductors from ALS data or aerial images. However, in many studies datasets have been small and numerical quality analyses have been omitted. Mapping of vegetation near power lines has been a less common research topic than mapping of the components, but several studies have also been carried out in this field, especially using optical aerial and satellite images. Based on the review we conclude that in future research more attention should be given to an integrated use of various data sources to benefit from the various techniques in an optimal way. Knowledge in related fields, such as vegetation monitoring from ALS, SAR and optical image data should be better exploited to develop useful monitoring approaches. Special attention should be given to rapidly developing remote sensing techniques such as UAVs and laser scanning from airborne and land-based platforms. To demonstrate and verify the capabilities of automated monitoring approaches, large tests in various environments

  5. Limiting electric fields of HVDC overhead power lines.

    PubMed

    Leitgeb, N

    2014-05-01

    As a consequence of the increased use of renewable energy and the now long distances between energy generation and consumption, in Europe, electric power transfer by high-voltage (HV) direct current (DC) overhead power lines gains increasing importance. Thousands of kilometers of them are going to be built within the next years. However, existing guidelines and regulations do not yet contain recommendations to limit static electric fields, which are one of the most important criteria for HVDC overhead power lines in terms of tower design, span width and ground clearance. Based on theoretical and experimental data, in this article, static electric fields associated with adverse health effects are analysed and various criteria are derived for limiting static electric field strengths.

  6. Steady-state and dynamic characteristics of a 20-kHz spacecraft power system - Control of harmonic resonance

    NASA Technical Reports Server (NTRS)

    Wasynczuk, O.; Krause, P. C.; Biess, J. J.; Kapustka, R.

    1990-01-01

    A detailed computer simulation was used to illustrate the steady-state and dynamic operating characteristics of a 20-kHz resonant spacecraft power system. The simulated system consists of a parallel-connected set of DC-inductor resonant inverters (drivers), a 440-V cable, a node transformer, a 220-V cable, and a transformer-rectifier-filter (TRF) AC-to-DC receiver load. Also included in the system are a 1-kW 0.8-pf RL load and a double-LC filter connected at the receiving end of the 20-kHz AC system. The detailed computer simulation was used to illustrate the normal steady-state operating characteristics and the dynamic system performance following, for example, TRF startup. It is shown that without any filtering the given system exhibits harmonic resonances due to an interaction between the switching of the source and/or load converters and the AC system. However, the double-LC filter at the receiving-end of the AC system and harmonic traps connected in series with each of the drivers significantly reduce the harmonic distortion of the 20-kHz bus voltage. Significant additional improvement in the waveform quality can be achieved by including a double-LC filter with each driver.

  7. Power Line Carrier Techniques Applied to Spacecraft Data Handling

    NASA Astrophysics Data System (ADS)

    Bedu, J.-Y.; Morisse, J.; Auvergne, X.; Plancke, P.

    Power Line Carrier (PLC) data transmission coupled with spread spectrum technique is evaluated for onboard satellite purpose. Power Line Carrier present a great advantage in terms of mass saving and integration cost by suppressing the data bus harness. Spread Spectrum techniques allows data transmission inside the power supply noise. This paper will address the major functionality keys of this transmission method and will define the main trades off to conduct. INTRODUCTION A major trend for the next satellite generation stands in the increase of the equipment unit's quantity, of their complexity and of their communication needs. A first approach to reduce the number of links and also the overall mass stands in multiplexing Acq/Ctr on data bus. ALCATEL SPACE with its so-called new avionics 4000 has made a significant step with an intensive use of the data bus : round 140 units on its proprietary OBDH-485 bus and round 10 units on the MIL-STD-1553 data bus for Telecom Geostationnary satellite class. According to this state of the art, the following step is the suppression of the data bus harness by means of Wireless or Power Line Carrier (PLC) techniques that has been identified as a development axis. Many PLC components are available for domestic/industry applications. Nevertheless, transmission levels, operating frequencies, radiation hardening performances of these parts are usually not compatible with space environment constraints. 2/12

  8. Raptor electrocution on power lines: Current issues and outlook

    USGS Publications Warehouse

    Lehman, Robert N.

    2001-01-01

    Electrocution on power lines is one of many human-caused mortality factors that affect raptors. Cost-effective and relatively simple raptor-safe standards for power line modification and construction have been available for over 25 years. During the 1970s and early 1980s, electric industry efforts to reduce raptor electrocutions were very coordinated and proactive, but predictions about resolving the problem were overly optimistic. Today, raptors continue to be electrocuted, possibly in large numbers. The electrocution problem has not been resolved, partly because of the sheer number of potentially lethal power poles in use and partly because electrocution risks may be more pervasive and sometimes less conspicuous than once believed. Also, responses to the problem by individual utilities have not been uniform, and deregulation of the electric industry during the 1990s may have deflected attention from electrocution issues. To control raptor electrocutions in the future, the industry must increase information sharing and technology transfer, increase efforts to retrofit lethal power poles, and above all ensure that every new and replacement line constructed incorporates raptor-safe standards at all phases of development. Finally, responsibility for the electrocution problem must be shared. Federal, state, and local governments, academic institutions, the conservation community, and the consumer all can play critical roles in an effort that will, by necessity, extend well into the new century.

  9. Harmonization of initial estimates of shale gas life cycle greenhouse gas emissions for electric power generation

    PubMed Central

    Heath, Garvin A.; O’Donoughue, Patrick; Arent, Douglas J.; Bazilian, Morgan

    2014-01-01

    Recent technological advances in the recovery of unconventional natural gas, particularly shale gas, have served to dramatically increase domestic production and reserve estimates for the United States and internationally. This trend has led to lowered prices and increased scrutiny on production practices. Questions have been raised as to how greenhouse gas (GHG) emissions from the life cycle of shale gas production and use compares with that of conventionally produced natural gas or other fuel sources such as coal. Recent literature has come to different conclusions on this point, largely due to differing assumptions, comparison baselines, and system boundaries. Through a meta-analytical procedure we call harmonization, we develop robust, analytically consistent, and updated comparisons of estimates of life cycle GHG emissions for electricity produced from shale gas, conventionally produced natural gas, and coal. On a per-unit electrical output basis, harmonization reveals that median estimates of GHG emissions from shale gas-generated electricity are similar to those for conventional natural gas, with both approximately half that of the central tendency of coal. Sensitivity analysis on the harmonized estimates indicates that assumptions regarding liquids unloading and estimated ultimate recovery (EUR) of wells have the greatest influence on life cycle GHG emissions, whereby shale gas life cycle GHG emissions could approach the range of best-performing coal-fired generation under certain scenarios. Despite clarification of published estimates through harmonization, these initial assessments should be confirmed through methane emissions measurements at components and in the atmosphere and through better characterization of EUR and practices. PMID:25049378

  10. Simple Harmonic Motion in Harmonic Plane Waves.

    ERIC Educational Resources Information Center

    Benumof, Reuben

    1980-01-01

    Discusses the distribution of kinetic and potential energy in transverse and longitudinal waves and examines the transmission of power and momentum. This discussion is intended to aid in understanding the simple harmonic motion of a particle involved in the propagation of a harmonic mechanical plane wave. (HM)

  11. Modelling of power lines in lightning incidence calculations

    SciTech Connect

    Mousa, A.M. ); Srivastava, K.D. )

    1990-01-01

    When applying the electrogeometric model to power lines to determine the frequency and characteristics of the collected lightning strokes, the power line has traditionally been represented by a set of horizontal wires, i.e. both the sag of the wires and the existence of the towers have been ignored. This approach has serious shortcomings including inability to determine the percentage of the strokes terminating on the towers, failure to correctly predict the effect of height on median current, and giving an approximate value for the number of collected strokes without telling the corresponding degree of error. This paper eliminates the above problems by presenting a computerized solution which takes into consideration the sag of the wires, the existence of the towers, and the inequality of the striking distances to towers and to wires. The features of the program are discussed in the paper, and some of its results are given.

  12. Power transmission line operating modes calculation with controllable phase shifters

    NASA Astrophysics Data System (ADS)

    Astashev, M. G.; Novikov, M. A.; Panfilov, D. I.; Rashitov, P. A.; Remizevich, T. V.; Fedorova, M. I.

    2016-12-01

    The article contains the analysis of the influence of the phase shifter (PS) on the energy processes in the power transmission line in terms of the two-unit model of the electric network. The approach to synthesis of the models regulated by the phase shifter providing for both calculation of the steady operation modes of the electric networks with the phase shifters and research of the electromagnetic processes and designing of the device itself is offered.

  13. Analysis of a high power microwave radial line slot antenna.

    PubMed

    Peng, Shengren; Yuan, Chengwei; Shu, Ting

    2013-07-01

    A traditional radial line slot antenna (RLSA) is a high gain planar array. To improve the power handling capacity, we design a radial line slow wave structure which replaces a traditional dielectric sheet in the radial waveguide of the traditional RLSA. This high power microwave (HPM) RLSA is fed from a double-layered radial line waveguide to realize the directional radiation of the microwave. However, the track of the widen slot array on the upper waveguide could cause large reflection, which disturbs the normal antenna operation, accordingly a reflection canceling slot is added to the lower waveguide, the key technology employed in the design of the HPM RLSA and the antenna return-loss is effectively improved. This article mainly gives the design theory of this antenna, which is confirmed by the simulations and experiments. At 9.4 GHz, the calculated aperture efficiency reaches more than 40%, the reflectance is less than 0.1, the radiation efficiency is more than 99% and its measured power-handling capacity exceeds 700 MW.

  14. HIGH FREQUENCY POWER TRANSMISSION LINE FOR CYCLOTRONS AND THE LIKE

    DOEpatents

    Armstrong, W.J.

    1954-04-20

    High-frequency power transmission systems, particularly a stacked capacitance alternating power current transmission line wherein maximum utilization of the effective conductios skin of the line conductors is achieved while enabling a low impedance to be obtained are reported. The transmission line consists of a number of flat metal strips with interleaved dielectric strips. The metal dielectric strips are coiled spirally with the axis of the spiral extending along the length of the strips, and the alternating metal strips at the output end have outwardly extending aligned lugs which are directly strapped together and connected to the respective terminals on the load. At the input end of the transmission line, similarly, the alternate metal strips are directly strapped together and connected to an altereating current source. With the arrangement described each metal strip conducts on both sides, so that the metal strips are designed to have a thickness corresponding to twice the depth of the "skin effect" conducting lamina of each conductor at the source frequency.

  15. Estimating magnetic fields of homes near transmission lines in the California Power Line Study.

    PubMed

    Vergara, Ximena P; Kavet, Robert; Crespi, Catherine M; Hooper, Chris; Silva, J Michael; Kheifets, Leeka

    2015-07-01

    The California Power Line Study is a case-control study investigating the relation between residences near transmission lines and risk of childhood leukemia. It includes 5788 childhood leukemia cases and 5788 matched primary controls born between 1986 and 2007. We describe the methodology for estimating magnetic fields at study residences as well as for characterizing sources of uncertainty in these estimates. Birth residences of study subjects were geocoded and their distances to transmission lines were ascertained. 302 residences were deemed sufficiently close to transmission lines to have non-zero magnetic fields attributable to the lines. These residences were visited and detailed data, describing the physical configuration and dimensions of the lines contributing to the magnetic field at the residence, were collected. Phasing, loading, and directional load flow data for years of birth and diagnosis for each subject as well as for the day of site visit were obtained from utilities when available; when yearly average load for a particular year was not available, extrapolated values based on expert knowledge and prediction models were obtained. These data were used to estimate the magnetic fields at the center, closest and farthest point of each residence. We found good correlation between calculated fields and spot measurements of fields taken on site during visits. Our modeling strategies yielded similar calculated field estimates, and they were in high agreement with utility extrapolations. Phasing was known for over 90% of the lines. Important sources of uncertainty included a lack of information on the precise location of residences located within apartment buildings or other complexes. Our findings suggest that we were able to achieve high specificity in exposure assessment, which is essential for examining the association between distance to or magnetic fields from power lines and childhood leukemia risk.

  16. Harmonic engine

    DOEpatents

    Bennett, Charles L.

    2009-10-20

    A high efficiency harmonic engine based on a resonantly reciprocating piston expander that extracts work from heat and pressurizes working fluid in a reciprocating piston compressor. The engine preferably includes harmonic oscillator valves capable of oscillating at a resonant frequency for controlling the flow of working fluid into and out of the expander, and also preferably includes a shunt line connecting an expansion chamber of the expander to a buffer chamber of the expander for minimizing pressure variations in the fluidic circuit of the engine. The engine is especially designed to operate with very high temperature input to the expander and very low temperature input to the compressor, to produce very high thermal conversion efficiency.

  17. Investigation of a stripline transmission line structure for gyromagnetic nonlinear transmission line high power microwave sources.

    PubMed

    Reale, D V; Parson, J M; Neuber, A A; Dickens, J C; Mankowski, J J

    2016-03-01

    A stripline gyromagnetic nonlinear transmission line (NLTL) was constructed out of yttrium iron garnet ferrite and tested at charge voltages of 35 kV-55 kV with bias fields ranging from 10 kA/m to 20 kA/m. Typically, high power gyromagnetic NLTLs are constructed in a coaxial geometry. While this approach has many advantages, including a uniform transverse electromagnetic (TEM) mode, simple interconnection between components, and the ability to use oil or pressurized gas as an insulator, the coaxial implementation suffers from complexity of construction, especially when using a solid insulator. By moving to a simpler transmission line geometry, NLTLs can be constructed more easily and arrayed on a single substrate. This work represents a first step in exploring the suitability of various transmission line structures, such as microstrips and coplanar waveguides. The resulting high power microwave (HPM) source operates in ultra high frequency (UHF) band with an average bandwidth of 40.1% and peak rf power from 2 MW to 12.7 MW.

  18. Predicted Performances of Power Line Communication in Aircraft

    NASA Astrophysics Data System (ADS)

    Degardin, V.; Junqua, I.; Lienard, M.; Degauque, P.; Bertuol, S.; Genoulaz, J.; Dunand, M.

    2012-05-01

    The possibility of using power line communication to transmit information in a large aircraft is studied. The communication link, which has been identified and chosen in the frame of the TAUPE European project, is the cabin lighting system since its tree shape and large structure allows covering most of the other possible applications. A statistical theoretical analysis, based on the multiconductor transmission line theory, has been carried out to determine the properties of the channel transfer function. This has been done in two steps: First a simplified network was considered to outline the parameters of the network geometry playing an important role on the path loss, and then by modelling a test bench which will be used as a demonstrator. The PLC link has been modelled for predicting data rate and bit error rate, taking the EMC constraints into account.

  19. Trend on High-speed Power Line Communication Technology

    NASA Astrophysics Data System (ADS)

    Ogawa, Osamu

    High-speed power line communication (PLC) is useful technology to easily build the communication networks, because construction of new infrastructure is not necessary. In Europe and America, PLC has been used for broadband networks since the beginning of 21th century. In Japan, high-speed PLC was deregulated only indoor usage in 2006. Afterward it has been widely used for home area network, LAN in hotels and school buildings and so on. And recently, PLC is greatly concerned as communication technology for smart grid network. In this paper, the author surveys the high-speed PLC technology and its current status.

  20. Power Line Communication (PLC) in Space - Current Status and Outlook

    NASA Astrophysics Data System (ADS)

    Wolf, J.

    2012-05-01

    The Power Line Communication (PLC) technology as known from various terrestrial applications, e.g. in building automation, in the automotive sector and on aircraft, appears to be a promising technology for the use on spacecraft. Starting from a critical overview on existing terrestrial PLC applications with their pros and cons, the paper gives a motivation for the introduction of the PLC technology on spacecraft, discusses the potential areas where it can be applied and is highlighting the potential problem areas. A short overview of on-going ESA PLC activities is provided and an outlook is given.

  1. Investigation into the Effects of Microsecond Power Line Transients on Line-Connected Capacitors

    NASA Technical Reports Server (NTRS)

    Javor, K.

    2000-01-01

    An investigation was conducted into the effect of power-line transients on capacitors used by NASA and installed on platform primary power inputs to avionics. The purpose was to investigate whether capacitor voltage ratings needs to be derated for expected spike potentials. Concerns had been voiced in the past by NASA suppliers that MIL-STD-461 CS06-like requirements were overly harsh and led to physically large capacitors. The author had previously predicted that electrical-switching spike requirements representative of actual power-line transient potentials, durations. and source impedance would require no derating. This investigation bore out that prediction. It was further determined that traditional low source impedance CS06-like transients also will not damage a capacitor, although the spikes themselves are not nearly as well filtered. This report should be used to allay fears that CS06-like requirements drive capacitor voltage derating. Only that derating required by the relatively long duration transients in power quality specification need concern the equipment designer.

  2. Investigation Into The Effects of Microsecond Power Line Transients On Line-Connected Capacitors

    NASA Technical Reports Server (NTRS)

    Javor, Ken

    1999-01-01

    An investigation was conducted into the effect of power-line transients on capacitors used by NASA and installed on platform primary power inputs to avionics. The purpose was to investigate whether capacitor voltage rating needs to be derated for expected spike potentials. Concerns had been voiced in the past by NASA suppliers that MIL-STD-461 CS06-like requirements were overly harsh and led to physically large capacitors. The author had previously predicted that electrical-switching spike requirements representative of actual power-line transient potentials, durations and source impedance would require no derating. This investigation bore out that prediction. It was further determined that traditional low source impedance CS06-like transients also will not damage a capacitor, although the spikes themselves are not nearly as well filtered. This report should be used to allay fears that CS06-like requirements drive capacitor voltage derating. Only that derating required by the relatively long duration transients in power quality specification need concern the equipment designer.

  3. Analysis of Harmonic Distortion in an Integrated Power System for Naval Applications

    DTIC Science & Technology

    2005-06-01

    circuit breaker with the highest current handling capabilities are 5000 amps steady state and 63kA fault. These ratings limit the power handling...reactance, and power capability. Figure 7-2 shows the fault current expected for subtransient reactances of 15%, 20%, and 25%. At 15%, the 63kA breaker

  4. The role of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the diagnosis of childhood febrile urinary tract infections

    PubMed Central

    İlarslan, Nisa Eda Çullas; Fitöz, Ömer Suat; Öztuna, Derya Gökmen; Küçük, Nuriye Özlem; Yalçınkaya, Fatma Fatoş

    2015-01-01

    Aim: This study assessed the ability of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the detection of childhood febrile urinary tract infections in comparison with the gold standard reference method: Tc-99m dimercaptosuccinicacid renal cortical scintigraphy. Material and Methods: This prospective study included 60 patients who were hospitalized with a first episode of febrile urinary tract infections. All children were examined with dimercaptosuccinicacid scan and tissue harmonic imaging ultrasound combined with power Doppler ultrasound within the first 3 days of admission. Results: Signs indicative of acute infection were observed in 29 patients according to the results of tissue harmonic imaging ultrasound combined with power Doppler ultrasound while dimercaptosuccinicacid scan revealed abnormal findings in 33 patients. The sensitivity, specificity, positive predictive value and negative predictive value of tissue harmonic imaging combined with power Doppler ultrasound using dimercaptosuccinicacid scintigraphy as the reference method in patients diagnosed with first episode febrile urinary tract infections were calculated as 57.58% (95% confidence interval: 40.81%–72.76%); 62.96% (95% confidence interval: 44.23%–78.47%); 65.52% (95% confidence interval: 52.04%–77%); 54.84% (95% confidence interval: 41.54%–67.52%); respectively. Conclusions: Although current results exhibit inadequate success of power Doppler ultrasound, this practical and radiation-free method may soon be comprise a part of the routine ultrasonographic evaluation of febrile urinary tract infections of childhood if patients are evaluated early and under appropriate sedation. PMID:26265892

  5. Fast-wave Power Flow Along SOL Field Lines In NSTX nd The Associated Power Deposition Profile Across The SOL In Front Of The Antenna

    SciTech Connect

    Perkins, Roy

    2013-06-21

    Fast-wave heating and current drive efficiencies can be reduced by a number of processes in the vicinity of the antenna and in the scrape off layer (SOL). On NSTX from around 25% to more than 60% of the high-harmonic fast-wave power can be lost to the SOL regions, and a large part of this lost power flows along SOL magnetic field lines and is deposited in bright spirals on the divertor floor and ceiling. We show that field-line mapping matches the location of heat deposition on the lower divertor, albeit with a portion of the heat outside of the predictions. The field-line mapping can then be used to partially reconstruct the profile of lost fast-wave power at the midplane in front of the antenna, and the losses peak close to the last closed flux surface (LCFS) as well as the antenna. This profile suggests a radial standing-wave pattern formed by fast-wave propagation in the SOL, and this hypothesis will be tested on NSTX-U. Advanced RF codes must reproduce these results so that such codes can be used to understand this edge loss and to minimize RF heat deposition and erosion in the divertor region on ITER.

  6. 50 CFR 29.21-8 - Electric power transmission line rights-of-way.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 9 2012-10-01 2012-10-01 false Electric power transmission line rights-of... General Regulations § 29.21-8 Electric power transmission line rights-of-way. By accepting a right-of-way for a power transmission line, the applicant thereby agrees and consents to comply with and be...

  7. 50 CFR 29.21-8 - Electric power transmission line rights-of-way.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 9 2013-10-01 2013-10-01 false Electric power transmission line rights-of... General Regulations § 29.21-8 Electric power transmission line rights-of-way. By accepting a right-of-way for a power transmission line, the applicant thereby agrees and consents to comply with and be...

  8. 50 CFR 29.21-8 - Electric power transmission line rights-of-way.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 9 2014-10-01 2014-10-01 false Electric power transmission line rights-of... General Regulations § 29.21-8 Electric power transmission line rights-of-way. By accepting a right-of-way for a power transmission line, the applicant thereby agrees and consents to comply with and be...

  9. 50 CFR 29.21-8 - Electric power transmission line rights-of-way.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Electric power transmission line rights-of... General Regulations § 29.21-8 Electric power transmission line rights-of-way. By accepting a right-of-way for a power transmission line, the applicant thereby agrees and consents to comply with and be...

  10. 50 CFR 29.21-8 - Electric power transmission line rights-of-way.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 8 2011-10-01 2011-10-01 false Electric power transmission line rights-of... General Regulations § 29.21-8 Electric power transmission line rights-of-way. By accepting a right-of-way for a power transmission line, the applicant thereby agrees and consents to comply with and be...

  11. Static air-gap eccentricity fault diagnosis using rotor slot harmonics in line neutral voltage of three-phase squirrel cage induction motor

    NASA Astrophysics Data System (ADS)

    Oumaamar, Mohamed El Kamel; Maouche, Yassine; Boucherma, Mohamed; Khezzar, Abdelmalek

    2017-02-01

    The mixed eccentricity fault detection in a squirrel cage induction motor has been thoroughly investigated. However, a few papers have been related to pure static eccentricity fault and the authors focused on the RSH harmonics presented in stator current. The main objective of this paper is to present an alternative method based on the analysis of line neutral voltage taking place between the supply and the stator neutrals in order to detect air-gap static eccentricity, and to highlight the classification of all RSH harmonics in line neutral voltage. The model of squirrel cage induction machine relies on the rotor geometry and winding layout. Such developed model is used to analyze the impact of the pure static air-gap eccentricity by predicting the related frequencies in the line neutral voltage spectrum. The results show that the line neutral voltage spectrum are more sensitive to the air-gap static eccentricity fault compared to stator current one. The theoretical analysis and simulated results are confirmed by experiments.

  12. A Line Weighted Frequency Droop Controller for Decentralized Enforcement of Transmission Line Power Flow Constraints in Inverter-Based Networks

    SciTech Connect

    Ainsworth, Nathan G; Grijalva, Prof. Santiago

    2013-01-01

    Recent works have shown that networks of voltagesource inverters implementing frequency droop control may be analyzed as consensus-like networks. Based on this understanding, we show that enforcement of network line power flows can be viewed as an edge-preservation problem in a -disk dynamic interaction graph. Inspired by other works solving similar problems in other domains, we propose a line weighted frequency droop controller such that a network of all active buses implementing this controller enforces the specified line power flow constraints without need for communication. We provide simulation results verifying that our proposed controller limits line power to enforce constraints, and otherwise acts as a traditional droop controller.

  13. Harmonic analysis of electrical distribution systems

    SciTech Connect

    1996-03-01

    This report presents data pertaining to research on harmonics of electric power distribution systems. Harmonic data is presented on RMS and average measurements for determination of harmonics in buildings; fluorescent ballast; variable frequency drive; georator geosine harmonic data; uninterruptible power supply; delta-wye transformer; westinghouse suresine; liebert datawave; and active injection mode filter data.

  14. Spherical harmonic analysis of the PSCz galaxy catalogue: redshift distortions and the real-space power spectrum

    NASA Astrophysics Data System (ADS)

    Tadros, H.; Ballinger, W. E.; Taylor, A. N.; Heavens, A. F.; Efstathiou, G.; Saunders, W.; Frenk, C. S.; Keeble, O.; McMahon, R.; Maddox, S. J.; Oliver, S.; Rowan-Robinson, M.; Sutherland, W. J.; White, S. D. M.

    1999-05-01

    We apply the formalism of spherical harmonic decomposition to the galaxy density field of the IRAS PSCz redshift survey. The PSCz redshift survey has almost all-sky coverage and includes IRAS galaxies to a flux limit of 0.6 Jy. Using maximum likelihood methods to examine (to first order) the distortion of the galaxy pattern resulting from redshift coordinates, we have measured the parameter beta=Omega^{0.6}/b. We also simultaneously measure either (a) the undistorted amplitude of perturbations in the galaxy distribution when a parametrized power spectrum is assumed, or (b) the shape and amplitude of the real-space power spectrum if the band-power in a set of passbands is measured in a step-wise fashion. These methods are extensively tested on a series of CDM, Lambda CDM and MDM simulations and are found to be unbiased. We obtain consistent results for the subset of the PSCz catalogue with flux above 0.75 Jy, but inclusion of galaxies to the formal flux limit of the catalogue gives variations which are larger than our internal errors. For the 0.75-Jy catalogue we find, in the case of a parametrized power spectrum, beta=0.58+/-0.26 and the amplitude of the real-space power measured at wavenumber k=0.1h Mpc^-1 is Delta_0.1=0.42+/-0.03. Freeing the shape of the power spectrum we find that beta=0.47+/-0.16 (conditional error) and Delta_0.1=0.47+/-0.03. The shape of the real-space power spectrum is consistent with a Gamma=0.2 CDM-like model, but does not strongly rule out a number of other models. Finally by combining our estimate of the amplitude of galaxy clustering and the distortion parameter we find the amplitude of mass fluctuations on a scale k=0.1h Mpc^-1 is Delta_rho=0.24Omega_0^-0.6, with an uncertainty of 50 per cent.

  15. A skeptic's view of PLR effects in the magnetosphere. [Power Line Radiation

    NASA Technical Reports Server (NTRS)

    Tsurutani, B. T.; Thorne, R. M.

    1981-01-01

    A summary is provided of the current state of knowledge concerning the effects of man-made Power Line Harmonic Radiation (PLR) on the earth's magnetosphere and its energetic particle population. It is generally agreed that PLR is strongly attenuated as it propagates into the outer magnetosphere (outside the plasmasphere) and, other than rare cases where ducting occurs, the emissions either do not manage to propagate to the equatorial plane or are sufficiently reduced in amplitude to be below the sensitivity of currently orbiting plasma wave instrumentation. In either case PLR emissions are too weak to have a significant direct effect on scattering the trapped particle population; any possible effects must be indirect. It has, therefore, been postulated that PLR can act as an 'embryonic emission' for triggering intense whistler mode 'chorus', which then via cyclotron resonant interactions, cause particle pitch-angle scattering. Points of disagreement are related to the geographic distribution of chorus, the chorus starting frequency, the Sunday effect, and PLR effects within the plasmasphere.

  16. New live line tester for porcelain suspension insulators on high-voltage power lines

    SciTech Connect

    Vaillancourt, G.H.; St-Jean, M. ); Bellerive, J.P. ); Jean, C. )

    1994-01-01

    Suspension insulator assemblies known as insulator strings are used in overhead power transmission lines to mechanically support high-voltage conductors while providing adequate insulation to withstand switching and lightning overvoltages. Since the useful life in service of the individual insulator elements making up these strings is hard to predict, they must be verified periodically to insure that adequate line reliability is maintained at all times. Over the years many testing methods have been used for this purpose, each one with its own advantages and disadvantages. Until now at Hydro-Quebec, porcelain insulators had been tested by the buzz method which simply consists of applying a short-circuit to each insulator in a string and listening for a buzz-like sound indicating a good insulator. However, safety considerations that preclude short-circuiting insulators and other disadvantages of that method have led Hydro-Quebec to undertake and complete the development of a new insulator tester. The working principle of this new device is based on the automatic measurement and recording of the electric field along the insulator string which decreases considerably in front of an internally-shorted insulator. The tester is slid along the string while the insulators are counted automatically. The information from tests on up to 200 strings can be stored in the device to be later transferred in a host computer for interpretation and/or permanent storage. The new tester also gives information on voltage distribution along the insulator strings which can be useful for the design of future power transmission lines.

  17. Biological effects of power line fields: New York State Power Lines Project Scientific Advisory Panel: Final report

    SciTech Connect

    Ahlbom, A.; Albert, E.N.; Fraser-Smith, A.C.; Grodzinsky, A.J.; Marron, M.T.; Martin, A.O.; Persinger, M.A.; Shelanski, M.L.; Wolpow, E.R.

    1987-07-01

    The New York State Power Lines Project was established to conduct research and to review the scientific literature to determine whether health hazards of electric and magnetic fields are possible. Particular attention was directed to the fields generated by 765-kV overhead transmission lines. The research program provided support to 16 research groups studying human, animal and isolated cell sensitivity to electric and magnetic fields. No effects were found on reproduction, growth or development. Several studies showed no evidence of genetic or chromosomal damage that might lead to inherited effects or cause cancer. While most measurements of behavior and brain function did not demonstrate changes, some did show changes that were small but consistent. Some of these appear to result from changes in body rhythms, and might interfere with normal sleep patterns. There were also changes in pain responses and in the ability of rats to learn. A more serious concern comes from a study of cancer in children suggesting that children with leukemia and brain cancer are more likely to live in homes where there are elevated 60-Hz magnetic field levels. Although much more research is needed before the question whether the magnetic fields actually cause or promote cancer can be resolved, the basis for such an hypothesis is now established. 159 refs., 12 figs., 7 tabs.

  18. A Novel Ku-Band/Ka-Band and Ka-Band/E-Band Multimode Waveguide Couplers for Power Measurement of Traveling-Wave Tube Amplifier Harmonic Frequencies

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.; Simons, Rainee N.

    2015-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler, fabricated from two dissimilar frequency band waveguides, is capable of isolating power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT) amplifier. Test results from proof-of-concept demonstrations are presented for a Ku-band/Ka-band MDC and a Ka-band/E-band MDC. In addition to power measurements at harmonic frequencies, a potential application of the MDC is in the design of a satellite borne beacon source for atmospheric propagation studies at millimeter-wave (mm-wave) frequencies (Ka-band and E-band).

  19. Harmonic moment dynamics in Laplacian growth.

    PubMed

    Leshchiner, Alexander; Thrasher, Matthew; Mineev-Weinstein, Mark B; Swinney, Harry L

    2010-01-01

    Harmonic moments are integrals of integer powers of z=x+iy over a domain. Here, the domain is an exterior of a bubble of air growing in an oil layer between two horizontal closely spaced plates. Harmonic moments are a natural basis for such Laplacian growth phenomena because, unlike other representations, these moments linearize the zero surface tension problem [S. Richardson, J. Fluid Mech. 56, 609 (1972)], so that all moments except the lowest one (the area of the bubble) are conserved in time. In our experiments, we directly determine the harmonic moments and show that for nonzero surface tension, all moments (except the lowest one) decay in time rather than exhibiting the divergences of other representations. Further, we derive an expression that relates the derivative of the k(th) harmonic moment M(k) to measurable quantities (surface tension, viscosity, the distance between the plates, and a line integral over the contour encompassing the growing bubble). The laboratory observations are in good accord with the expression we derive for dM(k)/dt , which is proportional to the surface tension; thus in the zero surface tension limit, the moments (above k=0) are all conserved, in accord with Richardson's theory. In addition, from the measurements of the time evolution of the harmonic moments we obtain a value for the surface tension that is within 20% of the accepted value. In conclusion, our analysis and laboratory observations demonstrate that an interface dynamics description in terms of harmonic moments is physically realizable and robust.

  20. Design of a high-power, high-gain, 2nd harmonic, 22.848 GHz gyroklystron

    SciTech Connect

    Veale, M.; Purohit, P.; Lawson, W.

    2013-08-15

    In this paper we consider the design of a four-cavity, high-gain K-band gyroklystron experiment for high gradient structure testing. The frequency doubling gyroklystron utilizes a beam voltage of 500 kV and a beam current of 200 A from a magnetron injection gun (MIG) originally designed for a lower-frequency device. The microwave circuit features input and gain cavities in the circular TE{sub 011} mode and penultimate and output cavities that operate at the second harmonic in the TE{sub 021} mode. We investigate the MIG performance and study the behavior of the circuit for different values of perpendicular to parallel velocity ratio (α= V{sub ⊥}/ V{sub z}). This microwave tube is expected to be able to produce at least 20 MW of power in 1μs pulses at a repetition rate of at least 120 Hz. A maximum efficiency of 26% and a large signal gain of 58 dB under zero-drive stable conditions were simulated for a velocity ratio equal to 1.35.

  1. 78 FR 76140 - Extension of Public Comment Period for the Champlain Hudson Power Express Transmission Line...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-16

    ... Extension of Public Comment Period for the Champlain Hudson Power Express Transmission Line Project Draft... Hudson Power Express Transmission Line Project Draft Environmental Impact Statement (DOE/EIS-0447). The... permit to the Applicant, Champlain Hudson Power Express, Inc. (CHPEI), to construct, operate,...

  2. Power conditioning unit for photovoltaic power systems

    NASA Astrophysics Data System (ADS)

    Beghin, G.; Nguyen Phuoc, V. T.

    Operational features and components of a power conditioning unit for interconnecting solar cell module powers with a utility grid are outlined. The two-stage unit first modifies the voltage to desired levels on an internal dc link, then inverts the current in 2 power transformers connected to a vector summation control to neutralize harmonic distortion up to the 11th harmonic. The system operates in parallel with the grid with extra inductors to absorb line-to-line voltage and phase differences, and permits peak power use from the PV array. Reactive power is gained internally, and a power system controller monitors voltages, frequencies, and currents. A booster preregulator adjusts the input voltage from the array to provide voltage regulation for the inverter, and can commutate 450 amps. A total harmonic distortion of less than 5 percent is claimed, with a rating of 5 kVA, 50/60 Hz, 3-phase, and 4-wire.

  3. Power Lines and Crops Can Be Good Neighbors

    SciTech Connect

    2010-08-01

    Two of the Pacific Northwest’s greatest economic assets are its wealth of agriculture and its clean and reliable electricity fueled largely by hydropower. Sometimes the two intersect. Transmission lines carrying electricity to the region’s farms, businesses and homes must, of necessity, span large areas where people grow crops and orchards. To ensure a safe and reliable flow of electricity across these expanses, trees and other vegetation must be managed to certain standards. At the same time, the Bonneville Power Administration — which owns and operates three-quarters of the region’s high-voltage transmission — recognizes the importance of our region’s agricultural bounty. We are committed to working with individuals and agricultural communities to facilitate ongoing land-use activities in transmission rights-of-way as long as those uses are compatible with transmission safety and reliability standards. Our goal with vegetation management is to keep you and your property safe while protecting the reliability of our region’s electricity system. By working together, BPA and landowners can protect the system and public safety.

  4. Measurements of Impedance and Attenuation at CENELEC Bands for Power Line Communications Systems

    PubMed Central

    Cavdar, I. Hakki; Karadeniz, Engin

    2008-01-01

    Power line impedance is a very important parameter on the design of power line communications (PLC) modem architecture. Variations on the impedance of the power line affect the communications circuit performance. In order to determine impedance of the power lines, measurements were carried out in Turkey at frequencies ranging from 10 to 170 kHz, (CENELEC A,B,C,D bands). Measurements were conducted in three categories: rural, urban and the industrial power lines. Experimental results are presented in graphical form. The measured impedances were determined as 3-17 ohms, 1-17 ohms, and 1-21 ohms for rural, urban and the industrial lines, respectively. A set of the formulas between impedance and frequency are developed on the power lines using the regression analysis from the obtained empirical data. Signal attenuations on the power lines in the CENELEC band are also measured for rural, urban and industrial regions. Attenuation measurements are repeated for phase-neutral, phase-ground and the neutral-ground conductors. Signal attenuations are found to be 4-30 dB, for different power lines. To establish validity of obtained results for the design of PLC systems, the results are compared with previous investigations. The effects of some household appliances such as TV, PC, UPS, lighting and cooling systems on the impedances and the attenuations for power line communications systems are observed. Some suggestions and proposals are presented for PLC modem designers. PMID:27873974

  5. Inspection Robot Based Mobile Sensing and Power Line Tracking for Smart Grid

    PubMed Central

    Byambasuren, Bat-erdene; Kim, Donghan; Oyun-Erdene, Mandakh; Bold, Chinguun; Yura, Jargalbaatar

    2016-01-01

    Smart sensing and power line tracking is very important in a smart grid system. Illegal electricity usage can be detected by remote current measurement on overhead power lines using an inspection robot. There is a need for accurate detection methods of illegal electricity usage. Stable and correct power line tracking is a very prominent issue. In order to correctly track and make accurate measurements, the swing path of a power line should be previously fitted and predicted by a mathematical function using an inspection robot. After this, the remote inspection robot can follow the power line and measure the current. This paper presents a new power line tracking method using parabolic and circle fitting algorithms for illegal electricity detection. We demonstrate the effectiveness of the proposed tracking method by simulation and experimental results. PMID:26907274

  6. Inspection Robot Based Mobile Sensing and Power Line Tracking for Smart Grid.

    PubMed

    Byambasuren, Bat-Erdene; Kim, Donghan; Oyun-Erdene, Mandakh; Bold, Chinguun; Yura, Jargalbaatar

    2016-02-19

    Smart sensing and power line tracking is very important in a smart grid system. Illegal electricity usage can be detected by remote current measurement on overhead power lines using an inspection robot. There is a need for accurate detection methods of illegal electricity usage. Stable and correct power line tracking is a very prominent issue. In order to correctly track and make accurate measurements, the swing path of a power line should be previously fitted and predicted by a mathematical function using an inspection robot. After this, the remote inspection robot can follow the power line and measure the current. This paper presents a new power line tracking method using parabolic and circle fitting algorithms for illegal electricity detection. We demonstrate the effectiveness of the proposed tracking method by simulation and experimental results.

  7. [The realization of tracking power-line interference adaptive coherent model base on part FFT].

    PubMed

    Yu, Chao; Li, Gang; Lin, Ling

    2007-08-01

    Adaptive coherent model can be easily implemented and it can simultaneously reject the power-line interference and baseline wander. But the relevancy of the filter's bandwidth at low-frequency and power-line interference limits its application on ECG filtering. A part fast Fourier transform (FFT) algorithm is presented. It is used to track power-line frequency and adjust the sample frequency. Experiments show that the method still rejects interference efficiently despite of the slow fluctuation of power-line frequency.

  8. a Meteorological Risk Assessment Method for Power Lines Based on GIS and Multi-Sensor Integration

    NASA Astrophysics Data System (ADS)

    Lin, Zhiyong; Xu, Zhimin

    2016-06-01

    Power lines, exposed in the natural environment, are vulnerable to various kinds of meteorological factors. Traditional research mainly deals with the influence of a single meteorological condition on the power line, which lacks of comprehensive effects evaluation and analysis of the multiple meteorological factors. In this paper, we use multiple meteorological monitoring data obtained by multi-sensors to implement the meteorological risk assessment and early warning of power lines. Firstly, we generate meteorological raster map from discrete meteorological monitoring data using spatial interpolation. Secondly, the expert scoring based analytic hierarchy process is used to compute the power line risk index of all kinds of meteorological conditions and establish the mathematical model of meteorological risk. By adopting this model in raster calculator of ArcGIS, we will have a raster map showing overall meteorological risks for power line. Finally, by overlaying the power line buffer layer to that raster map, we will get to know the exact risk index around a certain part of power line, which will provide significant guidance for power line risk management. In the experiment, based on five kinds of observation data gathered from meteorological stations in Guizhou Province of China, including wind, lightning, rain, ice, temperature, we carry on the meteorological risk analysis for the real power lines, and experimental results have proved the feasibility and validity of our proposed method.

  9. 18 CFR 12.43 - Power and communication lines and gas pipelines.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Power and communication lines and gas pipelines. 12.43 Section 12.43 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT SAFETY OF WATER...

  10. 18 CFR 12.43 - Power and communication lines and gas pipelines.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Power and communication lines and gas pipelines. 12.43 Section 12.43 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT SAFETY OF WATER...

  11. 18 CFR 12.43 - Power and communication lines and gas pipelines.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Power and communication lines and gas pipelines. 12.43 Section 12.43 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT SAFETY OF WATER...

  12. 18 CFR 12.43 - Power and communication lines and gas pipelines.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Power and communication lines and gas pipelines. 12.43 Section 12.43 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT SAFETY OF WATER...

  13. 18 CFR 12.43 - Power and communication lines and gas pipelines.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Power and communication lines and gas pipelines. 12.43 Section 12.43 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT SAFETY OF WATER...

  14. Millimeter-Gap Magnetically Insulated Transmission Line Power Flow Experiments

    SciTech Connect

    Hutsel, Brian Thomas; Stoltzfus, Brian S.; Fowler, William E.; LeChien, Keith R.; Mazarakis, Michael G.; Moore, James K.; Mulville, Thomas D.; Savage, Mark E.; Stygar, William A.; McKenney, John L.; Jones, Peter A.; MacRunnels, Diego J.; Long, Finis W.; Porter, John L.

    2014-09-01

    An experiment platform has been designed to study vacuum power flow in magnetically insulated transmission lines (MITLs). The platform was driven by the 400-GW Mykonos-V accelerator. The experiments conducted quantify the current loss in a millimeter-gap MITL with respect to vacuum conditions in the MITL for two different gap distances, 1.0 and 1.3 mm. The current loss for each gap was measured for three different vacuum pump down times. As a ride along experiment, multiple shots were conducted with each set of hardware to determine if there was a conditioning effect to increase current delivery on subsequent shots. The experiment results revealed large differences in performance for the 1.0 and 1.3 mm gaps. The 1.0 mm gap resulted in current loss of 40%-60% of peak current. The 1.3 mm gap resulted in current losses of less than 5% of peak current. Classical MITL models that neglect plasma expansion predict that there should be zero current loss, after magnetic insulation is established, for both of these gaps. The experiments result s indicate that the vacuum pressure or pump down time did not have a significant effect on the measured current loss at vacuum pressures between 1e-4 and 1e-5 Torr. Additionally, there was not repeatable evidence of a conditioning effect that reduced current loss for subsequent full-energy shots on a given set of hardware. It should be noted that the experiments conducted likely did not have large loss contributions due to ion emission from the anode due to the relatively small current densi-ties (25-40 kA/cm) in the MITL that limited the anode temperature rise due to ohmic heating. The results and conclusions from these experiments may have limited applicability to MITLs of high current density (>400 kA/cm) used in the convolute and load region of the Z which experience temperature increases of >400° C and generate ion emission from anode surfaces.

  15. Power line emission 50/60 Hz and Schumann resonances observed by microsatellite Chibis-M in the Earth's ionosphere

    NASA Astrophysics Data System (ADS)

    Dudkin, Denys; Pilipenko, Vyacheslav; Dudkin, Fedir; Pronenko, Vira; Klimov, Stanislav

    2015-04-01

    The overhead power lines are the sources of intense wideband electromagnetic (EM) emission, especially in ELF-VLF range, because of significant length (up to a few thousand kilometers) and strong 50/60 Hz currents with noticeable distortion. The radiation efficiency of the power line emission (PLE) increases with the harmonic order, so they are well observed by ground-based EM sensors. However their observations by low orbiting satellites (LEO) are very rare, particularly at basic harmonic 50/60 Hz, because of the ionospheric plasma opacity in ELF band. The Schumann resonance (SR) is the narrow-band EM noise that occurs due to the global thunderstorm activity in the Earth-ionosphere cavity. The first five eigenmodes of the SR are 7.8, 14.3, 20.8, 27.3 and 33.8 Hz and, thus, SR harmonics are also strongly absorbed by the Earth ionosphere. The published numerical simulations show that the penetration depth of such an ELF emission into the Earth's ionosphere is limited to 50-70 km for electric field and 120-240 km for magnetic field. From this follows, that PLE and SR can hardly ever be detected by LEO satellites, i.e. above the F-layer of ionosphere. In spite of this fact, these emissions were recently observed with use of the electric field antennas placed on the satellites C/NOFS (USA) and Chibis-M (Russia). Microsatellite Chibis-M was launched on January 24, 2012, at 23:18:30 UTC from the cargo ship "Progress M-13M" to circular orbit with altitude ~500 km and inclination ~52° . Chibis-M mass is about 40 kg where one third is a scientific instrumentation. The dimensions of the microsatellite case are 0.26x0.26x0.54 m with the outside mounted solar panels, service and scientific instrumentation. The main scientific objective of Chibis-M is the theoretical model verification for the atmospheric gamma-ray bursts. It requires the study of the accompanying EM processes such as the plasma waves produced by the lightning discharges in the VLF band. Chibis-M decayed on 15

  16. 77 FR 38793 - Grand Valley Rural Power Lines, Inc., Yampa Valley Electric Association, Inc., Intermountain...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-29

    ... Energy Regulatory Commission Grand Valley Rural Power Lines, Inc., Yampa Valley Electric Association, Inc., Intermountain Rural Electric Association, Tri-State Generation and Transmission Association, Inc. v. Public... CFR 385.206 and 385.212 (2011), Grand Valley Rural Power Lines, Inc., Yampa Valley...

  17. Multi-MW 22.8 GHz Harmonic Multiplier - RF Power Source for High-Gradient Accelerator R&D

    SciTech Connect

    Jay L. Hirshfield

    2012-07-26

    Electrodynamic and particle simulation studies have been carried out to optimize design of a two-cavity harmonic frequency multiplier, in which a linear electron beam is energized by rotating fields near cyclotron resonance in a TE111 cavity in a uniform magnetic field, and in which the beam then radiates coherently at the nth harmonic into a TEn11 output cavity. Examples are worked out in detail for 7th and 2nd harmonic converters, showing RF-to-RF conversion efficiencies of 45% and 88%, respectively at 19.992 GHz (K-band) and 5.712 GHz (C-band), for a drive frequency of 2.856 GHz. Details are shown of RF infrastructure (S-band klystron, modulator) and harmonic converter components (drive cavity, output cavities, electron beam source and modulator, beam collector) for the two harmonic converters to be tested. Details are also given for the two-frequency (S- and C-band) coherent multi-MW test stand for RF breakdown and RF gun studies.

  18. Research of Characteristics of the Low Voltage Power Line in Underground Coal Mine

    NASA Astrophysics Data System (ADS)

    Wei, Shaoliang; Qin, Shiqun; Gao, Wenchang; Cheng, Fengyu; Cao, Zhongyue

    The power line communications (PLCs) can count on existing electrical connections reaching each corner in the locations where such applications are required, so signal transmission over power lines is nowadays gaining more and more interest for applications like internet. The research of characteristics of the low voltage power line is the fundamental and importance task. This work presents a device to test the characteristics of the low voltage power line. The low voltage power line channel characteristics overground and the channel characteristics underground were tested in using this device. Experiments show that, the characteristics are different between the PLCs channel underground coal mine and the PLC channel overground. Different technology should be adopted to structure the PLCs channel model underground coal mine and transmit high speed digital signal. But how to use the technology better to the high-speed digital communication under coal mine is worth of further studying.

  19. Power Law Subordinacy and Singular Spectra.II. Line Operators

    NASA Astrophysics Data System (ADS)

    Jitomirskaya, Svetlana Ya.; Last, Yoram

    We study Hausdorff-dimensional spectral properties of certain ``whole-line'' quasiperiodic discrete Schrödinger operators by using the extension of the Gilbert-Pearson subordinacy theory that we previously developed in [19].

  20. High-power, single-frequency, continuous-wave second-harmonic-generation of ytterbium fiber laser in PPKTP and MgO:sPPLT.

    PubMed

    Kumar, S Chaitanya; Samanta, G K; Ebrahim-Zadeh, M

    2009-08-03

    Characteristics of high-power, narrow-linewidth, continuous-wave (cw) green radiation obtained by simple single-pass second-harmonic-generation (SHG) of a cw ytterbium fiber laser at 1064 nm in the nonlinear crystals of PPKTP and MgO:sPPLT are studied and compared. Temperature tuning and SHG power scaling up to nearly 10 W for input fundamental power levels up to 30 W are performed. Various contributions to thermal effects in both crystals, limiting the SHG conversion efficiency, are studied. Optimal focusing conditions and thermal management schemes are investigated to maximize SHG performance in MgO:sPPLT. Stable green output power and high spatial beam quality with M(2)<1.33 and M(2)<1.34 is achieved in MgO:sPPLT and PPKTP, respectively.

  1. Second harmonic inversion for ultrasound contrast harmonic imaging.

    PubMed

    Pasovic, Mirza; Danilouchkine, Mike; Faez, Telli; van Neer, Paul L M J; Cachard, Christian; van der Steen, Antonius F W; Basset, Olivier; de Jong, Nico

    2011-06-07

    Ultrasound contrast agents (UCAs) are small micro-bubbles that behave nonlinearly when exposed to an ultrasound wave. This nonlinear behavior can be observed through the generated higher harmonics in a back-scattered echo. In past years several techniques have been proposed to detect or image harmonics produced by UCAs. In these proposed works, the harmonics generated in the medium during the propagation of the ultrasound wave played an important role, since these harmonics compete with the harmonics generated by the micro-bubbles. We present a method for the reduction of the second harmonic generated during nonlinear-propagation-dubbed second harmonic inversion (SHI). A general expression for the suppression signals is also derived. The SHI technique uses two pulses, p' and p″, of the same frequency f(0) and the same amplitude P(0) to cancel out the second harmonic generated by nonlinearities of the medium. Simulations show that the second harmonic is reduced by 40 dB on a large axial range. Experimental SHI B-mode images, from a tissue-mimicking phantom and UCAs, show an improvement in the agent-to-tissue ratio (ATR) of 20 dB compared to standard second harmonic imaging and 13 dB of improvement in harmonic power Doppler.

  2. Design of T-Split Power Divider Using Double Ended Spur-Line DMS

    NASA Astrophysics Data System (ADS)

    Moyra, Tamasi; Parui, Susanta Kumar; Das, Santanu

    2016-09-01

    Power dividers and power combiners are passive microwave components for power dividing and power combining. In this article one T-split equal power divider has been designed by using conventional 50 Ω microstrip line and double ended spur line renamed as defected microstrip structures (DMS). Introducing DMS provides one stop band characteristics, changes the effective inductance and capacitance of the line by increasing effective dielectric constant, reduces the phase velocity and supports slow-wave propagation. Thus, increases the effective line impedance of the microstrip line. Consequently, all passive and active components that are implemented using DMS have a miniaturized size compared to conventional components. In this paper one 3 dB or equal power divider has been designed at 1.6 GHz in the first step. Where, 100 Ω output line is implemented using double ended spur type DMS on conventional 50 Ω microstrip line. In the second step each output port power has been divided equally into 6 dB in the next level of the branch. Design of those dividers are very simple and have wide applications in microwave circuits and feeds of array antennas.

  3. Electric Power Lines : Questions and Answers on Research into Health Effects.

    SciTech Connect

    United States. Bonneville Power Administration.

    1994-05-01

    Most people know that electric power lines, like the wiring in our homes, can cause serious electric shocks if we`re not careful. Many people also want to know whether the electric and magnetic fields (EMF) produced by power lines and other electrical devices cause health effects. The purpose of this booklet is to answer some common questions that the Bonneville Power Administration (BPA) receives about the possible effects of power lines on health. First, some basic electrical terms are defined, and electric and magnetic fields are debed. Next, answers are given to several questions about recent scientific studies. Some important information about electrical safety follows. We then describe how BPA is addressing public concerns about potential health effects of power lines. The last section tells you how to obtain more detailed information about the health and safety issues summarized in this booklet.

  4. Discriminating harmonicity

    NASA Astrophysics Data System (ADS)

    Kidd, Gerald; Mason, Christine R.; Brughera, Andrew; Chiu, Chung-Yiu Peter

    2003-08-01

    Simultaneous tones that are harmonically related tend to be grouped perceptually to form a unitary auditory image. A partial that is mistuned stands out from the other tones, and harmonic complexes with different fundamental frequencies can readily be perceived as separate auditory objects. These phenomena are evidence for the strong role of harmonicity in perceptual grouping and segregation of sounds. This study measured the discriminability of harmonicity directly. In a two interval, two alternative forced-choice (2I2AFC) paradigm, the listener chose which of two sounds, signal or foil, was composed of tones that more closely matched an exact harmonic relationship. In one experiment, the signal was varied from perfectly harmonic to highly inharmonic by adding frequency perturbation to each component. The foil always had 100% perturbation. Group mean performance decreased from greater than 90% correct for 0% signal perturbation to near chance for 80% signal perturbation. In the second experiment, adding a masker presented simultaneously with the signals and foils disrupted harmonicity. Both monaural and dichotic conditions were tested. Signal level was varied relative to masker level to obtain psychometric functions from which slopes and midpoints were estimated. Dichotic presentation of these audible stimuli improved performance by 3-10 dB, due primarily to a release from ``informational masking'' by the perceptual segregation of the signal from the masker.

  5. An algorithm for power line detection and warning based on a millimeter-wave radar video.

    PubMed

    Ma, Qirong; Goshi, Darren S; Shih, Yi-Chi; Sun, Ming-Ting

    2011-12-01

    Power-line-strike accident is a major safety threat for low-flying aircrafts such as helicopters, thus an automatic warning system to power lines is highly desirable. In this paper we propose an algorithm for detecting power lines from radar videos from an active millimeter-wave sensor. Hough Transform is employed to detect candidate lines. The major challenge is that the radar videos are very noisy due to ground return. The noise points could fall on the same line which results in signal peaks after Hough Transform similar to the actual cable lines. To differentiate the cable lines from the noise lines, we train a Support Vector Machine to perform the classification. We exploit the Bragg pattern, which is due to the diffraction of electromagnetic wave on the periodic surface of power lines. We propose a set of features to represent the Bragg pattern for the classifier. We also propose a slice-processing algorithm which supports parallel processing, and improves the detection of cables in a cluttered background. Lastly, an adaptive algorithm is proposed to integrate the detection results from individual frames into a reliable video detection decision, in which temporal correlation of the cable pattern across frames is used to make the detection more robust. Extensive experiments with real-world data validated the effectiveness of our cable detection algorithm.

  6. Lines of development of tower-type solar power plants

    NASA Astrophysics Data System (ADS)

    Henseler, H.-J.

    1981-10-01

    Problem areas in the development of tower-type solar power plants are discussed. The mode of functioning of such plants is briefly reviewed and the economic shortcomings of solar energy devices are summarized. Technical aspects and requirements of the system devices are summarized. Technical aspects and requirements of the system components are detailed, including the reflector, the receiver, the circuit, the tower, and the storage.

  7. Design of replica bit line control circuit to optimize power for SRAM

    NASA Astrophysics Data System (ADS)

    Pengjun, Wang; Keji, Zhou; Huihong, Zhang; Daohui, Gong

    2016-12-01

    A design of a replica bit line control circuit to optimize power for SRAM is proposed. The proposed design overcomes the limitations of the traditional replica bit line control circuit, which cannot shut off the word line in time. In the novel design, the delay of word line enable and disable paths are balanced. Thus, the word line can be opened and shut off in time. Moreover, the chip select signal is decomposed, which prevents feedback oscillations caused by the replica bit line and the replica word line. As a result, the switch power caused by unnecessary discharging of the bit line is reduced. A 2-kb SRAM is fully custom designed in an SMIC 65-nm CMOS process. The traditional replica bit line control circuit and the new replica bit line control circuit are used in the designed SRAM, and their performances are compared with each other. The experimental results show that at a supply voltage of 1.2 V, the switch power consumption of the memory array can be reduced by 53.7%. Project supported by the Zhejiang Provincial Natural Science Foundation of China (No. LQ14F040001), the National Natural Science Foundation of China (Nos. 61274132, 61234002, 61474068), and the K. C. Wong Magna Fund in Ningbo University.

  8. Enhancement of Second-Harmonic Power Due to Self-Construction of an Anti-Guide Structure in a Thin-Film Waveguide of a Nonlinear-Optical Photoconducting Polymer

    NASA Astrophysics Data System (ADS)

    Sassa, Takafumi; Umegaki, Shinsuke

    1998-04-01

    A theoretical analysis, to explain the increase of the Cerenkov-radiation-type second-harmonic power with time in a thin-film waveguide of a nonlinear-optical photoconducting polymer, is given. An anti-guide structure, which confines both a fundamental wave and its second-harmonic wave, is gradually constructed by reorientation of the nonlinear-optical chromophores within the fundamental beam width in the thin-film polymer. The space-charge field formed by the initially weak second-harmonic wave itself causes the reorientation.

  9. Electric Power Lines : Questions and Answers on Research into Health Effects.

    SciTech Connect

    United States. Bonneville Power Administration.

    1993-11-01

    Most people know that electric power lines, like the wiring in our homes, can cause serious electric shocks if we`re not careful. Many people also want to know whether the electric and magnetic fields (EMF) produced by power lines and other electrical devices cause health effects. The purpose of this pamphlet is to answer some common questions that the Bonneville Power Administration (BPA) receives about the possible effects of power lines on health. (BPA is the Pacific Northwest`s Federal electric power marketing agency.) First, some basic electrical terms are defined, and electric and magnetic fields are described. Next, answers are given to several questions about recent scientific studies. We then describe how BPA is addressing public concerns raised by these studies. Some important information about electrical safety follows. The last section tells you how to obtain more detailed information about the health and safety issues summarized in this pamphlet.

  10. On-line diagnostic system for power generators

    SciTech Connect

    Skormin, V.A.; Goodenough, G.S.; Huber, R.K.

    1996-12-31

    A novel approach to diagnostics of a power generator is developed. It utilizes readily available data acquired by the existing computer-based monitoring/control system. Diagnostic procedures detect various trends in the generator data and interpret these trends in the generator data and interpret these trends as changes in the generator performance caused by incipient failures. Results of trend analyses, subjected to statistical validation, facilitate failure prediction and identification thus providing the justification for service when needed. The procedures are incorporated in a diagnostic system implemented in a PC interfaced with the existing VAX-based process monitoring and control system. The diagnostic system provides graphical display of the diagnostic messages.

  11. Extended range harmonic filter

    NASA Technical Reports Server (NTRS)

    Jankowski, H.; Geia, A. J.; Allen, C. C.

    1973-01-01

    Two types of filters, leaky-wall and open-guide, are combined into single component. Combination gives 10 db or greater additional attenuation to fourth and higher harmonics, at expense of increasing loss of fundamental frequency by perhaps 0.05 to 0.08 db. Filter is applicable to all high power microwave transmitters, but is especially desirable for satellite transmitters.

  12. Analysis of crustal structure of Venus utilizing residual Line-of-Sight (LOS) gravity acceleration and surface topography data. A trial of global modeling of Venus gravity field using harmonic spline method

    NASA Technical Reports Server (NTRS)

    Fang, Ming; Bowin, Carl

    1992-01-01

    To construct Venus' gravity disturbance field (or gravity anomaly) with the spacecraft-observer line of site (LOS) acceleration perturbation data, both a global and a local approach can be used. The global approach, e.g., spherical harmonic coefficients, and the local approach, e.g., the integral operator method, based on geodetic techniques are generally not the same, so that they must be used separately for mapping long wavelength features and short wavelength features. Harmonic spline, as an interpolation and extrapolation technique, is intrinsically flexible to both global and local mapping of a potential field. Theoretically, it preserves the information of the potential field up to the bound by sampling theorem regardless of whether it is global or local mapping, and is never bothered with truncation errors. The improvement of harmonic spline methodology for global mapping is reported. New basis functions, a singular value decomposition (SVD) based modification to Parker & Shure's numerical procedure, and preliminary results are presented.

  13. Avian behavior and mortality at power lines in coastal South Carolina

    USGS Publications Warehouse

    Savereno, A.J.; Savereno, L.A.; Boettcher, R.; Haig, S.M.

    1996-01-01

    We compared avian behavior and mortality associated with two 115-kV transmission lines on the central South Carolina coast during 3,392 hours of observation from May 1991 through May 1994. One line was marked with 30-cm-diameter yellow aviation markers. The second line was unmarked, but was similar in most other aspects. We conducted ground searches (n = 445) beneath each line year-round to document avian mortality due to power-line collisions. At marked lines, birds that approached at line height changed behavior more at unmarked lines (P< 0.001), and fewer crossed between static and conductor wires. Collision rate was 53% lower at marked than unmarked lines. Among collisions at both sites, 82% of birds collided with static wires. Based on observed collisions and carcass recoveries, wading birds particularly appeared to be at risk. We concluded that aviation markers were effective at increasing line visibility and reducing collisions and recommend marking static wires of power lines in potentially sensitive areas.

  14. 29 CFR 1926.1410 - Power line safety (all voltages)-equipment operations closer than the Table A zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Power line safety (all voltages)-equipment operations... FOR CONSTRUCTION Cranes and Derricks in Construction § 1926.1410 Power line safety (all voltages... an energized power line is prohibited, except where the employer demonstrates that all of...

  15. 29 CFR 1926.1410 - Power line safety (all voltages)-equipment operations closer than the Table A zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... accessories) to a complete stop; wind conditions; degree of sway in the power line; lighting conditions, and... 29 Labor 8 2012-07-01 2012-07-01 false Power line safety (all voltages)-equipment operations... FOR CONSTRUCTION Cranes and Derricks in Construction § 1926.1410 Power line safety (all...

  16. 29 CFR 1926.1410 - Power line safety (all voltages)-equipment operations closer than the Table A zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... accessories) to a complete stop; wind conditions; degree of sway in the power line; lighting conditions, and... 29 Labor 8 2013-07-01 2013-07-01 false Power line safety (all voltages)-equipment operations... FOR CONSTRUCTION Cranes and Derricks in Construction § 1926.1410 Power line safety (all...

  17. 29 CFR 1926.1410 - Power line safety (all voltages)-equipment operations closer than the Table A zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... accessories) to a complete stop; wind conditions; degree of sway in the power line; lighting conditions, and... 29 Labor 8 2011-07-01 2011-07-01 false Power line safety (all voltages)-equipment operations... FOR CONSTRUCTION Cranes and Derricks in Construction § 1926.1410 Power line safety (all...

  18. Circuit and Method for Communication Over DC Power Line

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J.; Prokop, Norman F.

    2007-01-01

    A circuit and method for transmitting and receiving on-off-keyed (OOK) signals with fractional signal-to-noise ratios uses available high-temperature silicon- on-insulator (SOI) components to move computational, sensing, and actuation abilities closer to high-temperature or high-ionizing radiation environments such as vehicle engine compartments, deep-hole drilling environments, industrial control and monitoring of processes like smelting, and operations near nuclear reactors and in space. This device allows for the networking of multiple, like nodes to each other and to a central processor. It can do this with nothing more than the already in-situ power wiring of the system. The device s microprocessor allows it to make intelligent decisions within the vehicle operational loop and to effect control outputs to its associated actuators. The figure illustrates how each node converts digital serial data to OOK 18-kHz in transmit mode and vice-versa in receive mode; though operations at lower frequencies or up to a megahertz are within reason using this method and these parts. This innovation s technique modulates a DC power bus with millivolt-level signals through a MOSFET (metal oxide semiconductor field effect transistor) and resistor by OOK. It receives and demodulates this signal from the DC power bus through capacitive coupling at high temperature and in high ionizing radiation environments. The demodulation of the OOK signal is accomplished by using an asynchronous quadrature detection technique realized by a quasi-discrete Fourier transform through use of the quadrature components (0 and 90 phases) of the carrier frequency as generated by the microcontroller and as a function of the selected crystal frequency driving its oscillator. The detected signal is rectified using an absolute-value circuit containing no diodes (diodes being non-operational at high temperatures), and only operational amplifiers. The absolute values of the two phases of the received signal

  19. Period-doubling bifurcation in two-stage power factor correction converters using the method of incremental harmonic balance and Floquet theory

    NASA Astrophysics Data System (ADS)

    Wang, Fa-Qiang; Zhang, Hao; Ma, Xi-Kui

    2012-02-01

    In this paper, period-doubling bifurcation in a two-stage power factor correction converter is analyzed by using the method of incremental harmonic balance (IHB) and Floquet theory. A two-stage power factor correction converter typically employs a cascade configuration of a pre-regulator boost power factor correction converter with average current mode control to achieve a near unity power factor and a tightly regulated post-regulator DC—DC Buck converter with voltage feedback control to regulate the output voltage. Based on the assumption that the tightly regulated post-regulator DC—DC Buck converter is represented as a constant power sink and some other assumptions, the simplified model of the two-stage power factor correction converter is derived and its approximate periodic solution is calculated by the method of IHB. And then, the stability of the system is investigated by using Floquet theory and the stable boundaries are presented on the selected parameter spaces. Finally, some experimental results are given to confirm the effectiveness of the theoretical analysis.

  20. A second harmonic geomagnetic field line resonance at the inner edge of the plasma sheet - GEOS 1, ISEE 1, and ISEE 2 observations

    NASA Technical Reports Server (NTRS)

    Hughes, W. J.; Grard, R. J. L.

    1984-01-01

    A description is provided of observations made by GEOS 1, ISEE 1, and ISEE 2 of a hydromagnetic wave with a period approximately 90 s observed near 0200 LT between L = 9 and L = 6, close to the measured inner boundary of the plasma sheet. The wave magnetic oscillations perpendicular to and along the ambient field had similar amplitudes. Using primarily the transverse magnetic components, it is shown that the wave is a second harmonic resonance of the local geomagnetic field lines. ISEE 1 and 2 observed the opposite sense of polarization for about 30 min, although the spacecraft were separated by only 9 min in their orbit; this remarkable feature cannot be explained by either a stationary spatial boundary or a simple temporal boundary but could result from a rapid movement of the resonant region. It is argued that the most likely energy source is bounce resonance with medium energy (approximately 5 keV) ions. Calculations of the wave Poynting vector at ISEE 1 support this conclusion.

  1. Modification of atmospheric DC fields by space charge from high-voltage power lines

    NASA Astrophysics Data System (ADS)

    Fews, A. P.; Wilding, R. J.; Keitch, P. A.; Holden, N. K.; Henshaw, D. L.

    Corona ion discharge is responsible for a flux of small ions emanating from an overhead power line capable of modifying the ambient electrical environment. The ensuing space charge can be detected as a change in magnitude of the earth's natural DC electric field at ground level. DC field mill meters were used to measure the vertical component of electric fields upwind and downwind of 132 and 400 kV power lines. Evidence of space charge blowing downwind of power lines was observed in 21 out of 22 cases. Time series measurements recorded in the downwind direction were highly variable with fields of higher magnitude compared to those recorded upwind. Model DC field profiles were used to estimate a lower limit to the space charge density at body height arising from power lines. The average lower limit was ˜3000 cm -3 excess unipolar charges. The result suggests that between 10% and 60% of outdoor aerosols gain excess charge by the attachment of corona ions. Downwind of a 400 kV line in Somerset that was prone to excessive corona discharge, the estimated mean lower limit excess unipolar space charge density was ˜6000 cm -3, suggesting that up to 100% of aerosols gain excess charge by the attachment of corona ions. Investigations into the time variation of DC electric fields around motorways and the natural diurnal variation of the earth's DC field were also undertaken and compared to the power line data. The results show that the power line time series are clearly distinguishable from typical examples of both types of field variation, demonstrating the relatively highly charged atmospheres that generally exist around high-voltage power lines. The results are of potential public health concern, because they suggest a degree of aerosol charging that may result in a non-trivial increase in lung deposition of inhaled pollutant aerosols.

  2. Residual thermal stress of a mounted KDP crystal after cooling and its effects on second harmonic generation of a high-average-power laser

    NASA Astrophysics Data System (ADS)

    Su, Ruifeng; Liu, Haitao; Liang, Yingchun; Yu, Fuli

    2017-01-01

    Thermal problems are huge challenges for solid state lasers that are interested in high output power, cooling of the nonlinear optics is insufficient to completely solve the problem of thermally induced stress, as residual thermal stress remains after cooling, which is first proposed, to the best of our knowledge. In this paper a comprehensive model incorporating principles of thermodynamics, mechanics and optics is proposed, and it is used to study the residual thermal stress of a mounted KDP crystal after cooling process from mechanical perspective, along with the effects of the residual thermal stress on the second harmonic generation (SHG) efficiency of a high-average-power laser. Effects of the structural parameters of the mounting configuration of the KDP crystal on the residual thermal stress are characterized, as well as the SHG efficiency. The numerical results demonstrate the feasibility of solving the problems of residual thermal stress from the perspective on structural design of mounting configuration.

  3. Effects of conductor sag on spatial distribution of power line magnetic field

    SciTech Connect

    Mamishev, A.V.; Nevels, R.D.; Russell, B.D.

    1996-07-01

    Traditional extremely low frequency (ELF) magnetic field computation techniques assume that the current carrying power line conductors are straight horizontal wires. This assumption results in a model whose magnetic fields are distorted from those produced in reality. An exact solution and an approximation are proposed for modeling magnetic fields produced by the sagged conductors of power lines, by taking advantage of the fact that the equation of the catenary exactly describes the line sag. The proposed approaches differ in the required computational burden and in the precision of the results. A field mapping measurement example illustrates the applicability and the need for this analysis. The relative importance of the catenary effect is discussed.

  4. Widom line and noise-power spectral analysis of a supercritical fluid.

    PubMed

    Han, Sungho; Yu, Clare C

    2012-05-01

    We have performed extensive molecular dynamics simulations to study noise-power spectra of density and potential energy fluctuations of a Lennard-Jones model of a fluid in the supercritical region. Emanating from the liquid-vapor critical point, there is a locus of isobaric specific heat maxima, called the Widom line, which is often regarded as an extension of the liquid-vapor coexistence line. Our simulation results show that the noise-power spectrum of the density fluctuations on the Widom line of the liquid-vapor transition exhibits three distinct 1/f^{γ} behaviors with exponents γ=0, 1.2, and 2, depending on the frequency f. We find that the intermediate frequency region with an exponent γ∼ 1 appears as the temperature approaches the Widom temperature from above or below. On the other hand, we do not find three distinct regions of 1/f^{γ} in the power spectrum of the potential energy fluctuations on the Widom line. Furthermore, we find that the power spectra of both the density and potential energy fluctuations at low frequency have a maximum on the Widom line, suggesting that the noise power can provide an alternative signature of the Widom line.

  5. A study of electric power transmission lines for use on the lunar surface

    NASA Technical Reports Server (NTRS)

    Gordon, Lloyd B.; Gaustad, Krista L.

    1991-01-01

    Analytical models have been developed to study the operating characteristics of electrical transmission lines for use on the lunar surface. Important design considerations for a transmission line operating on the lunar surface are mass, temperature, and efficiency. Transmission line parameters which impact these considerations include voltage, power loss, and waveform. The electrical and thermal models developed are used to calculate transmission line mass, size, and temperature as a function of voltage, geometry, waveform, location, and efficiency. The analyses include ac and dc for above and below ground operation. Geometries studied include a vacuum-insulated, two-wire transmission line and a solid-dielectric insulated, coaxial transmission line. A brief discussion of design considerations and the models developed is followed by results for parameter studies for both dc and ac transmission lines.

  6. Harmonics and instabilities in switching circuits

    SciTech Connect

    Lasseter, R.H.; Dobson, I.; Jalali, S.G. . Coll. of Engineering)

    1993-05-01

    Over the last couple of years there has been significant activity in the development of Flexible AC Transmission Systems (FACTS). Much of this work has been directed towards advanced series compensation (ASC) systems based on a Thyristor Controlled Reactor (TCR) connected in parallel with a fixed capacitor. This results in a controllable series impedance element for use in transmission systems. FACTS devices generate harmonics which interact with the transmission system causing voltage distortions. These distortions can change the operation of such circuits. The authors have found new instabilities in both FACTS and static VAR circuits in which switching times change suddenly, or bifurcate as a system parameter varies slowly. The switching time bifurcation instabilities are explained and their mechanisms are illustrated by both analysis and simulation. The TCR is a periodically operated, nonlinear circuit which may be studied using a Poincare map. The Poincare map is computed and a simple formula for its Jacobian matrix is derived. This formula which describes the stability of the steady state periodic operation of the circuit is used to demonstrate that conventional bifurcations do not occur in this TCR example. The harmonic coupling solution method as developed by Bohmann and Lasseter has been extensively used to compute the steady state solutions of the TCR circuits. In this method, Fourier techniques are used to calculate the system harmonics. By expressing the TCR voltage and current as a Fourier series, a TCR harmonic admittance matrix is constructed and incorporated into a power system providing a general method of computing the power system harmonics. The authors have extended this method to single phase line commutated converters and shown how much circuit may have highly nonlinear and unexpected behavior.

  7. Do power lines and protected areas present a catch-22 situation for Cape vultures (Gyps coprotheres)?

    PubMed

    Phipps, W Louis; Wolter, Kerri; Michael, Michael D; MacTavish, Lynne M; Yarnell, Richard W

    2013-01-01

    Cape vulture Gyps coprotheres populations have declined across their range due to multiple anthropogenic threats. Their susceptibility to fatal collisions with the expanding power line network and the prevalence of carcasses contaminated with illegal poisons and other threats outside protected areas are thought to be the primary drivers of declines in southern Africa. We used GPS-GSM units to track the movements and delineate the home ranges of five adult (mean ±SD minimum convex polygon area = 121,655±90,845 km(2)) and four immature (mean ±SD minimum convex polygon area = 492,300±259,427 km(2)) Cape vultures to investigate the influence of power lines and their use of protected areas. The vultures travelled more than 1,000 km from the capture site and collectively entered five different countries in southern Africa. Their movement patterns and core foraging ranges were closely associated with the spatial distribution of transmission power lines and we present evidence that the construction of power lines has allowed the species to extend its range to areas previously devoid of suitable perches. The distribution of locations of known Cape vulture mortalities caused by interactions with power lines corresponded to the core ranges of the tracked vultures. Although some of the vultures regularly roosted at breeding colonies located inside protected areas the majority of foraging activity took place on unprotected farmland. Their ability to travel vast distances very quickly and the high proportion of time they spend in the vicinity of power lines and outside protected areas make Cape vultures especially vulnerable to negative interactions with the expanding power line network and the full range of threats across the region. Co-ordinated cross-border conservation strategies beyond the protected area network will therefore be necessary to ensure the future survival of threatened vultures in Africa.

  8. Do Power Lines and Protected Areas Present a Catch-22 Situation for Cape Vultures (Gyps coprotheres)?

    PubMed Central

    Phipps, W. Louis; Wolter, Kerri; Michael, Michael D.; MacTavish, Lynne M.; Yarnell, Richard W.

    2013-01-01

    Cape vulture Gyps coprotheres populations have declined across their range due to multiple anthropogenic threats. Their susceptibility to fatal collisions with the expanding power line network and the prevalence of carcasses contaminated with illegal poisons and other threats outside protected areas are thought to be the primary drivers of declines in southern Africa. We used GPS-GSM units to track the movements and delineate the home ranges of five adult (mean ±SD minimum convex polygon area  =  121,655±90,845 km2) and four immature (mean ±SD minimum convex polygon area  =  492,300±259,427 km2) Cape vultures to investigate the influence of power lines and their use of protected areas. The vultures travelled more than 1,000 km from the capture site and collectively entered five different countries in southern Africa. Their movement patterns and core foraging ranges were closely associated with the spatial distribution of transmission power lines and we present evidence that the construction of power lines has allowed the species to extend its range to areas previously devoid of suitable perches. The distribution of locations of known Cape vulture mortalities caused by interactions with power lines corresponded to the core ranges of the tracked vultures. Although some of the vultures regularly roosted at breeding colonies located inside protected areas the majority of foraging activity took place on unprotected farmland. Their ability to travel vast distances very quickly and the high proportion of time they spend in the vicinity of power lines and outside protected areas make Cape vultures especially vulnerable to negative interactions with the expanding power line network and the full range of threats across the region. Co-ordinated cross-border conservation strategies beyond the protected area network will therefore be necessary to ensure the future survival of threatened vultures in Africa. PMID:24137496

  9. Power lines, roads, and avian nest survival: effects on predator identity and predation intensity.

    PubMed

    DeGregorio, Brett A; Weatherhead, Patrick J; Sperry, Jinelle H

    2014-05-01

    1 Anthropogenic alteration of landscapes can affect avian nest success by influencing the abundance, distribution, and behavior of predators. Understanding avian nest predation risk necessitates understanding how landscapes affect predator distribution and behavior. 2 From a sample of 463 nests of 17 songbird species, we evaluated how landscape features (distance to forest edge, unpaved roads, and power lines) influenced daily nest survival. We also used video cameras to identify nest predators at 137 nest predation events and evaluated how landscape features influenced predator identity. Finally, we determined the abundance and distribution of several of the principal predators using surveys and radiotelemetry. 3 Distance to power lines was the best predictor of predator identity: predation by brown-headed cowbirds (Molothrus ater), corvids (Corvus sp. and Cyanocitta cristata), racers (Coluber constrictor), and coachwhips (Masticophis flagellum) increased with proximity to power lines, whereas predation by rat snakes (Elaphe obsoleta) and raptors decreased. In some cases, predator density may reliably indicate nest predation risk because racers, corvids, and cowbirds frequently used power line right-of-ways. 4 Of five bird species with enough nests to analyze individually, daily nest survival of only indigo buntings (Passerina cyanea) decreased with proximity to power lines, despite predation by most predators at our site being positively associated with power lines. For all nesting species combined, distance to unpaved road was the model that most influenced daily nest survival. This pattern is likely a consequence of rat snakes, the locally dominant nest predator (28% of predation events), rarely using power lines and associated areas. Instead, rat snakes were frequently associated with road edges, indicating that not all edges are functionally similar. 5 Our results suggest that interactions between predators and landscape features are likely to be specific to

  10. Bird behavior and mortality in relation to power lines in prairie habitats

    USGS Publications Warehouse

    Faanes, C.A.

    1987-01-01

    Research was conducted to determine the magnitude of avian mortality caused by power transmission lines in prairie habitats during the two spring and two fall migration periods between July 1980 and May 1982. Searches for dead birds were made at least twice weekly during each migration period. Study sites were selected to include 'worst-case' situations involving potentially large concentrations of birds.In total, 633 dead birds were found beneath 9.6 km of power lines. About 81% of the birds were found during fall migration. Removal of birds by scavengers was of minor, although local, importance, and observer error in finding birds was greatest in areas of dense vegetation. Total kill was estimated at 1,332 birds.Data were gathered on more than 7,000 bird flights observed in the vicinity of the power lines. Sixty-eight percent of the birds did not respond to the presence of the power lines. Flaring and climbing over the conductor or overhead ground wire occurred in about 25% of the flights. One hundred nine birds in 82 flocks were observed to collide with a power line. Of these birds, 87% flared to climb over the power line before colliding. The overhead ground wire was responsible for most deaths, as 102 of 109 birds collided with it.Whereas none of the mortality observed was considered to be biologically significant at the particular sites examined, the cumulative effect of mortality sustained from collisions with power lines may be important, particularly to populations of rare or endangered birds.

  11. Measurements and Modeling of Noise on 22.9-kV Medium-Voltage Underground Power Line for Broadband Power Line Communication

    NASA Astrophysics Data System (ADS)

    Lee, Seungjoon; Shin, Donghwan; Kim, Yonghwa; Lee, Jaejo; Eom, Kihwan

    This paper proposed the measurements and modeling of noise on the 22.9-kV Medium-Voltage (MV) underground power distribution cable for Broadband Power Line Communication (BPLC). The proposed measurement system was composed of inductive coupler and Digital Phosphor Oscilloscope (DPO). The measurement noise data was obtained from thirty-two pad mounted transformers in the test field located in Choji area of Ansan city. After conducting analysis of noise characteristics in time and frequency domain, the noise model are presented. In order to analyze the noise in frequency domain, Power Spectral Density (PSD) was computed with empirical data using Welch's method. The modeling of the power line noise at each frequency carried out using Cumulative Probability Distribution (CPD) of the noise power. It compared with common Cumulative Distribution Functions (CDF) of Nakagami-m distribution, Gaussian distribution, Gamma distribution. In low frequency range, gamma distribution was fitted with the CPD. Nakagami-m distribution provides a good fitting to the noise CPD above 20MHz frequency range.

  12. Predictive model of avian electrocution risk on overhead power lines.

    PubMed

    Dwyer, J F; Harness, R E; Donohue, K

    2014-02-01

    Electrocution on overhead power structures negatively affects avian populations in diverse ecosystems worldwide, contributes to the endangerment of raptor populations in Europe and Africa, and is a major driver of legal action against electric utilities in North America. We investigated factors associated with avian electrocutions so poles that are likely to electrocute a bird can be identified and retrofitted prior to causing avian mortality. We used historical data from southern California to identify patterns of avian electrocution by voltage, month, and year to identify species most often killed by electrocution in our study area and to develop a predictive model that compared poles where an avian electrocution was known to have occurred (electrocution poles) with poles where no known electrocution occurred (comparison poles). We chose variables that could be quantified by personnel with little training in ornithology or electric systems. Electrocutions were more common at distribution voltages (≤ 33 kV) and during breeding seasons and were more commonly reported after a retrofitting program began. Red-tailed Hawks (Buteo jamaicensis) (n = 265) and American Crows (Corvus brachyrhynchos) (n = 258) were the most commonly electrocuted species. In the predictive model, 4 of 14 candidate variables were required to distinguish electrocution poles from comparison poles: number of jumpers (short wires connecting energized equipment), number of primary conductors, presence of grounding, and presence of unforested unpaved areas as the dominant nearby land cover. When tested against a sample of poles not used to build the model, our model distributed poles relatively normally across electrocution-risk values and identified the average risk as higher for electrocution poles relative to comparison poles. Our model can be used to reduce avian electrocutions through proactive identification and targeting of high-risk poles for retrofitting.

  13. A novel high-power dual-band coupled-line Gysel power divider with impedance-transforming functions.

    PubMed

    Wang, Weimin; Wu, Yongle; Liu, Yuanan

    2014-01-01

    A novel coupled-line structure is proposed to design dual-band and high-power Gysel power dividers with inherent impedance-transforming functions. Based on traditional even- and odd-mode technique, the analytical design methods in closed-form formula are obtained and the accurate electrical parameters analysis is presented. Due to the usage of coupled-line sections, more design-parameter freedom and a wider frequency-ratio operation range for this kind of dual-band Gysel powder divider are obtained. Several numerical examples are designed and calculated to demonstrate flexible dual-band applications with different impedance-transforming functions. A practical microstrip power divider operating at 2 GHz and 3.2 GHz is designed, fabricated, and measured. The good agreement between the calculated and measured results verifies our proposed circuit structure and analytical design approach.

  14. A Novel High-Power Dual-Band Coupled-Line Gysel Power Divider with Impedance-Transforming Functions

    PubMed Central

    Wang, Weimin; Liu, Yuanan

    2014-01-01

    A novel coupled-line structure is proposed to design dual-band and high-power Gysel power dividers with inherent impedance-transforming functions. Based on traditional even- and odd-mode technique, the analytical design methods in closed-form formula are obtained and the accurate electrical parameters analysis is presented. Due to the usage of coupled-line sections, more design-parameter freedom and a wider frequency-ratio operation range for this kind of dual-band Gysel powder divider are obtained. Several numerical examples are designed and calculated to demonstrate flexible dual-band applications with different impedance-transforming functions. A practical microstrip power divider operating at 2 GHz and 3.2 GHz is designed, fabricated, and measured. The good agreement between the calculated and measured results verifies our proposed circuit structure and analytical design approach. PMID:24764768

  15. The contribution of radio-frequency rectification to field-aligned losses of high-harmonic fast wave power to the divertor in the National Spherical Torus eXperiment

    SciTech Connect

    Perkins, R. J. Hosea, J. C.; Jaworski, M. A.; Diallo, A.; Bell, R. E.; Bertelli, N.; Gerhardt, S.; Kramer, G. J.; LeBlanc, B. P.; Phillips, C. K.; Podestà, M.; Roquemore, L.; Taylor, G.; Wilson, J. R.; Ahn, J.-W.; Gray, T. K.; McLean, A.; Sabbagh, S.

    2015-04-15

    The National Spherical Torus eXperiment (NSTX) can exhibit a major loss of high-harmonic fast wave (HHFW) power along scrape-off layer (SOL) field lines passing in front of the antenna, resulting in bright and hot spirals on both the upper and lower divertor regions. One possible mechanism for this loss is RF sheaths forming at the divertors. Here, we demonstrate that swept-voltage Langmuir probe characteristics for probes under the spiral are shifted relative to those not under the spiral in a manner consistent with RF rectification. We estimate both the magnitude of the RF voltage across the sheath and the sheath heat flux transmission coefficient in the presence of the RF field. Although precise comparison between the computed heat flux and infrared (IR) thermography cannot yet be made, the computed heat deposition compares favorably with the projections from IR camera measurements. The RF sheath losses are significant and contribute substantially to the total SOL losses of HHFW power to the divertor for the cases studied. This work will guide future experimentation on NSTX-U, where a wide-angle IR camera and a dedicated set of coaxial Langmuir probes for measuring the RF sheath voltage directly will quantify the contribution of RF sheath rectification to the heat deposition from the SOL to the divertor.

  16. Measurements of the Ech Power and of the Transmission Line Losses on Diii-D

    NASA Astrophysics Data System (ADS)

    Cengher, M.; Lohr, J.; Gorelov, I. A.; Grosnickle, W. H.; Ponce, D.; Johnson, P.

    2009-04-01

    The measurement of the power injected by the electron cyclotron heating (ECH) system in the DIII-D tokamak is a critical requirement for analysis of experiments, for tuning the gyrotrons for maximum power and efficiency, for tracking long-term operational trends and for providing a warning of problems with the system. The ECH system at General Atomics consists of six 110 GHz, 1 MW class gyrotrons. The rf power generated by each gyrotron is determined from calorimetry, using the relevant temperature and flow measurements from the cooling circuits of cavity, matching optics unit and dummy loads. The rf pulse length and time dependence are measured using an rf monitor at the first miter bend in the transmission line. The direct measurement of the efficiencies of four of the transmission lines was performed using a high power, small dummy load (SDL) placed alternately in 2 positions of each DIII-D waveguide line, at accessible points close the beginning and the end of each line. Total losses in the transmission lines range from 21.2% to 30.7%. Experimental results are compared to theoretical predictions of the performance of the components and waveguide lines.

  17. Childhood cancer and exposure to corona ions from power lines: an epidemiological test.

    PubMed

    Swanson, J; Bunch, K J; Vincent, T J; Murphy, M F G

    2014-12-01

    We previously reported an association between childhood leukaemia in Britain and proximity of the child's address at birth to high-voltage power lines that declines from the 1960s to the 2000s. We test here whether a 'corona-ion hypothesis' could explain these results. This hypothesis proposes that corona ions, atmospheric ions produced by power lines and blown away from them by the wind, increase the retention of airborne pollutants in the airways when breathed in and hence cause disease. We develop an improved model for calculating exposure to corona ions, using data on winds from meteorological stations and considering the whole length of power line within 600 m of each subject's address. Corona-ion exposure is highly correlated with proximity to power lines, and hence the results parallel the elevations in leukaemia risk seen with distance analyses. But our model explains the observed pattern of leukaemia rates around power lines less well than straightforward distance measurements, and ecological considerations also argue against the hypothesis. This does not disprove the corona-ion hypothesis as the explanation for our previous results, but nor does it provide support for it, or, by extension, any other hypothesis dependent on wind direction.

  18. A Measurement and Power Line Communication System Design for Renewable Smart Grids

    NASA Astrophysics Data System (ADS)

    Kabalci, E.; Kabalci, Y.

    2013-10-01

    The data communication over the electric power lines can be managed easily and economically since the grid connections are already spread around all over the world. This paper investigates the applicability of Power Line Communication (PLC) in an energy generation system that is based on photovoltaic (PV) panels with the modeling study in Matlab/Simulink. The Simulink model covers the designed PV panels, boost converter with Perturb and Observe (P&O) control algorithm, full bridge inverter, and the binary phase shift keying (BPSK) modem that is utilized to transfer the measured data over the power lines. This study proposes a novel method to use the electrical power lines not only for carrying the line voltage but also to transmit the measurements of the renewable energy generation plants. Hence, it is aimed at minimizing the additional monitoring costs such as SCADA, Ethernet-based or GSM based systems by using the proposed technique. Although this study is performed with solar power plants, the proposed model can be applied to other renewable generation systems. Consequently, the usage of the proposed technique instead of SCADA or Ethernet-based systems eliminates additional monitoring costs.

  19. High-power 355 nm third-harmonic generation with effective walk-off compensation of LBO

    NASA Astrophysics Data System (ADS)

    Yan, Xingpeng; Liu, Qiang; Pei, Chuang; Wang, Dongsheng; Gong, Mali

    2014-04-01

    Walk-off compensation using wedged cut type-II LBO was investigated theoretically and experimentally. An algorithm is proposed to find the optimized wedged cut angle to compensate the walk-off effect completely. Using a pulsed Nd:Y V O4 MOPA laser as the fundamental frequency infrared (IR) source, 36.3 W 355 nm frequency converted ultraviolet (UV) light was obtained using an optimized wedged cut type-II LBO for walk-off compensated third-harmonic generation (THG), giving a conversion efficiency of 37.1% from IR to UV. A comparative experiment using a conventional cut type-II LBO was also implemented. The results indicate that optimized wedged cutting of type-II LBO is an effective approach for walk-off compensation in efficient THG. The output performance of angle and temperature tuning for wedged cut type-II LBO was also investigated.

  20. Transmission line design for a power distribution system at 20 kHz for aircraft

    NASA Technical Reports Server (NTRS)

    Zelby, L. W.; Mathes, J. B.; Shawver, J. W.

    1986-01-01

    A low inductance, low characteristic impedance transmission line was designed for a 20 kHz power distribution system. Several different conductor configurations were considered: strip lines, interdigitated metal ribbons, and standard insulated wires in multiwire configurations (circular and rectangular cylindrical arrangements). The final design was a rectangular arrangement of multiple wires of the same gauge with alternating polarities from wire to wire. This offered the lowest inductance per unit length (on the order of several nanohenries/meter) and the lowest characteristic impedance (on the order of one Ohm). Standard multipin connectors with gold-plated elements were recommended with this transmission line, the junction boxes to be internally connected with flat metal ribbons for low inductance, and the line to be constructed in sections of suitable length. Computer programs for the calculation of inductance of multiwire lines and of capacitances of strip lines were developed.

  1. Electric Power Lines : Questions and Answers on Research into Health Effects.

    SciTech Connect

    United States. Bonneville Power Administration.

    1995-06-01

    Most people know that electric power lines, like the wiring in our homes, can cause serious electric shocks if we`re not careful. Many people also want to know whether the EMF (electric and magnetic fields) produced by power lines and other electrical devices affect our health. Although no adverse health effects of electric power EMF have been confirmed, there is continued scientific uncertainty about this issue. Research on EMF is ongoing throughout the world. The purpose of this booklet is to answer some common questions that the BPA (Bonneville Power Administration) receives about the possible effects of power lines on health. First, some basic electrical terms are defined, and electric and magnetic fields are debed. Next, answers are given to several questions about recent scientific studies. Some important information about electrical safety follows. We then describe how BPA is addressing public concerns about potential health effects of power lines. The last section tells you how to obtain more detailed information about the health and safety issues summarized in this booklet.

  2. High-power ultraviolet 278 nm laser from fourth-harmonic generation of a Nd:YAG laser in CsB3O5.

    PubMed

    Wang, Zhichao; Yang, Feng; Zhang, Guochun; Bo, Yong; Liu, Shanshan; Xie, Shiyong; Xu, Yiting; Zong, Nan; Li, Fangqin; Liu, Biaolong; Xu, Jialin; Peng, Qinjun; Zhang, Jingyuan; Cui, Dafu; Wu, Yicheng; Xu, Zuyan

    2012-06-15

    We demonstrate a high-power UV 278 nm laser by fourth-harmonic generation (FHG) of a 1112 nm Nd:YAG laser in a nonlinear optical (NLO) crystal CsB3O5 (CBO) for the first time, to our best knowledge. A 30 W level diode-pumped Q-switched Nd:YAG laser at 1112 nm with beam quality factor M2=1.2 was used as the fundamental light source at a pulse width of 500 ns. With an LiB3O5 crystal, the 1112 nm laser was first frequency-doubled to 556 nm with an average output power of 13.5 W. It was then frequency doubled again in a CBO crystal to obtain the FHG output at 278 nm. The maximum average output power of the 278 nm laser is up to 1.5 W. The results demonstrated that CBO crystal is a promising NLO material for UV high-power lasers below 300 nm.

  3. Nonlinear femtosecond pump-probe spectroscopy using a power-encoded soliton delay line.

    PubMed

    Saint-Jalm, Sarah; Andresen, Esben Ravn; Bendahmane, Abdelkrim; Kudlinski, Alexandre; Rigneault, Hervé

    2016-01-01

    We show femtosecond time-resolved nonlinear pump-probe spectroscopy using a fiber soliton as the probe pulse. Furthermore, we exploit soliton dynamics to record an entire transient trace with a power-encoded delay sweep. The power-encoded delay line takes advantage of the dependency of the soliton trajectory in the (λ,z) space upon input power; the difference in accumulated group delay between trajectories converts a fast power sweep into a fast delay sweep. We demonstrate the concept by performing transient absorption spectroscopy in a test sample and validate it against a conventional pump-probe setup.

  4. An LSPR fiber optic sensor based on in-line micro-holes fabricated by a second harmonic 400nm femtosecond laser

    NASA Astrophysics Data System (ADS)

    Shiraishi, Masahiko; Goya, Kenji; Seki, Atsushi; Watanabe, Kazuhiro

    2016-02-01

    In this study, we have proposed a novel type of localized surface plasmon resonance (LSPR) fiber optic sensor based on in-line/pico-liter micro-holes which can be experimentally fabricated into the fiber waveguide by using a second harmonic 400 nm femtosecond laser. A repetitive pulse train of 1 kHz with a pulse width of 350 fs was irradiated onto a MMGI fiber optic to make three holes that penetrate through the fiber core and work as spectroscopic-microfluidic flow cells. In order to induce the interaction between transmitted light and gold nanoparticles (GNPs) adhered on the inner surface of the flow cells, micro-holes were designed to be the width of approximately 50 μm, along a direction perpendicular to an optical axis of an optical fiber. GNPs with approximately 100 nm of particle diameter adhered onto the inner surface according to 3-aminopropyltriethoxy silane treatment. The transmitted light through the micro-holes was obtained by optical instruments consisted of a white light source and an optical spectrum analyzer. In order to obtain the reference spectrum, the optical spectrum was acquired before dipping the sensor into the GNPs solution. After 30 min of immersing the sensor portion into the GNPs solution, the optical spectrum was also obtained. The reference spectrum which was considered as the baseline, was set to zero and then, the absorbance spectrum was calculated. The absorbance peak at a wavelength of 537 nm occurred in an air condition in the sensing area, which seemed like the resonance peak based on the LSPR.

  5. Passive wide spectrum harmonic filter for adjustable speed drives in oil and gas industry

    NASA Astrophysics Data System (ADS)

    Al Jaafari, Khaled Ali

    Non-linear loads such as variable speed drives constitute the bulky load of oil and gas industry power systems. They are widely used in driving induction and permanent magnet motors for variable speed applications. That is because variable speed drives provide high static and dynamic performance. Moreover, they are known of their high energy efficiency and high motion quality, and high starting torque. However, these non-linear loads are main sources of current and voltage harmonics and lower the quality of electric power system. In fact, it is the six-pulse and twelve-pulse diode and thyristor rectifiers that spoil the AC power line with the dominant harmonics (5th, 7th, 11th). They provide DC voltage to the inverter of the variable speed drives. Typical problems that arise from these harmonics are Harmonic resonances', harmonic losses, interference with electronic equipment, and line voltage distortion at the Point of Common Coupling (PCC). Thus, it is necessary to find efficient, reliable, and economical harmonic filters. The passive filters have definite advantage over active filters in terms of components count, cost and reliability. Reliability and maintenance is a serious issue in drilling rigs which are located in offshore and onshore with extreme operating conditions. Passive filters are tuned to eliminate a certain frequency and therefore there is a need to equip the system with more than one passive filter to eliminate all unwanted frequencies. An alternative solution is Wide Spectrum Harmonic passive filter. The wide spectrum harmonic filters are becoming increasingly popular in these applications and found to overcome some of the limitations of conventional tuned passive filter. The most important feature of wide spectrum harmonic passive filters is that only one capacitor is required to filter a wide range of harmonics. Wide spectrum filter is essentially a low-pass filter for the harmonic at fundamental frequency. It can also be considered as a

  6. 85Rb D1-Line Coherent-Population-Trapping Atomic Clock for Low-Power Operation

    NASA Astrophysics Data System (ADS)

    Goka, Shigeyoshi

    2010-06-01

    A 85Rb D1-line coherent-population-trapping (CPT) atomic clock with a natural-mixture Rb gas cell is demonstrated. D1-line excitation can generate a larger CPT resonance amplitude, and the choice of 85Rb rather than conventional 87Rb is because of its lower ground-state hyperfine-splitting frequency. The frequency deviation for the D1 line was measured using the same experimental setup as that for the D2 line except for the vertical-cavity surface-emitting laser (VCSEL) wavelength and RF power. In the case of D1-line excitation, the CPT resonance amplitude was 1.5 times that for the D2 line, and the light shift sensitivity was one-half that for the D2 line. The Allan standard deviations for the 85Rb D1 line, estimated from the frequency deviations, are <2.5×10-12 per day. In addition, the required RF is 1.5 GHz and its power is only -8.0 dBm.

  7. 85Rb D1-Line Coherent-Population-Trapping Atomic Clock for Low-Power Operation

    NASA Astrophysics Data System (ADS)

    Shigeyoshi Goka,

    2010-06-01

    A 85Rb D1-line coherent-population-trapping (CPT) atomic clock with a natural-mixture Rb gas cell is demonstrated. D1-line excitation can generate a larger CPT resonance amplitude, and the choice of 85Rb rather than conventional 87Rb is because of its lower ground-state hyperfine-splitting frequency. The frequency deviation for the D1 line was measured using the same experimental setup as that for the D2 line except for the vertical-cavity surface-emitting laser (VCSEL) wavelength and RF power. In the case of D1-line excitation, the CPT resonance amplitude was 1.5 times that for the D2 line, and the light shift sensitivity was one-half that for the D2 line. The Allan standard deviations for the 85Rb D1 line, estimated from the frequency deviations, are <2.5× 10-12 per day. In addition, the required RF is 1.5 GHz and its power is only -8.0 dBm.

  8. Visual based navigation for power line inspection by using virtual environments

    NASA Astrophysics Data System (ADS)

    Cerón, Alexander; Mondragón, Iván. F.; Prieto, Flavio

    2015-01-01

    Power line inspection is an important task for the maintenance of electrical infrastructure. UAVs (Unmanned aerial vehicle) can be very useful in the inspection process because the high costs of obtaining images of power lines from different perspectives and the logistic problems of manned flights. The use of the power line as a reference for navigation can be difficult because the different backgrounds, we consider the use of the tower as a reference in order to improve the orientation of the UAV respect to the electrical grid. In this work we generate a process for navigation based in tower detection. The navigation is performed by using the information extracted from a frontal camera in a visual control scheme and validated in virtual environments.

  9. A system for tranmitting low frequency analog signals over ac power lines

    DOEpatents

    Baker, S.P.; Durall, R.L.; Haynes, H.D.

    1987-07-30

    A system for transmitting low frequency analog signals over ac power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an ac power line. The modulation signal frequency range is selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the ac power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal. 4 figs.

  10. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-01-01

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  11. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-09-05

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  12. Design of an Ultra-Efficient GaN High Power Amplifier for Radar Front-Ends Using Active Harmonic Load-Pull

    NASA Technical Reports Server (NTRS)

    Thrivikraman, Tushar; Hoffman, James

    2012-01-01

    This work presents a new measurement technique, mixed-signal active harmonic load-pull (MSALP) developed by Anterverta-mw in partnership with Maury Microwave, that allows for wide-band ultra-high efficiency amplifiers to be designed using GaN technology. An overview of the theory behind active load-pull is presented and why load-pull is important for high-power device characterization. In addition, an example procedure is presented that outlines a methodology for amplifier design using this measurement system. Lastly, measured results of a 10W GaN amplifier are presented. This work aims to highlight the benefit of using this sophisticated measurement systems for to optimize amplifier design for real radar waveforms that in turn will simplify implementation of space-based radar systems

  13. Refining Estimates of Bird Collision and Electrocution Mortality at Power Lines in the United States

    PubMed Central

    Loss, Scott R.; Will, Tom; Marra, Peter P.

    2014-01-01

    Collisions and electrocutions at power lines are thought to kill large numbers of birds in the United States annually. However, existing estimates of mortality are either speculative (for electrocution) or based on extrapolation of results from one study to all U.S. power lines (for collision). Because national-scale estimates of mortality and comparisons among threats are likely to be used for prioritizing policy and management strategies and for identifying major research needs, these estimates should be based on systematic and transparent assessment of rigorously collected data. We conducted a quantitative review that incorporated data from 14 studies meeting our inclusion criteria to estimate that between 12 and 64 million birds are killed each year at U.S. power lines, with between 8 and 57 million birds killed by collision and between 0.9 and 11.6 million birds killed by electrocution. Sensitivity analyses indicate that the majority of uncertainty in our estimates arises from variation in mortality rates across studies; this variation is due in part to the small sample of rigorously conducted studies that can be used to estimate mortality. Little information is available to quantify species-specific vulnerability to mortality at power lines; the available literature over-represents particular bird groups and habitats, and most studies only sample and present data for one or a few species. Furthermore, additional research is needed to clarify whether, to what degree, and in what regions populations of different bird species are affected by power line-related mortality. Nonetheless, our data-driven analysis suggests that the amount of bird mortality at U.S. power lines is substantial and that conservation management and policy is necessary to reduce this mortality. PMID:24991997

  14. Refining estimates of bird collision and electrocution mortality at power lines in the United States.

    PubMed

    Loss, Scott R; Will, Tom; Marra, Peter P

    2014-01-01

    Collisions and electrocutions at power lines are thought to kill large numbers of birds in the United States annually. However, existing estimates of mortality are either speculative (for electrocution) or based on extrapolation of results from one study to all U.S. power lines (for collision). Because national-scale estimates of mortality and comparisons among threats are likely to be used for prioritizing policy and management strategies and for identifying major research needs, these estimates should be based on systematic and transparent assessment of rigorously collected data. We conducted a quantitative review that incorporated data from 14 studies meeting our inclusion criteria to estimate that between 12 and 64 million birds are killed each year at U.S. power lines, with between 8 and 57 million birds killed by collision and between 0.9 and 11.6 million birds killed by electrocution. Sensitivity analyses indicate that the majority of uncertainty in our estimates arises from variation in mortality rates across studies; this variation is due in part to the small sample of rigorously conducted studies that can be used to estimate mortality. Little information is available to quantify species-specific vulnerability to mortality at power lines; the available literature over-represents particular bird groups and habitats, and most studies only sample and present data for one or a few species. Furthermore, additional research is needed to clarify whether, to what degree, and in what regions populations of different bird species are affected by power line-related mortality. Nonetheless, our data-driven analysis suggests that the amount of bird mortality at U.S. power lines is substantial and that conservation management and policy is necessary to reduce this mortality.

  15. Numerical simulation of overvoltage caused by lightning on aerial power lines, including the corona effect

    NASA Astrophysics Data System (ADS)

    Ahcene, Z.; Bernard, G.

    1981-12-01

    A corona effect analog model is studied, and the influence of surges due to lightning on power lines is discussed. The effect of a lightning strike on lines with and without guard cables was simulated. Results show that the surge is very strongly damped as it travels away from the strike point. The corona effect lengthens front times and dampens the high frequency components of the propagated waves.

  16. Long integral temperature Brillouin sensor for off- shore wind energy power supply lines

    NASA Astrophysics Data System (ADS)

    Quintela, M. A.; Ullán, A.; Quintela, A.; Galindez, C.; Perez-Herrera, R. A.; López-Amo, M.; Lopez-Higuera, J. M.

    2011-05-01

    A hybrid Erbium-Brillouin fiber laser sensor to measure the temperature along 22 km fiber is proposed and experimentally demonstrated. A multi-line laser oscillation is induced by the Brillouin gain of different concatenated transducer fiber sections placed in the ring cavity. Integral temperature measurements of each fiber section are obtained through each laser line. This sensor can be used to monitor the temperature of off-shore wind energy power cables.

  17. 29 CFR 1926.1407 - Power line safety (up to 350 kV)-assembly and disassembly.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... so that it is in view of the operator and (except for overhead gantry and tower cranes) at least two... Cranes and Derricks in Construction § 1926.1407 Power line safety (up to 350 kV)—assembly and disassembly...) Assembly/disassembly below power lines prohibited. No part of a crane/derrick, load line, or...

  18. 29 CFR 1926.1407 - Power line safety (up to 350 kV)-assembly and disassembly.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... so that it is in view of the operator and (except for overhead gantry and tower cranes) at least two... Cranes and Derricks in Construction § 1926.1407 Power line safety (up to 350 kV)—assembly and disassembly...) Assembly/disassembly below power lines prohibited. No part of a crane/derrick, load line, or...

  19. 29 CFR 1926.1407 - Power line safety (up to 350 kV)-assembly and disassembly.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... so that it is in view of the operator and (except for overhead gantry and tower cranes) at least two... Cranes and Derricks in Construction § 1926.1407 Power line safety (up to 350 kV)—assembly and disassembly...) Assembly/disassembly below power lines prohibited. No part of a crane/derrick, load line, or...

  20. 29 CFR 1926.1407 - Power line safety (up to 350 kV)-assembly and disassembly.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... so that it is in view of the operator and (except for overhead gantry and tower cranes) at least two... Cranes and Derricks in Construction § 1926.1407 Power line safety (up to 350 kV)—assembly and disassembly...) Assembly/disassembly below power lines prohibited. No part of a crane/derrick, load line, or...

  1. On the application of a machine learning technique to fault diagnosis of power distribution lines

    SciTech Connect

    Togami, Masato; Abe, Norihiro; Kitahashi, T.; Ogawa, Harunao

    1995-10-01

    This paper presents one method for fault diagnosis of power distribution lines by using a decision tree. The conventional method, using a decision tree, applies only to discrete attribute values. To apply it to fault diagnosis of power distribution lines, in practice it must be revised in order to treat attributes whose values range over certain widths. This is because the sensor value or attribute value varies owing to the resistance of the fault point or is influenced by noise. The proposed method is useful when the attribute value has such a property, and it takes into consideration the cost of acquiring the information and the probability of the occurrence of a fault.

  2. Comparison of charged nanoparticle concentrations near busy roads and overhead high-voltage power lines.

    PubMed

    Jayaratne, E R; Ling, X; Morawska, L

    2015-09-01

    Overhead high-voltage power lines are known sources of corona ions. These ions rapidly attach to aerosols to form charged particles in the environment. Although the effect of ions and charged particles on human health is largely unknown, much attention has focused on the increasing exposure as a result of the expanding power network in urban residential areas. However, it is not widely known that a large number of charged particles in urban environments originate from motor vehicle emissions. In this study, for the first time, we compare the concentrations of charged nanoparticles near busy roads and overhead power lines. We show that large concentrations of both positive and negative charged nanoparticles are present near busy roadways and that these concentrations commonly exceed those under high-voltage power lines. We estimate that the concentration of charged nanoparticles found near two freeways carrying around 120 vehicles per minute exceeded the corresponding maximum concentrations under two corona-emitting overhead power lines by as much as a factor of 5. The difference was most pronounced when a significant fraction of traffic consisted of heavy-duty diesel vehicles which typically have high particle and charge emission rates.

  3. Magnet power supply control of the NSLS VUV and x-ray storage rings transfer lines

    SciTech Connect

    Klein, J.D.; Ramamoorthy, S.; Singh, O.; Smith, J.D.

    1985-01-01

    The transfer lines for NSLS VUV and x-ray storage rings have been split. New power supplies have been incorporated with existing ones. The existing microprocessor system has been upgraded in order to control the additional functions. This system expands the input/output port of the microprocessor to an addressable serial/parallel link to each magnet power supply. The implementation of this system will be discussed.

  4. Modified DSTATCOM Topology with Reduced DC Link Voltage for Reactive and Harmonic Power Compensation of Unbalanced Nonlinear Load in Distribution System

    NASA Astrophysics Data System (ADS)

    Geddada, Nagesh; Karanki, Srinivas B.; Mishra, Mahesh K.

    2014-06-01

    This paper proposes a modified four-leg distribution static compensator (DSTATCOM) topology for compensation of unbalanced and nonlinear loads in three-phase four-wire distribution system. DSTATCOM, connected in parallel to the load, supplies reactive and harmonic powers demanded by unbalanced nonlinear loads. In this proposed topology, the voltage source inverter (VSI) of DSTATCOM is connected to point of common coupling (point of interconnection of source, load, DSTATCOM) through interface inductor and series capacitance, unlike the conventional topology which consists of interface inductor alone. Load compensation with a lower value of input DC link voltage of VSI is possible in this modified topology compared to conventional topology. A comparative study on modified and conventional topologies in terms of voltage rating of inverter power switches, switching losses in VSI and power rating of input DC capacitor of VSI is presented. The detailed design aspects of DC link capacitor and interface series capacitor are also presented. The reference filter currents are generated using instantaneous symmetrical component theory and are tracked using hysteresis current control technique. A detailed simulation study is carried out, to compare the compensation performances of conventional, modified topologies using PSCAD simulator and experimental studies are done to validate the simulation results.

  5. In-Containment Signal Acquisition and Data Transmission via Power Lines within High Dose Areas of Nuclear Power Plants

    SciTech Connect

    Mueller Steffen; Wibbing Sascha; Weigel Robert; Koelpin Alexander; Dennerlein, Juergen; Janke, Iryna; Weber, Johannes

    2015-07-01

    Signal acquisition and data transmission for innovative sensor systems and networks inside the containment of nuclear power plants (NPPs) is still a challenge with respect to safety, performance, reliability, availability, and costs. This especially applies to equipment upgrades for existing plants, special measurements, but also for new builds. This paper presents a novel method for efficient and cost-effective sensor signal acquisition and data transmission via power lines, in order to cope with the disadvantages of common system architectures that often suffer from poor signal integrity due to raw data transmissions via long cables, huge efforts and costs for installation, and low flexibility with respect to maintenance and upgrades. A transmitter-receiver architecture is proposed that allows multiplexing of multiple sensor inputs for unidirectional point-to-point transmission by superimposing information signals on existing AC or DC supply lines, but also on active and inactive sensor wires, or spare cables, using power line communication (PLC) technology. Based on commercial off-the-shelf (COTS) electronic parts, a radiation hard transmitter hardware is designed to operate in harsh environment within the containment during full plant operation. The system's modular approach allows application specific trade-offs between redundancy and throughput regarding data transmission, as well as various sensor input front-ends which are compatible with state of the art systems. PLC technology eliminates the need for costly installation of additional cables and wall penetrations, while providing a complementary and diverse communication technology for upgrades of existing systems. At the receiver side in low dose areas, signals are extracted from the power line, demodulated, and de-multiplexed, in order to regain the original sensor signal information and provide it either in analog or digital output format. Successful laboratory qualification tests, field trails, and a

  6. The effect analysis of strain rate on power transmission tower-line system under seismic excitation.

    PubMed

    Tian, Li; Wang, Wenming; Qian, Hui

    2014-01-01

    The effect analysis of strain rate on power transmission tower-line system under seismic excitation is studied in this paper. A three-dimensional finite element model of a transmission tower-line system is created based on a real project. Using theoretical analysis and numerical simulation, incremental dynamic analysis of the power transmission tower-line system is conducted to investigate the effect of strain rate on the nonlinear responses of the transmission tower and line. The results show that the effect of strain rate on the transmission tower generally decreases the maximum top displacements, but it would increase the maximum base shear forces, and thus it is necessary to consider the effect of strain rate on the seismic analysis of the transmission tower. The effect of strain rate could be ignored for the seismic analysis of the conductors and ground lines, but the responses of the ground lines considering strain rate effect are larger than those of the conductors. The results could provide a reference for the seismic design of the transmission tower-line system.

  7. High precision ultrasonic guided wave technique for inspection of power transmission line

    NASA Astrophysics Data System (ADS)

    Cheng, Jun; Qiu, Jinhao; Ji, Hongli; Wang, Enrong; Takagi, Toshiyuki; Uchimoto, Tetsuya

    2017-01-01

    Due to the merits of high inspection speed and long detecting distance, Ultrasonic Guided Wave(UGW) method has been commonly applied to the on-line maintenance of power transmission line. However, the guided wave propagation in this structure is very complicated, leading to the unfavorable defect localization accuracy. Aiming at this situation, a high precision UGW technique for inspection of local surface defect in power transmission line is proposed. The technique is realized by adopting a novel segmental piezoelectric ring transducer and transducer mounting scheme, combining with the comprehensive characterization of wave propagation and circumferential defect positioning with multiple piezoelectric elements. Firstly, the propagation path of guided waves in the multi-wires of transmission line under the proposed technique condition is investigated experimentally. Next, the wave velocities are calculated by dispersion curves and experiment test respectively, and from comparing of the two results, the guided wave mode propagated in transmission line is confirmed to be F(1,1) mode. Finally, the axial and circumferential positioning of local defective wires in transmission line are both achieved, by using multiple piezoelectric elements to surround the stands and send elastic waves into every single wire. The proposed research can play a role of guiding the development of highly effective UGW method and detecting system for multi-wire transmission line.

  8. The Effect Analysis of Strain Rate on Power Transmission Tower-Line System under Seismic Excitation

    PubMed Central

    Wang, Wenming

    2014-01-01

    The effect analysis of strain rate on power transmission tower-line system under seismic excitation is studied in this paper. A three-dimensional finite element model of a transmission tower-line system is created based on a real project. Using theoretical analysis and numerical simulation, incremental dynamic analysis of the power transmission tower-line system is conducted to investigate the effect of strain rate on the nonlinear responses of the transmission tower and line. The results show that the effect of strain rate on the transmission tower generally decreases the maximum top displacements, but it would increase the maximum base shear forces, and thus it is necessary to consider the effect of strain rate on the seismic analysis of the transmission tower. The effect of strain rate could be ignored for the seismic analysis of the conductors and ground lines, but the responses of the ground lines considering strain rate effect are larger than those of the conductors. The results could provide a reference for the seismic design of the transmission tower-line system. PMID:25105157

  9. Bias-field controlled phasing and power combination of gyromagnetic nonlinear transmission lines.

    PubMed

    Reale, D V; Bragg, J-W B; Gonsalves, N R; Johnson, J M; Neuber, A A; Dickens, J C; Mankowski, J J

    2014-05-01

    Gyromagnetic Nonlinear Transmission Lines (NLTLs) generate microwaves through the damped gyromagnetic precession of the magnetic moments in ferrimagnetic material, and are thus utilized as compact, solid-state, frequency agile, high power microwave (HPM) sources. The output frequency of a NLTL can be adjusted by control of the externally applied bias field and incident voltage pulse without physical alteration to the structure of the device. This property provides a frequency tuning capability not seen in many conventional e-beam based HPM sources. The NLTLs developed and tested are mesoband sources capable of generating MW power levels in the L, S, and C bands of the microwave spectrum. For an individual NLTL the output power at a given frequency is determined by several factors including the intrinsic properties of the ferrimagnetic material and the transmission line structure. Hence, if higher power levels are to be achieved, it is necessary to combine the outputs of multiple NLTLs. This can be accomplished in free space using antennas or in a transmission line via a power combiner. Using a bias-field controlled delay, a transient, high voltage, coaxial, three port, power combiner was designed and tested. Experimental results are compared with the results of a transient COMSOL simulation to evaluate combiner performance.

  10. Bias-field controlled phasing and power combination of gyromagnetic nonlinear transmission lines

    SciTech Connect

    Reale, D. V. Bragg, J.-W. B.; Gonsalves, N. R.; Johnson, J. M.; Neuber, A. A.; Dickens, J. C.; Mankowski, J. J.

    2014-05-15

    Gyromagnetic Nonlinear Transmission Lines (NLTLs) generate microwaves through the damped gyromagnetic precession of the magnetic moments in ferrimagnetic material, and are thus utilized as compact, solid-state, frequency agile, high power microwave (HPM) sources. The output frequency of a NLTL can be adjusted by control of the externally applied bias field and incident voltage pulse without physical alteration to the structure of the device. This property provides a frequency tuning capability not seen in many conventional e-beam based HPM sources. The NLTLs developed and tested are mesoband sources capable of generating MW power levels in the L, S, and C bands of the microwave spectrum. For an individual NLTL the output power at a given frequency is determined by several factors including the intrinsic properties of the ferrimagnetic material and the transmission line structure. Hence, if higher power levels are to be achieved, it is necessary to combine the outputs of multiple NLTLs. This can be accomplished in free space using antennas or in a transmission line via a power combiner. Using a bias-field controlled delay, a transient, high voltage, coaxial, three port, power combiner was designed and tested. Experimental results are compared with the results of a transient COMSOL simulation to evaluate combiner performance.

  11. INSTRUMENTS AND METHODS OF INVESTIGATION: Generation of high-order harmonics of high-power lasers in plasmas produced under irradiation of solid target surfaces by a prepulse

    NASA Astrophysics Data System (ADS)

    Ganeev, Rashid A.

    2009-01-01

    Research on high-order harmonic generation in laser-produced plasmas is reviewed. We analyze the conditions for the generation of harmonics (up to the 101st order, λ = 7.9 nm) in the propagation of laser radiation through a weakly ionized plasma prepared by irradiating the surfaces of different targets with a laser prepulse. We discuss the findings of investigations into the resonance intensity enhancement of individual harmonics in a number of plasma formations, which have demonstrated a substantial increase in the conversion efficiency in the plateau region of the harmonic-order distribution (in particular, of the 13th harmonic in indium plasmas with the efficiency 10-4). We review the results of investigations of harmonic generation in nanoparticle-containing plasmas. Different techniques for increasing the intensity and order of the generated harmonics are discussed.

  12. In-Containment Signal Conditioning and Transmission via Power Lines within High Dose Rate Areas of Nuclear Power Plants

    SciTech Connect

    Mueller, Steffen; Weigel, Robert; Koelpin, Alexander; Dennerlein, Juergen; Janke, Iryna; Weber, Johannes

    2015-07-01

    Signal conditioning and transmission for sensor systems and networks within the containment of nuclear power plants (NPPs) still poses a challenge to engineers, particularly in the case of equipment upgrades for existing plants, temporary measurements, decommissioning of plants, but also for new builds. This paper presents an innovative method for efficient and cost-effective instrumentation within high dose rate areas inside the containment. A transmitter-receiver topology is proposed that allows simultaneous, unidirectional point-to-point transmission of multiple sensor signals by superimposing them on existing AC or DC power supply cables using power line communication (PLC) technology. Thereby the need for costly installation of additional cables and containment penetrations is eliminated. Based on commercial off-the-shelf (COTS) electronic parts, a radiation hard transmitter is designed to operate in harsh environment within the containment during full plant operation. Hardware modularity of the transmitter allows application specific tradeoffs between redundancy and channel bandwidth. At receiver side in non-radiated areas, signals are extracted from the power line, demodulated, and provided either in analog or digital output format. Laboratory qualification tests and field test results within a boiling water reactor (BWR) are validating the proof of concept of the proposed system. (authors)

  13. Direct and nearby lightning strike interaction with test power distribution lines

    NASA Astrophysics Data System (ADS)

    Schoene, Jens Daniel

    The interaction of direct and nearby rocket-triggered lightning with two unenergized three-phase power distribution lines of about 800 m length was studied at the International Center for Lightning Research and Testing in Florida. A horizontally-configured line was tested in 1999 and 2000, a vertically-configured line in 2001, 2002, and 2003, and a vertically-configured line with overhead ground wire in 2004. All lines were equipped with arresters and, additionally, in 2003, the vertical line had a polemounted transformer. During the 2000, 2001, and 2002 direct strike experiments, arresters frequently failed, but there was no arrester failures either during the 2003 direct strike experiment when the transformer was on the line or during the 2004 direct strike experiment when the lightning current was injected into the overhead ground wire. All line configurations except the one tested in 2004 commonly exhibited flashovers. The division of return stroke currents for the vertically-configured line was initially similar to the division on the horizontally-configured line (that is, the arresters closest to the strike point conducted the bulk of the impulsive current). After some tens of microseconds the currents in all arresters on the vertically-configured line equalized, while the close arrester currents on the horizontally-configured line still conducted significantly more current than the remote arresters. The lightning current division for direct strikes to a phase conductor is successfully modeled with the Electromagnetic Transient Program (EMTP) for the vertically-configured line and, if the residual voltage of the close arresters is reduced by 20%, successfully modeled for the horizontally-configured line. Currents on the vertically-configured line induced by nearby lightning strikes were measured and compared to results calculated using the LIOV-EMTP96 code. It was found that during a lightning strike 11 m from a grounded line pole, a significant fraction of

  14. Evaluation of line focus solar central power systems. Volume II. Systems evaluation

    SciTech Connect

    Not Available

    1980-03-15

    An evaluation was completed to ascertain the applicability of line focus technologies to electrical power applications and to compare their performance and cost potential with point focus central receiver power systems. It was concluded that although the high temperature line focus (SRI) and fixed mirror line focus (GA) concepts duplicate the heat source characteristics and power conversion technology of the central receiver concepts these configurations do not offer a sufficient improvement in cost to warrant full scale development. The systems are, however, less complex than their point focus counterpart and should the central receiver system development falter they provide reasonable technology alternatives. The parabolic trough concept (BDM) was found to provide a low temperature technology alternative to the central receiver concept with promising performance and cost potential. Its continued development is recommended, with special emphasis on lower temperature (< 700/sup 0/F) applications. Finally, a variety of new promising line focus power system configurations were identified for a range of utility and industrial applications and recommendations were made on their implementation. This volume contains the detailed report. (WHK)

  15. NEW APPROACHES: Magnetic and electric field strengths of high voltage power lines and household appliances

    NASA Astrophysics Data System (ADS)

    Austin, Lydia

    1997-03-01

    A readily obtainable meter can be used to measure the magnetic and electric field strengths of high voltage power lines and household appliances. Simple calculations show that all likely exposures are below, mostly well below, the maximum exposures recommended by the World Health Organisation.

  16. Power Line Technician. Second Edition. Module C. Instructor's Manual [and] Student Workbook.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This module is the third in a series that is designed to help students achieve greater professional and personal success as power line technicians. Each module represents one or more complete units of instruction with components organized into one instructor and one student "package": the instructor's manual and the student workbook. The…

  17. Power Line Technician. Second Edition. Module D. Instructor's Manual [and] Student Workbook.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This module is the fourth in a series that is designed to help students achieve greater professional and personal success as power line technicians. Each module represents one or more complete units of instruction with components organized into one instructor and one student "package": the instructor's manual and the student workbook.…

  18. Wired: impacts of increasing power line use by a growing bird population

    NASA Astrophysics Data System (ADS)

    Moreira, Francisco; Encarnação, Vitor; Rosa, Gonçalo; Gilbert, Nathalie; Infante, Samuel; Costa, Julieta; D’Amico, Marcello; Martins, Ricardo C.; Catry, Inês

    2017-02-01

    Power lines are increasingly widespread across many regions of the planet. Although these linear infrastructures are known for their negative impacts on bird populations, through collision and electrocution, some species take advantage of electricity pylons for nesting. In this case, estimation of the net impact of these infrastructures at the population level requires an assessment of trade-offs between positive and negative impacts. We compiled historical information (1958–2014) of the Portuguese white stork Ciconia ciconia population to analyze long-term changes in numbers, distribution range and use of nesting structures. White stork population size increased 660% up to 12000 breeding pairs between 1984 and 2014. In the same period, the proportion of nests on electricity pylons increased from 1% to 25%, likely facilitated by the 60% increase in the length of the very high tension power line grid (holding the majority of the nests) in the stork’s distribution range. No differences in breeding success were registered for storks nesting on electricity pylons versus other structures, but a high risk of mortality by collision and electrocution with power lines was estimated. We discuss the implications of this behavioral change, and of the management responses by power line companies, both for stork populations and for managers.

  19. Power Line Technician. Second Edition. Module B. Instructor's Manual [and] Student Workbook.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This module is the second in a series that is designed to help students achieve greater professional and personal success as power line technicians. Each module represents one or more complete units of instruction with components organized into one instructor and one student "package": the instructor's manual and the student workbook.…

  20. 76 FR 76044 - Safety Zone; Power Line Replacement, West Bay, Panama City, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-06

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Power Line Replacement, West Bay, Panama... prohibited to all vessels and persons unless specifically authorized by the Captain of the Port (COTP) Mobile.... Coast Guard Sector Mobile (spw), Building 102, Brookley Complex South Broad Street Mobile, AL...

  1. Power Line Technician. Second Edition. Module A. Instructor's Manual [and] Student Workbook.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This module is the first in a series that is designed to help students achieve greater professional and personal success as power line technicians. Each module represents one or more complete units of instruction with components organized into one instructor and one student "package": the instructor's manual and the student workbook. The…

  2. Magnetic fields dispersed by high-voltage power lines: an advanced evaluation method based on 3-D models of electrical lines and the territory.

    PubMed

    Andreuccetti, D; Zoppetti, N

    2004-01-01

    An advanced numerical evaluation tool is proposed for calculating the magnetic flux density dispersed by high-voltage power lines. When compared to existing software packages based on the application of standardized methods, this tool turned out to be particularly suitable for making accurate evaluations on vast portions of the territory, especially when the contribution of numerous aerial and/or underground lines must be taken into account. The aspects of the tool of greatest interest are (1) the interaction with an electronic archive of power lines, from which all the information necessary for the calculation is obtained; (2) the use of three-dimensional models of both the power lines and the territory crossed by these; (3) the direct interfacing with electronic cartography; and finally (4) the use of a representation procedure for the results that is based on contour maps. The tool had proven to be very useful especially for Environmental Impact Assessment procedures relative to new power lines.

  3. Waveguide harmonic damper for klystron amplifier.

    SciTech Connect

    Kang, Y.

    1998-10-27

    A waveguide harmonic damper was designed for removing the harmonic frequency power from the klystron amplifiers of the APS linac. Straight coaxial probe antennas are used in a rectangular waveguide to form a damper. A linear array of the probe antennas is used on a narrow wall of the rectangular waveguide for damping klystron harmonics while decoupling the fundamental frequency in dominent TE{sub 01} mode. The klystron harmonics can exist in the waveguide as waveguide higher-order modes above cutoff. Computer simulations are made to investigate the waveguide harmonic damping characteristics of the damper.

  4. Power line characterization from an airborne data collection with a millimeter wave radar

    NASA Astrophysics Data System (ADS)

    Goshi, Darren S.; Bui, Long Q.

    2014-05-01

    Enhancing the operational safety of small, maneuverable rotorcraft has been a critical consideration in the development of next generation situational awareness sensor suites. From landing assistance to target detection and obstacle avoidance, millimeter wave radars have become the leading candidate for such solutions due to their ability to operate in degraded visual environments, whether it is weather, induced debris, or night conditions that must be dealt with. Power lines pose arguably the largest safety risk for helicopter operation due to their difficulty in detection and proper identification to support avoidance maneuvering, where even under perfect conditions they can be nearly invisible to the naked eye. The backscatter phenomenology from braided power lines has been well-studied and formulated in previous literature, albeit mainly in controlled laboratory settings or limited field trials. Subsequently, the ability to simply detect power lines at operational distances up to around 2 km has been demonstrated. In this work, an analysis is performed on the measureable characteristics of power lines captured in a representative operational environment for helicopters. The test location included a diverse set of power line configurations with surrounding ground and tower clutter, representing a realistic scenario. A radiometrically calibrated w-band real-beam FMCW sensor allows the study and estimation of target RCS, as well as evaluation against the developed theory. All analysis is performed on dynamically captured data from a helicopter, where platform dynamics and system stability also play a significant role in a processed result. Results from this work will aid the effective development of next generation situational awareness systems.

  5. Voltages induced on a power distribution line by overhead cloud lightning

    NASA Technical Reports Server (NTRS)

    Yacoub, Ziad; Rubinstein, Marcos; Uman, Martin A.; Thomson, Ewen M.; Medelius, Pedro J.

    1991-01-01

    Voltages induced by overhead cloud lightning on a 448 m open circuited power distribution line and the corresponding north-south component of the lightning magnetic field were simultaneously measured at the NASA Kennedy Space Center during the summer of 1986. The incident electric field was calculated from the measured magnetic field. The electric field was then used as an input to the computer program, EMPLIN, that calculated the voltages at the two ends of the power line. EMPLIN models the frequency domain field/power coupling theory found, for example, in Ianoz et al. The direction of the source, which is also one of the inputs to EMPLIN, was crudely determined from a three station time delay technique. The authors found reasonably good agreement between calculated and measured waveforms.

  6. A Bayesian Prediction Framework of Weather Based Power Line Damages in the Northeast

    NASA Astrophysics Data System (ADS)

    frediani, M.; Anagnostou, E. N.; Wanik, D.; Scerbo, D.

    2012-12-01

    This study aims to evaluate the predictability of damages to overhead power distribution lines from severe weather events in the New England area. During storms, trees and branches can come down and interact with power lines that results in significant interruptions to electricity distribution, causing major interruptions to residents and monetary losses to the utility company. In Connecticut, a densely forested state, severe winds and precipitation (in the form of rain and snow) from storms are key weather factors that challenge the power grid infrastructure vulnerability. Evaluating the local predictability of these impacts may aid local power utilities with crew allocation and preparedness during an event. A probabilistic approach to damage prediction caused by trees subjected to severe weather is being investigated in the region. This study specifically, explores the feasibility of applying Bayesian inversion technique to weather parameters by developing a damage decision tree composed of various meteorological and static parameters, like wind gust, precipitation (rain and snow accumulation and rates), high canopy forest density and tree trimming history for the power distribution lines. The resulting decision tree can be used as a Bayesian inversion database to predict the probability distribution of damages given a storm forecast. The Bayesian database is based on a historical data source provided by The Connecticut Light & Power Company (Connecticut's primary power utility) containing geographical information of trouble spots caused by thunderstorm and winter/snow-storm events; power line specifications and trimming history; and high-resolution model analysis of those storms. The analysis is based on a 2-sqkm model grid cropped over the state of Connecticut comprising a database of 3,307 pixels per storm. Each storm pixel is flagged to contain power line damages or no-damages. A total of 50 storm simulations is used to build the database. Pairs of

  7. Analytical and numerical prediction of harmonic sound power in the inlet of aero-engines with emphasis on transonic rotation speeds

    NASA Astrophysics Data System (ADS)

    Lewy, Serge; Polacsek, Cyril; Barrier, Raphael

    2014-12-01

    Tone noise radiated through the inlet of a turbofan is mainly due to rotor-stator interactions at subsonic regimes (approach flight), and to the shock waves attached to each blade at supersonic helical tip speeds (takeoff). The axial compressor of a helicopter turboshaft engine is transonic as well and can be studied like turbofans at takeoff. The objective of the paper is to predict the sound power at the inlet radiating into the free field, with a focus on transonic conditions because sound levels are much higher. Direct numerical computation of tone acoustic power is based on a RANS (Reynolds averaged Navier-Stokes) solver followed by an integration of acoustic intensity over specified inlet cross-sections, derived from Cantrell and Hart equations (valid in irrotational flows). In transonic regimes, sound power decreases along the intake because of nonlinear propagation, which must be discriminated from numerical dissipation. This is one of the reasons why an analytical approach is also suggested. It is based on three steps: (i) appraisal of the initial pressure jump of the shock waves; (ii) 2D nonlinear propagation model of Morfey and Fisher; (iii) calculation of the sound power of the 3D ducted acoustic field. In this model, all the blades are assumed to be identical such that only the blade passing frequency and its harmonics are predicted (like in the present numerical simulations). However, transfer from blade passing frequency to multiple pure tones can be evaluated in a fourth step through a statistical analysis of irregularities between blades. Interest of the analytical method is to provide a good estimate of nonlinear acoustic propagation in the upstream duct while being easy and fast to compute. The various methods are applied to two turbofan models, respectively in approach (subsonic) and takeoff (transonic) conditions, and to a Turbomeca turboshaft engine (transonic case). The analytical method in transonic appears to be quite reliable by comparison

  8. Study of magnetic fields from power-frequency current on water lines.

    PubMed

    Lanera, D; Zapotosky, J E; Colby, J A

    1997-01-01

    The magnetic fields from power-frequency current flowing on water lines were investigated in a new approach that involved an area-wide survey in a small town. Magnetic fields were measured outside the residence under power cables and over water lines, and each residence was characterized as to whether it received water from a private well or the municipal water system. The magnetic field data revealed two statistical modes when they were related to water supply type. The data also showed that in the case of the high mode, the magnetic field remained constant along the line formed by power drop wires, at the back of the house, and the water hookup service, in front of the house, all the way to the street. The patterns are explained by the coincidence of measurement points and the presence of net current flowing on power mains, power drop conductors, residential plumbing, water service hookups, and water mains. These patterns, together with other characteristics of this magnetic field source, such as the gradual spatial fall-off of this field and the presence of a constant component in the time sequence, portray a magnetic field more uniform and constant in the residential environment than has been thought to exist. Such characteristics make up for the weakness of the source and make net current a significant source of exposure in the lives of individuals around the house, when human exposure to magnetic fields is assumed to be a cumulative effect over time. This, together with the bimodal statistical distribution of the residential magnetic field (related to water supply type), presents opportunities for retrospective epidemiological analysis. Water line type and its ability to conduct power-frequency current can be used as the historical marker for a bimodal exposure inference, as Wertheimer et al. have shown.

  9. Full wave simulations of fast wave efficiency and power losses in the scrape-off layer of tokamak plasmas in mid/high harmonic and minority heating regimes

    SciTech Connect

    Bertelli, N.; Jaeger, E. F.; Hosea, J. C.; Phillips, C. K.; Berry, L.; Bonoli, P. T.; Gerhardt, S. P.; Green, D.; LeBlanc, B.; Perkins, R. J.; Qin, C. M.; Pinsker, R. I.; Prater, R.; Ryan, P. M.; Taylor, G.; Valeo, E. J.; Wilson, J. R.; Wright, J. C.; Zhang, X. J.

    2015-12-17

    Here, several experiments on different machines and in different fast wave (FW) heating regimes, such as hydrogen minority heating and high harmonic fast waves (HHFW), have found strong interaction between radio-frequency (RF) waves and the scrape-off layer (SOL) region. This paper examines the propagation and the power loss in the SOL by using the full wave code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain and a collisional damping parameter is used as a proxy to represent the real, and most likely nonlinear, damping processes. 2D and 3D AORSA results for the National Spherical Torus eXperiment (NSTX) have shown a strong transition to higher SOL power losses (driven by the RF field) when the FW cut-off is removed from in front of the antenna by increasing the edge density. Here, full wave simulations have been extended for 'conventional' tokamaks with higher aspect ratios, such as the DIII-D, Alcator C-Mod, and EAST devices. DIII-D results in HHFW regime show similar behavior found in NSTX and NSTX-U, consistent with previous DIII-D experimental observations. In contrast, a different behavior has been found for C-Mod and EAST, which operate in the minority heating regime.

  10. Full wave simulations of fast wave efficiency and power losses in the scrape-off layer of tokamak plasmas in mid/high harmonic and minority heating regimes

    DOE PAGES

    Bertelli, N.; Jaeger, E. F.; Hosea, J. C.; ...

    2015-12-17

    Here, several experiments on different machines and in different fast wave (FW) heating regimes, such as hydrogen minority heating and high harmonic fast waves (HHFW), have found strong interaction between radio-frequency (RF) waves and the scrape-off layer (SOL) region. This paper examines the propagation and the power loss in the SOL by using the full wave code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain and a collisional damping parameter is used as a proxy to represent the real, and most likely nonlinear, damping processes. 2D and 3D AORSAmore » results for the National Spherical Torus eXperiment (NSTX) have shown a strong transition to higher SOL power losses (driven by the RF field) when the FW cut-off is removed from in front of the antenna by increasing the edge density. Here, full wave simulations have been extended for 'conventional' tokamaks with higher aspect ratios, such as the DIII-D, Alcator C-Mod, and EAST devices. DIII-D results in HHFW regime show similar behavior found in NSTX and NSTX-U, consistent with previous DIII-D experimental observations. In contrast, a different behavior has been found for C-Mod and EAST, which operate in the minority heating regime.« less

  11. Combined diplexer and harmonic filter

    NASA Technical Reports Server (NTRS)

    Allen, C. C.

    1973-01-01

    By using two directional filters having circular waveguide filter cavities, diplexing and harmonic filtering functions can be combined into a more compact integrated waveguide assembly. Device is filter which passes power within its pass band limits, but also has a directional characteristic so power transmitted into two-port output waveguide will travel in only one direction.

  12. Power Requirements for Bi-Harmonic Amplitude and Bias Modulation Control of a Flapping Wing Micro Air Vehicle

    DTIC Science & Technology

    2013-03-01

    N Yaw Moment P Power R Wingspan RBI Rotation Matrix from the Inertial Reference Frame to the Body Frame Re Reynolds Number S Wing Area X Axial Force...Y Z ]T are the axial forces, RBI is a rotation matrix from the inertial frame to the body frame , and g is the gravitational acceleration. [41] This...with the load on the system. There is advantageous energetic expenditure when mechanical systems operate at resonance . [16] The advantage of low

  13. High precision cell slicing by harmonically actuated ultra-sharp SixNy blades

    NASA Astrophysics Data System (ADS)

    Jeong, Hwapyeong; Li, Tao; Gianchandani, Yogesh B.; Park, Jaesung

    2015-02-01

    We describe a micro-knife system with an ultra-sharp blade that is harmonically actuated by lead zirconate titanate (PZT). In particular, harmonic actuation along its cutting direction is demonstrated to provide clean and sharp cut lines for hepatocytes. Such performance is not provided by ordinary ultrasonic actuation. The blade is 500 nm-thick silicon nitride (SixNy); it can cut a single cell. Finite element analysis and measurements of displacement around resonant frequencies were used to optimize the dimensions, driving frequency and voltage. To evaluate the cutting precision, commercial scalpels and the SixNy blade without and with harmonic actuation were compared. When used to cut primary hepatocytes in a mono-layer, a commercial stainless scalpel burst cells, and the SixNy blade without harmonic actuation cut cells with a wide and ragged line. However, due to the controlled ultrasonic mode shape, operating frequency, high frequency and low applied power, the SixNy blade with harmonic actuation at 1Vpp and 70.1 kHz provided a clean and sharp cut line which was as narrow as 2 µm. The SixNy blade with harmonic actuation has potential applications as a tool for minimally invasive surgery.

  14. Multivariable time series prediction for the icing process on overhead power transmission line.

    PubMed

    Li, Peng; Zhao, Na; Zhou, Donghua; Cao, Min; Li, Jingjie; Shi, Xinling

    2014-01-01

    The design of monitoring and predictive alarm systems is necessary for successful overhead power transmission line icing. Given the characteristics of complexity, nonlinearity, and fitfulness in the line icing process, a model based on a multivariable time series is presented here to predict the icing load of a transmission line. In this model, the time effects of micrometeorology parameters for the icing process have been analyzed. The phase-space reconstruction theory and machine learning method were then applied to establish the prediction model, which fully utilized the history of multivariable time series data in local monitoring systems to represent the mapping relationship between icing load and micrometeorology factors. Relevant to the characteristic of fitfulness in line icing, the simulations were carried out during the same icing process or different process to test the model's prediction precision and robustness. According to the simulation results for the Tao-Luo-Xiong Transmission Line, this model demonstrates a good accuracy of prediction in different process, if the prediction length is less than two hours, and would be helpful for power grid departments when deciding to take action in advance to address potential icing disasters.

  15. INVESTIGATION OF A DYNAMIC POWER LINE RATING CONCEPT FOR IMPROVED WIND ENERGY INTEGRATION OVER COMPLEX TERRAIN

    SciTech Connect

    Jake P. Gentle; Kurt S Myers; Tyler B Phillips; Inanc Senocak; Phil Anderson

    2014-08-01

    Dynamic Line Rating (DLR) is a smart grid technology that allows the rating of power line to be based on real-time conductor temperature dependent on local weather conditions. In current practice overhead power lines are generally given a conservative rating based on worst case weather conditions. Using historical weather data collected over a test bed area, we demonstrate there is often additional transmission capacity not being utilized with the current static rating practice. We investigate a new dynamic line rating methodology using computational fluid dynamics (CFD) to determine wind conditions along transmission lines at dense intervals. Simulated results are used to determine conductor temperature by calculating the transient thermal response of the conductor under variable environmental conditions. In calculating the conductor temperature, we use both a calculation with steady-state assumption and a transient calculation. Under low wind conditions, steady-state assumption predicts higher conductor temperatures that could lead to curtailments, whereas transient calculations produce conductor temperatures that are significantly lower, implying the availability of additional transmission capacity.

  16. Multivariable Time Series Prediction for the Icing Process on Overhead Power Transmission Line

    PubMed Central

    Li, Peng; Zhao, Na; Zhou, Donghua; Cao, Min; Li, Jingjie; Shi, Xinling

    2014-01-01

    The design of monitoring and predictive alarm systems is necessary for successful overhead power transmission line icing. Given the characteristics of complexity, nonlinearity, and fitfulness in the line icing process, a model based on a multivariable time series is presented here to predict the icing load of a transmission line. In this model, the time effects of micrometeorology parameters for the icing process have been analyzed. The phase-space reconstruction theory and machine learning method were then applied to establish the prediction model, which fully utilized the history of multivariable time series data in local monitoring systems to represent the mapping relationship between icing load and micrometeorology factors. Relevant to the characteristic of fitfulness in line icing, the simulations were carried out during the same icing process or different process to test the model's prediction precision and robustness. According to the simulation results for the Tao-Luo-Xiong Transmission Line, this model demonstrates a good accuracy of prediction in different process, if the prediction length is less than two hours, and would be helpful for power grid departments when deciding to take action in advance to address potential icing disasters. PMID:25136653

  17. Virginia Power's generic main steam-line-break DNBR (departure from nucleate boiling ratio) analysis

    SciTech Connect

    Anderson, R.C.; Harrell, J.R.; Erb, J.O.

    1990-06-01

    Virginia Power operates four nuclear reactors, two units each at the Surry and North Anna Power stations. The original operating licenses were based on acceptable analysis results of the accidents in the final safety analysis report (FSAR). The assumptions of these analyses must be verified on a reload basis. Included in these FSAR accidents is the main steam-line-break (MSLB) event. The plant FSARs describe the MSLB analyses, which is summarized as follows. The plant is assumed to be at hot zero power at end of life, when the moderator temperature coefficient (MTC) is most negative. The MSLB rapidly cools the secondary side, followed by a primary cooldown in one loop. The surge of cold water into the core, coupled with the negative MTC, results in high local power factors, which in turn can result in a violation of the departure from nucleate boiling ratio (DNBR) limit. The three-dimensional power distribution is calculated at several key state points. These distributions are then subjected to core thermal-hydraulic analysis by the COBRA code. The W-3 correlation is used to calculate the state-point DNBRs. Both the physics and the DNBR calculations have been repeated on a reload basis. As a result, Virginia Power has accumulated a reasonably large data base of MSLB DNBRs for both Surry and North Anna. Virginia Power now uses the power peaking factors criterion to verify that the MSLB analysis remains bounding on a reload basis.

  18. Observation of dynamic interactions between fundamental and second-harmonic modes in a high-power sub-terahertz gyrotron operating in regimes of soft and hard self-excitation.

    PubMed

    Saito, Teruo; Tatematsu, Yoshinori; Yamaguchi, Yuusuke; Ikeuchi, Shinji; Ogasawara, Shinya; Yamada, Naoki; Ikeda, Ryosuke; Ogawa, Isamu; Idehara, Toshitaka

    2012-10-12

    Dynamic mode interaction between fundamental and second-harmonic modes has been observed in high-power sub-terahertz gyrotrons [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009); T. Saito et al. Phys. Plasmas 19, 063106 (2012)]. Interaction takes place between a parasitic fundamental or first-harmonic (FH) mode and an operating second-harmonic (SH) mode, as well as among SH modes. In particular, nonlinear excitation of the parasitic FH mode in the hard self-excitation regime with assistance of a SH mode in the soft self-excitation regime was clearly observed. Moreover, both cases of stable two-mode oscillation and oscillation of the FH mode only were observed. These observations and theoretical analyses of the dynamic behavior of the mode interaction verify the nonlinear hard self-excitation of the FH mode.

  19. K-Band Power Enbedded Transmission Line (ETL) MMIC Amplifiers for Satellite Communication Applications

    NASA Technical Reports Server (NTRS)

    Tserng, Hua-Quen; Ketterson, Andrew; Saunier, Paul; McCarty, Larry; Davis, Steve

    1998-01-01

    The design, fabrication, and performance of K-band high-efficiency, linear power pHEMT amplifiers implemented in Embedded Transmission Line (ETL) MMIC configuration with unthinned GaAs substrate and topside grounding are reported. A three-stage amplifier achieved a power-added efficiency of 40.5% with 264 mW output at 20.2 GHz. The linear gain is 28.5 dB with 1-dB gain compression output power of 200 mW and 31% power-added efficiency. The carrier-to-third-order intermodulation ratio is approx. 20 dBc at the 1-dB compression point. A RF functional yield of more than 90% has been achieved.

  20. Parametric analysis of hollow conductor parallel and coaxial transmission lines for high frequency space power distribution

    NASA Technical Reports Server (NTRS)

    Jeffries, K. S.; Renz, D. D.

    1984-01-01

    A parametric analysis was performed of transmission cables for transmitting electrical power at high voltage (up to 1000 V) and high frequency (10 to 30 kHz) for high power (100 kW or more) space missions. Large diameter (5 to 30 mm) hollow conductors were considered in closely spaced coaxial configurations and in parallel lines. Formulas were derived to calculate inductance and resistance for these conductors. Curves of cable conductance, mass, inductance, capacitance, resistance, power loss, and temperature were plotted for various conductor diameters, conductor thickness, and alternating current frequencies. An example 5 mm diameter coaxial cable with 0.5 mm conductor thickness was calculated to transmit 100 kW at 1000 Vac, 50 m with a power loss of 1900 W, an inductance of 1.45 micron and a capacitance of 0.07 micron-F. The computer programs written for this analysis are listed in the appendix.

  1. Onboard power line conditioning system for an electric or hybrid vehicle

    DOEpatents

    Kajouke, Lateef A.; Perisic, Milun

    2016-06-14

    A power line quality conditioning system for a vehicle includes an onboard rechargeable direct current (DC) energy storage system and an onboard electrical system coupled to the energy storage system. The energy storage system provides DC energy to drive an electric traction motor of the vehicle. The electrical system operates in a charging mode such that alternating current (AC) energy from a power grid external to the vehicle is converted to DC energy to charge the DC energy storage system. The electrical system also operates in a vehicle-to-grid power conditioning mode such that DC energy from the DC energy storage system is converted to AC energy to condition an AC voltage of the power grid.

  2. Harmonic engine

    DOEpatents

    Bennett, Charles L.; Sewall, Noel; Boroa, Carl

    2014-08-19

    An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a harmonic oscillator inlet valve capable of oscillating at a resonant frequency for controlling the flow of working fluid into of the engine. In particular, the inlet valve includes an inlet valve head and a spring arranged together as a harmonic oscillator so that the inlet valve head is moveable from an unbiased equilibrium position to a biased closed position occluding an inlet. Upon releasing the inlet valve the inlet valve head undergoes a single oscillation past the equilibrium positio to a maximum open position and returns to a biased return position close to the closed position to choke the flow and produce a pressure drop across the inlet valve causing the inlet valve to close. Protrusions carried either by the inlet valve head or piston head are used to bump open the inlet valve from the closed position and initiate the single oscillation of the inlet valve head, and protrusions carried either by the outlet valve head or piston head are used to close the outlet valve ahead of the bump opening of the inlet valve.

  3. A Tesla-pulse forming line-plasma opening switch pulsed power generator

    NASA Astrophysics Data System (ADS)

    Novac, B. M.; Kumar, R.; Smith, I. R.

    2010-10-01

    A pulsed power generator based on a high-voltage Tesla transformer which charges a 3.85 Ω/55 ns water-filled pulse forming line to 300 kV has been developed at Loughborough University as a training tool for pulsed power students. The generator uses all forms of insulation specific to pulsed power technology, liquid (oil and water), gas (SF6), and magnetic insulation in vacuum, and a number of fast voltage and current sensors are implemented for diagnostic purposes. A miniature (centimeter-size) plasma opening switch has recently been coupled to the output of the pulse forming line, with the overall system comprising the first phase of a program aimed at the development of a novel repetitive, table-top generator capable of producing 15 GW pulses for high power microwave loads. Technical details of all the generator components and the main experimental results obtained during the program and demonstrations of their performance are presented in the paper, together with a description of the various diagnostic tools involved. In particular, it is shown that the miniature plasma opening switch is capable of reducing the rise time of the input current while significantly increasing the load power. Future plans are outlined in the conclusions.

  4. The ac power line protection for an IEEE 587 Class B environment

    NASA Technical Reports Server (NTRS)

    Roehr, W. D.; Clark, O. M.

    1984-01-01

    The 587B series of protectors are unique, low clamping voltage transient suppressors to protect ac-powered equipment from the 6000V peak open-circuit voltage and 3000A short circuit current as defined in IEEE standard 587 for Category B transients. The devices, which incorporate multiple-stage solid-state protector components, were specifically designed to operate under multiple exposures to maximum threat levels in this severe environment. The output voltage peaks are limited to 350V under maximum threat conditions for a 120V ac power line, thus providing adequate protection to vulnerable electronic equipment. The principle of operation and test performance data is discussed.

  5. Development of On-Line Monitoring Systems for High Temperature Components in Power Plants

    PubMed Central

    Zhang, Hongcai; Jia, Jiuhong; Wang, Ning; Hu, Xiaoyin; Tu, Shan-Tung; Zhou, Shaoping; Wang, Zhengdong

    2013-01-01

    To accurately detect deformation and extend the component life beyond the original design limits, structural safety monitoring techniques have attracted considerable attention in the power and process industries for decades. In this paper an on-line monitoring system for high temperature pipes in a power plant is developed. The extension-based sensing devices are amounted on straight pipes, T-Joints and elbows of a main steam pipeline. During on-site monitoring for more than two years, most of the sensors worked reliably and steadily. However, the direct strain gauge could not work for long periods because of the high temperature environment. Moreover, it is found that the installation and connection of the extensometers can have a significant influence on the measurement results. The on-line monitoring system has a good alarming function which is demonstrated by detecting a steam leakage of the header. PMID:24233026

  6. Attenuation Characteristic Modeling of Power-line Channel in Cargo Ships

    NASA Astrophysics Data System (ADS)

    Tsuzuki, Shinji; Ishii, Seiichiro; Nishioka, Jun; Yamada, Yoshio

    Power-line communication (PLC) based local area network (LAN) in cargo ships is one of the promising applications of the PLC technology. In this paper, the signal attenuation characteristic when transmitting with the differential-mode (DIF) and the common-mode (COM) has been modeled respectively to design the PLC network in a cargo ship. The characteristic has been analyzed from the measured transfer function of 440V power-line channels for reefer containers in two typical ships. The measured transfer function was averaged from 2M to 30MHz (or until the measurement limit frequency) and approximated by the number of branches and the length of a signal propagating route. The mean accuracy of the obtained approximation equations was ±4dB. The area where the signal attenuation of COM transmission is less than that of DIF transmission has been studied from the equations.

  7. A simple packet retransmission strategy for throughput and delay enhancement on power line communication channels

    SciTech Connect

    Onunga, J.O. ); Donaldson, R.W. . Dept. of Electrical Engineering)

    1993-07-01

    A new, simple, and effective communication protocol is developed and evaluated for use on power line distribution networks. The protocol involves retransmission of unacknowledged packets, which are sent in either single or multiple (N) copies in accordance with estimates of communication link quality. Multiple packet copies can be code combined at the receiver, using majority voting on each bit position, to reduce packet error rates. Adaptive link quality estimates are based on the receipt or absence of positive acknowledgements. Information throughput efficiency is calculated and N optimized in terms of system variables. Performance benefits of code combining are clearly demonstrated. The algorithm was implemented and tested using a five-station intrabuilding power line communications network operating at 1.2, 2.4, 4.8 and 9.6 kbit/s data rate. Substantial throughput and delay improvement occurred on poor quality links, without degrading performance on good links.

  8. Harmonic generation with a dual frequency pulse.

    PubMed

    Keravnou, Christina P; Averkiou, Michalakis A

    2014-05-01

    Nonlinear imaging was implemented in commercial ultrasound systems over the last 15 years offering major advantages in many clinical applications. In this work, pulsing schemes coupled with a dual frequency pulse are presented. The pulsing schemes considered were pulse inversion, power modulation, and power modulated pulse inversion. The pulse contains a fundamental frequency f and a specified amount of its second harmonic 2f. The advantages and limitations of this method were evaluated with both acoustic measurements of harmonic generation and theoretical simulations based on the KZK equation. The use of two frequencies in a pulse results in the generation of the sum and difference frequency components in addition to the other harmonic components. While with single frequency pulses, only power modulation and power modulated pulse inversion contained odd harmonic components, with the dual frequency pulse, pulse inversion now also contains odd harmonic components.

  9. High Power, Pulsed, RF Generation from Nonlinear Lumped Element Transmission Lines (NLETLs)

    DTIC Science & Technology

    2011-02-05

    attracted interest, most recently silicon carbide ( SiC ) and gallium nitride1 (GaN). A fundamental and important limitation of solid-state power...quite high. Wide band-gap semiconductor materials such as SiC and GaN break down at a higher voltage and are hence able to operate with lower...Voltage Experiments matched diodes created from the same silicon wafer, which was coincident ally useful for certain multiple line NLETL configurations

  10. Analysis of the grounding system for a mobile communication site placed on HV power line mast

    NASA Astrophysics Data System (ADS)

    Bîrsan, I.; Munteanu, C.; Horgoș, M.; Ilut, T.

    2016-08-01

    This paper aims to analyze the potential distribution on the soil surface or potential variation on the main directions inside computing mobile site. I want to study a system made the earth a mobile communications site, antennas operator and the system of which the earth is placed on a High Voltage Power Line Mast (LEA 110 KV). I made direct measurements and I use a 3D software for analyze the results and simulating some possible solutions.

  11. Horizontal cryogenic bushing for the termination of a superconducting power-transmission line

    DOEpatents

    Minati, K.F.; Morgan, G.H.; McNerney, A.J.; Schauer, F.

    1982-07-29

    A termination for a superconducting power transmission line is disclosed which is comprised of a standard air entrance insulated vertical bushing with an elbow, a horizontal cryogenic bushing linking the pressurized cryogenic cable environment to the ambient temperature bushing and a stress cone which terminated the cable outer shield and transforms the large radial voltage gradient in the cable dielectric into a much lower radial voltage gradient in the high density helium coolant at the cold end of the cryogenic bushing.

  12. Termination for a superconducting power transmission line including a horizontal cryogenic bushing

    DOEpatents

    Minati, Kurt F.; Morgan, Gerry H.; McNerney, Andrew J.; Schauer, Felix

    1984-01-01

    A termination for a superconducting power transmission line is disclosed which is comprised of a standard air entrance insulated vertical bushing with an elbow, a horizontal cryogenic bushing linking the pressurized cryogenic cable environment to the ambient temperature bushing and a stress cone which terminates the cable outer shield and transforms the large radial voltage gradient in the cable dielectric into a much lower radial voltage gradient in the high density helium coolant at the cold end of the cryogenic bushing.

  13. High-average-power narrow-line-width sum frequency generation 589 nm laser

    NASA Astrophysics Data System (ADS)

    Lu, Yanhua; Fan, Guobin; Ren, Huaijin; Zhang, Lei; Xu, Xiafei; Zhang, Wei; Wan, Min

    2015-10-01

    An 81 W average-power all-solid-state sodium beacon laser at 589 nm with a repetition rate of 250 Hz is introduced, which is based on a novel sum frequency generation idea between two high-energy, different line widths, different beam quality infrared lasers (a 1064 nm laser and a 1319 nm laser). The 1064 nm laser, which features an external modulated CW single frequency seed source and two stages of amplifiers, can provide average-power of 150 W, beam quality M2 of ~1.8 with ultra-narrow line width (< 100 kHz). The 1319 nm laser can deliver average-power of 100 W, beam quality M2 of ~3.0 with a narrow line width of ~0.3 GHz. By sum frequency mixing in a LBO slab crystal (3 mm x 12 mm x 50 mm), pulse energy of 325 mJ is achieved at 589 nm with a conversion efficiency of 32.5 %. Tuning the center wavelength of 1064 nm laser by a PZT PID controller, the target beam's central wavelength is accurately locked to 589.15910 nm with a line width of ~0.3 GHz, which is dominated mainly by the 1319 nm laser. The beam quality is measured to be M2 < 1.3. The pulse duration is measured to be 150 μs in full-width. To the best of our knowledge, this represents the highest average-power for all-solid-state sodium beacon laser ever reported.

  14. Radiatively driven winds for different power law spectra. [for explaining narrow and broad quasar absorption lines

    NASA Technical Reports Server (NTRS)

    Beltrametti, M.

    1980-01-01

    The analytic solutions for radiatively driven winds are given for the case in which the winds are driven by absorption of line and continuum radiation. The wind solutions are analytically estimated for different parameters of the central source and for different power law spectra. For flat spectra, three sonic points can exist; it is shown, however, that only one of these sonic points is physically realistic. Parameters of the central source are given which generate winds of further interest for explaining the narrow and broad absorption lines in quasars. For the quasar model presented here, winds which could give rise to the narrow absorption lines are generated by central sources with parameters which are not realistic for quasars.

  15. Development of Getting Up Detection and Report Device using Power Line Communication and Mat-Sensor

    NASA Astrophysics Data System (ADS)

    Haruyama, Kazuo; Tanaka, Kanya; Kobayashi, Shigeki; Yasuoka, Katsunori; Uchibori, Akihiko; Oka, Masato

    In this paper, we propose the getting up detection and report device which can be installed in middle-small facilities and ordinary houses. This device combines a mat sensor which detects rising and a power line communication (PLC) device as a reporting system. This device does not need any additional construction for installation as long as facilities equip electric power supply 100V for ordinary businesses. At first, the mat sensor in the system detects rising of an elderly person or lying down to bed. The PLC system sends ON/OFF signal and reports to nurses and staff members in their rooms. Since the main objective of the PLC system is to keep exact detection and transmission of the mat-sensor ON/OFF signal, high-speed network is not necessary. It is required that the system should be robust against noises of household electrical appliances. We used the selected-career method as a transmission method in which we located 2 lines of tone frequency (132kHz or 115kHz) for the power line transmission in the device. The effectiveness of the proposed device has been confirmed by the field experiments in welfare facilities for elderly people.

  16. Alleviation SSR and Low Frequency Power Oscillations in Series Compensated Transmission Line using SVC Supplementary Controllers

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjiv; Kumar, Narendra

    2016-07-01

    In this work, supplementary sub-synchronous damping controllers (SSDC) are proposed for damping sub-synchronous oscillations in power systems with series compensated transmission lines. Series compensation have extensively been used as effective means of increasing the power transfer capability of a transmission lines and improving transient stability limits of power systems. Series compensation with transmission lines may cause sub-synchronous resonance (SSR). The eigenvalue investigation tool is used to ascertain the existence of SSR. It is shown that the addition of supplementary controller is able to stabilize all unstable modes for T-network model. Eigenvalue investigation and time domain transient simulation of detailed nonlinear system are considered to investigate the performance of the controllers. The efficacies of the suggested supplementary controllers are compared on the IEEE first benchmark model for computer simulations of SSR by means of time domain simulation in Matlab/Simulink environment. Supplementary SSDC are considered in order to compare effectiveness of SSDC during higher loading in alleviating the small signal stability problem.

  17. Design and fabrication of the high-power RF transmission line into the PEFP linac tunnel

    NASA Astrophysics Data System (ADS)

    Seol, Kyung-Tae; Kwon, Hyeok-Jung; Kim, Han-Sung; Cho, Yong-Sub

    2012-07-01

    The 100-MeV proton linear accelerator (linac) for the Proton Engineering Frontier Project (PEFP) has been developed and will be installed at the Gyeong-ju site. For the linac, a total of 11 sets of RF systems are required, and the waveguide layout was fixed to install high-power RF (HPRF) systems. One of the important interfaces with the building construction is the high-power radio-frequency (HPRF) transmission line embedded in the tunnel, which is used to transmit 1-MW RF power to each cavity in the tunnel. The waveguide section penetrating into the linac tunnel was designed with a bending structure for radiation shielding, and the dependence of its voltage standing-wave ratio (VSWR) on the chamfer length of the bending was calculated. The HPRF transmission line was fabricated into a piece of waveguide to prevent moisture and any foreign debris inside the 2.5-m thick concrete block. Air leakage was checked with a pressure of 0.25 psig of nitrogen gas, and a maximum VSWR of 1.196 was obtained by measuring the vector reflection coefficients with the quarter-wave transmission section. In this paper, the design and the fabrication of the HPRF transmission line into the PEFP linac tunnel are presented.

  18. Electromagnetic fields and cancer in children residing near Norwegian high-voltage power lines.

    PubMed

    Tynes, T; Haldorsen, T

    1997-02-01

    The aim of the nested case-control study reported here was to test the hypothesis that exposure to electromagnetic fields of the type generated by high-voltage power lines increases the incidence of cancer in children aged 0-14 years. The study population comprised children who during at least one of the years 1960, 1970, 1980, 1985, 1987, or 1989 had lived in a census ward crossed by a high-voltage power line. The cases were diagnosed from 1965 to 1989 and were matched to controls by year of birth, sex, and municipality. Exposure to electric and magnetic fields was calculated by means of computer programs in which power line characteristics and distance were taken into account. No association was found between exposure to time-weighted average exposure to magnetic fields and cancer at all sites, brain tumors, lymphoma, or leukemia. Cancer at other sites showed elevated odds ratios in the two highest exposure categories in some, but not all, measures of exposure. This study provides little support for an association between children's exposure to magnetic fields and cancer and no support for an association between leukemia and such exposure, but no firm conclusions can be drawn owing to the small numbers involved.

  19. Performance Of The DIII-D ECH High Power Transmission Lines And Launching Systems

    NASA Astrophysics Data System (ADS)

    Cengher, Mirela; Lohr, J.; Gorelov, Y.; Torrezan, A.; Ponce, D.; Moeller, C.; Ellis, R. A.; Kolemen, E.

    2015-11-01

    The Electron Cyclotron Heating (ECH) transmission system on the DIII D tokamak consists of corrugated coaxial 31.75 mm waveguide transmission lines and steerable launching mirrors. Total power injected into plasma can reach up to 3.5 MW, with pulse length up to 5 seconds. The ECH power injected to the tokamak from each gyrotron is measured on a shot-to-shot basis and shows individual average injected powers from a gyrotron into the plasma between 540 and 700 kW. The transmission coefficient including the waveguide line and the MOU is between -1.04 dB and -1.43 dB. The maximum ECH energy injected into DIII-D is 16.6 MJ. The HE11 mode content is over 85 % for all the lines. The four dual waveguide launchers have increased poloidal scanning speed, and can steer the RF beams 40 degrees poloidally in 200 ms, with real-time poloidal motion control by the plasma control system. A new method of in-situ calibration of the mirror angle was used in conjunction with the upgrading of the encoders and motors for the launchers. Work supported by US DOE under DE-FC02-04ER54698 and DE-AC02-09CH11466.

  20. Distributed Power-Line Outage Detection Based on Wide Area Measurement System

    PubMed Central

    Zhao, Liang; Song, Wen-Zhan

    2014-01-01

    In modern power grids, the fast and reliable detection of power-line outages is an important functionality, which prevents cascading failures and facilitates an accurate state estimation to monitor the real-time conditions of the grids. However, most of the existing approaches for outage detection suffer from two drawbacks, namely: (i) high computational complexity; and (ii) relying on a centralized means of implementation. The high computational complexity limits the practical usage of outage detection only for the case of single-line or double-line outages. Meanwhile, the centralized means of implementation raises security and privacy issues. Considering these drawbacks, the present paper proposes a distributed framework, which carries out in-network information processing and only shares estimates on boundaries with the neighboring control areas. This novel framework relies on a convex-relaxed formulation of the line outage detection problem and leverages the alternating direction method of multipliers (ADMM) for its distributed solution. The proposed framework invokes a low computational complexity, requiring only linear and simple matrix-vector operations. We also extend this framework to incorporate the sparse property of the measurement matrix and employ the LSQRalgorithm to enable a warm start, which further accelerates the algorithm. Analysis and simulation tests validate the correctness and effectiveness of the proposed approaches. PMID:25051035

  1. Distributed power-line outage detection based on wide area measurement system.

    PubMed

    Zhao, Liang; Song, Wen-Zhan

    2014-07-21

    In modern power grids, the fast and reliable detection of power-line outages is an important functionality, which prevents cascading failures and facilitates an accurate state estimation to monitor the real-time conditions of the grids. However, most of the existing approaches for outage detection suffer from two drawbacks, namely: (i) high computational complexity; and (ii) relying on a centralized means of implementation. The high computational complexity limits the practical usage of outage detection only for the case of single-line or double-line outages. Meanwhile, the centralized means of implementation raises security and privacy issues. Considering these drawbacks, the present paper proposes a distributed framework, which carries out in-network information processing and only shares estimates on boundaries with the neighboring control areas. This novel framework relies on a convex-relaxed formulation of the line outage detection problem and leverages the alternating direction method of multipliers (ADMM) for its distributed solution. The proposed framework invokes a low computational complexity, requiring only linear and simple matrix-vector operations. We also extend this framework to incorporate the sparse property of the measurement matrix and employ the LSQRalgorithm to enable a warm start, which further accelerates the algorithm. Analysis and simulation tests validate the correctness and effectiveness of the proposed approaches.

  2. A Novel Uniform Discrete Multitone Transceiver with Power-Allocation for Digital Subscriber Line

    NASA Astrophysics Data System (ADS)

    Baig, Sobia; Junaid Mughal, Muhammad

    A novel Uniform Discrete Multitone (DMT) transceiver is proposed, utilizing a wavelet packet based filter bank transmultiplexer in conjunction with a DMT transceiver. The proposed transceiver decomposes the channel spectrum into subbands of equal bandwidth. The objective is to minimize the bit error rate (BER), which is increased by channel-noise amplification. This noise amplification is due to the Zero-Forcing equalization (ZFE) technique. Quantization of the channel-noise amplification is presented, based on post-equalization signal-to-noise ratio (SNR) and probability of error in all subbands of the Uniform DMT system. A modified power loading algorithm is applied to allocate variable power according to subband gains. A BER performance comparison of the Uniform DMT with variable and uniform power-loading and with a conventional DMT system in a Digital Subscriber Line (DSL) channel is presented.

  3. The effects of lightning and high altitude electromagnetic pulse on power distribution lines

    SciTech Connect

    Uman, M.A.; Rubinstein, M.; Yacoub, Z.

    1995-01-01

    We simultaneously recorded the voltages induced by lightning on both ends of an unenergized 448-meter long unenergized electric power line and the lightning vertical electric and horizontal magnetic fields at ground level near the line. The lightning data studied and presented here were due both to cloud lightning and to very close (about 20 m from the line) artificially initiated lightning. For cloud sources, a frequency-domain computer program called EMPLIN was used to calculate induced line voltages as a function of source elevation, angle of incidence, and wave polarization of the radiated cloud discharge pulses in order to compare with the measurements. For very-close lightning, the measured line voltages could be grouped into two categories, those in which multiple, similarly shaped, evenly spaced pulses were observed, which we call oscillatory, and those dominated by a principal pulse with subsidiary oscillations of much smaller amplitude, which we call impulsive. The amplitude of the induced voltage ranged from tens of kilovolts for oscillatory voltages to hundreds of kilovolts for impulsive voltages. A new technique is derived for the calculation of the electromagnetic fields from nearby lightning to ground above an imperfectly conducting ground. This technique was used in conjunction with an existing time domain coupling theory and lightning return stroke model to calculate voltages at either end of the line. The results show fair agreement with the measured oscillatory voltage waveforms if corona is ignored and improved results when corona effects are modeled. The modeling of the impulsive voltage, for which local flashover probably successful. In an attempt to understand better the sources of the line voltages for very close lightning, measurements of the horizontal and vertical electric fields 30 m from triggered lightning were obtained.

  4. Real-time simulation of power transmission lines using Marti model with optimal fitting on dual-DSP card

    SciTech Connect

    Dufour, C.; Le-Huy, H.; El Hakimi, A.; Soumagne, J.C.

    1996-01-01

    Real-time simulation of a small power network containing a Marti modeled transmission line is made using 2 parallel DSP`s. A new fitting method is used in the modeling of the Marti line which is optimized with regards to the fitting error curve. Results are presented which show the time costs of the Marti line modeling versus constant-parameter line modeling and the time savings by using two parallel DSP`s.

  5. An interactive 2-D power-line modeling and simulation tool

    NASA Astrophysics Data System (ADS)

    Hull, David; Adelman, Ross

    2012-06-01

    The U.S. Army Research Laboratory's Power-Line unmanned aerial vehicle (UAV) Modeling and Simulation (ARL-PLUMS) is a tool for estimating and analyzing quasi-static electric and magnetic fields due to power lines. This tool consists of an interactive 2-D graphical user interface (GUI) and a compute engine that can be used to calculate and visualize the E-Field and H-Field due to as many as seven conductors (two 3-phase circuits and a ground wire). ARL-PLUMS allows the user to set the geometry of the lines and the load conditions on those lines, and then calculate Ey, Ez, Hy, or Hz along a linear path or cutting plane, or in the form of a movie. The path can be along the ground or in the air to simulate the fields that might be observed, for example, by a robotic vehicle or a UAV. ARL-PLUMS makes several simplifying assumptions in order to allow simulations to be completed on a laptop PC interactively. In most cases, the results are excellent, providing a "90% solution" in just a few minutes of total modeling and simulation time. This paper describes the physics used by ARL-PLUMS, including the simplifying assumptions and the 2-D Method of Moments solver. Examples of electric and magnetic fields for different wire configurations, including typical 3-phase distribution and transmissions lines, are provided. Comparisons to similar results using a full 3-D model are also shown, and a discussion of errors that may be expected from the 2-D simulations is provided.

  6. Mapping threats to power line corridors for Connecticut rights-of-way management.

    PubMed

    Poulos, H M; Camp, A E

    2011-02-01

    Trees are a major threat to power line security across forested regions of the world. We developed a decision support system for identifying locations in Connecticut, USA where trees have grown tall enough to make contact with transmission lines during storms. We used the Random Forest algorithm, danger tree presence/absence data, and 25 raster environmental datasets to develop (1) an understanding of the abiotic environmental settings that host danger trees and (2) a spatially explicit map of danger tree distributions across Connecticut power line corridors. Danger trees were prevalent in locations (1) with an infrequent history of storms; (2) forested and residential land uses; and (3) low to middle elevations. Products from this research can be transferred to adaptive right-of-way management because they present managers with key information on where danger trees are likely to occur, and the methods presented herein have great potential for future application to other regions managers seek to identify high priority areas for danger tree removal.

  7. Tracking Comb Filter Suppresses Welder Harmonics

    NASA Technical Reports Server (NTRS)

    Delcher, Ray C.

    1992-01-01

    Tracking comb filter includes charge-coupled-device delay line and phase-locked loop. Filter removes harmonics of frequency of repetition of welding-current pulses from acoustic-emission signal. Spurious signals reduced almost to fundamental limit.

  8. Intelligent Video Surveillance for Detecting Snow and Ice Coverage on Electrical Insulators of Power Transmission Lines

    NASA Astrophysics Data System (ADS)

    Gu, Irene Y. H.; Sistiaga, Unai; Berlijn, Sonja M.; Fahlström, Anders

    One of the problems for electrical power delivery through power lines in northern countries is when snow or ice accumulates on electrical insulators. This could lead to snow or ice-induced outages and voltage collapse, causing huge economic loss. This paper proposes a novel real-time intelligent surveillance and image analysis system for detecting and estimating the snow and ice coverage on electric insulators using images captured from an outdoor 420 kV power transmission line. In addition, the swing angle of insulators is estimated, as large swing angles due to wind cause short circuits. Hybrid techniques by combining histogram, edges, boundaries and cross-correlations are employed for handling a broad range of scenarios caused by changing weather and lighting conditions. Experiments have been conducted on the captured images over several month periods. Results have shown that the proposed system has provided valuable estimation results. For image pixels related to snows on the insulator, the current system has yielded an average detection rate of 93% for good quality images, and 67.6% for images containing large amount of poor quality ones, and the corresponding average false alarm ranges from 9% to 18.1%. Further improvement may be achieved by using video-based analysis and improved camera settings.

  9. Design method for a laser line beam shaper of a general 1D angular power distribution

    NASA Astrophysics Data System (ADS)

    Oved, E.; Oved, A.

    2016-05-01

    Laser line is a beam of laser, spanned in one direction using a beam shaper to form a fan of light. This illumination tool is important in laser aided machine vision, 3D scanners, and remote sensing. For some applications the laser line should have a specific angular power distribution. If the distribution is nonsymmetrical, the beam shaper is required to be nonsymmetrical freeform, and its design process using optical design software is time consuming due to the long optimization process which usually converges to some local minimum. In this paper we introduce a new design method of a single element refractive beam shaper of any predefined general 1D angular power distribution. The method makes use of a notion of "prism space", a geometrical representation of all double refraction prisms, and any 1D beam shaper can be described by a continuous curve in this space. It is shown that infinitely many different designs are possible for any given power distribution, and it is explained how an optimal design is selected among them, based on criteria such as high transmission, low surface slopes, robustness to manufacturing errors etc. The method is non-parametric and hence does not require initial guess of a functional form, and the resultant optical surfaces are described by a sequence of points, rather than by an analytic function.

  10. A proposal to Improve Electric Power Transmission Efficiency of the Transmission line from Yekepa to Buchanan of the CLSG Power System Redevelopment Interconnection Project Using FACTS Devices

    NASA Astrophysics Data System (ADS)

    Jackson, Samuel Mulbah

    This Work examined improving the electric power transmission efficiency of a portion of the CLSG (Cote d'Ivoire, Liberia, Sierra Leone, and Guinea) Interconnection Redevelopment Project of 1141 km high voltage transmission line. As with all ac transmission, present, new, and upgraded, they exhibit four electrical properties: resistance, inductance, capacitance, and conductance. These parameters affect the transmission line's ability to fulfil its function as part of the power system. A transmission system functions are to transport electric power from a generating source to a central point, to transport bulk power from a central point to wholesale delivery points (sub transmission substations), and to act as a tie points with interconnecting transmission lines from other power systems for emergency or economic reasons. In this work a portion of the CLSG Interconnection was simulated in MATLAB using different loading conditions. In determining voltage, current, and power, all sending end and receiving end quantities were determined at different sending end power levels. This was done on an incremental basis starting from 25 MW to 300 MW at 0.8 power factor. The results obtained from these produced data that were then used to plot graphs, among them the voltage profiles of the line at different loading conditions. The line loadability curves produced at different loading conditions were also plotted. So these curves provided illumination on the behavior and deficiencies of the line. Those deficiencies meant that there was a need for modification so as to keep the system in a safe operating voltage condition at different loading conditions. The line was compensated where needed, employing shunt capacitive compensation under different loading conditions for the purpose of making the receiving end voltage equal with the sending end voltage or within usable voltage levels. The line compensation provided a flat voltage profile at those loading conditions.

  11. Assessment of the ability of myocardial contrast echocardiography with harmonic power Doppler imaging to identify perfusion abnormalities in patients with Kawasaki disease at rest and during dipyridamole stress.

    PubMed

    Ishii, M; Himeno, W; Sawa, M; Iemura, M; Furui, J; Muta, H; Sugahara, Y; Egami, K; Akagi, T; Ishibashi, M; Kato, H

    2002-01-01

    The aim of our study was to assess the ability of myocardial contrast echocardiography (MCE) with harmonic power Doppler imaging (HPDI) to identify perfusion abnormalities in patients with Kawasaki disease at rest and during pharmacological stress imaging with dipyridamole. Results were compared with those of 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) imaging as the clinical reference standard. MCE with HPDI was performed on 20 patients with a history of Kawasaki disease. Images were obtained at baseline and during dipyridamole infusion (0.56 mg x kg(-1)) in the apical two- and four-chamber views. Myocardial opacification suitable for the analysis was obtained in all patients. Nine patients with stenotic lesions had a reversible defect after dipyridamole infusion detected by both MCE with HPDI and SPECT, and 3 patients with a history of myocardial infarction had a partially or completely irreversible defect detected by both methods. Three patients with coronary aneurysm without stenotic lesion, 4 patients with regressed coronary aneurysm, and 2 patients with normal coronary artery in acute phase also had normal perfusion at rest and after pharmacological stress by both methods. A 96% concordance (kappa = 0.87) was obtained when comparing the respective segmental perfusion scores using the two methods at baseline, and an 86% concordance (kappa = 0.81) was obtained at postdipyridamole infusion. After combining baseline and postdipyridamole images, each segment was labeled as having normal perfusion, irreversible defects, or reversible defects. Using these classifications, concordance for the two methods was 92% (kappa = 0.87). MCE with HPDI is a safe and feasible method by which to detect asymptomatic ischemia due to severe stenotic lesion, and it may be an important addition to the modalities used to identify patients at risk for myocardial infarction as a complication of Kawasaki disease.

  12. Implications of Field Line Tracing for Power and Particle Handling in NCSX

    NASA Astrophysics Data System (ADS)

    Grossman, A.; Mioduszewki, P. K.

    2002-11-01

    Recent experience with power and particle handling in W7-AS shows that there is substantial improvement when the plasma-wall interaction is systematized with the use of a divertor. The improvements with a divertor include achievement of record values of beta, increases in energy confinement with density, decreases in impurity and particle confinement and full density control. With the healing of islands just inside the LCMS of NCSX, the finite beta tracing of field lines outside of the LCMS via the MFBE_2001 code shows that a sufficiently long connection length (>100m) can be achieved to yield a temperature separation between divertor and LCMS sufficiently large for divertor operation. Significant flux expansion and stochastic field line structure with Kolmogorov lengths measuring several toroidal revolutions suggests that the divertor is a feasible option for NCSX.

  13. Solving Man-Induced Large-Scale Conservation Problems: The Spanish Imperial Eagle and Power Lines

    PubMed Central

    López-López, Pascual; Ferrer, Miguel; Madero, Agustín; Casado, Eva; McGrady, Michael

    2011-01-01

    Background Man-induced mortality of birds caused by electrocution with poorly-designed pylons and power lines has been reported to be an important mortality factor that could become a major cause of population decline of one of the world rarest raptors, the Spanish imperial eagle (Aquila adalberti). Consequently it has resulted in an increasing awareness of this problem amongst land managers and the public at large, as well as increased research into the distribution of electrocution events and likely mitigation measures. Methodology/Principal Findings We provide information of how mitigation measures implemented on a regional level under the conservation program of the Spanish imperial eagle have resulted in a positive shift of demographic trends in Spain. A 35 years temporal data set (1974–2009) on mortality of Spanish imperial eagle was recorded, including population censuses, and data on electrocution and non-electrocution of birds. Additional information was obtained from 32 radio-tracked young eagles and specific field surveys. Data were divided into two periods, before and after the approval of a regional regulation of power line design in 1990 which established mandatory rules aimed at minimizing or eliminating the negative impacts of power lines facilities on avian populations. Our results show how population size and the average annual percentage of population change have increased between the two periods, whereas the number of electrocuted birds has been reduced in spite of the continuous growing of the wiring network. Conclusions Our results demonstrate that solving bird electrocution is an affordable problem if political interest is shown and financial investment is made. The combination of an adequate spatial planning with a sustainable development of human infrastructures will contribute positively to the conservation of the Spanish imperial eagle and may underpin population growth and range expansion, with positive side effects on other endangered

  14. On-Line Condition Monitoring of a Power Transmission Unit of a Rail Vehicle

    NASA Astrophysics Data System (ADS)

    Deuszkiewicz, P.; Radkowski, S.

    2003-11-01

    The paper addresses the issue of selection of diagnostic parameters and methods of an object's condition classification. The research was conducted for a power transmission unit of a commuter train. We analysed the vibration of the axle box as measured on the track for systems before and after an overhaul. In the final part of the paper, we proposed an algorithm that can be used to identify the technical condition of a machine while using neural networks and we also described the operation of an on-line diagnostic system.

  15. Achieving EMC Emissions Compliance for an Aeronautics Power Line Communications System

    NASA Astrophysics Data System (ADS)

    Dominiak, S.; Vos, G.; ter Meer, T.; Widmer, H.

    2012-05-01

    Transmitting data over the power distribution network - Power Line Communications (PLC) -provides an interesting solution to reducing the weight and complexity of wiring networks in commercial aircraft. One of the potential roadblocks for the introduction of this technology is achieving EMC emissions compliance. In this article an overview of the EMC conducted and radiated emissions testing for PLC- enabled aeronautics equipment is presented. Anomalies resulting from chamber resonances leading to discrepancies between the conducted emissions tests and the measured radiated emissions are identified and described. Measurements made according to the current version of the civil aeronautical EMC standard, EUROCAE ED-14F (RTCA DO-160F), show that PLC equipment can achieve full EMC emissions compliance.

  16. Transmission line pulse system for avalanche characterization of high power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Riccio, Michele; Ascione, Giovanni; De Falco, Giuseppe; Maresca, Luca; De Laurentis, Martina; Irace, Andrea; Breglio, Giovanni

    2013-05-01

    Because of the increasing in power density of electronic devices for medium and high power application, reliabilty of these devices is of great interest. Understanding the avalanche behaviour of a power device has become very important in these last years because it gives an indication of the maximum energy ratings which can be seen as an index of the device ruggedness. A good description of this behaviour is given by the static IV blocking characteristc. In order to avoid self heating, very relevant in high power devices, very short pulses of current have to be used, whose value can change from few milliamps up to tens of amps. The most used method to generate short pulses is the TLP (Transmission Line Pulse) test, which is based on charging the equivalent capacitance of a transmission line to high value of voltage and subsequently discharging it onto a load. This circuit let to obtain very short square pulses but it is mostly used for evaluate the ESD capability of semiconductor and, in this environment, it generates pulses of low amplitude which are not high enough to characterize the avalanche behaviour of high power devices . Advanced TLP circuit able to generate high current are usually very expensive and often suffer of distorption of the output pulse. In this article is proposed a simple, low cost circuit, based on a boosted-TLP configuration, which is capable to produce very square pulses of about one hundreds of nanosecond with amplitude up to some tens of amps. A prototype is implemented which can produce pulses up to 20A of amplitude with 200 ns of duration which can characterize power devices up to 1600V of breakdown voltage. Usage of microcontroller based logic make the circuit very flexible. Results of SPICE simulation are provided, together with experimental results. To prove the effectiveness of the circuit, the I-V blocking characteristics of two commercial devices, namely a 600V PowerMOS and a 1200V Trench-IGBT, are measured at different

  17. High power microwave beam steering based on gyromagnetic nonlinear transmission lines

    SciTech Connect

    Romanchenko, I. V. Rostov, V. V.; Gunin, A. V.; Konev, V. Yu.

    2015-06-07

    We demonstrate electronically controlled beam steering by high power RF pulses produced by two gyromagnetic nonlinear transmission lines (NLTLs) connected to a one high voltage driver. Each NLTL is capable of producing several ns RF pulses with peak power from 50 to 700 MW (6% standard deviation) at frequencies from 0.5 to 1.7 GHz (1% standard deviation) with 100 Hz repetition rate. Using a helix antenna allows irradiating of RF pulses with almost circular polarization and 350 MW maximum peak power, which corresponds to 350 kV effective potential of radiation. At the installation of two identical channels, we demonstrate the possibility of beam steering within ±15° in the horizontal plane by coherent RF pulses with circular polarization at 1.0 GHz center frequency. Fourfold increase in the power flux density for in-phase irradiation of RF pulses is confirmed by comparison with one-channel operation.

  18. Nonlinearity of superconducting transmission line and microstrip resonator

    SciTech Connect

    Vendik, O.G.; Vendik, I.B.; Samoilova, T.B.

    1997-02-01

    The simplest model of nonlinear response of a superconducting thin film is used for modeling the nonlinear phenomena in a superconducting transmission line and a microstrip resonator. The specified characteristic power of the transmission line is suggested to use as a fitting parameter for numerical description of the microstrip line nonlinearity at microwaves. Quantitative agreement of simulated and experimental data has been obtained for the incident power dependent transmission coefficient of a microstrip line section and a high quality microstrip resonator. Numerical results have also been obtained for the power of the third harmonic radiated from the nonlinear resonator.

  19. Assessment of frequent cutting as a plant-community management technique in power-line corridors

    NASA Astrophysics Data System (ADS)

    Luken, James O.; Hinton, Andrew C.; Baker, Douglas G.

    1991-05-01

    Repeated cutting of vegetation at or near ground level in power-line corridors is a common practice for inhibiting tree growth and regeneration. However, few data exist on long-term community responses. In this study, we sampled 20 northern Kentucky power-line corridors and compared their seedling and sapling communities to the edges and interiors of adjacent undisturbed forests. Mean seedling and sapling density in corridors was roughly twice that of adjacent undisturbed forest interiors, suggesting that repeated cutting is not a viable method of inhibiting tree regeneration. Corridor communities were dominated by Robinia pseudoacacia (black locust) and Fraxinus americana (white ash), but ordinations indicated strong similaritties among communities in corridors and adjacent forests. Many of the tree species found in adjacent forests, with the exception of a few shade-tolerant species, had highest seedling and sapling densities in corridors. Stump or root sprouting by many species appears to regenerate forests quickly after cutting. However, disturbed soil and detritus accumulations caused by management crews and their equipment may also create a large variety of microsites for seedling establishment. Because repeated cutting selects for dominance by species with highest sprout growth rates, it should not be used as the sole management technique. It may instead be used to alter the vigor, stature, and stored reserves of trees so that herbicides or other methods of tree control can be used more efficiently.

  20. A power line data communication interface using spread spectrum technology in home automation

    SciTech Connect

    Shwehdi, M.H.; Khan, A.Z.

    1996-07-01

    Building automation technology is rapidly developing towards more reliable communication systems, devices that control electronic equipments. These equipment if controlled leads to efficient energy management, and savings on the monthly electricity bill. Power Line communication (PLC) has been one of the dreams of the electronics industry for decades, especially for building automation. It is the purpose of this paper to demonstrate communication methods among electronic control devices through an AC power line carrier within the buildings for more efficient energy control. The paper outlines methods of communication over a powerline, namely the X-10 and CE bus. It also introduces the spread spectrum technology as to increase speed to 100--150 times faster than the X-10 system. The powerline carrier has tremendous applications in the field of building automation. The paper presents an attempt to realize a smart house concept, so called, in which all home electronic devices from a coffee maker to a water heater microwave to chaos robots will be utilized by an intelligent network whenever one wishes to do so. The designed system may be applied very profitably to help in energy management for both customer and utility.

  1. Current densities and total contact currents associated with 400 kV power line tasks.

    PubMed

    Korpinen, Leena; Kuisti, Harri; Elovaara, Jarmo

    2013-12-01

    The aim of the study was to analyze all current values from measured periods while performing tasks on 400 kV power lines. Our aim was also to study the average current densities and average total contact currents caused by electric fields in 400 kV power line tasks. Two workers simulated the following tasks: (A) climbing up a portal tower, (B) climbing up a portal transposing tower, (C) working on the cross-arm of a portal tower, (D) climbing up a portal tube tower, (E) climbing up a Tannenbaum tower on the side of the energized circuit with the other circuit unenergized, (F) climbing up a Tannenbaum tower with both circuits energized, and (G) climbing up a Donau tower. The highest average current density in the neck was 2.5 mA/m(2) (calculated internal electric field 31.5-63.0 mV/m), and the highest average of the contact currents was 240.0 µA. All measured values at 400 kV towers were lower than the limit value of 10 mA/m(2) in the first version of Directive 2004/40/EC and the basic restrictions (0.1 and 0.8 V/m) of the International Commission on Non-ionizing Radiation Protection.

  2. Treatment of biodiversity issues in impact assessment of electricity power transmission lines: A Finnish case review

    SciTech Connect

    Soederman, Tarja . E-mail: tarja.soderman@ymparisto.fi

    2006-05-15

    The Environmental Impact Assessment (EIA) process concerning the route of a 400 kV power transmission line between Loviisa and Hikiae in southern Finland was reviewed in order to assess how biodiversity issues are treated and to provide suggestions on how to improve the effectiveness of treatment of biodiversity issues in impact assessment of linear development projects. The review covered the whole assessment process, including interviews of stakeholders, participation in the interest group meetings and review of all documents from the project. The baseline studies and assessment of direct impacts in the case study were detailed but the documentation, both the assessment programme and the assessment report, only gave a partial picture of the assessment process. All existing information, baseline survey and assessment methods should be addressed in the scoping phase in order to promote interaction between all stakeholders. In contrast to the assessment of the direct effects, which first emphasized impacts on the nationally important and protected flying squirrel but later expanded to deal with the assessment of impacts on ecologically important sites, the indirect and cumulative impacts of the power line were poorly addressed. The public was given the opportunity to become involved in the EIA process. However, they were more concerned with impacts on their properties and less so on biodiversity and species protection issues. This suggests that the public needs to become more informed about locally important features of biodiversity.

  3. The role of power line rights-of-way as an alternative habitat for declined mire butterflies.

    PubMed

    Lensu, Terhi; Komonen, Atte; Hiltula, Outi; Päivinen, Jussi; Saari, Veli; Kotiaho, Janne S

    2011-10-01

    Habitat loss is one of the greatest threats for biodiversity. In Finland, two thirds of natural mires have been drained for silviculture, which transforms open wetlands into dense forests. However, vegetation management of power line rights-of-way (ROW) maintain the drained mires as open areas. The aim of this study was to determine the effect of the power line ROW vegetation management on butterfly abundance, species richness and community structure by comparing the managed power line ROWs to unmanaged drained control sites and to natural mires. The species richness or abundance of mire butterflies did not differ between the power line ROWs and natural mires. In contrast, both species richness and abundance of butterflies was low on the unmanaged control sites. Tree canopy cover had a negative effect on mire butterflies and this is most likely related to changes in microclimate. The results indicate that the active vegetation removal in the power line ROWs maintain alternative habitats for mire butterflies; yet, the power line ROWs cannot substitute the natural mires.

  4. 75 FR 75170 - Minnkota Power Cooperative, Inc.: Bemidji to Grand Rapids 230 kV Transmission Line Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-02

    ... Rural Utilities Service Minnkota Power Cooperative, Inc.: Bemidji to Grand Rapids 230 kV Transmission... to Grand Rapids 230 kV Transmission Line Project (Project) in Beltrami, Hubbard, Itasca, and Cass... construct the 230 kilovolt (kV) transmission line between the Wilton Substation near Bemidji, Minnesota...

  5. 40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment ENVIRONMENTAL... power line voltage and ambient temperature. (a) Overview. (1) This test procedure is a combined... temperature. Tests shall be conducted in a temperature-controlled environment over four 6-hour time...

  6. Harmonics and instabilities in switching circuits. Final Report

    SciTech Connect

    Lasseter, R.H.; Dobson, I.; Jalali, S.G.

    1993-05-01

    Over the last couple of years there has been significant activity in the development of Flexible AC Transmission Systems (FACTS). Much of this work has been directed towards advanced series compensation (ASC) systems based on a Thyristor Controlled Reactor (TCR) connected in parallel with a fixed capacitor. This results in a controllable series impedance element for use in transmission systems. FACTS devices generate harmonics which interact with the transmission system causing voltage distortions. These distortions can change the operation of such circuits. The authors have found new instabilities in both FACTS and static VAR circuits in which switching times change suddenly, or bifurcate as a system parameter varies slowly. The switching time bifurcation instabilities are explained and their mechanisms are illustrated by both analysis and simulation. The TCR is a periodically operated, nonlinear circuit which may be studied using a Poincare map. The Poincare map is computed and a simple formula for its Jacobian matrix is derived. This formula which describes the stability of the steady state periodic operation of the circuit is used to demonstrate that conventional bifurcations do not occur in this TCR example. The harmonic coupling solution method as developed by Bohmann and Lasseter has been extensively used to compute the steady state solutions of the TCR circuits. In this method, Fourier techniques are used to calculate the system harmonics. By expressing the TCR voltage and current as a Fourier series, a TCR harmonic admittance matrix is constructed and incorporated into a power system providing a general method of computing the power system harmonics. The authors have extended this method to single phase line commutated converters and shown how much circuit may have highly nonlinear and unexpected behavior.

  7. Power lines: Urban space, energy development and the making of the modern Southwest

    NASA Astrophysics Data System (ADS)

    Needham, Todd Andrew

    "Power Lines: Urban Space, Energy Development, and the Making of the Modern Southwest" explores the social and environmental transformation of the postwar Southwest and the resulting disputes between urban boosters, federal officials, Native Americans, and environmental activists. The dissertation focuses on the infrastructure built to provide the burgeoning populations of Phoenix, Los Angeles, and other Southwestern cities with electricity. This infrastructure allowed metropolitan boosters in the Southwest to attract Cold War defense manufacturing and to build a new suburban landscape even as industrialization on Indian lands provided electricity for those landscapes. Tracing the transition of electrical generation from a dispersed geography relying on local resources to a centralized geography utilizing primarily coal from Navajo land, "Power Lines" demonstrates the increasing centrality of Indian lands and labor to the metropolitan Southwest. Paying close attention to these networks reveals the far-reaching changes caused by postwar metropolitan growth. "Power Lines" challenges understandings of urban space that neglect the material resources that allow cities to "live." As the nation's cities and suburbs became increasingly energy-intensive, electrical utilities reached deep into the metropolitan periphery, transforming landscapes hundreds of miles from city centers into urban space. The construction of the new "geography of power" in the Southwest also reflects the impact of growth liberalism on postwar growth, as federal money funded suburban, manufacturing, and infrastructure developments. This pursuit of growth produced new political struggles, both as the development of energy resources conflicted with emerging environmentalist sensibilities and as American Indians increasingly resented the industrialization of their land for the benefit of others. By the 1970s, the simultaneous pursuit and criticism of growth came to define the modern Southwest. The

  8. On-line calibration of process instrumentation channels in nuclear power plants

    SciTech Connect

    Hashemian, H.M.; Farmer, J.P.

    1995-04-01

    An on-line instrumentation monitoring system was developed and validated for use in nuclear power plants. This system continuously monitors the calibration status of instrument channels and determines whether or not they require manual calibrations. This is accomplished by comparing the output of each instrument channel to an estimate of the process it is monitoring. If the deviation of the instrument channel from the process estimate is greater than an allowable limit, then the instrument is said to be {open_quotes}out of calibration{close_quotes} and manual adjustments are made to correct the calibration. The success of the on-line monitoring system depends on the accuracy of the process estimation. The system described in this paper incorporates both simple intercomparison techniques as well as analytical approaches in the form of data-driven empirical modeling to estimate the process. On-line testing of the calibration of process instrumentation channels will reduce the number of manual calibrations currently performed, thereby reducing both costs to utilities and radiation exposure to plant personnel.

  9. Seasonal and Local Characteristics of Lightning Outages of Power Distribution Lines in Hokuriku Area

    NASA Astrophysics Data System (ADS)

    Sugimoto, Hitoshi; Shimasaki, Katsuhiko

    The proportion of the lightning outages in all outages on Japanese 6.6kV distribution lines is high with approximately 20 percent, and then lightning protections are very important for supply reliability of 6.6kV lines. It is effective for the lightning performance to apply countermeasures in order of the area where a large number of the lightning outages occur. Winter lightning occurs in Hokuriku area, therefore it is also important to understand the seasonal characteristics of the lightning outages. In summer 70 percent of the lightning outages on distribution lines in Hokuriku area were due to sparkover, such as power wire breakings and failures of pole-mounted transformers. However, in winter almost half of lightning-damaged equipments were surge arrester failures. The number of the lightning outages per lightning strokes detected by the lightning location system (LLS) in winter was 4.4 times larger than that in summer. The authors have presumed the occurrence of lightning outages from lightning stroke density, 50% value of lightning current and installation rate of lightning protection equipments and overhead ground wire by multiple regression analysis. The presumed results suggest the local difference in the lightning outages.

  10. Health monitoring of electric power communication line using a distributed optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Lu, Lidong; Liang, Yun; Li, Binglin; Guo, Jinghong; Zhang, Hao; Zhang, Xuping

    2014-11-01

    Optical fiber ground wire (OPGW) is used for both the earth line and communication line in electric power systems. It is important to find an effective to monitor the status of OPGW and diagnose some possible damages. Fault location of the optical fiber transmission line, lightning stroke location and early-warning of ice covering of OPGW are common tasks for OPGW health monitoring and maintenance. As to these issues, Brillouin optical time domain reflectometry (BOTDR) is employed for the health monitoring of OPGW. In experiment, a positive electrode with high pulsed current and a negative electrode are adopted to form a lightning impulse system with duration time of 200ms for simulation of the lightning stroke process, and a tensile force loading apparatus is also constructed to simulate the strain influence of the ice covering on the OPGW. Experimental results demonstrate that the BOTDR can sensitively locate the lightning stroke incidents with the quantity of electric discharging larger than 100C and the strain component has little interference on temperature monitoring as the fiber contained in the OPGW is generally free of strain, and in the ice covering condition the strain feature appears only when the extra tensile force on the OPGW is over 30kN. In addition, the vibration of OPGW does not disturb both the temperature and strain monitoring. As to further applications of distributed optical fiber sensors (DOFS) for the OPGW health monitoring, it is important to enhance its spatial resolution.

  11. Wire Marking Results in a Small but Significant Reduction in Avian Mortality at Power Lines: A BACI Designed Study

    PubMed Central

    Barrientos, Rafael; Ponce, Carlos; Palacín, Carlos; Martín, Carlos A.; Martín, Beatriz; Alonso, Juan Carlos

    2012-01-01

    Background Collision with electric power lines is a conservation problem for many bird species. Although the implementation of flight diverters is rapidly increasing, few well-designed studies supporting the effectiveness of this costly conservation measure have been published. Methodology/Principal Findings We provide information on the largest worldwide marking experiment to date, including carcass searches at 35 (15 experimental, 20 control) power lines totalling 72.5 km, at both transmission (220 kV) and distribution (15 kV–45 kV) lines. We found carcasses of 45 species, 19 of conservation concern. Numbers of carcasses found were corrected to account for carcass losses due to removal by scavengers or being overlooked by researchers, resulting in an estimated collision rate of 8.2 collisions per km per month. We observed a small (9.6%) but significant decrease in the number of casualties after line marking compared to before line marking in experimental lines. This was not observed in control lines. We found no influence of either marker size (large vs. small spirals, sample of distribution lines only) or power line type (transmission vs. distribution, sample of large spirals only) on the collision rate when we analyzed all species together. However, great bustard mortality was slightly lower when lines were marked with large spirals and in transmission lines after marking. Conclusions Our results confirm the overall effectiveness of wire marking as a way to reduce, but not eliminate, bird collisions with power lines. If raw field data are not corrected by carcass losses due to scavengers and missed observations, findings may be biased. The high cost of this conservation measure suggests a need for more studies to improve its application, including wire marking with non-visual devices. Our findings suggest that different species may respond differently to marking, implying that species-specific patterns should be explored, at least for species of conservation

  12. Computer vision-guided robotic system for electrical power lines maintenance

    NASA Astrophysics Data System (ADS)

    Tremblay, Jack; Laliberte, T.; Houde, Regis; Pelletier, Michel; Gosselin, Clement M.; Laurendeau, Denis

    1995-12-01

    The paper presents several modules of a computer vision assisted robotic system for the maintenance of live electrical power lines. The basic scene of interest is composed of generic components such as a crossarm, a power line and a porcelain insulator. The system is under the supervision of an operator which validates each subtask. The system uses a 3D range finder mounted at the end effector of a 6 dof manipulator for the acquisition of range data on the scene. Since more than one view is required to obtain enough information on the scene, a view integration procedure is applied to the data in order to merge the information in a single reference frame. A volumetric description of the scene, in this case an octree, is built using the range data. The octree is transformed into an occupancy grid which is used for avoiding collisions between the manipulator and the components of the scene during the line manipulation step. The collision avoidance module uses the occupancy grid to create a discrete electrostatic potential field representing the various goals (e.g. objects of interest) and obstacles in the scene. The algorithm takes into account the articular limits of the robot and uses a redundant manipulator to ensure that the collision avoidance constraints do not compete with the task which is to reach a given goal with the end-effector. A pose determination algorithm called Iterative Closest Point is presented. The algorithm allows to compute the pose of the various components of the scene and allows the robot to manipulate these components safely. The system has been tested on an actual scene. The manipulation was successfully implemented using a synchronized geometry range finder mounted on a PUMA 760 robot manipulator under the control of Cartool.

  13. Voltage harmonic elimination with RLC based interface smoothing filter

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, K.; Ramachandaramurthy, V. K.

    2015-04-01

    A method is proposed for designing a Dynamic Voltage Restorer (DVR) with RLC interface smoothing filter. The RLC filter connected between the IGBT based Voltage Source Inverter (VSI) is attempted to eliminate voltage harmonics in the busbar voltage and switching harmonics from VSI by producing a PWM controlled harmonic voltage. In this method, the DVR or series active filter produces PWM voltage that cancels the existing harmonic voltage due to any harmonic voltage source. The proposed method is valid for any distorted busbar voltage. The operating VSI handles no active power but only harmonic power. The DVR is able to suppress the lower order switching harmonics generated by the IGBT based VSI. Good dynamic and transient results obtained. The Total Harmonic Distortion (THD) is minimized to zero at the sensitive load end. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of RLC filter. Simulated results are presented.

  14. Color harmonization for images

    NASA Astrophysics Data System (ADS)

    Tang, Zhen; Miao, Zhenjiang; Wan, Yanli; Wang, Zhifei

    2011-04-01

    Color harmonization is an artistic technique to adjust a set of colors in order to enhance their visual harmony so that they are aesthetically pleasing in terms of human visual perception. We present a new color harmonization method that treats the harmonization as a function optimization. For a given image, we derive a cost function based on the observation that pixels in a small window that have similar unharmonic hues should be harmonized with similar harmonic hues. By minimizing the cost function, we get a harmonized image in which the spatial coherence is preserved. A new matching function is proposed to select the best matching harmonic schemes, and a new component-based preharmonization strategy is proposed to preserve the hue distribution of the harmonized images. Our approach overcomes several shortcomings of the existing color harmonization methods. We test our algorithm with a variety of images to demonstrate the effectiveness of our approach.

  15. Second Harmonic Breakdown in KSTAR

    SciTech Connect

    Bae, Y. S.; England, A. C.; Kwon, M.; Lee, G. S.

    2007-09-28

    An 84-GHz electron cyclotron heating (ECH) system is being installed on the KSTAR tokamak. KSTAR adopts ECH-assisted start-up for the flexibility and reliability of the KSTAR operation with the plasma breakdown voltage reduced. The available maximum power of the 84 GHz ECH system is presently 500 kW with maximum duration of 2 s. Currently, the second harmonic ECH-assisted start-up is under consideration because a low toroidal field of B{sub T}{approx}1.5 T is desirable for safety and also for the high-beta experiments in the initial operation phase. The studies in this paper are on the effectiveness of the second harmonic breakdown using a 0-D time dependent plasma evolution code and the comparison with the recent DIII-D experimental results on the second harmonic pre-ionization.

  16. Application of offset-CT scanning to the inspection of high power feeder lines and connections

    NASA Astrophysics Data System (ADS)

    Schneberk, Daniel; Maziuk, Robert; Soyfer, Boris; Shashishekhar, N.; Alreja, Rahul

    2016-02-01

    VJT is developing techniques and scanning methods for the in-situ Radiographic and Computed Tomographic inspection of underground high-power feeder cables. The goals for the inspection are to measure the 3D state of the cables and the cable-connections. Recent in-situ Digital Radiographic inspections performed by VJT have demonstrated the value of NDE inspection information for buried power lines. These NDE data have raised further questions as to the exact state of the cables and connections and pointed to the need for more 3D information of the type provided by volumetric CT scanning. VJT is pursuing a three phased approach to address the many issues involved in this type of inspection: 1) develop a high-power feeder-cable test-bed CT scanner, 2) acquire scans on underground feeder pipes that have been removed from service, and 3) from the work in 1) and 2) develop limited-angle CT scanning methods for extending in-situ Digital Radiography to volumetric CT measurements. To this end, VJT has developed and fielded a high-energy test-bed Gantry-type CT scanner (the source and detector move around the object) with a number of important properties. First, the geometry of the gantry-scans can be configured to match the techniques used in the in-situ radiographic inspection. The same X-ray source is employed as in portable Radiographic inspections, a 7.5 MeV Betatron coupled to a Perkin-Elmer Amorphous Silicon detector. Offset-CT scanning is employed as the high-power feeder line assembly is larger than the detector. A description of this scanner and the scan geometry will be presented showing the connection to in-situ radiography. Results from the CT scans of high-power feeder-cable specimens removed from service will be presented with a focus on the inspection potential of volumetric CT data on these assemblies. An evaluation of the scan performance properties of these data compared to the spectrum of life-cycle inspection issues will be presented. Continuing and

  17. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

    National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

  18. Novel high-frequency, high-power, pulsed oscillator based on a transmission line transformer.

    PubMed

    Burdt, R; Curry, R D

    2007-07-01

    Recent analysis and experiments have demonstrated the potential for transmission line transformers to be employed as compact, high-frequency, high-power, pulsed oscillators with variable rise time, high output impedance, and high operating efficiency. A prototype system was fabricated and tested that generates a damped sinusoidal wave form at a center frequency of 4 MHz into a 200 Omega load, with operating efficiency above 90% and peak power on the order of 10 MW. The initial rise time of the pulse is variable and two experiments were conducted to demonstrate initial rise times of 12 and 3 ns, corresponding to a spectral content from 4-30 and from 4-100 MHz, respectively. A SPICE model has been developed to accurately predict the circuit behavior and scaling laws have been identified to allow for circuit design at higher frequencies and higher peak power. The applications, circuit analysis, test stand, experimental results, circuit modeling, and design of future systems are all discussed.

  19. Investigation of potential driver modules and transmission lines for a high frequency power system on the space station

    NASA Technical Reports Server (NTRS)

    Brush, Harold T.

    1986-01-01

    The feasibility of using Series Resonant Inverter as the driver module for high frequency power system on the Space Station was assessed. The performance of the Series Resonant Inverter that was used in the testing of the single-phase, 2.0-kw resonant AC power system breadboard is summarized. The architecture is descirbed and the driver modules of the 5.0 kw AC power system breadboard are analyzed. An investigation of the various types of transmission lines is continued. Measurements of equivalent series resistor and inductor and equivalent parallel capacitors are presented. In particular, a simplified approach is utilized to describe the optimal transmission line.

  20. Multilayer optics to be used as FEL fundamental suppressors for harmonics selection

    NASA Astrophysics Data System (ADS)

    Pelizzo, M. G.; Corso, A. J.; Monaco, G.; Nicolosi, P.; Suman, M.; Zuppella, P.; Cocco, D.

    2011-04-01

    Pump and probe experiments are one of the most attractive and powerful tools offered by a free electron laser facility. In these experiments it is fundamental to pump the system with a particular wavelength (usually the fundamental one) and to probe it with a second wavelength (e.g. higher emitted harmonics). Radiation emitted at the fundamental wavelength is 100 or more times the number of photons emitted in higher harmonics; selection of higher harmonics can be therefore critical. Multilayer (ML) mirrors that are able to provide high reflectivity peak at the desired harmonic wavelength while rejecting the fundamental have been designed and their application is foreseen to the FERMI@Elettra FEL beam transport system. The photon beam will be split into two and one of these will pass through a set of ML mirrors optimized for third harmonics selection; this scheme is also useable to realize a delay line in which the few nanosecond time delay will be controlled by changing the mirrors distance. A set of target wavelengths has been considered and multilayer structure materials have been selected. The MLs have been designed using a method based on the control of standing wave distribution at the fundamental and third harmonics wavelength, using a capping layer as a key element to achieve the willing rejection. Fabrication and test of such structures are foreseen.

  1. Flight route Designing and mission planning Of power line inspecting system Based On multi-sensor UAV

    NASA Astrophysics Data System (ADS)

    Xiaowei, Xie; Zhengjun, Liu; Zhiquan, Zuo

    2014-03-01

    In order to obtain various information of power facilities such as spatial location, geometry, images data and video information in the infrared and ultraviolet band and so on, Unmanned Aerial Vehicle (UAV) power line inspecting system needs to integrate a variety of sensors for data collection. Low altitude and side-looking imaging are required for UAV flight to ensure sensors to acquire high-quality data and device security. In this paper, UAV power line inspecting system is deferent from existing ones that used in Surveying and Mapping. According to characteristics of UAV for example equipped multiple sensor, side-looking imaging, working at low altitude, complex terrain conditions and corridor type flight, this paper puts forward a UAV power line inspecting scheme which comprehensively considered of the UAV performance, sensor parameters and task requirements. The scheme is finally tested in a region of Guangdong province, and the preliminary results show that the scheme is feasible.

  2. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  3. Efficient Second Harmonic Conversion of Broadband High-Peak-Power Nd:Glass Laser Radiation Using Large-Aperture KDP Crystals in Quadrature

    DTIC Science & Technology

    1989-06-23

    pp. 3633-3643, October 1982. 16. W. Seka, S. D. Jacobs, J. E. Rizzo , R. Boni, and R. S. Craxton, ’Demonstration of High Efficiency Third Harmonic...2156-2170, November 1980. 26. N. Bloembergen, Nonlinear Optics. New York: Benjamin , 1965. 27. J. F. Reintjes, Naval Research Laboratory, private comm

  4. Unsupervised learning technique for surface electromyogram denoising from power line interference and baseline wander.

    PubMed

    Niegowski, Maciej; Zivanovic, Miroslav; Gomez, Marisol; Lecumberri, Pablo

    2015-01-01

    We present a novel approach to single-channel power line interference (PLI) and baseline wander (BW) removal from surface electromyograms (EMG). It is based on non-negative matrix factorization (NMF) using a priori knowledge about the interferences. It performs a linear decomposition of the input signal spectrogram into non-negative components, which represent the PLI, BW and EMG spectrogram estimates. They all exhibit very different time-frequency patterns: PLI and BW are both sparse whereas EMG is noise-like. Initialization of the classical NMF algorithm with accurately designed PLI, BW and EMG structures and a carefully adjusted matrix decomposition rank increases the separation performance. The comparative study suggests that the proposed method outperforms two state-of-the-art reference methods.

  5. Spectral response of atmospheric electric field measurements near AC high voltage power lines

    NASA Astrophysics Data System (ADS)

    Silva, H. G.; Matthews, J. C.; Wright, M. D.; Shallcross, D. E.

    2015-10-01

    To understand the influence of corona ion emission on the atmospheric electrical field, measurements were made near to two AC high voltage power lines. A JCI 131 field-mill recorded the atmospheric electric field over one year. Meteorological measurements were also taken. The data series is divided in four zones (dependent on wind direction): whole zones, Z0; zone 1, Z1; zone 2, Z2; zone 3, Z3. Z3 is the least affected by corona ion emission and for that reason it is used as a reference against Z1 and Z2, which are strongly influenced by this phenomena. Analysis was undertaken for all weather days and dry days only. The Lomb-Scargle strategy developed for unevenly spaced time-series is used to calculate the spectral response of the aforementioned zones. Only frequencies above 1 minute are considered.

  6. Measurements of induced voltages and currents in a distribution power line and associated atmospheric parameters

    NASA Technical Reports Server (NTRS)

    Santiago-Perez, Julio

    1988-01-01

    The frequency and intensity of thunderstorms around the Kennedy Space Center (KSC) has affected scheduled launch, landing, and other ground operations for many years. In order to protect against and provide safe working facilities, KSC has performed and hosted several studies on lightning phenomena. For the reasons mentioned above, KSC has established the Atmospheric Science Field Laboratory (ASFL). At these facilities KSC launches wire-towing rockets into thunderstorms to trigger natural lightning to the launch site. A program named Rocket Triggered Lightning Program (RTLP) is being conducted at the ASFL. This report calls for two of the experiments conducted in the summer 1988 Rocket Triggered Lightning Program. One experiment suspended an electric field mill over the launching areas from a balloon about 500 meters high to measure the space charges over the launching area. The other was to connect a waveform recorder to a nearby distribution power line to record currents and voltages wave forms induced by natural and triggered lightning.

  7. Ergonomics hazards analysis of linemen's power line fixing work in China.

    PubMed

    Yu, Ming; Sun, Linyan; Du, Jianhua; Wu, Fengge

    2009-01-01

    This study used qualitative and quantitative methods, such as OWAS (Ovako working posture analysis system) and behavior observation, to analyze musculoskeletal disorder (MSD) risk factors of power line fixing work in China. Video-based sampling was used to record and analyze the frequency and posture of on-pole activities. Those key subtasks showed ergonomics characteristics of on-pole fixing tasks. Insulator-fixing was the longest subtask (33% of total working time). Bar-installing was the second longest (26% of total working time). It was evident that bar-installing and insulator-fixing were full of hazardous risks. The action categories of the 2 subtasks were higher than of the other ones. The 2 subtasks were also time-consuming, difficult and induced MSDs. Assistant linemen faced more hazardous factors than chief linemen.

  8. Tucson Electric Power Company Sahuarita-Nogales Transmission Line Draft Environmental Impact Statement

    SciTech Connect

    N /A

    2003-08-27

    Tucson Electric Power Company (TEP) has applied to the U.S. Department of Energy (DOE) for a Presidential Permit to construct and operate a double-circuit, 345,000-volt (345-kV) electric transmission line across the United States border with Mexico. Under Executive Order (EO) 10485 of September 3, 1953, as amended by EO 12038 of February 3, 1978, a Presidential Permit is required to construct, connect, operate, or maintain facilities at the U.S. international border for the transmission of electric energy between the United States and a foreign country. DOE has determined that the issuance of a Presidential Permit to TEP for the proposed project would constitute a major Federal action that may have a significant impact on the environment within the meaning of the ''National Environmental Policy Act of 1969'' (NEPA) 42 United States Code (U.S.C.) {section}4321 et seq. For this reason, DOE has prepared this Draft Environmental Impact Statement (EIS) to evaluate potential environmental impacts from the proposed Federal action (granting a Presidential Permit for the proposed transmission facilities) and reasonable alternatives, including the No Action Alternative. This EIS was prepared in accordance with Section 102(2)(c) of NEPA, Council of Environmental Quality (CEQ) regulations (40 Code of Federal Regulations [CFR] 1500-1508), and DOE NEPA Implementing Procedures (10 CFR 1021). DOE is the lead Federal Agency, as defined by 40 CFR 1501.5. The U.S. Department of Agriculture Forest Service (USFS), the Bureau of Land Management (BLM) of the U.S. Department of the Interior, and the U.S. Section of the International Boundary and Water Commission, U.S. and Mexico (USIBWC), are cooperating agencies. Each of these organizations will use the EIS for its own NEPA purposes, as described in the Federal Agencies' Purpose and Need and Authorizing Actions section of this summary. The 345-kV double-circuit transmission line would consist of twelve transmission line wires, or

  9. On-line mechanical tube cleaning for steam electric power plants. Final report

    SciTech Connect

    Not Available

    1994-02-18

    In July 1991, Superior I.D. Tube Cleaners, Inc. (SIDTEC{trademark}) received a grant through the Department of Energy and the Energy Related Invention Program to conduct a long term demonstration of a proprietary technology for on-line mechanical condenser tube cleaning in thermal Power plants on open or once-through cooling water systems where the warmed condenser cooling water is discharged through a canal. The purpose of the demonstration was to confirm and establish the use of this mechanical method as an alternative to the application of chemical biocides in condenser cooling water for the control of biofouling, the growth of micro-organisms which can reduce a unit`s operating efficiency. The SIDTEC on-line mechanical tube cleaner, the Rocket{trademark}, is used to physically remove accumulated deposits on the water side of the main steam condenser, and the non-intrusive tube cleaner recovery system, the Skimmer{trademark}, is used to recover and recirculate tube cleaners. The periodic circulation of tube cleaners can maintain optimum condenser cleanliness and improve unit heat rate. Thermal power plants which discharge condenser cooling water through a canal now have a viable alternative to the chemical treatment of condenser cooling water, whether the principal foulant is biofouling, chemical scaling, silting, or a combination of the three. At prices competitive with scale inhibitors, and a fraction of competing mechanical systems, this technology is provided as a service requiring no capital investment; minimal retrofit modifications to plant structures or equipment; can be installed and maintained without a unit shutdown; does not add any restrictions in the cooling water system; and is environmentally benign.

  10. Imprint of DESI fiber assignment on the anisotropic power spectrum of emission line galaxies

    NASA Astrophysics Data System (ADS)

    Pinol, Lucas; Cahn, Robert N.; Hand, Nick; Seljak, Uroš; White, Martin

    2017-04-01

    The Dark Energy Spectroscopic Instrument (DESI), a multiplexed fiber-fed spectrograph, is a Stage-IV ground-based dark energy experiment aiming to measure redshifts for 29 million Emission-Line Galaxies (ELG), 4 million Luminous Red Galaxies (LRG), and 2 million Quasi-Stellar Objects (QSO). The survey design includes a pattern of tiling on the sky, the locations of the fiber positioners in the focal plane of the telescope, and an observation strategy determined by a fiber assignment algorithm that optimizes the allocation of fibers to targets. This strategy allows a given region to be covered on average five times for a five-year survey, with a typical variation of about 1.5 about the mean, which imprints a spatially-dependent pattern on the galaxy clustering. We investigate the systematic effects of the fiber assignment coverage on the anisotropic galaxy clustering of ELGs and show that, in the absence of any corrections, it leads to discrepancies of order ten percent on large scales for the power spectrum multipoles. We introduce a method where objects in a random catalog are assigned a coverage, and the mean density is separately computed for each coverage factor. We show that this method reduces, but does not eliminate the effect. We next investigate the angular dependence of the contaminated signal, arguing that it is mostly localized to purely transverse modes. We demonstrate that the cleanest way to remove the contaminating signal is to perform an analysis of the anisotropic power spectrum P(k,μ) and remove the lowest μ bin, leaving μ > 0 modes accurate at the few-percent level. Here, μ is the cosine of the angle between the line-of-sight and the direction of vec k. We also investigate two alternative definitions of the random catalog and show that they are comparable but less effective than the coverage randoms method.

  11. Overhead electric power transmission line jumpering system for bundles of five or more subconductors

    DOEpatents

    Winkelman, Paul F.

    1982-01-01

    Jumpering of electric power transmission lines at a dead end tower. Two transmission line conductor bundles each contain five or more spaced apart subconductors (5) arranged in the shape of a cylinder having a circular cross section. The ends of each bundle of subconductors are attached with insulators to a dead end tower (1). Jumpering allows the electric current to flow between the two bundles of subconductors using jumper buses, internal jumper conductors, and external jumper conductors. One or more current collecting jumper buses (37) are located inside each bundle of subconductors with each jumper bus being attached to the end of a subconductor. Small-diameter internal jumper conductors (33) are located in the inherently electrically shielded area inside each bundle of subconductors with each subconductor (except ones having an attached jumper bus) having one internal jumper conductor connected between that subconductor's end and a jumper bus. Large-diameter external jumper conductors (9) are located outside each bundle of subconductors with one or more external jumper conductors being connected between the jumper buses in one bundle of subconductors and the jumper buses in the other bundle.

  12. Air ion mobility spectra and concentrations upwind and downwind of overhead AC high voltage power lines

    NASA Astrophysics Data System (ADS)

    Wright, Matthew D.; Buckley, Alison J.; Matthews, James C.; Shallcross, Dudley E.; Henshaw, Denis L.

    2014-10-01

    Corona ions produced by high-voltage power lines (HVPLs) can alter the nearby electrical environment, potentially increasing aerosol charge levels downwind. However, there is a lack of knowledge concerning the concentration and mobility of ions from AC HVPLs and their dispersion away from the line. We present ion concentration and mobility measurements made near AC HVPLs in South-West England. Examples of typical mobility spectra are shown highlighting features commonly observed. Corona was observed during 33 of 46 measurements, at 9 of 11 sites, with positive or ‘bipolar' (both polarities) ion production commonly seen. Ion production usually increases atmospheric concentrations by only a modest amount, but extreme cases can enhance concentration by an order of magnitude or more. A polarity imbalance is required to increase aerosol charge via ion attachment; this was observed on 15 of 24 days when positive corona was observed, but was not seen for negative ions. Ion mobility was higher downwind compared with upwind for both ion polarities, but the increase was not statistically significant. Future work should focus on identifying and characterising ‘heavy-producing' HVPLs, and obtaining results in conditions which may favour negative ion production e.g. high humidity, inclement weather or during nighttime.

  13. Harmonization of Biodiesel Specifications

    SciTech Connect

    Alleman, T. L.

    2008-02-01

    Worldwide biodiesel production has grown dramatically over the last several years. Biodiesel standards vary across countries and regions, and there is a call for harmonization. For harmonization to become a reality, standards have to be adapted to cover all feedstocks. Additionally, all feedstocks cannot meet all specifications, so harmonization will require standards to either tighten or relax. For harmonization to succeed, the biodiesel market must be expanded with the alignment of test methods and specification limits, not contracted.

  14. Line-Focus Solar Power Plant Cost Reduction Plan (Milestone Report)

    SciTech Connect

    Kutscher, C.; Mehos, M.; Turchi, C.; Glatzmaier, G.; Moss, T.

    2010-12-01

    Line-focus solar collectors, in particular parabolic trough collectors, are the most mature and proven technology available for producing central electricity from concentrated solar energy. Because this technology has over 25 years of successful operational experience, resulting in a low perceived risk, it is likely that it will continue to be a favorite of investors for some time. The concentrating solar power (CSP) industry is developing parabolic trough projects that will cost billions of dollars, and it is supporting these projects with hundreds of millions of dollars of research and development funding. While this technology offers many advantages over conventional electricity generation -- such as utilizing plentiful domestic renewable fuel and having very low emissions of greenhouse gases and air pollutants -- it provides electricity in the intermediate power market at about twice the cost of its conventional competitor, combined cycle natural gas. The purpose of this document is to define a set of activities from fiscal year 2011 to fiscal year 2016 that will make this technology economically competitive with conventional means.

  15. Implementation of an on-line monitoring system for transmitters in a CANDU nuclear power plant

    NASA Astrophysics Data System (ADS)

    Labbe, A.; Abdul-Nour, G.; Vaillancourt, R.; Komljenovic, D.

    2012-05-01

    Many transmitters (pressure, level and flow) are used in a nuclear power plant. It is necessary to calibrate them periodically to ensure that their measurements are accurate. These calibration tasks are time consuming and often contribute to worker radiation exposure. Human errors can also sometimes degrade their performance since the calibration involves intrusive techniques. More importantly, experience has shown that the majority of current calibration efforts are not necessary. These facts motivated the nuclear industry to develop new technologies for identifying drifting instruments. These technologies, well known as on-line monitoring (OLM) techniques, are non-intrusive and allow focusing the maintenance efforts on the instruments that really need a calibration. Although few OLM systems have been implemented in some PWR and BWR plants, these technologies are not commonly used and have not been permanently implemented in a CANDU plant. This paper presents the results of a research project that has been performed in a CANDU plant in order to validate the implementation of an OLM system. An application project, based on the ICMP algorithm developed by EPRI, has been carried out in order to evaluate the performance of an OLM system. The results demonstrated that the OLM system was able to detect the drift of an instrument in the majority of the studied cases. A feasibility study has also been completed and has demonstrated that the implementation of an OLM system at a CANDU nuclear power plant could be advantageous under certain conditions.

  16. NIOSH alert: Request for assistance in preventing electrocutions of crane operators and crew members working near overhead power lines

    SciTech Connect

    1995-05-01

    In this alert, NIOSH warned that crane operators and crew members may be electrocuted when working near overhead power lines. Five cases were described which resulted in six electrocutions. Case 1 involved a 29 year old who pushed the crane cable on a 1 yard cement bucket into a 7,200 volt power line. Case 2 involved a 33 year old well driller who was electrocuted when a metal pipe lifted by a truck mounted crane contacted a 12,000 volt overhead power line. The third case involved a 24 year old forman for a telecommunications company who was electrocuted when he grabbed the door handle of a truck mounted crane whose boom was in contact with a 7,200 volt overhead power line. Case 4 involved a 37 year old construction laborer electrocuted while pulling a wire rope attached to a crane cable toward a load. The fifth case involved a 20 year old male truck driver and his 70 year old male employer who were electrocuted when the boom of a truck mounted crane contacted a 7,200 volt conductor of an overhead power line.

  17. MR harmonic quad study

    SciTech Connect

    Yang, M.-J.; /Fermilab

    1995-01-01

    To understand the effect of Main Ring harmonic quadruple correctors. Previous data taken with the harmonic quads did not agree well with the SYNCH calculation. The ultimate goal of this study was to be able to change the harmonic quads and verify the changes in lattice function.

  18. Self-tuning wireless power transmission scheme based on on-line scattering parameters measurement and two-side power matching.

    PubMed

    Luo, Yanting; Yang, Yongmin; Chen, Zhongsheng

    2014-04-10

    Sub-resonances often happen in wireless power transmission (WPT) systems using coupled magnetic resonances (CMR) due to environmental changes, coil movements or component degradations, which is a serious challenge for high efficiency power transmission. Thus self-tuning is very significant to keep WPT systems following strongly magnetic resonant conditions in practice. Traditional coupled-mode ways is difficult to solve this problem. In this paper a two-port power wave model is presented, where power matching and the overall systemic power transmission efficiency are firstly defined by scattering (S) parameters. Then we propose a novel self-tuning scheme based on on-line S parameters measurements and two-side power matching. Experimental results testify the feasibility of the proposed method. These findings suggest that the proposed method is much potential to develop strongly self-adaptive WPT systems with CMR.

  19. Solving the 56Ni Puzzle of Magnetar-powered Broad-lined Type IC Supernovae

    NASA Astrophysics Data System (ADS)

    Wang, Ling-Jun; Han, Yan-Hui; Xu, Dong; Wang, Shan-Qin; Dai, Zi-Gao; Wu, Xue-Feng; Wei, Jian-Yan

    2016-11-01

    Broad-lined Type Ic supernovae (SNe Ic-BL) are of great importance because their association with long-duration gamma-ray bursts (LGRBs) holds the key to deciphering the central engine of LGRBs, which refrains from being unveiled despite decades of investigation. Among the two popularly hypothesized types of central engine, i.e., black holes and strongly magnetized neutron stars (magnetars), there is mounting evidence that the central engine of GRB-associated SNe (GRB-SNe) is rapidly rotating magnetars. Theoretical analysis also suggests that magnetars could be the central engine of SNe Ic-BL. What puzzled the researchers is the fact that light-curve modeling indicates that as much as 0.2{--}0.5 {M}⊙ of 56Ni was synthesized during the explosion of the SNe Ic-BL, which is unfortunately in direct conflict with current state-of-the-art understanding of magnetar-powered 56Ni synthesis. Here we propose a dynamic model of magnetar-powered SNe to take into account the acceleration of the ejecta by the magnetar, as well as the thermalization of the injected energy. Assuming that the SN kinetic energy comes exclusively from the magnetar acceleration, we find that although a major fraction of the rotational energy of the magnetar is to accelerate the SN ejecta, a tiny fraction of this energy deposited as thermal energy of the ejecta is enough to reduce the needed 56Ni to 0.06 M ⊙ for both SN 1997ef and SN 2007ru. We therefore suggest that magnetars could power SNe Ic-BL in aspects both of energetics and of 56Ni synthesis.

  20. The Power Behind the Controversy: Understanding Local Policy Elites' Perceptions on the Benefits and Risks Associated with High Voltage Power Line Installation in the State of Arkansas

    NASA Astrophysics Data System (ADS)

    Moyer, Rachael M.

    Following a proposal for the installation of high voltage power lines in northwest Arkansas, a controversial policy debate emerged. Proponents of the transmission line argue that such an installation is inevitable and necessary to efficiently and reliably support the identified electric load in the region. Opponents claim that the lines will degrade the natural environment and hamper the tourism-based local economy in affected regions, notably in Ozark Mountain areas. This study seeks to understand how local policy elites perceive the benefits and risks associated with proposed transmission lines, which is a critical step in comprehending the formation and changes of related government policies. First, based upon the dual process theory of judgment, this study systematically investigates the triadic relationships between (a) more profound personal value predispositions, (b) affects and feelings, and (c) perceived benefits and risks related to the proposed installation of high voltage power lines among local policy elites in the state of Arkansas. Next, this study focuses more specifically on the role of value predispositions, specific emotional dimensions of affect heuristics, and perceptions pertaining to high voltage power line risks and benefits. Using original data collected from a statewide Internet survey of 420 local leaders and key policymakers about their opinions on the related issues, other factors claimed by previous literature, including trust, knowledge level, and demographic characteristics are considered. Analytical results suggest that grid-group cultural predispositions, as deeply held core values within local policy elites' individual belief systems, both directly and indirectly -- through affective feelings -- shape perceived utility associated with the installation of high voltage power lines. Recognizing that risk perceptions factor into policy decisions, some practical considerations for better designing policy addressing controversial issues

  1. Relative accuracy of grid references derived from postcode and address in UK epidemiological studies of overhead power lines.

    PubMed

    Swanson, J; Vincent, T J; Bunch, K J

    2014-12-01

    In the UK, the location of an address, necessary for calculating the distance to overhead power lines in epidemiological studies, is available from different sources. We assess the accuracy of each. The grid reference specific to each address, provided by the Ordnance Survey product Address-Point, is generally accurate to a few metres, which will usually be sufficient for calculating magnetic fields from the power lines. The grid reference derived from the postcode rather than the individual address is generally accurate to tens of metres, and may be acceptable for assessing effects that vary in the general proximity of the power line, but is probably not acceptable for assessing magnetic-field effects.

  2. Dynamics and control of instrumented harmonic drives

    NASA Technical Reports Server (NTRS)

    Kazerooni, H.; Ellis, S. R. (Principal Investigator)

    1995-01-01

    Since torque in harmonic drives is transmitted by a pure couple, harmonic drives do not generate radial forces and therefore can be instrumented with torque sensors without interference from radial forces. The installation of torque sensors on the stationary component of harmonic drives (the Flexipline cup in this research work) produce backdrivability needed for robotic and telerobotic compliant maneuvers. Backdrivability of a harmonic drive, when used as torque increaser, means that the output shaft can be rotated via finite amount of torque. A high ratio harmonic drive is non-backdrivable because its output shaft cannot be turned by applying a torque on it. This article first develops the dynamic behavior of a harmonic drive, in particular the non-backdrivability, in terms of a sensitivity transfer function. The instrumentation of the harmonic drive with torque sensor is then described. This leads to a description of the control architecture which allows modulation of the sensitivity transfer function within the limits established by the closed-loop stability. A set of experiments on an active hand controller, powered by a DC motor coupled to an instrumented harmonic drive, is given to exhibit this method's limitations.

  3. Adaptive settings of distance relay for MOV-protected series compensated line with distributed capacitance considering wind power

    NASA Astrophysics Data System (ADS)

    Sivov, Oleg Viktorovich

    Series compensated lines are protected from overvoltage by metal-oxide-varistors (MOVs) connected in parallel with the capacitor bank. The nonlinear characteristics of MOV devices add complexity to fault analysis and distance protection operation. During faults, the impedance of the line is modified by an equivalent impedance of the parallel MOV/capacitor circuit, which affects the distance protection. The intermittent wind generation introduces additional complexity to the system performance and distance protection. Wind variation affects the fault current level and equivalent MOV/capacitor impedance during a fault, and hence the distance relay operation. This thesis studies the impact of the intermittent wind power generation on the operation of MOV during faults. For the purpose of simulation, an equivalent wind farm model is proposed to generate a wind generation profile using wind farm generation from California independent system operator (ISO) as a guide for wind power variation to perform the study. The IEEE 12-bus test system is modified to include MOV-protected series capacitor and the equivalent wind farm model. The modified test system is simulated in the MATLAB/Simulink environment. The study has been achieved considering three phase and single line to ground (SLG) faults on the series compensated line to show the effect of wind variation on the MOV operation. This thesis proposes an adaptive setting method for the mho relay distance protection of series compensated line considering effects of wind power variation and MOV operation. The distributed parameters of a transmission line are taken into account to avoid overreaching and underreaching of distance relays. The study shows that variable wind power affects system power flow and fault current in the compensated line during a fault which affects the operation of MOVs for different fault conditions. The equivalent per-phase impedance of the MOV/capacitor circuit has an effect on the system operation

  4. Investigation of potential driver modules and transmission lines for a high frequency power system on the space station

    NASA Technical Reports Server (NTRS)

    Brush, H. T.

    1986-01-01

    The objective was to assess the feasibility of using the Series Resonant inverter as the driver module for the high frequency power system on the Space Station. This study evaluates the performance of the Series Resonant driver when it was operated with a dc input voltage and run through a series of tests to determine its start-up performance, response to load changes, load regulation, and efficiency. Also, this study compares the Series Resonant driver to another kind of driver that uses a Power Transistor snubber. An investigation of the various types of transmission lines is initiated. In particular, a simplified approach is utilized to describe the optimal transmission line.

  5. 140 W high power all-fiber laser at 1940 nm with narrow spectral line-width by MOPA configuration

    NASA Astrophysics Data System (ADS)

    Yang, C.; Ju, Y. L.; Yao, B. Q.; Dai, T. Y.; Duan, X. M.; Zhang, Z. G.; Liu, W.

    2016-08-01

    We report a diode-pumped Tm3+-doped double-clad all-fiber laser operating at 1940 nm with a master oscillator power amplifier configuration; 50 W of seed was generated in master oscillator with 144 W pump power, corresponding to a slope efficiency of 40.1 %. With 212 W pump power, the seed was amplified to 140.9 W in power amplifier, corresponding to a slope efficiency of 47.1 %. The peak wavelength was 1939.57 nm with a narrow spectral line-width of 0.09 nm. The beam quality factor of M 2 was 1.29. Neither amplified spontaneous emission nor parasitic lasing was observed during the amplification process. The output power was only limited by the pump power.

  6. Practice and power: a review and interpretive synthesis focused on the exercise of discretionary power in policy implementation by front-line providers and managers.

    PubMed

    Gilson, Lucy; Schneider, Helen; Orgill, Marsha

    2014-12-01

    Tackling the implementation gap is a health policy concern in low- and middle-income countries (LMICs). Limited attention has so far been paid to the influence of power relations over this gap. This article presents, therefore, an interpretive synthesis of qualitative health policy articles addressing the question: how do actors at the front line of health policy implementation exercise discretionary power, with what consequences and why? The article also demonstrates the particular approach of thematic synthesis and contributes to discussion of how such work can inform future health policy research. The synthesis drew from a broader review of published research on any aspect of policy implementation in LMICs for the period 1994-2009. From an initial set of 50 articles identified as relevant to the specific review question, a sample of 16 articles were included in this review. Nine report experience around decentralization, a system-level change, and seven present experience of implementing a range of reproductive health (RH) policies (new forms of service delivery). Three reviewers were involved in a systematic process of data extraction, coding, analysis, synthesis and article writing. The review findings identify: the practices of power exercised by front-line health workers and their managers; their consequences for policy implementation and health system performance; the sources of this power and health workers' reasons for exercising power. These findings also provide the basis for an overarching synthesis of experience, highlighting the importance of actors, power relations and multiple, embedded contextual elements as dimensions of health system complexity. The significance of this synthesis lies in its insights about: the micropractices of power exercised by front-line providers; how to manage this power through local level strategies both to influence and empower providers to act in support of policy goals; and the focus and nature of future research on

  7. Power and false-positive rate in QTL detection with near-isogenic line libraries.

    PubMed

    Falke, K C; Frisch, M

    2011-04-01

    Libraries of near-isogenic lines (NILs) were used for quantitative trait locus (QTL) detection in model species and economically important crops. The experimental design and genetic architecture of the considered traits determine the statistical properties of QTL detection. The objectives of our simulation study were to (i) investigate the population sizes required to develop NIL libraries in barley and maize, (ii) compare NIL libraries with nonoverlapping and overlapping donor segments and (iii) study the number of QTLs and the size of their effects with respect to the power and the false-positive rate of QTL detection. In barley, the development of NIL libraries with target segment lengths of 10 c and marker distances of 5 cM was possible using a BC(3)S(2) backcrossing scheme and population sizes of 140. In maize, population sizes larger than 200 were required. Selection for the recipient parent genome at markers flanking the target segments with distances between 5 and 10 cM was required for an efficient control of the false-positive rate. NIL libraries with nonoverlapping donor chromosome segments had a greater power of QTL detection and a smaller false-positive rate than libraries with overlapping segments. Major genes explaining 30% of the genotypic difference between the donor and recipient were successfully detected even with low heritabilities of 0.5, whereas for minor genes explaining 5 !or 10%, high heritabilities of 0.8 or 0.9 were required. The presented results can assist geneticists and breeders in the efficient development of NIL libraries for QTL detection.

  8. Characterization of vertical electric fields and associated voltages induced on a overhead power line from close artificially initiated lightning

    NASA Astrophysics Data System (ADS)

    Rubinstein, Marcos; Uman, Martin A.; Thomson, Ewen M.; Medelius, Pedro J.

    1991-08-01

    Measurements were characterized of simultaneous vertical electric fields and voltages induced at both ends of a 448 m overhead power line by artificially initiated lightning return strokes. The lightning discharges struck ground about 20 m from one end of the line. The measured line voltages could be grouped into two categories: those in which multiple, similarly shaped, evenly spaced pulses were observed, which are called oscillatory; and those dominated by a principal pulse with subsidiary oscillations of much smaller amplitude, which are called impulsive. Voltage amplitudes range from tens of kilovolts for oscillatory voltages to hundreds of kilovolts for impulsive voltages.

  9. Folsom-Nimbus 115 kV transmission line replacement for Western Area Power Administration: Environmental assessment

    SciTech Connect

    Not Available

    1980-07-01

    The Western Area Power Administration (Western) proposes to replace the existing Folsom-Nimbus 115 kV electrical transmission line along the American River between Folsom Dam and Nimbus Dam in Sacramento County, California. The need to replace the line is attributed to the deterioration of the existing wood pole structures by the acorn woodpecker; thus resulting in increased maintenance and hazard potential. The need for the replacement of the Folsom-Nimbus transmission line has resulted in the evaluation by Western of various routing alternatives. These alternatives were evaluated in terms of design, economic and environmental considerations. 60 refs., 19 figs., 4 tabs.

  10. 41 CFR 102-75.380 - May power transmission lines and rights-of-way be disposed of in other ways?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false May power transmission... REGULATION REAL PROPERTY 75-REAL PROPERTY DISPOSAL Surplus Real Property Disposal Power Transmission Lines § 102-75.380 May power transmission lines and rights-of-way be disposed of in other ways? Yes,...

  11. Measuring Spherical Harmonic Coefficients on a Sphere

    SciTech Connect

    Pollaine, S; Haan, S W

    2003-05-16

    The eigenfunctions of Rayleigh-Taylor modes on a spherical capsule are the spherical harmonics Y{sub l,m} These can be measured by measuring the surface perturbations along great circles and fitting them to the first few modes by a procedure described in this article. For higher mode numbers, it is more convenient to average the Fourier power spectra along the great circles, and then transform them to spherical harmonic modes by an algorithm derived here.

  12. Compact fluorescent lamps, LED lamps and harmonic distortion

    NASA Astrophysics Data System (ADS)

    Franco, A. M. R.; Debatin, R. M.; Cotia, F. C. G.; Silva, M. V. M.; Ribeiro, R. S.; Zampilis, R. R. N.

    2015-01-01

    The aim of this paper is to evaluate the harmonic distortion in the current waveform of Compact Fluorescent Lamps (CFL) and Lamps Lighting Emitting Diode (LED). For this, we analysed the power factor, voltage waveform, current waveform, total harmonic distortion (THD) and active power consumed.

  13. Coherent harmonic production using a two-section undulator FEL

    SciTech Connect

    Jaroszynski, D.A.; Prazeres, R.; Glotin, F.

    1995-12-31

    We present measurements and a theoretical analysis of a new method of generating harmonic radiation in a free-electron laser oscillator with a two section undulator in a single optical cavity. To produce coherent harmonic radiation the undulator is arranged so that the downstream undulator section resonance frequency matches a harmonic of the upstream undulator. Both the fundamental and the harmonic optical fields evolve in the same optical cavity and are coupled out with different extraction fractions using a hole in one of the cavity mirrors. We present measurements that show that the optical power at the second and third harmonic can be enhanced by more than an order of magnitude in this fundamental/harmonic configuration. We compare the production of harmonic radiation of a two sectioned fundamental/harmonic undulator with that produced from a FEL operating at its highest efficiency with a step-tapered undulator, where the bunching at the end of the first section is very large. We examine, the dependence of the harmonic power on the intracavity power by adjusting the optical cavity desynchronism, {delta}L. We also examine the evolution of the fundamental and harmonic powers as a function of cavity roundtrip number to evaluate the importance of the small signal gain at the harmonic. We compare our measurements with predictions of a multi-electron numerical model that follows the evolution of fundamental and harmonic power to saturation. This fundamental/harmonic mode, of operation of the FEL may have useful applications in the production of coherent X-ray and VUV radiation, a spectral range where high reflectivity optical cavity mirrors are difficult or impossible to manufacture.

  14. Reliability assessment of an OVH HV power line truss transmission tower subjected to seismic loading

    NASA Astrophysics Data System (ADS)

    Winkelmann, Karol; Jakubowska, Patrycja; Soltysik, Barbara

    2017-03-01

    The study focuses on the reliability of a transmission tower OS24 ON150 + 10, an element of an OVH HV power line, under seismic loading. In order to describe the seismic force, the real-life recording of the horizontal component of the El Centro earthquake was adopted. The amplitude and the period of this excitation are assumed random, their variation is described by Weibull distribution. The possible space state of the phenomenon is given in the form of a structural response surface (RSM methodology), approximated by an ANOVA table with directional sampling (DS) points. Four design limit states are considered: stress limit criterion for a natural load combination, criterion for an accidental combination (one-sided cable snap), vertical and horizontal translation criteria. According to these cases the HLRF reliability index β is used for structural safety assessment. The RSM approach is well suited for the analysis - it is numerically efficient, not excessively time consuming, indicating a high confidence level. Given the problem conditions, the seismic excitation is shown the sufficient trigger to the loss of load-bearing capacity or stability of the tower.

  15. Developing Effective Continuous On-Line Monitoring Technologies to Manage Service Degradation of Nuclear Power Plants

    SciTech Connect

    Meyer, Ryan M.; Ramuhalli, Pradeep; Bond, Leonard J.; Cumblidge, Stephen E.

    2011-09-30

    Recently, there has been increased interest in using prognostics (i.e, remaining useful life (RUL) prediction) for managing and mitigating aging effects in service-degraded passive nuclear power reactor components. A vital part of this philosophy is the development of tools for detecting and monitoring service-induced degradation. Experience with in-service degradation has shown that rapidly-growing cracks, including several varieties of stress corrosion cracks (SCCs), can grow through a pipe in less than one fuel outage cycle after they initiate. Periodic inspection has limited effectiveness at detecting and managing such degradation requiring a more versatile monitoring philosophy. Acoustic emission testing (AET) and guided wave ultrasonic testing (GUT) are related technologies with potential for on-line monitoring applications. However, harsh operating conditions within NPPs inhibit the widespread implementation of both technologies. For AET, another hurdle is the attenuation of passive degradation signals as they travel though large components, relegating AET to targeted applications. GUT is further hindered by the complexity of GUT signatures limiting its application to the inspection of simple components. The development of sensors that are robust and inexpensive is key to expanding the use of AET and GUT for degradation monitoring in NPPs and improving overall effectiveness. Meanwhile, the effectiveness of AET and GUT in NPPs can be enhanced through thoughtful application of tandem AET-GUT techniques.

  16. Environmental justice: a contrary finding for the case of high-voltage electric power transmission lines.

    PubMed

    Wartenberg, Daniel; Greenberg, Michael R; Harris, Gerald

    2010-05-01

    Environmental justice is the consideration of whether minority and/or lower-income residents in a geographic area are likely to have disproportionately higher exposures to environmental toxins than those living elsewhere. Such situations have been identified for a variety of factors, such as air pollution, hazardous waste, water quality, noise, residential crowding, and housing quality. This study investigates the application of this concept to high-voltage electric power transmission lines (HVTL), which some perceive as a health risk because of the magnetic fields they generate, and also as esthetically unpleasing. We mapped all 345 kV and higher voltage HVTL in New York State and extracted and summarized proximate US Census sociodemographic and housing characteristic data into four categories on the basis of distances from HVTL. Contrary to our expectation, people living within 2000 ft from HVTL were more likely to be exposed to magnetic fields, white, of higher income, more educated and home owners, than those living farther away, particularly in urban areas. Possible explanations for these patterns include the desire for the open space created by the rights-of-way, the preference for new homes/subdivisions that are often located near HVTL, and moving closer to HVTL before EMFs were considered a risk. This study suggests that environmental justice may not apply to all environmental risk factors and that one must be cautious in generalizing. In addition, it shows the utility of geographical information system methodology for summarizing information from extremely large populations, often a challenge in epidemiology.

  17. A Study on the Performance of Wavelet OFDM in Power Line

    NASA Astrophysics Data System (ADS)

    Koga, Hisao; Kodama, Nobutaka

    Recently, the demand of high speed network in home is increasing. Some Multicarrier Modulation (MCM) based systems use FFT OFDM, and some use a Wavelet OFDM in place of FFT OFDM. Wavelet transforms consist of an M-band transmultiplexers, which use filters of greater length than the rectangular windows used in FFT OFDM. The use of symbols of longer duration allows obtaining lower side-lobe levels with respect to FFT OFDM. Better stop-band attenuation results in both lower levels of inter-carrier interference (ICI) and greater robustness to narrowband interference. For the power line channel, we have chosen two channels measured by network analyzer. The root mean square (R.M.S.) delay spreads of Channels A and B are 0.22 [μsec] and 1.1 [μsec], respectively. In this paper, the PHY (Physical layer) data rates [Mbps] achievable by Wavelet OFDM over Channels A and B are shown for two different kinds of FEC. Then, the effects of ISI and ICI on Wavelet OFDM can be compensated by increasing the number of carriers. Finally, it is shown that Wavelet OFDM characteristic is better than that of FFT OFDM about PHY rates [Mbps] with the same channels.

  18. Target and nontarget discrimination of herbicides applied to vegetation in a power-line corridor

    NASA Astrophysics Data System (ADS)

    Luken, James O.; Beiting, Steven W.; Kareth, Scott K.; Kumler, Robyn L.; Liu, Jun H.; Seither, Craig A.

    1994-03-01

    We tested two cutting regimens (cut/spray and cut/delay spray) and four radiarc-applied herbicides (Garlon + Tordon, Accord, Accord + Escort, and Krenite) in an Ohio power-line corridor to determine which management combination best eliminated target species (i.e., trees) and preserved nontarget species (i.e., low shrubs, vines, perennial herbs, and grasses). When spraying was delayed after cutting, the herbicide with the least impact on nontarget species (Krenite) also was least efficient at killing target trees. Spraying soon after cutting improved tree-killing efficiency of several herbicides, but it also increased the negative impact on nontarget species. The herbicide with the most consistent tree-killing ability (Accord + Escort) had the most impact on nontarget species. Because none of the herbicide/cutting treatments performed ideally, resource managers must decide the acceptable impact on nontarget species when considering herbicide use. Future success of herbicides as part of an integrated succession management approach requires more selective application methods and formulations so that target effects can be maximized and nontarget effects can be minimized.

  19. Imprint of DESI fiber assignment on anisotropic power spectrum of emission line galaxies

    NASA Astrophysics Data System (ADS)

    Cahn, Robert N.; Pinol, Lucas; Hand, Nicholas; McDonald, Patrick; Seljak, Uros

    2017-01-01

    The Dark Energy Spectroscopic Instrument (DESI), a multiplexed fiber-fed spectrograph, is a Stage-IV ground-based dark energy experiment aiming to measure redshifts for 29 million Emission-Line Galaxies (ELG), 4 million Luminous Red Galaxies (LRG), and 2 million Quasi-Stellar Objects (QSO). The survey design includes an observation strategy determined by a fiber assignment algorithm that optimizes the allocation of fibers to targets. We investigate the systematic effects of the fiber assignment coverage on the anisotropic galaxy clustering of ELGs and show that, in the absence of any corrections, it leads to discrepancies of order ten percent on large scales for the power spectrum multipoles. We introduce a method where objects in a random catalog are assigned a coverage, and the mean density is separately computed for each coverage factor, and show that this method reduces, but does not eliminate the effect. The angular dependence of the contaminating signal is mostly in purely transverse modes. We find that the effect can be mitigated by binning in angle and excluding contributions near the transverse direction. This material is based upon work supported in part by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Contract No. DE-AC02-05CH11231.

  20. Electrocution of Raptors on Power Lines: A Review of Necropsy Methods and Findings.

    PubMed

    Kagan, R A

    2016-09-01

    Decades after the problem was first identified, power line electrocution continues to be a cause of avian mortality. Currently, several federal laws protect eagles and other migratory birds, meaning that utility companies may be liable for electrocution-related deaths. Veterinarians and veterinary pathologists called upon to diagnose and treat electrocuted birds should keep this in mind when conducting clinical and postmortem examinations. This review details necropsy findings and methods used to diagnose electrocution. A combination of gross, subgross, and radiographic examinations can aid in identification of subtle injury. Diagnosis is made based on the presence of skin and/or feather burns. Other necropsy findings may include skin lacerations, subcutaneous burns, bruising, limb avulsion, hemopericardium, and vascular rupture. At the US Fish and Wildlife Service's National Forensics Laboratory, from 2000 to 2015, 417 raptor deaths were determined to have been caused by electrocution. Bald eagles and golden eagles were the most commonly submitted species. In a retrospective review of 377 cases, for which whole bodies were submitted, 18% of the electrocuted birds had only a single, small (less than 3 cm in diameter) external burn. Small, isolated burns tended to occur on the undersides of the wings at and distal to the elbow and on the lower legs and feet. These areas should be most carefully examined in cases where electrocution injury is not immediately apparent.

  1. Assessment of electromagnetic field levels from surrounding high-tension overhead power lines for proposed land use.

    PubMed

    Al-Bassam, E; Elumalai, A; Khan, A; Al-Awadi, L

    2016-05-01

    The surrounding outdoor environment for new development has a big effect on the indoor quality of life. The main aim of this work was to determine the suitability of the area for building new schools with reference to electromagnetic field (EMF) effects. The specific objective of this study was to detect the safe distance from the EMF posed by the high-tension overhead power lines in the vicinity of the specified area. The measurements were taken for both the electric and magnetic fields in different months in order to detect the highest EMF levels during the peak power load season. EMDEX II with E-probe and EMDEX II with Linda were used for the measurements. These instruments were all calibrated by ENERTECH Company in USA. The EMF associated with high tension transmission lines that surrounded the proposed site has to be below 0.2 μT (Italian EMF regulations are the most suitable regulations for the establishment of schools in Kuwait). The safety clearance distance from the existing 300-kV high-tension power line has been assigned as 200 m and from other existing 132-kV high-tension power line was 50 m. The proposed site with its predefined boundaries has a magnetic field below the Italian EMF regulations for the establishment of new schools.

  2. Artificial Ionization and UHF Radar Response Associated with HF Frequencies near Electron Gyro-Harmonics (Invited)

    NASA Astrophysics Data System (ADS)

    Watkins, B. J.; Fallen, C. T.; Secan, J. A.

    2013-12-01

    We present new results from O-mode ionospheric heating experiments at the HAARP facility in Alaska to demonstrate that the magnitude of artificial ionization production is critically dependent on the choice of HF frequency near gyro-harmonics. For O-mode heating in the lower F-region ionosphere, typically about 200 km altitude, artificial ionization enhancements are observed in the lower ionosphere (about 150 - 220 km) and also in the topside ionosphere above about 500 km. Lower ionosphere density enhancements are inferred from HF-enhanced ion and plasma-line signals observed with UHF radar. Upper ionospheric density enhancements have been observed with TEC (total electron content) experiments by monitoring satellite radio beacons where signal paths traverse the HF-modified ionosphere. Both density enhancements and corresponding upward plasma fluxes have also been observed in the upper ionosphere via in-situ satellite observations. The data presented focus mainly on observations near the third and fourth gyro-harmonics. The specific values of the height-dependent gyro-harmonics have been computed from a magnetic model of the field line through the HF heated volume. Experiments with several closely spaced HF frequencies around the gyro-harmonic frequency region show that the magnitude of the lower-ionosphere artificial ionization production maximizes for HF frequencies about 1.0 - 1.5 MHz above the gyro-harmonic frequency. The response is progressively larger as the HF frequency is increased in the frequency region near the gyro-harmonics. For HF frequencies that are initially greater than the gyro-harmonic value the UHF radar scattering cross-section is relatively small, and non-existent or very weak signals are observed; as the signal returns drop in altitude due to density enhancements the HF interaction region passes through lower altitudes where the HF frequency is less than the gyro-harmonic value, for these conditions the radar scattering cross-section is

  3. Reactive Power Compensator.

    DOEpatents

    El-Sharkawi, M.A.; Venkata, S.S.; Chen, M.; Andexler, G.; Huang, T.

    1992-07-28

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation. 26 figs.

  4. Reactive power compensator

    DOEpatents

    El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.; Chen, Mingliang; Andexler, George; Huang, Tony

    1992-01-01

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

  5. Cryogenic-temperature profiling of high-power superconducting lines using local and distributed optical-fiber sensors.

    PubMed

    Chiuchiolo, Antonella; Palmieri, Luca; Consales, Marco; Giordano, Michele; Borriello, Anna; Bajas, Hugues; Galtarossa, Andrea; Bajko, Marta; Cusano, Andrea

    2015-10-01

    This contribution presents distributed and multipoint fiber-optic monitoring of cryogenic temperatures along a superconducting power transmission line down to 30 K and over 20 m distance. Multipoint measurements were conducted using fiber Bragg gratings sensors coated with two different functional overlays (epoxy and poly methyl methacrylate (PMMA)) demonstrating cryogenic operation in the range 300-4.2 K. Distributed measurements exploited optical frequency-domain reflectometry to analyze the Rayleigh scattering along two concatenated fibers with different coatings (acrylate and polyimide). The integrated system has been placed along the 20 m long cryostat of a superconducting power transmission line, which is currently being tested at the European Organization for Nuclear Research (CERN). Cool-down events from 300-30 K have been successfully measured in space and time, confirming the viability of these approaches to the monitoring of cryogenic temperatures along a superconducting transmission line.

  6. Workshop on Harmonic Oscillators

    NASA Technical Reports Server (NTRS)

    Han, D. (Editor); Kim, Y. S. (Editor); Zachary, W. W. (Editor)

    1993-01-01

    Proceedings of a workshop on Harmonic Oscillators held at the College Park Campus of the University of Maryland on March 25 - 28, 1992 are presented. The harmonic oscillator formalism is playing an important role in many branches of physics. This is the simplest mathematical device which can connect the basic principle of physics with what is observed in the real world. The harmonic oscillator is the bridge between pure and applied physics.

  7. High power 4.65 μm single-wavelength laser by second-harmonic generation of pulsed TEA CO2 laser in AgGaSe2 and ZnGeP2

    NASA Astrophysics Data System (ADS)

    Li, D. J.; Guo, J.; Yang, G. L.; Meng, F. J.; Zhang, L. M.; Xie, J. J.; Chen, F.; Shao, C. L.; Zhang, C. S.; Geng, Y. M.; Li, S. M.

    2012-04-01

    A high power 4.65 μm single-wavelength laser by second-harmonic generation (SHG) of TEA CO2 laser pulses in silver gallium selenide (AgGaSe2) and zinc germanium phosphide (ZnGeP2) crystals is reported. Experimental results show that the average output power of SHG laser is not only restricted by the damage threshold of the nonlinear crystals, but also limited by the irradiated power of fundamental-wave laser depending on the operating repetition-rate. It is found that ZnGeP2 can withstand higher 9.3 μm laser irradiation intensity than AgGaSe2. As a result, using a parallel array stacked by seven ZnGeP2 crystals, an average power of 20.3 W 4.65 μm laser is obtained at 250 Hz. To the best of our knowledge, it is the highest output power for SHG of CO2 laser by far.

  8. Electric Power High-Voltage Transmission Lines: Design Options, Cost, and Electric and Magnetic Field Levels

    SciTech Connect

    Stoffel, J. B.; Pentecost, E. D.; Roman, R. D.; Traczyk, P. A.

    1994-11-01

    The aim of this report is to provide background information about (1) the electric and magnetic fields (EMFs) of high-voltage transmission lines at typical voltages and line configurations and (2) typical transmission line costs to assist preparers and reviewers of the section on alternatives in environmental documents. This report will give the reviewing individual a better appreciation of the factors affecting EMF strengths near high-voltage transmission lines and the approaches that might be used to reduce EMF impacts on humans and other biological species in the vicinity of high-voltage overhead or underground alternating-current (ac) or direct-current (dc) transmission lines.

  9. Radiological Assessment for the Removal of Legacy BPA Power Lines that Cross the Hanford Site

    SciTech Connect

    Millsap, William J.; Brush, Daniel J.

    2013-11-13

    This paper discusses some radiological field monitoring and assessment methods used to assess the components of an old electrical power transmission line that ran across the Hanford Site between the production reactors area (100 Area) and the chemical processing area (200 Area). This task was complicated by the presence of radon daughters -- both beta and alpha emitters -- residing on the surfaces, particularly on the surfaces of weathered metals and metals that had been electrically-charged. In many cases, these activities were high compared to the DOE Surface Contamination Guidelines, which were used as guides for the assessment. These methods included the use of the Toulmin model of argument, represented using Toulmin diagrams, to represent the combined force of several strands of evidences, rather than a single measurement of activity, to demonstrate beyond a reasonable doubt that no or very little Hanford activity was present and mixed with the natural activity. A number of forms of evidence were used: the overall chance of Hanford contamination; measurements of removable activity, beta and alpha; 1-minute scaler counts of total surface activity, beta and alpha, using "background makers"; the beta activity to alpha activity ratios; measured contamination on nearby components; NaI gamma spectral measurements to compare uncontaminated and potentially-contaminated spectra, as well as measurements for the sentinel radionuclides, Am- 241 and Cs-137 on conducting wire; comparative statistical analyses; and in-situ measurements of alpha spectra on conducting wire showing that the alpha activity was natural Po-210, as well as to compare uncontaminated and potentially-contaminated spectra.

  10. Stability and harmonics in thyristor controlled reactors

    SciTech Connect

    Bohmann, L.J.; Lasseter, R.H. )

    1990-04-01

    Harmonics that arise from the interaction of thyristor controlled reactors (TCRs) and power systems can sometimes cause stability problems that are difficult to analyze since the harmonics are affected by the power system. The classical method for calculating harmonics is to calculate the harmonic current assuming an infinite bus at the high side of the TCR transformer. This current is then used as a harmonic current source on the ac system. The basic problem with this method is that many of the interactions between the ac system and the TCR are neglected. In this paper two methods for studying the neglected interactions are described. The first uses state variables to analyze the circuit containing the TCR. The resulting equations are linear differential equations with periodic coefficients. This formulation allows the study of stability, periodic operation, and resonance which can not be achieved by other methods. The second method uses a fourier matrix description of the TCR. In this model the coupling between the different harmonics due to the switching is clearly shown.

  11. Covariant harmonic oscillators and coupled harmonic oscillators

    NASA Technical Reports Server (NTRS)

    Han, Daesoo; Kim, Young S.; Noz, Marilyn E.

    1995-01-01

    It is shown that the system of two coupled harmonic oscillators shares the basic symmetry properties with the covariant harmonic oscillator formalism which provides a concise description of the basic features of relativistic hadronic features observed in high-energy laboratories. It is shown also that the coupled oscillator system has the SL(4,r) symmetry in classical mechanics, while the present formulation of quantum mechanics can accommodate only the Sp(4,r) portion of the SL(4,r) symmetry. The possible role of the SL(4,r) symmetry in quantum mechanics is discussed.

  12. High-voltage overhead power lines in epidemiology: patterns of time variations in current load and magnetic fields.

    PubMed

    Reitan, J B; Tynes, T; Kvamshagen, K A; Vistnes, A I

    1996-01-01

    In epidemiological studies of electromagnetic fields and health effects, exposure classification is crucial. There is no generally accepted biophysical interaction mechanism, but many studies are based on the hypothesis of a causal relationship with the strength of magnetic field. Some definition of the magnitude of exposure must be used, e.g., mean magnetic flux density, the integral of magnetic flux and time, or a peak value. Magnetic fields around a particular power line depend on the current load. The aim of the present study was to follow variations in line current load in the power supply system of the largest Norwegian city on a yearly, monthly, daily and diurnal basis. Fairly large variations in load were found, but increases in consumption were not necessarily reflected in current load on high voltage lines. The correlation between outdoor temperature and current load varied widely, depending on the type of power station feeding the line in question. The registered time variations are large enough to interfere with epidemiological classification of residences and testing of epidemiological hypotheses.

  13. Diode end-pumped high-power Q-switched double Nd:YAG slab laser and its efficient near-field second-harmonic generation.

    PubMed

    Zhu, Peng; Li, Daijun; Qi, Bingsong; Schell, Alexander; Shi, Peng; Haas, Claus; Fu, Shaojun; Wu, Nianle; Du, Keming

    2008-10-01

    We reported on an all-solid-state double Nd:YAG slab laser. The laser was based on two diode end-pumped Nd:YAG slabs and a stable-unstable hybrid resonator. A cw output of 189 W and an average Q-switched output of 169 W at 10 kHz with an M(2) factor of 1.5 in the slow direction and 1.7 in the fast direction were obtained. We demonstrated efficient near-field frequency doubling by imaging the one-dimensional top-hat near-field to a lithium triborate frequency doubler. We obtained 93 W green light at 10 kHz with a pulse width of 10.7 ns. The efficiency of second-harmonic generation was up to 57%.

  14. Photovoltaic power system tests on an 8-kilowatt single-phase line-commutated inverter

    NASA Technical Reports Server (NTRS)

    Stover, J. B.

    1978-01-01

    Efficiency and power factor were measured as functions of solar array voltage and current. The effects of input shunt capacitance and series inductance were determined. Tests were conducted from 15 to 75 percent of the 8 kW rated inverter input power. Measured efficiencies ranged from 76 percent to 88 percent at about 50 percent of rated inverter input power. Power factor ranged from 36 percent to 72 percent.

  15. Coaxial line configuration for microwave power transmission study of YBa2Cu3O(7-delta) thin films

    NASA Technical Reports Server (NTRS)

    Chorey, C. M.; Miranda, F. A.; Bhasin, K. B.

    1991-01-01

    Microwave transmission measurements through YBa2Cu3O(7-delta) (YBCO) high-transition-temperature superconducting thin films on lanthanum aluminate (LaAlO3) have been performed in a coaxial line at 10 GHz. LaAlO3 substrates were ultrasonically machined into washer-shaped discs, polished, and coated with laser-ablated YBCO. These samples were mounted in a 50-ohm coaxial air line to form a short circuit. The power transmitted through the films as a function of temperature was used to calculate the normal state conductivity and the magnetic penetration depth for the films.

  16. Coaxial line configuration for microwave power transmission study of YBa2Cu3O(7-delta) thin films

    NASA Astrophysics Data System (ADS)

    Chorey, C. M.; Miranda, F. A.; Bhasin, K. B.

    1991-12-01

    Microwave transmission measurements through YBa2Cu3O(7-delta) (YBCO) high-transition-temperature superconducting thin films on lanthanum aluminate (LaAlO3) have been performed in a coaxial line at 10 GHz. LaAlO3 substrates were ultrasonically machined into washer-shaped discs, polished, and coated with laser-ablated YBCO. These samples were mounted in a 50-ohm coaxial air line to form a short circuit. The power transmitted through the films as a function of temperature was used to calculate the normal state conductivity and the magnetic penetration depth for the films.

  17. Modified ADALINE algorithm for harmonic estimation and selective harmonic elimination in inverters

    NASA Astrophysics Data System (ADS)

    Vasumathi, B.; Moorthi, S.

    2011-11-01

    In digital signal processing, algorithms are very well developed for the estimation of harmonic components. In power electronic applications, an objective like fast response of a system is of primary importance. An effective method for the estimation of instantaneous harmonic components, along with conventional harmonic elimination technique, is presented in this article. The primary function is to eliminate undesirable higher harmonic components from the selected signal (current or voltage) and it requires only the knowledge of the frequency of the component to be eliminated. A signal processing technique using modified ADALINE algorithm has been proposed for harmonic estimation. The proposed method stays effective as it converges to a minimum error and brings out a finer estimation. A conventional control based on pulse width modulation for selective harmonic elimination is used to eliminate harmonic components after its estimation. This method can be applied to a wide range of equipment. The validity of the proposed method to estimate and eliminate voltage harmonics is proved with a dc/ac inverter as a simulation example. Then, the results are compared with existing ADALINE algorithm for illustrating its effectiveness.

  18. 33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... communication lines over reservoirs. 222.3 Section 222.3 Navigation and Navigable Waters CORPS OF ENGINEERS... communication lines over reservoirs. (a) Purpose. This regulation prescribes the minimum vertical clearances to... reservoir projects. (b) Applicability. This regulation applies to all field operating agencies having...

  19. Comparative study of reference currents and DC bus voltage control for Three-Phase Four-Wire Four-Leg SAPF to compensate harmonics and reactive power with 3D SVM.

    PubMed

    Chebabhi, A; Fellah, M K; Kessal, A; Benkhoris, M F

    2015-07-01

    In this paper the performances of three reference currents and DC bus voltage control techniques for Three-Phase Four-Wire Four-Leg SAPF are compared for balanced and unbalanced load conditions. The main goals are to minimize the harmonics, reduce the magnitude of neutral current, eliminate the zero-sequence current components caused by single-phase nonlinear loads and compensate the reactive power, and on the other hand improve performances such as robustness, stabilization, trajectory pursuit, and reduce time response. The three techniques are analyzed mathematically and simulation results are compared. The techniques considered for comparative study are the PI Control, Sliding Mode Control and the Backstepping Control. Synchronous reference frame theory (SRF) in the dqo-axes is used to generate the reference currents, of the inverter.

  20. Nuclear techniques for the on-line bulk analysis of carbon in coal-fired power stations.

    PubMed

    Sowerby, B D

    2009-09-01

    Carbon trading schemes usually require large emitters of CO(2), such as coal-fired power stations, to monitor, report and be audited on their CO(2) emissions. The emission price provides a significant additional incentive for power stations to improve efficiency. In the present paper, previous work on the bulk determination of carbon in coal is reviewed and assessed. The most favourable method is that based on neutron inelastic scattering. The potential role of on-line carbon analysers in improving boiler efficiency and in carbon accounting is discussed.

  1. Centaur feedline dynamics study using power spectral methods. [fundamental mode resonant frequencies of RL-10 oxygen and hydrogen feed lines

    NASA Technical Reports Server (NTRS)

    Lorenzo, C. F.

    1974-01-01

    Tests were conducted to determine the dynamic characteristics of the Centaur/RL-10 oxygen and hydrogen feedlines. The fundamental-mode resonant frequencies were determined by applying power spectral methods to noise-generated data from hot firings of the RL-10 engine. The effect of net positive suction pressure of the main feed pumps on resonant frequency characteristics was determined to be a straight-line relation. Power spectral methods were also used to determine the dynamic characteristics of the boost pumps.

  2. Design concepts for a pulse power test facility to simulate EMP surges in overhead power lines. Part I. Fast pulse

    SciTech Connect

    Ramrus, A.

    1986-02-01

    Objective of the study was to create conceptual designs of high voltage pulsers capable of simulating two types of electromagnetic pulses (EMPs) caused by a high-altitude nuclear burst; the slow rise time magnetohydrodynamic (MHD-EMP) and the fast rise time high-altitude EMP (HEMP). The pulser design was directed towards facilities capable of performing EMP vulnerability testing of components used in the national electric power system.

  3. Power Line Noise in Transient Electromagnetic (TEM) Data: Identification and Removal in a Practical Field Study.

    NASA Astrophysics Data System (ADS)

    Jernsletten, J. A.

    2004-05-01

    INTRODUCTION: To evaluate the appropriateness of TEM in mapping deep groundwater tables (in Mars analog environmnets), a field study was carried out in the desert ~30 miles SW of Tucson, Arizona. The study was also designed to observe effects of powerline noise on TEM data. The clay-rich soil in the area is quite conductive. The study consisted of 40 in-loop TEM stations, divided into 3 lines, for 4 line-km of data. The survey was carried out by a crew of one person, with square Tx wire loops 100 m on a side, and a ferrite-core magnetic coil Rx antenna in the center of each Tx loop. Maximum useful depth of investigation achieved was ~600 m. TEM DATA: The field area is surrounded by powerlines on all 4 sides: Line 1 has the outside of the first Tx loop under the powerline to the West; Line 2 starts with the powerline to the North passing above just inside its first Tx loop, and ends with the outside of the last station's transmitter loop ~20 m shy of the powerline to the South; finally, Line 3 starts ~50 m East of the powerline to the West, and runs parallel to the powerline to the South along its entire length, at a separation distance of ~70 m. Line 3 was placed largely in an effort to obeserve powerline noise. The decay curve for the first station on Line 1(Line 1/Station 50) is raised above the other curves from Line 1. This is due to the charge (noise) from the adjacent powerline, which is at a distance of ~50 m from the Rx coil. In effect, the transient decay is recorded as being slower than it would be without the presence of the powerline. This also artficially lowers the apparent resistivity, readily observed in Line 1/Station 50 data. These effects are present to a lesser extent (lower magnitude noise) in the data from Line1/Station 150, the second station on Line 1. On the smooth-model inversion cross-section of the data from Line 1, the effects of the powerline noise appears as a pulling up of the low-resistivity water table contact towards the surface

  4. Relationship between Emergency Restoration Time of Power Distribution Line after a Disaster and Geographical Characteristics of its Area

    NASA Astrophysics Data System (ADS)

    Sagai, Shigeo; Terano, Takao

    The effect of an outage caused by a disaster is serious to the society, because the power distribution line is a common basic infrastructure for life support. And the time estimation of emergency restoration process of power distribution line after a disaster is an emerging problem for the safety and security of the society. But the time estimation is a difficult problem and the only practical method in use is a simple approximation method, which doesn't take account of geographical characteristics of the objective area. So, we developed a method which can take account of the influences caused by the geographical characteristics of the objective area on the estimation of the emergency restoration. In this article, we describe an experimental analysis by the method.

  5. Development of An On-Line, Core Power Distribution Monitoring System

    SciTech Connect

    Tunc ALdemir; Don Miller; Peng Wang

    2007-10-02

    The objective of the proposed work was to develop a software package that can construct in three-dimensional core power distributions using the signals from constant temperature power sensors distributed in the reactor core. The software developed uses a mode-based state/parameter estmation technique that is particularly attractive when there are model uncertainties and/or large signal noise. The software yields the expected value of local power at the detector locations and points in between, as well as the probability distribution of the local power density

  6. Test Results from a Simulated High Voltage Lunar Power Transmission Line

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, OH was modified to simulate high voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high frequency AC power to a lunar facility located at a distance.

  7. Test Results From a Simulated High-Voltage Lunar Power Transmission Line

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur; Hervol, David

    2008-01-01

    The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio was modified to simulate high-voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high-frequency ac power to a lunar facility located at a distance.

  8. Three-dimensional analysis of harmonic generation in self-amplified spontaneous emission.

    SciTech Connect

    Huang, Z.; Kim, K.-J.

    1999-09-01

    In a high-gain free-electron laser, strong bunching at the fundamental wavelength can drive substantial harmonic bunching and sizable power levels at the harmonic frequencies. In this paper, we investigate the three-dimensional evolution of the harmonic fields based on the coupled Maxwell-Vlasov equations that take into account the nonlinear harmonic interaction. Each harmonic field is the sum of a self-amplified term and a term driven by the nonlinear harmonic interaction. In the exponential gain regime, the growth rate of the dominant nonlinear term is much faster than that of the self-amplified harmonic field. As a result, the gain length and the transverse profile of the first few harmonics are completely determined by those of the fundamental. A percentage of the fundamental power level is found at the third harmonic frequency right before saturation for the current self-amplified spontaneous emission projects.

  9. Urban Power Line Corridors as Novel Habitats for Grassland and Alien Plant Species in South-Western Finland

    PubMed Central

    Lampinen, Jussi; Ruokolainen, Kalle; Huhta, Ari-Pekka

    2015-01-01

    Regularly managed electric power line corridors may provide habitats for both early-successional grassland plant species and disturbance-dependent alien plant species. These habitats are especially important in urban areas, where they can help conserve native grassland species and communities in urban greenspace. However, they can also provide further footholds for potentially invasive alien species that already characterize urban areas. In order to implement power line corridors into urban conservation, it is important to understand which environmental conditions in the corridors favor grassland species and which alien species. Likewise it is important to know whether similar environmental factors in the corridors control the species composition of the two groups. We conducted a vegetation study in a 43 kilometer long urban power line corridor network in south-western Finland, and used generalized linear models and distance-based redundancy analysis to determine which environmental factors best predict the occurrence and composition of grassland and alien plant species in the corridors. The results imply that old corridors on dry soils and steep slopes characterized by a history as open areas and pastures are especially suitable for grassland species. Corridors suitable for alien species, in turn, are characterized by productive soils and abundant light and are surrounded by a dense urban fabric. Factors controlling species composition in the two groups are somewhat correlated, with the most important factors including light abundance, soil moisture, soil calcium concentration and soil productivity. The results have implications for grassland conservation and invasive alien species control in urban areas. PMID:26565700

  10. Urban Power Line Corridors as Novel Habitats for Grassland and Alien Plant Species in South-Western Finland.

    PubMed

    Lampinen, Jussi; Ruokolainen, Kalle; Huhta, Ari-Pekka

    2015-01-01

    Regularly managed electric power line corridors may provide habitats for both early-successional grassland plant species and disturbance-dependent alien plant species. These habitats are especially important in urban areas, where they can help conserve native grassland species and communities in urban greenspace. However, they can also provide further footholds for potentially invasive alien species that already characterize urban areas. In order to implement power line corridors into urban conservation, it is important to understand which environmental conditions in the corridors favor grassland species and which alien species. Likewise it is important to know whether similar environmental factors in the corridors control the species composition of the two groups. We conducted a vegetation study in a 43 kilometer long urban power line corridor network in south-western Finland, and used generalized linear models and distance-based redundancy analysis to determine which environmental factors best predict the occurrence and composition of grassland and alien plant species in the corridors. The results imply that old corridors on dry soils and steep slopes characterized by a history as open areas and pastures are especially suitable for grassland species. Corridors suitable for alien species, in turn, are characterized by productive soils and abundant light and are surrounded by a dense urban fabric. Factors controlling species composition in the two groups are somewhat correlated, with the most important factors including light abundance, soil moisture, soil calcium concentration and soil productivity. The results have implications for grassland conservation and invasive alien species control in urban areas.

  11. Number of lightning discharges causing damage to lightning arrester cables for aerial transmission lines in power systems

    SciTech Connect

    Nikiforov, E. P.

    2009-07-15

    Damage by lightning discharges to lightning arrester cables for 110-175 kV aerial transmission lines is analyzed using data from power systems on incidents with aerial transmission lines over a ten year operating period (1997-2006). It is found that failures of lightning arrester cables occur when a tensile force acts on a cable heated to the melting point by a lightning current. The lightning currents required to heat a cable to this extent are greater for larger cable cross sections. The probability that a lightning discharge will develop decreases as the amplitude of the lightning current increases, which greatly reduces the number of lightning discharges which damage TK-70 cables compared to TK-50 cables. In order to increase the reliability of lightning arrester cables for 110 kV aerial transmission lines, TK-70 cables should be used in place of TK-50 cables. The number of lightning discharges per year which damage lightning arrester cables is lowered when the density of aerial transmission lines is reduced within the territory of electrical power systems. An approximate relationship between these two parameters is obtained.

  12. Active harmonic filter technology and market assessment. Final report

    SciTech Connect

    Bhattacharya, S.; Divan, D.; Sutherland, P.

    1998-08-01

    Non-linear loads such as three-phase rectifiers, adjustable speed drives (ASDs), and arcing loads can cause voltage distortion and other power quality problems due to their interaction with the power grid. This report provides a technical and marketing assessment of active harmonic filters, a promising approach to preventing these problems at their source. Although predicting the direction and magnitude of harmonic currents is difficult due to highly interconnected nature of distribution systems, even small harmonic producing loads can result in high levels of harmonic current flow between the utility and a customer and can also cause a resonance problem at sites far removed from the harmonic producing load. The best way to keep voltage distortion low in a utility system is to constrain the harmonic currents at their sources. However, since regulation of harmonic pollution does not provide any additional value to the customer, it is unlikely that any controls will be implemented on a consistent basis in the absence of mandatory requirements. In the United States, a step toward a standard operating practice is the IEEE 519-1992 recommended harmonic standard that provides guidelines for limiting harmonic currents by industrial plants. This report identifies the equipment likely to produce harmonic loads and explains the kinds of problems that harmonic currents can cause in a utility distribution system. It describes possible solutions to these problems, including harmonic filtering and other technologies. The report examines the prospects for wider use of active harmonic filter technology and discusses the important marketing issues for potential active filter marketers and manufacturers, such as the barriers to and drivers of increased use of active filter technology and the price points for active filters.

  13. Optimization of fluid line sizes with pumping power penalty IBM-360 computer program

    NASA Technical Reports Server (NTRS)

    Jelinek, D.

    1972-01-01

    Computer program has been developed to calculate and total weights for tubing, fluid in tubing, and weight of fuel cell power source necessary to power pump based on flow rate and pressure drop. Program can be used for fluid systems used in any type of aircraft, spacecraft, trucks, ships, refineries, and chemical processing plants.

  14. Cancer cell line identification by short tandem repeat profiling: power and limitations.

    PubMed

    Parson, Walther; Kirchebner, Romana; Mühlmann, Roswitha; Renner, Kathrin; Kofler, Anita; Schmidt, Stefan; Kofler, Reinhard

    2005-03-01

    Cancer cell lines are used worldwide in biological research, and data interpretation depends on unambiguous attribution of the respective cell line to its original source. Short-tandem-repeat (STR) profiling (DNA fingerprinting) is the method of choice for this purpose; however, the genetic stability of cell lines under various experimental conditions is not well defined. We tested the effect of long-term culture, subcloning, and generation of drug-resistant subclones on fingerprinting profiles in four widely used leukemia cell lines. The DNA fingerprinting profile remained unaltered in two of them (U937 and K562) throughout 12 months in culture, and the vast majority of subclones derived therefrom by limiting dilution after long-term culture revealed the same profile, indicating a high degree of stability and clonotypic homogeneity. In contrast, two other cell lines (CCRF-CEM and Jurkat) showed marked alterations in DNA fingerprinting profiles during long-term culture. Limiting dilution subcloning revealed extensive clonotypic heterogeneity with subclones differing in up to eight STR loci from the parental culture. Similar heterogeneity was observed in subclones generated by selection culture for drug resistance where DNA fingerprinting proved useful in identifying possible resistance mechanisms. Thus, common tissue culture procedures may dramatically affect the fingerprinting profile of certain cell lines and thus render definition of their origin difficult.

  15. Harmonic Oscillators as Bridges between Theories

    NASA Astrophysics Data System (ADS)

    Kim, Y. S.; Noz, Marilyn E.

    2005-03-01

    Other than scattering problems where perturbation theory is applicable, there are basically two ways to solve problems in physics. One is to reduce the problem to harmonic oscillators, and the other is to formulate the problem in terms of two-by-two matrices. If two oscillators are coupled, the problem combines both two-by-two matrices and harmonic oscillators. This method then becomes a powerful research tool to cover many different branches of physics. Indeed, the concept and methodology in one branch of physics can be translated into another through the common mathematical formalism. It is noted that the present form of quantum mechanics is largely a physics of harmonic oscillators. Special relativity is the physics of the Lorentz group which can be represented by the group of by two-by-two matrices commonly called SL(2, c). Thus the coupled harmonic oscillators can therefore play the role of combining quantum mechanics with special relativity. Both Paul A. M. Dirac and Richard P. Feynman were fond of harmonic oscillators, while they used different approaches to physical problems. Both were also keenly interested in making quantum mechanics compatible with special relativity. It is shown that the coupled harmonic oscillators can bridge these two different approaches to physics.

  16. A Study on Modeling of Transmission Line in Digital Type Real-Time Power System Simulator

    NASA Astrophysics Data System (ADS)

    Yasuda, Yuji; Yokoyama, Akihiko; Tada, Yasuyuki

    In modern power systems, it is important to analyze various kindes of dynamic phenomena which appear in the system. When the effectiveness of new power electronics based apparatus, protective relay systems and etc. is tested, a real-time power system simulator is becoming a very effective tool. In general, however, it is very expensive and it is very difficult for beginners to understand how to use it. Therefore, studies on low-cost and easy-use real-time power system simulators have so far been done. We have developed models of power system components for the real-time power system simulator using DSP (Digital Signal Processor) combined with commercial CAD (Computer Aided Design) soft "MATLAB/SIMULINK". The use of commercial softwares can drastically decrease the development cost of the simulator. In this paper, a simplified reduction model of unbalanced three-phase transmission network with mutual impedance is proposed for analysis of various kinds of stability phenomena by use of the digital simulator. The proposed network model is constructed automatically and efficiently even for connection of both current source type models and voltage source type models of power apparatus such as generators, FACTS devices and loads.

  17. Cell-line selectivity improves the predictive power of pharmacogenomic analyses and helps identify NADPH as biomarker for ferroptosis sensitivity

    PubMed Central

    Shimada, Kenichi; Hayano, Miki; Pagano, Nen; Stockwell, Brent

    2016-01-01

    Precision medicine in oncology requires not only identification of cancer-associated mutations, but also effective drugs for each cancer genotype, which is still a largely unsolved problem. One approach for the latter challenge has been large-scale testing of small molecules in genetically characterized cell lines. We hypothesized that compounds with high cell-line-selective lethality exhibited consistent results across such pharmacogenomic studies. We analyzed the compound sensitivity data of 6,259 lethal compounds from the NCI-60 project. 2,565 cell-line-selective lethal compounds were identified and grouped into 18 clusters based on their GI50 profiles across the 60 cell lines, which were shown to represent distinct mechanisms of action. Further transcriptome analysis revealed a biomarker, NADPH abundance, for predicting sensitivity to ferroptosis-inducing compounds, which we experimentally validated. In summary, incorporating cell-line selectivity filters improves the predictive power of pharmacogenomic analyses and enables discovery of biomarkers that predict the sensitivity of cells to specific cell death inducers. PMID:26853626

  18. Cell-Line Selectivity Improves the Predictive Power of Pharmacogenomic Analyses and Helps Identify NADPH as Biomarker for Ferroptosis Sensitivity.

    PubMed

    Shimada, Kenichi; Hayano, Miki; Pagano, Nen C; Stockwell, Brent R

    2016-02-18

    Precision medicine in oncology requires not only identification of cancer-associated mutations but also effective drugs for each cancer genotype, which is still a largely unsolved problem. One approach for the latter challenge has been large-scale testing of small molecules in genetically characterized cell lines. We hypothesized that compounds with high cell-line-selective lethality exhibited consistent results across such pharmacogenomic studies. We analyzed the compound sensitivity data of 6,259 lethal compounds from the NCI-60 project. A total of 2,565 cell-line-selective lethal compounds were identified and grouped into 18 clusters based on their median growth inhibitory GI50 profiles across the 60 cell lines, which were shown to represent distinct mechanisms of action. Further transcriptome analysis revealed a biomarker, NADPH abundance, for predicting sensitivity to ferroptosis-inducing compounds, which we experimentally validated. In summary, incorporating cell-line-selectivity filters improves the predictive power of pharmacogenomic analyses and enables discovery of biomarkers that predict the sensitivity of cells to specific cell death inducers.

  19. Health responses to a new high-voltage power line route: design of a quasi-experimental prospective field study in the Netherlands

    PubMed Central

    2014-01-01

    Background New high-voltage power transmission lines will be introduced due to increasing demand for reliable and renewable energy supplies. Some residents associate non-specific health complaints with exposure to electromagnetic fields from nearby power lines. This study protocol describes the design and rationale of a prospective study investigating whether the introduction of a new power line triggers health responses in residents living nearby. Methods/Design The study is designed as a quasi-experimental field study with two pretests during the construction of a new power line route, and two posttests after it has been put into operation. Key outcomes are self-reported non-specific somatic and cognitive health complaints, and attribution of these health complaints to a power line. The main determinant is proximity to the new power line route. One member of every household (n = 2379) residing in close proximity (0-500 meters) to the overhead parts of a new power line route in the Netherlands is invited to participate, as well as a sample of household members (n = 2382) residing farther away (500-2000 meters). Multilevel analysis will be employed to test whether an increase in key outcome measures is related to proximity to the line. Longitudinal structural equation models will be applied to test to what extent health responses are mediated by psychosocial health mechanisms and moderated by negative oriented personality traits. Discussion This is the first study to investigate health responses to a new power line route in a prospective manner. The results will provide theoretical insight into psychosocial mechanisms operating during the introduction of an environmental health risk, and may offer suggestions to policymakers and other stakeholders for minimizing adverse health responses when introducing new high-voltage power lines. PMID:24606914

  20. Harmonic millimeter radiation from a microwave FEL amplifier

    NASA Astrophysics Data System (ADS)

    Liu, Y.-H.; Marshall, T. C.

    1997-02-01

    In this project, an electron beam is bunched at a microwave frequency and the harmonics of this bunching drive radiation at millimeter wavelengths, using a FEL, configured as a single-pass travelling wave amplifier. A 10 kW 24 GHz microwave input signal grows to ˜200 kW level using the lower-frequency unstable root of the waveguide FEL dispersion relation. The Columbia FEL facility operates at this frequency in the TE11 mode, using a helical undulator (1.85 cm period) and a 3 mm diameter 600 kV electron beam contained in a 8.7 mm ID cylindrical waveguide. The harmonic currents set up by the microwave are found to cause growth of harmonic power under two conditions. First, we choose the parameters of the device so that the upper frequency root corresponds to the third harmonic, in which case we observe a small amount of third-harmonic emission in the TE11 mode, accompanied by comparable second harmonic. The millimeter harmonic radiation produced is coherent and phase-related to the microwave source. Second, we have found substantial emission at the seventh harmonic, most likely from the TE72 mode — which, in cylindrical waveguide geometry, travels at very nearly the same wave speed as the 24 GHz TE11 power. In order to excite the seventh-harmonic radiation, the electron beam must be displaced from the system axis — ˜2 mm in this device. The seventh-harmonic output is potentially an attractive choice for a CW FEL which must generate appreciable power at ˜2 mm wavelength for plasma electron cyclotron heating since we can produce this radiation for electron beam energy as low as 400 kV. We present a theoretical model of the experiment which predicts that if the microwave signal is strong enough to drive the FEL into saturation, the harmonic emission becomes powerful.

  1. The influence of lightning induced voltage on the distribution power line polymer insulators.

    PubMed

    Izadi, Mahdi; Abd Rahman, Muhammad Syahmi; Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

    2017-01-01

    Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance.

  2. The influence of lightning induced voltage on the distribution power line polymer insulators

    PubMed Central

    Ab-Kadir, Mohd Zainal Abidin; Gomes, Chandima; Jasni, Jasronita; Hajikhani, Maryam

    2017-01-01

    Protection of medium voltage (MV) overhead lines against the indirect effects of lightning is an important issue in Malaysia and other tropical countries. Protection of these lines against the indirect effects of lightning is a major concern and can be improved by several ways. The choice of insulator to be used for instance, between the glass, ceramic or polymer, can help to improve the line performance from the perspective of increasing the breakdown strength. In this paper, the electrical performance of a 10 kV polymer insulator under different conditions for impulse, weather and insulator angle with respect to a cross-arm were studied (both experimental and modelling) and the results were discussed accordingly. Results show that the weather and insulator angle (with respect to the cross-arm) are surprisingly influenced the values of breakdown voltage and leakage current for both negative and positive impulses. Therefore, in order to select a proper protection system for MV lines against lightning induced voltage, consideration of the local information concerning the weather and also the insulator angles with respect to the cross-arm are very useful for line stability and performance. PMID:28234930

  3. 33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.3 Clearances for power and... reservoir projects. (b) Applicability. This regulation applies to all field operating agencies having...

  4. 33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.3 Clearances for power and... reservoir projects. (b) Applicability. This regulation applies to all field operating agencies having...

  5. 33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.3 Clearances for power and... reservoir projects. (b) Applicability. This regulation applies to all field operating agencies having...

  6. Feasibility Implementation of Voltage-Current Waveform Telemetry System in Power Delivery System

    NASA Astrophysics Data System (ADS)

    Furukawa, Tatsuya; Akagi, Keita; Fukumoto, Hisao; Itoh, Hideaki; Wakuya, Hiroshi; Hirata, Kenji; Ohchi, Masashi

    The electric power is indispensable for modern life. However, there is a problem of harmonic disturbance when the harmonic power runs into electronic devices. To overcome the problem and realize a stable supply of the electric power is an important issue. In this study, we have developed a voltage-current waveform telemetry system for the remote measurement of the harmonics in the power delivery lines. The system consists of sensors, preamplifiers, a single board computer, and power collectors. Improvements are made on all of these components except the sensors. The power collector is a coil that can be placed around the same power line that we measure. We have designed the power collector by a finite element method(FEM) so that it can provide enough electricity for the computer to work properly. Thus, no other power source such as a battery except the secondary rechargeable battery for the recovery is necessary at the measurement place. The preamplifier in the new system is a single-supply differential amplifier circuit, and the single board computer has an inexpensive SH-3 CPU. Through experiments, we have confirmed that the power collector can provide sufficient electricity and that the new system can successfully measure the waveforms and the harmonics in power delivery systems.

  7. A computerized on-line power loss testing system for the steel industry, based on the RCP compensation technique

    SciTech Connect

    Khanlou, A.; Moses, A.J.; Meydan, T.; Beckley, P.

    1995-11-01

    The design and development of a novel, non-enwrapping power loss testing system which can be used to grade electrical steels directly on the production line has been described. The developed system incorporates the use of Rogowski Chattock Potentiometer (RCP) coils. These coils function as a zero field potential indicator between two defined points along the measuring region of a single specimen of electrical steel, hence making the surface magnetic field proportional to the magnetizing current. This enables the field component necessary for power loss measurement to be obtained from the magnetizing current which is more convenient in an on-line situation. The developed system has been fully computerized and it is shown that under static laboratory conditions the system correlates well with a deviation of only 2.5% from values obtained using the current standard, the Epstein Frame. The effect of strip motion on the measurements has also been investigated and discussed to understand how the system will perform on the actual production line.

  8. Exploring the power of rice (O. sativa x O. rufipogon) chromosome segment substitution line libraries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgressive variation was reported as an increase in grain yield for several rice (Oryza sativa x O. rufipogon) advanced backcross mapping populations. The objective of this study was to develop chromosome segment substitution line (CSSL) libraries to further dissect the reported transgressive var...

  9. Circuit for Communication over DC Power Line Using High Temperature Electronics

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J. (Inventor); Prokop, Norman F. (Inventor)

    2014-01-01

    A high temperature communications circuit includes a power conductor for concurrently conducting electrical energy for powering circuit components and transmitting a modulated data signal, and a demodulator for demodulating the data signal and generating a serial bit stream based on the data signal. The demodulator includes an absolute value amplifier for conditionally inverting or conditionally passing a signal applied to the absolute value amplifier. The absolute value amplifier utilizes no diodes to control the conditional inversion or passing of the signal applied to the absolute value amplifier.

  10. C IV and He II line emission of Lyman α blobs: powered by shock-heated gas

    NASA Astrophysics Data System (ADS)

    Cabot, Samuel; Cen, Renyue; Zheng, Zheng

    2017-01-01

    Utilizing ab initio ultrahigh resolution hydrodynamical simulations, we investigate the properties of the interstellar and circumgalactic medium of Lyα blobs (LABs) at z = 3, focusing on three important emission lines: Lyα 1216 Å, He II 1640 Å and C IV 1549 Å. Their relative strengths provide a powerful probe of the thermodynamic properties of the gas when confronted with observations. By adjusting the dust attenuation effect using one parameter and matching the observed size-luminosity relation of LABs using another parameter, we show that our simulations can reproduce the observed C IV/Lyα and He II/Lyα ratios adequately. This analysis provides the first successful physical model to account for simultaneously the LAB luminosity function, luminosity-size relation and the C IV/Lyα and He II/Lyα ratios, with only two parameters. The physical underpinning for this model is that, in addition to the stellar component for the Lyα emission, the Lyα and C IV emission lines due to shock-heated gas are primarily collisional excitation driven and the He II emission line collisional ionization driven. We find that the density, temperature and metallicity of the gas responsible for each emission line is significantly distinct, in a multiphase interstellar and circumgalactic medium that is shock heated primarily by supernovae and secondarily by gravitational accretion of gas.

  11. An Insight on Right of Way and its Cost for Power Transmission Cable and Conventional Overhead Transmission Lines

    NASA Astrophysics Data System (ADS)

    Khandelwal, P.; Pachori, A.; Khandelwal, T.

    2013-12-01

    This paper provides the complete information related to Right of Way (RoW) for the construction of new power transmission line (TL) in terms of present cost for overhead transmission line and underground XLPE transmission cable. The former part of the paper describes the general procedure and rules for acquisition of land for RoW by transmission asset owner (TAO) while in the later part the cost associated to acquire RoW and its impact on the cost of adjacent land have been detailed. It also discusses the actual dismantling cost including the cost of waste metal what TAO get after completion of lifecycle of TL due to increase in metal prices. In this paper cost of RoW after completion of lifecycle of TL is also highlighted. This paper compares the cost of RoW for overhead transmission line and underground XLPE transmission cable for construction of new TL. Also for old transmission infrastructure cost of RoW for change from overhead transmission line to underground XLPE transmission cable is detailed by application of replacement model.

  12. Finite time-Lyapunov based approach for robust adaptive control of wind-induced oscillations in power transmission lines

    NASA Astrophysics Data System (ADS)

    Ghabraei, Soheil; Moradi, Hamed; Vossoughi, Gholamreza

    2016-06-01

    Large amplitude oscillation of the power transmission lines, which is also known as galloping phenomenon, has hazardous consequences such as short circuiting and failure of transmission line. In this article, to suppress the undesirable vibrations of the transmission lines, first the governing equations of transmission line are derived via mode summation technique. Then, due to the occurrence of large amplitude vibrations, nonlinear quadratic and cubic terms are included in the derived linear equations. To suppress the vibrations, arbitrary number of the piezoelectric actuators is assumed to exert the actuation forces. Afterwards, a Lyapunov based approach is proposed for the robust adaptive suppression of the undesirable vibrations in the finite time. To compensate the supposed parametric uncertainties with unknown bands, proper adaption laws are introduced. To avoid the vibration devastating consequences as quickly as possible, appropriate control laws are designed. The vibration suppression in the finite time with supposed adaption and control laws is mathematically proved via Lyapunov finite time stability theory. Finally, to illustrate and validate the efficiency and robustness of the proposed finite time control scheme, a parametric case study with three piezoelectric actuators is performed. It is observed that the proposed active control strategy is more efficient and robust than the passive control methods.

  13. Spectroscopy of emission-line nebulae in powerful radio galaxies - Interpretation

    NASA Astrophysics Data System (ADS)

    Baum, S. A.; Heckman, T. M.; van Breugel, W.

    1992-04-01

    Long-slit optical spectra of the emission-line nebulae associated with 21 low-redshift (less than 0.2) radio galaxies are analyzed. Nebulae are classified kinematically into three types: rotators, calm nonrotators, and violent nonrotators; these types are characterized. It is proposed that the rotators have dynamically young disks of gas recently acquired by the radio galaxy in an interaction or merger with a gas-rich galaxy. This is consistent with the data on the morphologies, colors, and stellar dynamics of radio galaxies with strong emission lines. It is inferred from the association of the large-scale gas kinematics with the radio and optical properties of an active galaxy that the angular momentum of the gas which fuels the AGN may be an important parameter in the determinant of how activity is manifest in an AGN.

  14. Magnetic fields of high voltage power lines and risk of cancer in Finnish adults: nationwide cohort study.

    PubMed Central

    Verkasalo, P. K.; Pukkala, E.; Kaprio, J.; Heikkilä, K. V.; Koskenvuo, M.

    1996-01-01

    OBJECTIVE: To investigate the risk of cancer in association with magnetic fields in Finnish adults living close to high voltage power lines. DESIGN: Nationwide cohort study. SUBJECTS: 383,700 people who lived during 1970-89 within 500 metres of overhead power lines of 110-400 kV in a magnetic field calculated to be > or = 0.01 microT. Study subjects were identified by record linkages of nationwide registers. MAIN OUTCOME MEASURES: Numbers of observed and expected cases of cancer, standardised incidence ratios, and incidence rate ratios adjusted for sex, age, calendar year, and social class--for example, by continuous cumulative exposure per 1 microT year with 95% confidence intervals from multiplicative models for all cancers combined and 21 selected types. RESULTS: Altogether 8415 cases of cancer were observed (standardised incidence ratio 0.98; 95% confidence interval 0.96 to 1.00) in adults. All incidence rate ratios for both sexes combined were non-significant and between 0.91 and 1.11. Significant excesses were observed in multiple myeloma in men (incidence rate ratio 1.22) and in colon cancer in women (1.16). CONCLUSIONS: Typical residential magnetic fields generated by high voltage power lines do not seem to be related to the risk of overall cancer in adults. The previously suggested associations between extremely low frequency magnetic fields and tumours of the nervous system, lymphoma, and leukaemia in adults and breast cancer in women were not confirmed. PMID:8898595

  15. 33 CFR 222.3 - Clearances for power and communication lines over reservoirs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.3 Clearances for power and... reservoir projects. (b) Applicability. This regulation applies to all field operating agencies having Civil... Code (ANSI C2), available from IEEE Service Center, 445 Hoes Lane, Piscataway, N.J. 08854....

  16. NEW APPROACHES: Stroboscopic measurement of the power-line frequency using a bicycle

    NASA Astrophysics Data System (ADS)

    Giordano, José Luis

    1997-07-01

    When certain rotating bodies are viewed in artificial light a stroboscopic efect can be observed that would not be seen in daylight. A simple analysis of this effect is presented here together with an experiment using a bicycle and a tachometer that allows students to determine the frequency of the mains electricity powering the light.

  17. Thomson Parabola Spectrometer: a powerful tool to get on-line plasma information

    SciTech Connect

    Altana, C.; Schillaci, F.; Anzalone, A.; Cirrone, G.A.P; Tudisco, S.; Lanzalone, G.; Muoio, A.

    2015-07-01

    In this contribution we report the results of an experimental measurement performed with a TPS developed at INFN-LNS within the ELIMED project, by means of a powerful and self-consistent technique as a diagnostic tool for the ionic acceleration study in laser-generated-plasmas. (authors)

  18. Development of (RE)BCO cables for HTS power transmission lines

    NASA Astrophysics Data System (ADS)

    Mukoyama, S.; Yagi, M.; Masuda, T.; Amemiya, N.; Ishiyama, A.; Kashima, N.; Nagaya, S.; Aoki, Y.; Yoshizumi, M.; Yamada, Y.; Izumi, T.; Shiohara, Y.

    2009-10-01

    High-temperature superconducting (HTS) power cables transmit bulk power with lower loss than conventional cables. Moreover, HTS cables are expected to be constructed as a new underground cable in urban areas at lower cost compared to a high voltage XLPE cable. To put promising HTS cables to practical use, we need (RE)BCO tapes with long length, high critical current, and low cost. Recently many organizations have improved the performance of the (RE)BCO tapes, such as YBCO tapes, or other coated conductor tapes that are made with a variety of different processes. We have fabricated the conductors for the HTS power cable that was constructed of different kinds of (RE)BCO tapes and measured the I c and AC losses. We achieved significantly low AC loss of 0.1 W/m at 1 kA in the HTS conductor using narrow slit tapes that were cut by laser. Moreover, a 20 m long HTS power cable model and a cable intermediate joint were developed. Short circuit current tests were conducted on the cable system that consisted of two 10 m cables, a cable joint, and two terminations. The cables and the joint withstood the short circuit current of 31.5 kA for 2 s without damage.

  19. Low-power integrated-circuit driver for ferrite-memory word lines

    NASA Technical Reports Server (NTRS)

    Katz, S.

    1970-01-01

    Composite circuit uses both n-p-n bipolar and p-channel MOS transistors /BIMOS/. The BIMOS driver provides 1/ ease of integrated circuit construction, 2/ low standby power consumption, 3/ bidirectional current pulses, and 4/ current-pulse amplitudes and rise times independent of active device parameters.

  20. Contact Line Instability of Gravity-Driven Flow of Power-Law Fluids.

    PubMed

    Hu, Bin; Kieweg, Sarah L

    2015-11-01

    The moving contact line of a thin fluid film can often corrugate into fingers, which is also known as a fingering instability. Although the fingering instability of Newtonian fluids has been studied extensively, there are few studies published on contact line fingering instability of non-Newtonian fluids. In particular, it is still unknown how shear-thinning rheological properties can affect the formation, growth, and shape of a contact line instability. Our previous study (Hu and Kieweg, 2012) showed a decreased capillary ridge formation for more shear-thinning fluids in a 2D model (i.e. 1D thin film spreading within the scope of lubrication theory). Those results motivated this study's hypothesis: more shear-thinning fluids should have suppressed finger growth and longer finger wavelength, and this should be evident in linear stability analysis (LSA) and 3D (i.e. 2D spreading) numerical simulations. In this study, we developed a LSA model for the gravity-driven flow of shear-thinning films, and carried out a parametric study to investigate the impact of shear-thinning on the growth rate of the emerging fingering pattern. A fully 3D model was also developed to compare and verify the LSA results using single perturbations, and to explore the result of multiple-mode, randomly imposed perturbations. Both the LSA and 3D numerical results confirmed that the contact line fingers grow faster for Newtonian fluids than the shear-thinning fluids on both vertical and inclined planes. In addition, both the LSA and 3D model indicated that the Newtonian fluids form fingers with shorter wavelengths than the shear-thinning fluids when the plane is inclined; no difference in the most unstable (i.e. emerging) wavelength was observed at vertical. This study also showed that the distance between emerging fingers was smaller on a vertical plane than on a less-inclined plane for shear-thinning fluids, as previously shown for Newtonian fluids. For the first time for shear

  1. Optical harmonic generator

    DOEpatents

    Summers, Mark A.; Eimerl, David; Boyd, Robert D.

    1985-01-01

    A pair of uniaxial birefringent crystal elements are fixed together to form a serially arranged, integral assembly which, alternatively, provides either a linearly or elliptically polarized second-harmonic output wave or a linearly polarized third-harmonic output wave. The "extraordinary" or "e" directions of the crystal elements are oriented in the integral assembly to be in quadrature (90.degree.). For a second-harmonic generation in the Type-II-Type-II angle tuned case, the input fundamental wave has equal amplitude "o" and "e" components. For a third-harmonic generation, the input fundamental wave has "o" and "e" components whose amplitudes are in a ratio of 2:1 ("o":"e" reference first crystal). In the typical case of a linearly polarized input fundamental wave this can be accomplished by simply rotating the crystal assembly about the input beam direction by 10.degree.. For both second and third harmonic generation input precise phase-matching is achieved by tilting the crystal assembly about its two sensitive axes ("o").

  2. Optical harmonic generator

    DOEpatents

    Summers, M.A.; Eimerl, D.; Boyd, R.D.

    1982-06-10

    A pair of uniaxial birefringent crystal elements are fixed together to form a serially arranged, integral assembly which, alternatively, provides either a linearly or elliptically polarized second-harmonic output wave or a linearly polarized third-harmonic output wave. The extraordinary or e directions of the crystal elements are oriented in the integral assembly to be in quadrature (90/sup 0/). For a second-harmonic generation in the Type-II-Type-II angle tuned case, the input fundamental wave has equal amplitude o and e components. For a third-harmonic generation, the input fundamental wave has o and e components whose amplitudes are in a ratio of 2:1 (o:e reference first crystal). In the typical case of a linearly polarized input fundamental wave this can be accomplished by simply rotating the crystal assembly about the input beam direction by 10/sup 0/. For both second and third harmonic generation input precise phase-matching is achieved by tilting the crystal assembly about its two sensitive axeses (o).

  3. Relationship Between Selected Strength and Power Assessments to Peak and Average Velocity of the Drive Block in Offensive Line Play.

    PubMed

    Jacobson, Bert H; Conchola, Eric C; Smith, Doug B; Akehi, Kazuma; Glass, Rob G

    2016-08-01

    Jacobson, BH, Conchola, EC, Smith, DB, Akehi, K, and Glass, RG. Relationship between selected strength and power assessments to peak and average velocity of the drive block in offensive line play. J Strength Cond Res 30(8): 2202-2205, 2016-Typical strength training for football includes the squat and power clean (PC) and routinely measured variables include 1 repetition maximum (1RM) squat and 1RM PC along with the vertical jump (VJ) for power. However, little research exists regarding the association between the strength exercises and velocity of an actual on-the-field performance. The purpose of this study was to investigate the relationship of peak velocity (PV) and average velocity (AV) of the offensive line drive block to 1RM squat, 1RM PC, the VJ, body mass (BM), and body composition. One repetition maximum assessments for the squat and PC were recorded along with VJ height, BM, and percent body fat. These data were correlated with PV and AV while performing the drive block. Peal velocity and AV were assessed using a Tendo Power and Speed Analyzer as the linemen fired, from a 3-point stance into a stationary blocking dummy. Pearson product analysis yielded significant (p ≤ 0.05) correlations between PV and AV and the VJ, the squat, and the PC. A significant inverse association was found for both PV and AV and body fat. These data help to confirm that the typical exercises recommended for American football linemen is positively associated with both PV and AV needed for the drive block effectiveness. It is recommended that these exercises remain the focus of a weight room protocol and that ancillary exercises be built around these exercises. Additionally, efforts to reduce body fat are recommended.

  4. Modelling and optimization of transient processes in line focusing power plants with single-phase heat transfer medium

    NASA Astrophysics Data System (ADS)

    Noureldin, K.; González-Escalada, L. M.; Hirsch, T.; Nouri, B.; Pitz-Paal, R.

    2016-05-01

    A large number of commercial and research line focusing solar power plants are in operation and under development. Such plants include parabolic trough collectors (PTC) or linear Fresnel using thermal oil or molten salt as the heat transfer medium (HTM). However, the continuously varying and dynamic solar condition represent a big challenge for the plant control in order to optimize its power production and to keep the operation safe. A better understanding of the behaviour of such power plants under transient conditions will help reduce defocusing instances, improve field control, and hence, increase the energy yield and confidence in this new technology. Computational methods are very powerful and cost-effective tools to gain such understanding. However, most simulation models described in literature assume equal mass flow distributions among the parallel loops in the field or totally decouple the flow and thermal conditions. In this paper, a new numerical model to simulate a whole solar field with single-phase HTM is described. The proposed model consists of a hydraulic part and a thermal part that are coupled to account for the effect of the thermal condition of the field on the flow distribution among the parallel loops. The model is specifically designed for large line-focusing solar fields offering a high degree of flexibility in terms of layout, condition of the mirrors, and spatially resolved DNI data. Moreover, the model results have been compared to other simulation tools, as well as experimental and plant data, and the results show very good agreement. The model can provide more precise data to the control algorithms to improve the plant control. In addition, short-term and accurate spatially discretized DNI forecasts can be used as input to predict the field behaviour in-advance. In this paper, the hydraulic and thermal parts, as well as the coupling procedure, are described and some validation results and results of simulating an example field are

  5. The harmonic oscillator and nuclear physics

    NASA Technical Reports Server (NTRS)

    Rowe, D. J.

    1993-01-01

    The three-dimensional harmonic oscillator plays a central role in nuclear physics. It provides the underlying structure of the independent-particle shell model and gives rise to the dynamical group structures on which models of nuclear collective motion are based. It is shown that the three-dimensional harmonic oscillator features a rich variety of coherent states, including vibrations of the monopole, dipole, and quadrupole types, and rotations of the rigid flow, vortex flow, and irrotational flow types. Nuclear collective states exhibit all of these flows. It is also shown that the coherent state representations, which have their origins in applications to the dynamical groups of the simple harmonic oscillator, can be extended to vector coherent state representations with a much wider range of applicability. As a result, coherent state theory and vector coherent state theory become powerful tools in the application of algebraic methods in physics.

  6. Joint terminals and relay optimization for two-way power line information exchange systems with QoS constraints

    NASA Astrophysics Data System (ADS)

    Wu, Xiaolin; Rong, Yue

    2015-12-01

    The quality-of-service (QoS) criteria (measured in terms of the minimum capacity requirement in this paper) are very important to practical indoor power line communication (PLC) applications as they greatly affect the user experience. With a two-way multicarrier relay configuration, in this paper we investigate the joint terminals and relay power optimization for the indoor broadband PLC environment, where the relay node works in the amplify-and-forward (AF) mode. As the QoS-constrained power allocation problem is highly non-convex, the globally optimal solution is computationally intractable to obtain. To overcome this challenge, we propose an alternating optimization (AO) method to decompose this problem into three convex/quasi-convex sub-problems. Simulation results demonstrate the fast convergence of the proposed algorithm under practical PLC channel conditions. Compared with the conventional bidirectional direct transmission (BDT) system, the relay-assisted two-way information exchange (R2WX) scheme can meet the same QoS requirement with less total power consumption.

  7. High harmonic terahertz confocal gyrotron with nonuniform electron beam

    SciTech Connect

    Fu, Wenjie; Guan, Xiaotong; Yan, Yang

    2016-01-15

    The harmonic confocal gyrotron with nonuniform electron beam is proposed in this paper in order to develop compact and high power terahertz radiation source. A 0.56 THz third harmonic confocal gyrotron with a dual arc section nonuniform electron beam has been designed and investigated. The studies show that confocal cavity has extremely low mode density, and has great advantage to operate at high harmonic. Nonuniform electron beam is an approach to improve output power and interaction efficiency of confocal gyrotron. A dual arc beam magnetron injection gun for designed confocal gyrotron has been developed and presented in this paper.

  8. Impact of Line Width and Power of Laser on Radio over Fiber System

    NASA Astrophysics Data System (ADS)

    Sharma, Sakshi; Bhatia, Kamaljeet Singh; Kaur, Harsimrat

    2015-03-01

    In order to increase the capacity of the existing optical communication networks advanced modulation schemes are utilized. Keeping this in view, an radio-over-fiber subcarrier multiplexing (SCM) employing ASK modulation technique is proposed. Response of the system is analysed by varying the linewidth and the power of the CW Laser and the optimum value is concluded for the same so as to achieve reliable communication.

  9. The HEMP (high altitude electromagnetic pulse) response of an overhead power distribution line

    SciTech Connect

    Tesche, F.M.; Barnes, P.R.

    1988-01-01

    A study of the HEMP response of a realistic power distribution system was undertaken, and its results are described in this paper. This study involved the following elements: (1) the use of the new HEMP environment, (2) the use of a multiconductor coupling model, and (3) the measurement of the pulse response of an actual distribution transformer to permit the use of this data in the analysis.

  10. Harmonic uniflow engine

    DOEpatents

    Bennett, Charles L.

    2016-03-22

    A reciprocating-piston uniflow engine includes a harmonic oscillator inlet valve capable of oscillating at a resonant frequency for controlling the flow of working fluid into the engine. In particular, the inlet valve includes an inlet valve head and a spring arranged together as a harmonic oscillator so that the inlet valve head is moveable from an unbiased equilibrium position to a biased closed position occluding an inlet. When released, the inlet valve head undergoes a single oscillation past the equilibrium position to a maximum open position and returns to a biased return position close to the closed position to choke the flow and produce a pressure drop across the inlet valve causing the inlet valve to close. In other embodiments, the harmonic oscillator arrangement of the inlet valve enables the uniflow engine to be reversibly operated as a uniflow compressor.

  11. SULFUR REMOVAL FROM PIPE LINE NATURAL GAS FUEL: APPLICATION TO FUEL CELL POWER GENERATION SYSTEMS

    SciTech Connect

    King, David L.; Birnbaum, Jerome C.; Singh, Prabhakar

    2003-11-21

    Pipeline natural gas is being considered as the fuel of choice for utilization in fuel cell-based distributed generation systems because of its abundant supply and the existing supply infrastructure (1). For effective utilization in fuel cells, pipeline gas requires efficient removal of sulfur impurities (naturally occurring sulfur compounds or sulfur bearing odorants) to prevent the electrical performance degradation of the fuel cell system. Sulfur odorants such as thiols and sulfides are added to pipeline natural gas and to LPG to ensure safe handling during transportation and utilization. The odorants allow the detection of minute gas line leaks, thereby minimizing the potential for explosions or fires.

  12. Enhanced Harmonic Up-Conversion Using a Hybrid HGHG-EEHG Scheme

    SciTech Connect

    Marksteiner, Quinn R.; Bishofberger, Kip A.; Carlsten, Bruce E.; Freund, Henry P.; Yampolsky, Nikolai A.

    2012-04-30

    We introduce a novel harmonic generation scheme which can be used, for a given desired harmonic, to achieve higher bunching factors, weaker chicanes, and/or less final energy spread than can be achieved using Echo-Enabled Harmonic Generation. This scheme only requires a single laser with relatively low power, and is a hybrid of High-Gain Harmonic Generation and EEHG. We present a design of this scheme applied to the Next Generation Light Source (NGLS).

  13. A three-phase converter model for harmonic analysis of HVDC systems

    SciTech Connect

    Xu, W.; Drakos, J.E.; Mansour, Y.; Chang, A. )

    1994-07-01

    An equivalent circuit model is presented to model bridge converters for three-phase HVDC harmonic power flow analysis. The validity and accuracy of the model are verified by comparing simulation results against field test results. The model is interfaced with a multiphase harmonic load flow program to investigate the generation of non-characteristic harmonics from HVDC links and the flow of HVDC harmonics in a real system.

  14. Harmonic Frequency Lowering

    PubMed Central

    Kirchberger, Martin

    2016-01-01

    A novel algorithm for frequency lowering in music was developed and experimentally tested in hearing-impaired listeners. Harmonic frequency lowering (HFL) combines frequency transposition and frequency compression to preserve the harmonic content of music stimuli. Listeners were asked to make judgments regarding detail and sound quality in music stimuli. Stimuli were presented under different signal processing conditions: original, low-pass filtered, HFL, and nonlinear frequency compressed. Results showed that participants reported perceiving the most detail in the HFL condition. In addition, there was no difference in sound quality across conditions. PMID:26834122

  15. Booster Double Harmonic Setup Notes

    SciTech Connect

    Gardner, C. J.

    2015-02-17

    The motivation behind implementing a booster double harmonic include the reduced transverse space charge force from a reduced peak beam current and reduced momentum spread of the beam, both of which can be achieved from flattening the RF bucket. RF capture and acceleration of polarized protons (PP) is first set up in the single harmonic mode with RF harmonic h=1. Once capture and acceleration have been set up in the single harmonic mode, the second harmonic system is brought on and programmed to operate in concert with the single harmonic system.

  16. Dash line glass- and sapphire-cutting with high power USP laser

    NASA Astrophysics Data System (ADS)

    Mishchik, Konstantin; Chassagne, Bruno; Javaux-Léger, Clémentine; Hönninger, Clemens; Mottay, Eric; Kling, Rainer; Lopez, John

    2016-03-01

    Glass cutting is a subject of high interest for flat panel display and consumer electronics industries. Among laser-based, water jet-based and diamond tool-based existing solutions, ultra-short pulses (USP) appear as a promising technology since this laser technology has the unique capacity to produce highly localized bulk modification owing to non-linear absorption. The cutting using USP lasers could be performed either by full ablation which is slow and generates a lot of dust, by controlled fracture propagation which is slow as well and may lead to path deviation, by stealth dicing which produces rough sidewalls, or by self-breaking induced by in-volume laser irradiation. The laser treatment is often continuous which is not necessary to perform glass cutting and may lead to over-exposure. In this paper we report on single pass glass and sapphire cutting using an USP laser (20W @200kHz or 8W@2MHz) using dash line laser treatment along the cutting trajectory. In-volume energy deposition was done along the glass thickness owing to a Bessel beam. The results will be discussed in terms of sidewall profile and roughness, path deviation, rim sharpness, energy dose and feed rate. Dash line treatment enables to tune the energy deposition and to produce the cutting effect but with a narrower heat affected zone, a better sidewall quality and a more accurate trajectory control of the cutting path.

  17. Current densities and total contact currents for 110 and 220 kV power line tasks.

    PubMed

    Korpinen, Leena; Kuisti, Harri; Elovaara, Jarmo

    2014-10-01

    The aim of this study was to analyze all values of electric current from measured periods while performing tasks on 110 and 220 kV power lines. Additionally, the objective was to study the average current densities and average total contact currents caused by electric fields in 110 and 220 kV power line tasks. One worker simulated the following tasks: (A) tested insulation voltage at a 110 kV portal tower, (B) checked the wooden towers for rot at a 110 kV portal tower, (C) tested insulation voltage at a 220 kV portal tower, and (D) checked the wooden towers for rot at a 220 kV portal tower. The highest average current density in the neck was 2.0 mA/m(2) (calculated internal electric field was 19.0-38.0 mV/m), and the highest average contact current was 234 µA. All measured values at 110 and 220 kV towers were lower than the basic restrictions (0.1 and 0.8 V/m) of the International Commission on Non-ionizing Radiation Protection.

  18. Childhood cancer and magnetic fields from high-voltage power lines in England and Wales: a case–control study

    PubMed Central

    Kroll, M E; Swanson, J; Vincent, T J; Draper, G J

    2010-01-01

    Background: Epidemiological evidence suggests that chronic low-intensity extremely-low-frequency magnetic-field exposure is associated with increased risk of childhood leukaemia; it is not certain the association is causal. Methods: We report a national case–control study relating childhood cancer risk to the average magnetic field from high-voltage overhead power lines at the child's home address at birth during the year of birth, estimated using National Grid records. From the National Registry of Childhood Tumours, we obtained records of 28 968 children born in England and Wales during 1962–1995 and diagnosed in Britain under age 15. We selected controls from birth registers, matching individually by sex, period of birth, and birth registration district. No participation by cases or controls was required. Results: The estimated relative risk for each 0.2 μT increase in magnetic field was 1.14 (95% confidence interval 0.57 to 2.32) for leukaemia, 0.80 (0.43–1.51) for CNS/brain tumours, and 1.34 (0.84–2.15) for other cancers. Conclusion: Although not statistically significant, the estimate for childhood leukaemia resembles results of comparable studies. Assuming causality, the estimated attributable risk is below one case per year. Magnetic-field exposure during the year of birth is unlikely to be the whole cause of the association with distance from overhead power lines that we previously reported. PMID:20877338

  19. VLF Radio Field Strength Measurement of power line carrier system in San Diego, California

    NASA Technical Reports Server (NTRS)

    Mertel, H. K.

    1981-01-01

    The radio frequency interference (RFI) potential was evaluated for a Powerline Carriet (PLC) installed in San Diego which monitors the performance of an electrical power system. The PLC system generated 30 amperes at 5.79 kHz. The RF radiations were measured to be (typically) 120 dBuV/m at the beginning of the 12 kV powerline and 60 dBuV/m at the end of the powerline. The RF fields varied inversely as the distance squared. Measurements were also performed with a 45 kHz PLC system. The RF fields were of similar amplitude.

  20. Development and testing of a prototype on-line radioiodine monitor for nuclear power stations

    SciTech Connect

    Tseng, T.T.; Jester, W.A.; Baratta, A.J.; McMaster, I.B.; Miller, D.W.

    1986-01-01

    A prototype on-line monitor has been developed which is capable of detecting radioiodine in the presence of as much as 1 X 10(6) higher concentration of noble gases. The system contains two identical radiation monitoring chambers through which the monitored air and a purging gas alternately cycle. Each chamber contains a silver zeolite filter which has a high retention of the various forms of airborne radioiodine but low retention of noble gases. During the purging cycle the radioactive noble gases are quickly purged from the filter and chamber and the lower levels of radioiodine accumulated on the filter are detected. This system has been successfully tested using short-lived radionuclides simulating vented reactor gases resulting from an abnormal condition.

  1. Power lines: Derrida, discursive psychology and the management of accusations of teacher bullying.

    PubMed

    Hepburn, A

    2000-12-01

    This study connects broad issues of classroom control and the disciplining of pupils by teachers with a detailed examination of the way teachers deal with an implied accusation that they have been bullying. The analysis of interviews develops with reference to discursive psychology and Derrida's development of deconstruction. Billig's (1992) insights into ways that participants' accounts can neutralize threats to established social arrangements are employed in relating detailed analytic points to the broader power relations between teacher and pupil. Interviews were conducted with Scottish secondary school teachers, and subjected to close textual analysis. This resulted in the development of three themes: (1) Subjectivity Construction, in which the functional role of the construction of mental entities is examined; (2) Normalizing Techniques, identifying strategies whereby intimidation can be constructed as normal; and (3) Figuration, examining the utility of figurative language--metaphors, maxims, and so on. These themes display the subtlety and complexity of teachers' strategies for distancing themselves from being held accountable for reported intimidation. To conclude, three broader features of the study are discussed: the contribution to discursive psychology that Derrida's deconstructive philosophy can make; the respecification of psychology and subjectivity as participants' resources for action; and the contribution that this type of detailed study can make to issues of power and social critique.

  2. Stimulated Brillouin scattering during electron gyro-harmonic heating at EISCAT

    NASA Astrophysics Data System (ADS)

    Fu, H. Y.; Scales, W. A.; Bernhardt, P. A.; Briczinski, S. J.; Kosch, M. J.; Senior, A.; Rietveld, M. T.; Yeoman, T. K.; Ruohoniemi, J. M.

    2015-08-01

    Observations of secondary radiation, stimulated electromagnetic emission (SEE), produced during ionospheric modification experiments using ground-based, high-power, high-frequency (HF) radio waves are considered. The High Frequency Active Auroral Research Program (HAARP) facility is capable of generating narrowband SEE in the form of stimulated Brillouin scatter (SBS) and stimulated ion Bernstein scatter (SIBS) in the SEE spectrum. Such narrowband SEE spectral lines have not been reported using the European Incoherent Scatter (EISCAT) heater facility before. This work reports the first EISCAT results of narrowband SEE spectra and compares them to SEE previously observed at HAARP during electron gyro-harmonic heating. An analysis of experimental SEE data shows observations of emission lines within 100 Hz of the pump frequency, interpreted as SBS, during the 2012 July EISCAT campaign. Experimental results indicate that SBS strengthens as the pump frequency approaches the third electron gyro-harmonic. Also, for different heater antenna beam angles, the CUTLASS radar backscatter induced by HF radio pumping is suppressed near electron gyro-harmonics, whereas electron temperature enhancement weakens as measured by EISCAT/UHF radar. The main features of these new narrowband EISCAT observations are generally consistent with previous SBS measurements at HAARP.

  3. Harmonically excited orbital variations

    SciTech Connect

    Morgan, T.

    1985-08-06

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs.

  4. Stress in Harmonic Serialism

    ERIC Educational Resources Information Center

    Pruitt, Kathryn Ringler

    2012-01-01

    This dissertation proposes a model of word stress in a derivational version of Optimality Theory (OT) called Harmonic Serialism (HS; Prince and Smolensky 1993/2004, McCarthy 2000, 2006, 2010a). In this model, the metrical structure of a word is derived through a series of optimizations in which the "best" metrical foot is chosen…

  5. Introducing Simple Harmonic Motion.

    ERIC Educational Resources Information Center

    Roche, John

    2002-01-01

    Explains the origin and significance of harmonic motion which is an important topic that has wide application in the world. Describes the phenomenon by using an auxiliary circle to help illustrate the key relationships between acceleration, displacement, time, velocity, and phase. (Contains 16 references.) (Author/YDS)

  6. A Harmonic Motion Experiment

    ERIC Educational Resources Information Center

    Gluck, P.; Krakower, Zeev

    2010-01-01

    We present a unit comprising theory, simulation and experiment for a body oscillating on a vertical spring, in which the simultaneous use of a force probe and an ultrasonic range finder enables one to explore quantitatively and understand many aspects of simple and damped harmonic motions. (Contains 14 figures.)

  7. Line-focus solar central power system, Phase I. Final report, 29 September 1978 to 30 April 1980. Volume II. Text

    SciTech Connect

    Slemmons, A J

    1980-04-01

    The conceptual design, parametric analysis, cost and performance analysis, and a commercial assessment of a 100-MWe high-temperature line-focus central power system are presented. Parametric analyses and conceptual design of the heliostat subsystem, receiver subsystem, heat transport subsystem, energy storage subsystem, electrical power generating subsystem, and master control subsystem are included. A market analysis and development plan are given. (WHK)

  8. Adaptive optics for high power beam lines using diamond crystal monochromators

    SciTech Connect

    Sharma, S.; Berman, L.E.; Hastings, J.B.; Hart, M.

    1992-12-31

    Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arc- seconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper we describe the results achieved by optimization of adaptive crystal optics for diamond crystals.

  9. Adaptive optics for high power beam lines using diamond crystal monochromators

    SciTech Connect

    Sharma, S.; Berman, L.E.; Hastings, J.B. ); Hart, M. )

    1992-01-01

    Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arc- seconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper we describe the results achieved by optimization of adaptive crystal optics for diamond crystals.

  10. Thomson Parabola Spectrometer: a powerful tool for on-line plasma analysis

    SciTech Connect

    Altana, C.; Muoio, A.; Schillaci, F.; Tudisco, S.; Brandi, F.; Cristoforetti, G.; Koester, P.; Fulgentini, L.; Labate, L.; Gizzi, L.A.

    2015-07-01

    In this paper we report on a new powerful and self-consistent analysis technique aimed in order to get information online on laser generated plasmas. Performance of the method has been carried out during two set of measurement by using two different lasers. The first set of data has been collected at LENS Laboratory of INFN-LNS in Catania by using a laser which produces pulses having energies of 2 J and temporal duration of 6 ns, while the second set of data has been collected at ILIL of INO-CNR in Pisa with a laser system capable of delivering pulses of up to 10 mJ in 40 fs. (authors)

  11. Young children's harmonic perception.

    PubMed

    Costa-Giomi, Eugenia

    2003-11-01

    Harmony and tonality are two of the most difficult elements for young children to perceive and manipulate and are seldom taught in the schools until the end of early childhood. Children's gradual harmonic and tonal development has been attributed to their cumulative exposure to Western tonal music and their increasing experiential knowledge of its rules and principles. Two questions that are relevant to this problem are: (1) Can focused and systematic teaching accelerate the learning of the harmonic/tonal principles that seem to occur in an implicit way throughout childhood? (2) Are there cognitive constraints that make it difficult for young children to perceive and/or manipulate certain harmonic and tonal principles? A series of studies specifically addressed the first question and suggested some possible answers to the second one. Results showed that harmonic instruction has limited effects on children's perception of harmony and indicated that the drastic improvement in the perception of implied harmony noted approximately at age 9 is due to development rather than instruction. I propose that young children's difficulty in perceiving implied harmony stems from their attention behaviors. Older children have less memory constraints and more strategies to direct their attention to the relevant cues of the stimulus. Younger children focus their attention on the melody, if present in the stimulus, and specifically on its concrete elements such as rhythm, pitch, and contour rather than its abstract elements such as harmony and key. The inference of the abstract harmonic organization of a melody required in the perception of implied harmony is thus an elusive task for the young child.

  12. Quaternionic Harmonic Analysis of Texture

    SciTech Connect

    Mason, J.

    2012-10-01

    QHAT uses various functions and data structures native to MATLAB to analyze crystallographic texture information using harmonic functions on the space of rotations represented as normalized quaternions. These harmonic functions generalize the spherical harmonics in three dimensions, and form the basis for the irreducible representations of the four-dimensional rotation group. This allows the basis of harmonic functions to be reduced to linearly independent combinations that satisfy the crystal and sample symmetry point groups.

  13. A compact dual-wavelength Nd:LuVO4 laser with adjustable power-ratio between 1064 nm and 1342 nm lines by controlling polarization dependent loss

    NASA Astrophysics Data System (ADS)

    Qi, Yaoyao; Yu, Haijuan; Zhang, Jingyuan; Zhang, Ling; He, Chaojian; Lin, Xuechun

    2017-01-01

    We demonstrate a compact dual-wavelength operation of Nd:LuVO4 laser with a power-ratio adjustable between 1064 nm and 1342 nm lines in a compound cavity configuration. The output power at two wavelengths of the laser indicates that it depends not only on pumping-power and but also on the controllable polarization loss in the cavity. Also, the power-ratio, defined as ratio between the output power at 1064 nm and that at 1342 nm, can be adjusted from 0 to 8 or higher accurately by rotating a quarter-wave plate (QWP) in the cavity.

  14. Harmonization, Trade, and the Environment.

    ERIC Educational Resources Information Center

    Stevens, Candice

    1993-01-01

    Discusses the harmonization of international methods for the development and administration of product standards. Defines the term "harmonization" and discusses the harmonization of environmental policies and purposes involving product standards; environmental regulations on production methods, technologies, and practices; and life-cycle…

  15. Reclamation and revegetation along a 250-mile 500 kV power line corridor

    SciTech Connect

    Griffith, E.F.

    1990-12-31

    Reclamation and revegetation success along the Montana Power Company Colstrip to Deepdale 500 kV powerline was monitored from 1985 through 1989. Followup revegetation was hampered by inadequate road and tower site earth work as a result of premature release of the reclamation bond. Drought conditions in 1985 and 1988 seriously affected revegetation efforts, especially on difficult sites. Weed control improved markedly, and all ROW areas are weed free except those next to infested range and cropland where a major cooperative effort is needed to control weeds. Access roads in previously unroaded areas resulted in changes of access, management practices, and cattle grazing behavior, all of which adversely affected revegetation success. Erosion, exacerbated by undersized culverts, the presence of very erodible soils, the occasional untrained contractor, is now the major ROW maintenance concern. Observation of the revegetation efforts clearly shows the need for adequate and appropriate reclamation by qualified equipment operators up front, and a patient, measured effort of continued revegetation, weed control and erosion control over the long term. The bond period of 5 years may not be long enough to achieve the 90 percent revegetation success required by the permit. Future projects guidelines should consider look to a flexible timeframe and more realistic vegetation requirements to account for the effects of non-construction related impacts.

  16. Harmonic skeleton guided evaluation of stenoses in human coronary arteries.

    PubMed

    Yang, Yan; Zhu, Lei; Haker, Steven; Tannenbaum, Allen R; Giddens, Don P

    2005-01-01

    This paper presents a novel approach that three-dimensionally visualizes and evaluates stenoses in human coronary arteries by using harmonic skeletons. A harmonic skeleton is the center line of a multi-branched tubular surface extracted based on a harmonic function, which is the solution of the Laplace equation. This skeletonization method guarantees smoothness and connectivity and provides a fast and straightforward way to calculate local cross-sectional areas of the arteries, and thus provides the possibility to localize and evaluate coronary artery stenosis, which is a commonly seen pathology in coronary artery disease.

  17. Distance to High-Voltage Power Lines and Risk of Childhood Leukemia – an Analysis of Confounding by and Interaction with Other Potential Risk Factors

    PubMed Central

    Pedersen, Camilla; Bräuner, Elvira V.; Rod, Naja H.; Albieri, Vanna; Andersen, Claus E.; Ulbak, Kaare; Hertel, Ole; Johansen, Christoffer; Schüz, Joachim; Raaschou-Nielsen, Ole

    2014-01-01

    We investigated whether there is an interaction between distance from residence at birth to nearest power line and domestic radon and traffic-related air pollution, respectively, in relation to childhood leukemia risk. Further, we investigated whether adjusting for potential confounders alters the association between distance to nearest power line and childhood leukemia. We included 1024 cases aged <15, diagnosed with leukemia during 1968–1991, from the Danish Cancer Registry and 2048 controls randomly selected from the Danish childhood population and individually matched by gender and year of birth. We used geographical information systems to determine the distance between residence at birth and the nearest 132–400 kV overhead power line. Concentrations of domestic radon and traffic-related air pollution (NOx at the front door) were estimated using validated models. We found a statistically significant interaction between distance to nearest power line and domestic radon regarding risk of childhood leukemia (p = 0.01) when using the median radon level as cut-off point but not when using the 75th percentile (p = 0.90). We found no evidence of an interaction between distance to nearest power line and traffic-related air pollution (p = 0.73). We found almost no change in the estimated association between distance to power line and risk of childhood leukemia when adjusting for socioeconomic status of the municipality, urbanization, maternal age, birth order, domestic radon and traffic-related air pollution. The statistically significant interaction between distance to nearest power line and domestic radon was based on few exposed cases and controls and sensitive to the choice of exposure categorization and might, therefore, be due to chance. PMID:25259740

  18. Distance to high-voltage power lines and risk of childhood leukemia--an analysis of confounding by and interaction with other potential risk factors.

    PubMed

    Pedersen, Camilla; Bräuner, Elvira V; Rod, Naja H; Albieri, Vanna; Andersen, Claus E; Ulbak, Kaare; Hertel, Ole; Johansen, Christoffer; Schüz, Joachim; Raaschou-Nielsen, Ole

    2014-01-01

    We investigated whether there is an interaction between distance from residence at birth to nearest power line and domestic radon and traffic-related air pollution, respectively, in relation to childhood leukemia risk. Further, we investigated whether adjusting for potential confounders alters the association between distance to nearest power line and childhood leukemia. We included 1024 cases aged <15, diagnosed with leukemia during 1968-1991, from the Danish Cancer Registry and 2048 controls randomly selected from the Danish childhood population and individually matched by gender and year of birth. We used geographical information systems to determine the distance between residence at birth and the nearest 132-400 kV overhead power line. Concentrations of domestic radon and traffic-related air pollution (NOx at the front door) were estimated using validated models. We found a statistically significant interaction between distance to nearest power line and domestic radon regarding risk of childhood leukemia (p = 0.01) when using the median radon level as cut-off point but not when using the 75th percentile (p = 0.90). We found no evidence of an interaction between distance to nearest power line and traffic-related air pollution (p = 0.73). We found almost no change in the estimated association between distance to power line and risk of childhood leukemia when adjusting for socioeconomic status of the municipality, urbanization, maternal age, birth order, domestic radon and traffic-related air pollution. The statistically significant interaction between distance to nearest power line and domestic radon was based on few exposed cases and controls and sensitive to the choice of exposure categorization and might, therefore, be due to chance.

  19. Demonstration of an on-line creep and fatigue monitoring system at the Contra Costa Power Plant

    SciTech Connect

    Copeland, J.F.; Carney, C.E.; Sherlock, T.P. ); Shirmohamadi, M.; Curtis, D.J. ); Scheibel, J.R. )

    1991-01-01

    The objective of this paper to develop an integrated method for evaluating creep-fatigue damage accumulation and crack growth at critical fossil plant steam piping locations using existing instrumentation and available plant operating data. The resulting methodology permits the cumulative damage and structural integrity of steam piping and other components to be monitored and tracked, based on actual plant operating cycles and temperatures. The methodology has been implemented in a software system called Creep-FatiguePro. A prototype system has been installed and tested for a limited number of locations at the Pacific Gas and Electric Company's Contra Costa Power Plant. The results of this pilot plant demonstration show the feasibility of such an on-line monitoring system. Based upon these results, such a system is felt to offer significant cost-benefit advantages in optimizing plant maintenance and life assessment activities.

  20. Placement of Base Stations in Broadband Power Line Communications Access Networks by Means of Multi-criteria Optimization

    NASA Astrophysics Data System (ADS)

    Haidine, Abdelfatteh; Lehnert, Ralf

    Broadband Power Line Communications (B-PLC) technology is an alternative for broadband access networks, allowing bit rates up to currently 200Mbps. This technique uses the wiring of the low-voltage grid in order to offer to the users the telecommunications services, such as Internet, VoIP, VoD, etc. The B-PLC design process is sub-divided into two parts: the Generalized Base Station Placement (GBSP) problem and the PLC Channel Allocation Problem (P-CAP). This paper focuses on GBSP that is modeled as multi-criteria combinatorial optimization problem. Based on our published mathematical modeling, this paper supplies more numerical experiments for the evaluation of Multi-Objective Evolutionary Algorithms (MOEAs) in solving GBSP. Their performance is compared with the single-objective optimization.