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Sample records for acoustic transmission line

  1. Comparison of Transmission Line Methods for Surface Acoustic Wave Modeling

    NASA Technical Reports Server (NTRS)

    Wilson, William; Atkinson, Gary

    2009-01-01

    Surface Acoustic Wave (SAW) technology is low cost, rugged, lightweight, extremely low power and can be used to develop passive wireless sensors. For these reasons, NASA is investigating the use of SAW technology for Integrated Vehicle Health Monitoring (IVHM) of aerospace structures. To facilitate rapid prototyping of passive SAW sensors for aerospace applications, SAW models have been developed. This paper reports on the comparison of three methods of modeling SAWs. The three models are the Impulse Response Method (a first order model), and two second order matrix methods; the conventional matrix approach, and a modified matrix approach that is extended to include internal finger reflections. The second order models are based upon matrices that were originally developed for analyzing microwave circuits using transmission line theory. Results from the models are presented with measured data from devices. Keywords: Surface Acoustic Wave, SAW, transmission line models, Impulse Response Method.

  2. INSTRUMENTATION FOR SURVEYING ACOUSTIC SIGNALS IN NATURAL GAS TRANSMISSION LINES

    SciTech Connect

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Deepak Mehra

    2003-09-01

    In the U.S. natural gas is distributed through more than one million miles of high-pressure transmission pipelines. If all leaks and infringements could be detected quickly, it would enhance safety and U.S. energy security. Only low frequency acoustic waves appear to be detectable over distances up to 60 km where pipeline shut-off valves provide access to the inside of the pipeline. This paper describes a Portable Acoustic Monitoring Package (PAMP) developed to record and identify acoustic signals characteristic of: leaks, pump noise, valve and flow metering noise, third party infringement, manual pipeline water and gas blow-off, etc. This PAMP consists of a stainless steel 1/2 inch NPT plumbing tree rated for use on 1000 psi pipelines. Its instrumentation is designed to measure acoustic waves over the entire frequency range from zero to 16,000 Hz by means of four instruments: (1) microphone, (2) 3-inch water full range differential pressure transducer with 0.1% of range sensitivity, (3) a novel 3 inch to 100 inch water range amplifier, using an accumulator with needle valve and (4) a line-pressure transducer. The weight of the PAMP complete with all accessories is 36 pounds. This includes a remote control battery/switch box assembly on a 25-foot extension chord, a laptop data acquisition computer on a field table and a sun shield.

  3. Finite-difference, time-domain analysis of a folded acoustic transmission line.

    PubMed

    Jackson, Charles M

    2005-03-01

    Recently designed, modern versions of renais sance woodwind instruments such as the recorder and serpent use square cross sections and a folded acoustic transmission line. Conventional microwave techniques would expect that this bend would cause unwanted reflections and impedance discontinuities. This paper analyses the folded acoustic transmission line using finite-difference, time-domain techniques and shows that the discontinuity can be compensated with by the use of a manufacturable method. PMID:15857045

  4. Acoustical transmission-line model of the middle-ear cavities and mastoid air cells.

    PubMed

    Keefe, Douglas H

    2015-04-01

    An acoustical transmission line model of the middle-ear cavities and mastoid air cell system (MACS) was constructed for the adult human middle ear with normal function. The air-filled cavities comprised the tympanic cavity, aditus, antrum, and MACS. A binary symmetrical airway branching model of the MACS was constructed using an optimization procedure to match the average total volume and surface area of human temporal bones. The acoustical input impedance of the MACS was calculated using a recursive procedure, and used to predict the input impedance of the middle-ear cavities at the location of the tympanic membrane. The model also calculated the ratio of the acoustical pressure in the antrum to the pressure in the middle-ear cavities at the location of the tympanic membrane. The predicted responses were sensitive to the magnitude of the viscothermal losses within the MACS. These predicted input impedance and pressure ratio functions explained the presence of multiple resonances reported in published data, which were not explained by existing MACS models.

  5. Acoustical transmission-line model of the middle-ear cavities and mastoid air cells

    PubMed Central

    Keefe, Douglas H.

    2015-01-01

    An acoustical transmission line model of the middle-ear cavities and mastoid air cell system (MACS) was constructed for the adult human middle ear with normal function. The air-filled cavities comprised the tympanic cavity, aditus, antrum, and MACS. A binary symmetrical airway branching model of the MACS was constructed using an optimization procedure to match the average total volume and surface area of human temporal bones. The acoustical input impedance of the MACS was calculated using a recursive procedure, and used to predict the input impedance of the middle-ear cavities at the location of the tympanic membrane. The model also calculated the ratio of the acoustical pressure in the antrum to the pressure in the middle-ear cavities at the location of the tympanic membrane. The predicted responses were sensitive to the magnitude of the viscothermal losses within the MACS. These predicted input impedance and pressure ratio functions explained the presence of multiple resonances reported in published data, which were not explained by existing MACS models. PMID:25920840

  6. Random and systematic measurement errors in acoustic impedance as determined by the transmission line method

    NASA Technical Reports Server (NTRS)

    Parrott, T. L.; Smith, C. D.

    1977-01-01

    The effect of random and systematic errors associated with the measurement of normal incidence acoustic impedance in a zero-mean-flow environment was investigated by the transmission line method. The influence of random measurement errors in the reflection coefficients and pressure minima positions was investigated by computing fractional standard deviations of the normalized impedance. Both the standard techniques of random process theory and a simplified technique were used. Over a wavelength range of 68 to 10 cm random measurement errors in the reflection coefficients and pressure minima positions could be described adequately by normal probability distributions with standard deviations of 0.001 and 0.0098 cm, respectively. An error propagation technique based on the observed concentration of the probability density functions was found to give essentially the same results but with a computation time of about 1 percent of that required for the standard technique. The results suggest that careful experimental design reduces the effect of random measurement errors to insignificant levels for moderate ranges of test specimen impedance component magnitudes. Most of the observed random scatter can be attributed to lack of control by the mounting arrangement over mechanical boundary conditions of the test sample.

  7. NEMS With Broken T Symmetry: Graphene Based Unidirectional Acoustic Transmission Lines

    PubMed Central

    Zanjani, Mehdi B.; Davoyan, Arthur R.; Engheta, Nader; Lukes, Jennifer R.

    2015-01-01

    In this work we discuss the idea of one-way acoustic signal isolation in low dimensional nanoelectromechanical oscillators. We report a theoretical study showing that one-way conversion between in-phase and anti-phase vibrational modes of a double layer graphene nanoribbon is achieved by introducing spatio-temporal modulation of system properties. The required modulation length in order to reach full conversion between the two modes is subsequently calculated. Generalization of the method beyond graphene nanoribbons and realization of a NEMS signal isolator are also discussed. PMID:25993637

  8. Series Transmission Line Transformer

    DOEpatents

    Buckles, Robert A.; Booth, Rex; Yen, Boris T.

    2004-06-29

    A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

  9. Transmission Line Security Monitor

    SciTech Connect

    2011-01-01

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  10. Transmission Line Security Monitor

    ScienceCinema

    None

    2016-07-12

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  11. Printed circuit dispersive transmission line

    DOEpatents

    Ikezi, H.; Lin-Liu, Y.R.; DeGrassie, J.S.

    1991-08-27

    A printed circuit dispersive transmission line structure is disclosed comprising an insulator, a ground plane formed on one surface of the insulator, a first transmission line formed on a second surface of the insulator, and a second transmission line also formed on the second surface of the insulator and of longer length than the first transmission line and periodically intersecting the first transmission line. In a preferred embodiment, the transmission line structure exhibits highly dispersive characteristics by designing the length of one of the transmission line between two adjacent periodic intersections to be longer than the other. 5 figures.

  12. Printed circuit dispersive transmission line

    DOEpatents

    Ikezi, Hiroyuki; Lin-Liu, Yuh-Ren; DeGrassie, John S.

    1991-01-01

    A printed circuit dispersive transmission line structure is disclosed comprising an insulator, a ground plane formed on one surface of the insulator, a first transmission line formed on a second surface of the insulator, and a second transmission line also formed on the second surface of the insulator and of longer length than the first transmission line and periodically intersecting the first transmission line. In a preferred embodiment, the transmission line structure exhibits highly dispersive characteristics by designing the length of one of the transmission line between two adjacent periodic intersections to be longer than the other.

  13. Drill string transmission line

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David S.; Bradford, Kline; Fox, Joe

    2006-03-28

    A transmission line assembly for transmitting information along a downhole tool comprising a pin end, a box end, and a central bore traveling between the pin end and the box end, is disclosed in one embodiment of the invention as including a protective conduit. A transmission line is routed through the protective conduit. The protective conduit is routed through the central bore and the ends of the protective conduit are routed through channels formed in the pin end and box end of the downhole tool. The protective conduit is elastically forced into a spiral or other non-linear path along the interior surface of the central bore by compressing the protective conduit to a length within the downhole tool shorter than the protective conduit.

  14. A Quantitative Transmission Line Experiment

    ERIC Educational Resources Information Center

    Johnston, D. C.; Silbernagel, B. G.

    1969-01-01

    Describes modifications of a commercially available strip-type transmission line, which makes possible reproducible measurements of standing waves on the line. Experimental data yield values for the characteristic impedance, phase velocity and line wavelength of radiation in the transmission line, and the dielectric constant of material in the…

  15. Acoustic transmission through a fuselage sidewall

    NASA Technical Reports Server (NTRS)

    Wilby, J. F.; Scharton, T. D.

    1973-01-01

    A definition is given of an idealized fuselage sidewall structure and a simplified analytical model for determining acoustical transmission from the exterior to the interior of a fuselage was constructed. The representation of the sidewall structure chosen for the analytical model excludes complicating effects such as cabin pressurization, acoustic transmission through windows or door seal leaks, aerodynamic excitation, and structural vibration excitation of the fuselage skin.

  16. EC Transmission Line Materials

    SciTech Connect

    Bigelow, Tim S

    2012-05-01

    The purpose of this document is to identify materials acceptable for use in the US ITER Project Office (USIPO)-supplied components for the ITER Electron cyclotron Heating and Current Drive (ECH&CD) transmission lines (TL), PBS-52. The source of material property information for design analysis shall be either the applicable structural code or the ITER Material Properties Handbook. In the case of conflict, the ITER Material Properties Handbook shall take precedence. Materials selection, and use, shall follow the guidelines established in the Materials Assessment Report (MAR). Materials exposed to vacuum shall conform to the ITER Vacuum Handbook. [Ref. 2] Commercial materials shall conform to the applicable standard (e.g., ASTM, JIS, DIN) for the definition of their grade, physical, chemical and electrical properties and related testing. All materials for which a suitable certification from the supplier is not available shall be tested to determine the relevant properties, as part of the procurement. A complete traceability of all the materials including welding materials shall be provided. Halogenated materials (example: insulating materials) shall be forbidden in areas served by the detritiation systems. Exceptions must be approved by the Tritium System and Safety Section Responsible Officers.

  17. Extraordinary transmission of gigahertz surface acoustic waves.

    PubMed

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H; Wright, Oliver B

    2016-09-19

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3-50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging.

  18. Extraordinary transmission of gigahertz surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H.; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H.; Wright, Oliver B.

    2016-09-01

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3–50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging.

  19. Extraordinary transmission of gigahertz surface acoustic waves.

    PubMed

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H; Wright, Oliver B

    2016-01-01

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3-50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging. PMID:27640998

  20. Extraordinary transmission of gigahertz surface acoustic waves

    PubMed Central

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H.; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H.; Wright, Oliver B.

    2016-01-01

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3–50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging. PMID:27640998

  1. Asymmetric acoustic transmission in multiple frequency bands

    NASA Astrophysics Data System (ADS)

    Sun, Hong-xiang; Yuan, Shou-qi; Zhang, Shu-yi

    2015-11-01

    We report both experimentally and numerically that the multi-band device of the asymmetric acoustic transmission is realized by placing two periodic gratings with different periods on both sides of two brass plates immersed in water. The asymmetric acoustic transmission can exist in four frequency bands below 1500 kHz, which arises from the interaction between various diffractions from the two gratings and Lamb modes in the brass plates immersed in water. The results indicate that the device has the advantages of multiple band, broader bandwidth, and simpler structure. Our finding should have great potential applications in ultrasonic devices.

  2. Asymmetric acoustic transmission in multiple frequency bands

    SciTech Connect

    Sun, Hong-xiang; Yuan, Shou-qi; Zhang, Shu-yi

    2015-11-23

    We report both experimentally and numerically that the multi-band device of the asymmetric acoustic transmission is realized by placing two periodic gratings with different periods on both sides of two brass plates immersed in water. The asymmetric acoustic transmission can exist in four frequency bands below 1500 kHz, which arises from the interaction between various diffractions from the two gratings and Lamb modes in the brass plates immersed in water. The results indicate that the device has the advantages of multiple band, broader bandwidth, and simpler structure. Our finding should have great potential applications in ultrasonic devices.

  3. Electrical transmission line diametrical retainer

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David; Dahlgren, Scott; Sneddon, Cameron; Briscoe, Michael; Fox, Joe

    2004-12-14

    The invention is a mechanism for retaining an electrical transmission line. In one embodiment of the invention it is a system for retaining an electrical transmission line within down hole components. In accordance with one aspect of the invention, the system includes a plurality of downhole components, such as sections of pipe in a drill string. The system also includes a coaxial cable running between the first and second end of a drill pipe, the coaxial cable having a conductive tube and a conductive core within it. The invention allows the electrical transmission line to with stand the tension and compression of drill pipe during routine drilling cycles.

  4. Acoustic energy transmission in cast iron pipelines

    NASA Astrophysics Data System (ADS)

    Kiziroglou, Michail E.; Boyle, David E.; Wright, Steven W.; Yeatman, Eric M.

    2015-12-01

    In this paper we propose acoustic power transfer as a method for the remote powering of pipeline sensor nodes. A theoretical framework of acoustic power propagation in the ceramic transducers and the metal structures is drawn, based on the Mason equivalent circuit. The effect of mounting on the electrical response of piezoelectric transducers is studied experimentally. Using two identical transducer structures, power transmission of 0.33 mW through a 1 m long, 118 mm diameter cast iron pipe, with 8 mm wall thickness is demonstrated, at 1 V received voltage amplitude. A near-linear relationship between input and output voltage is observed. These results show that it is possible to deliver significant power to sensor nodes through acoustic waves in solid structures. The proposed method may enable the implementation of acoustic - powered wireless sensor nodes for structural and operation monitoring of pipeline infrastructure.

  5. Acoustic data transmission through a drillstring

    DOEpatents

    Drumheller, D.S.

    1992-07-07

    A method and apparatus for acoustically transmitting data along a drillstring are presented. In accordance with one embodiment of the present invention, acoustic data signals are conditioned to counteract distortions caused by the drillstring. Preferably, this conditioning step comprises multiplying each frequency component of the data signal by exp ([minus]ikL) where L is the transmission length of the drillstring, k is the wave number in the drillstring at the frequency of each component and i is ([minus]1)[sup 1/2]. In another embodiment of this invention, data signals having a frequency content in at least one passband of the drillstring are generated preferably traveling in only one direction (e.g., up the drillstring) while echoes in the drillstring resulting from the data transmission are suppressed. 20 figs.

  6. Acoustic data transmission through a drillstring

    DOEpatents

    Drumheller, Douglas S.

    1992-01-01

    A method and apparatus for acoustically transmitting data along a drillstring is presented. In accordance with one embodiment of the present invention, acoustic data signals are conditioned to counteract distortions caused by the drillstring. Preferably, this conditioning step comprises multiplying each frequency component of the data signal by exp (-ikL) where L is the transmission length of the drillstring, k is the wave number in the drillstring at the frequency of each component and i is (-1).sup.1/2. In another embodiment of this invention, data signals having a frequency content in at least one passband of the drillstring are generated preferably traveling in only one direction (e.g., up the drillstring) while echoes in the drillstring resulting from the data transmission are suppressed.

  7. Pneumothorax effects on pulmonary acoustic transmission.

    PubMed

    Mansy, Hansen A; Balk, Robert A; Warren, William H; Royston, Thomas J; Dai, Zoujun; Peng, Ying; Sandler, Richard H

    2015-08-01

    Pneumothorax (PTX) is an abnormal accumulation of air between the lung and the chest wall. It is a relatively common and potentially life-threatening condition encountered in patients who are critically ill or have experienced trauma. Auscultatory signs of PTX include decreased breath sounds during the physical examination. The objective of this exploratory study was to investigate the changes in sound transmission in the thorax due to PTX in humans. Nineteen human subjects who underwent video-assisted thoracic surgery, during which lung collapse is a normal part of the surgery, participated in the study. After subjects were intubated and mechanically ventilated, sounds were introduced into their airways via an endotracheal tube. Sounds were then measured over the chest surface before and after lung collapse. PTX caused small changes in acoustic transmission for frequencies below 400 Hz. A larger decrease in sound transmission was observed from 400 to 600 Hz, possibly due to the stronger acoustic transmission blocking of the pleural air. At frequencies above 1 kHz, the sound waves became weaker and so did their changes with PTX. The study elucidated some of the possible mechanisms of sound propagation changes with PTX. Sound transmission measurement was able to distinguish between baseline and PTX states in this small patient group. Future studies are needed to evaluate this technique in a wider population.

  8. Pneumothorax effects on pulmonary acoustic transmission

    PubMed Central

    Balk, Robert A.; Warren, William H.; Royston, Thomas J.; Dai, Zoujun; Peng, Ying; Sandler, Richard H.

    2015-01-01

    Pneumothorax (PTX) is an abnormal accumulation of air between the lung and the chest wall. It is a relatively common and potentially life-threatening condition encountered in patients who are critically ill or have experienced trauma. Auscultatory signs of PTX include decreased breath sounds during the physical examination. The objective of this exploratory study was to investigate the changes in sound transmission in the thorax due to PTX in humans. Nineteen human subjects who underwent video-assisted thoracic surgery, during which lung collapse is a normal part of the surgery, participated in the study. After subjects were intubated and mechanically ventilated, sounds were introduced into their airways via an endotracheal tube. Sounds were then measured over the chest surface before and after lung collapse. PTX caused small changes in acoustic transmission for frequencies below 400 Hz. A larger decrease in sound transmission was observed from 400 to 600 Hz, possibly due to the stronger acoustic transmission blocking of the pleural air. At frequencies above 1 kHz, the sound waves became weaker and so did their changes with PTX. The study elucidated some of the possible mechanisms of sound propagation changes with PTX. Sound transmission measurement was able to distinguish between baseline and PTX states in this small patient group. Future studies are needed to evaluate this technique in a wider population. PMID:26023225

  9. Pneumothorax effects on pulmonary acoustic transmission.

    PubMed

    Mansy, Hansen A; Balk, Robert A; Warren, William H; Royston, Thomas J; Dai, Zoujun; Peng, Ying; Sandler, Richard H

    2015-08-01

    Pneumothorax (PTX) is an abnormal accumulation of air between the lung and the chest wall. It is a relatively common and potentially life-threatening condition encountered in patients who are critically ill or have experienced trauma. Auscultatory signs of PTX include decreased breath sounds during the physical examination. The objective of this exploratory study was to investigate the changes in sound transmission in the thorax due to PTX in humans. Nineteen human subjects who underwent video-assisted thoracic surgery, during which lung collapse is a normal part of the surgery, participated in the study. After subjects were intubated and mechanically ventilated, sounds were introduced into their airways via an endotracheal tube. Sounds were then measured over the chest surface before and after lung collapse. PTX caused small changes in acoustic transmission for frequencies below 400 Hz. A larger decrease in sound transmission was observed from 400 to 600 Hz, possibly due to the stronger acoustic transmission blocking of the pleural air. At frequencies above 1 kHz, the sound waves became weaker and so did their changes with PTX. The study elucidated some of the possible mechanisms of sound propagation changes with PTX. Sound transmission measurement was able to distinguish between baseline and PTX states in this small patient group. Future studies are needed to evaluate this technique in a wider population. PMID:26023225

  10. Acoustic asymmetric transmission based on time-dependent dynamical scattering

    PubMed Central

    Wang, Qing; Yang, Yang; Ni, Xu; Xu, Ye-Long; Sun, Xiao-Chen; Chen, Ze-Guo; Feng, Liang; Liu, Xiao-ping; Lu, Ming-Hui; Chen, Yan-Feng

    2015-01-01

    An acoustic asymmetric transmission device exhibiting unidirectional transmission property for acoustic waves is extremely desirable in many practical scenarios. Such a unique property may be realized in various configurations utilizing acoustic Zeeman effects in moving media as well as frequency-conversion in passive nonlinear acoustic systems and in active acoustic systems. Here we demonstrate a new acoustic frequency conversion process in a time-varying system, consisting of a rotating blade and the surrounding air. The scattered acoustic waves from this time-varying system experience frequency shifts, which are linearly dependent on the blade’s rotating frequency. Such scattering mechanism can be well described theoretically by an acoustic linear time-varying perturbation theory. Combining such time-varying scattering effects with highly efficient acoustic filtering, we successfully develop a tunable acoustic unidirectional device with 20 dB power transmission contrast ratio between two counter propagation directions at audible frequencies. PMID:26038886

  11. Extraordinary acoustic transmission mediated by Helmholtz resonators

    SciTech Connect

    Koju, Vijay; Rowe, Ebony; Robertson, William M.

    2014-07-15

    We demonstrate perfect transmission of sound through a rigid barrier embedded with Helmholtz resonators. The resonators are confined within a waveguide and they are oriented such that one neck protrudes onto each side of the barrier. Perfect sound transmission occurs even though the open area of the necks is less than 3% of the barrier area. Maximum transmission occurs at the resonant frequency of the Helmholtz resonator. Because the dimensions of the Helmholtz resonators are much smaller than the resonant wavelength, the transmission is independent of the direction of sound on the barrier and of the relative placement of the necks. Further, we show that the transmitted sound experiences a continuous phase transition of π radians as a function of frequency through resonance. In simulations of adjacent resonators with slightly offset resonance frequencies, the phase difference leads to destructive interference. By expanding the simulation to a linear array of tuned Helmholtz resonators we show that it is possible to create an acoustic lens. The ability of Helmholtz resonator arrays to manipulate the phase of a plane acoustic wave enables a new class of sonic beam-forming devices analogous to diffractive optics.

  12. Nonceramic insulators for transmission lines

    SciTech Connect

    Schneider, H.M. . High Voltage Transmission Research Center); Hall, J.F. ); Karady, G. ); Rendowden, J. )

    1989-10-01

    Progress in development of nonceramic transmission lines insulator technology is reviewed. The results of a survey to utilities in the United States are presented to indicate the range of applications, distribution by voltage class, appraisal of performance, and failure modes. Concerns expressed by utility representatives at a recent workshop are described and future research and standardization needs are presented.

  13. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, R.B.

    1985-08-15

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  14. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, Russell B.

    1987-01-01

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  15. Coiled transmission line pulse generators

    DOEpatents

    McDonald, Kenneth Fox

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  16. Acoustic transmission through compound subwavelength slit arrays

    NASA Astrophysics Data System (ADS)

    Ward, G. P.; Hibbins, A. P.; Sambles, J. R.; Smith, J. D.

    2016-07-01

    The angular dependence of the transmission of sound in air through four types of two-dimensional slit arrays formed of aluminium slats is explored, both experimentally and numerically. For a simple, subwavelength periodic slit array, it is well known that Fabry-Perot-like waveguide resonances, supported by the slit cavities, coupled to diffracted evanescent waves, result in enhanced acoustic transmission at frequencies determined by the length, width, and separation of each slit cavity. We demonstrate that altering the spacing or width of some of the slits to form a compound array (i.e., an array having a basis comprised of more than one slit) results in sharp dips in the transmission spectra, which may have a strong angular dependence. These features correspond to phase resonances, which have been studied extensively in the electromagnetic case. This geometry allows for additional near-field configurations compared to the simple array, whereby the field in adjacent cavities can be out of phase. Several types of compound slit arrays are investigated; one such structure is optimized to minimize the effect of boundary-layer loss mechanisms present in each slit cavity, thereby achieving a deep, sharp transmission minimum in a broad maximum.

  17. Acoustic radiation from lined, unflanged ducts: Acoustic source distribution program

    NASA Technical Reports Server (NTRS)

    Beckemeyer, R. J.; Sawdy, D. T.

    1971-01-01

    An acoustic radiation analysis was developed to predict the far-field characteristics of fan noise radiated from an acoustically lined unflanged duct. This analysis is comprised of three modular digital computer programs which together provide a capability of accounting for the impedance mismatch at the duct exit plane. Admissible duct configurations include circular or annular, with or without an extended centerbody. This variation in duct configurations provides a capability of modeling inlet and fan duct noise radiation. The computer programs are described in detail.

  18. Superconducting transmission line particle detector

    DOEpatents

    Gray, K.E.

    1988-07-28

    A microvertex particle detector for use in a high energy physic collider including a plurality of parallel superconducting thin film strips separated from a superconducting ground plane by an insulating layer to form a plurality of superconducting waveguides. The microvertex particle detector indicates passage of a charged subatomic particle by measuring a voltage pulse measured across a superconducting waveguide caused by the transition of the superconducting thin film strip from a superconducting to a non- superconducting state in response to the passage of a charged particle. A plurality of superconducting thin film strips in two orthogonal planes plus the slow electromagnetic wave propagating in a superconducting transmission line are used to resolve N/sup 2/ ambiguity of charged particle events. 6 figs.

  19. Superconducting transmission line particle detector

    DOEpatents

    Gray, Kenneth E.

    1989-01-01

    A microvertex particle detector for use in a high energy physic collider including a plurality of parallel superconducting thin film strips separated from a superconducting ground plane by an insulating layer to form a plurality of superconducting waveguides. The microvertex particle detector indicates passage of a charged subatomic particle by measuring a voltage pulse measured across a superconducting waveguide caused by the transition of the superconducting thin film strip from a superconducting to a non-superconducting state in response to the passage of a charged particle. A plurality of superconducting thin film strips in two orthogonal planes plus the slow electromagnetic wave propogating in a superconducting transmission line are used to resolve N.sup.2 ambiguity of charged particle events.

  20. Magnetically insulated transmission line oscillator

    DOEpatents

    Bacon, L.D.; Ballard, W.P.; Clark, M.C.; Marder, B.M.

    1987-05-19

    A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields are produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap. 11 figs.

  1. Magnetically insulated transmission line oscillator

    DOEpatents

    Bacon, Larry D.; Ballard, William P.; Clark, M. Collins; Marder, Barry M.

    1988-01-01

    A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields arfe produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap.

  2. Acoustic data transmission through a drill string

    DOEpatents

    Drumheller, D.S.

    1988-04-21

    Acoustical signals are transmitted through a drill string by canceling upward moving acoustical noise and by preconditioning the data in recognition of the comb filter impedance characteristics of the drill string. 5 figs.

  3. Broadband enhanced transmission of acoustic waves through serrated metal gratings

    NASA Astrophysics Data System (ADS)

    Qi, Dong-Xiang; Fan, Ren-Hao; Deng, Yu-Qiang; Peng, Ru-Wen; Wang, Mu; Jiangnan University Collaboration

    In this talk, we present our studies on broadband properties of acoustic waves through metal gratings. We have demonstrated that serrated metal gratings, which introduce gradient coatings, can give rise to broadband transmission enhancement of acoustic waves. Here, we have experimentally and theoretically studied the acoustic transmission properties of metal gratings with or without serrated boundaries. The average transmission is obviously enhanced for serrated metal gratings within a wide frequency range, while the Fabry-Perot resonance is significantly suppressed. An effective medium hypothesis with varying acoustic impedance is proposed to analyze the mechanism, which was verified through comparison with finite-element simulation. The serrated boundary supplies gradient mass distribution and gradient normal acoustic impedance, which could efficiently reduce the boundary reflection. Further, by increasing the region of the serrated boundary, we present a broadband high-transmission grating for wide range of incident angle. Our results may have potential applications to broadband acoustic imaging, acoustic sensing and new acoustic devices. References: [1] Dong-Xiang Qi, Yu-Qiang Deng, Di-Hu Xu, Ren-Hao Fan, Ru-Wen Peng, Ze-Guo Chen, Ming-Hui Lu, X. R. Huang and Mu Wang, Appl. Phys. Lett. 106, 011906 (2015); [2] Dong-Xiang Qi, Ren-Hao Fan, Ru-Wen Peng, Xian-Rong Huang, Ming-Hui Lu, Xu Ni, Qing Hu, and Mu Wang, Applied Physics Letters 101, 061912 (2012).

  4. Detonator comprising a nonlinear transmission line

    SciTech Connect

    Elizondo-Decanini, Juan M

    2014-12-30

    Detonators are described herein. In a general embodiment, the detonator includes a nonlinear transmission line that has a variable capacitance. Capacitance of the nonlinear transmission line is a function of voltage on the nonlinear transmission line. The nonlinear transmission line receives a voltage pulse from a voltage source and compresses the voltage pulse to generate a trigger signal. Compressing the voltage pulse includes increasing amplitude of the voltage pulse and decreasing length of the voltage pulse in time. An igniter receives the trigger signal and detonates an explosive responsive to receipt of the trigger signal.

  5. RF Transmission Lines on Silicon Substrates

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.

    1999-01-01

    A review of RF transmission lines on silicon substrates is presented. Through measurements and calculated results, it is shown that attenuation is dominated by conductor loss if silicon substrates with a resistivity greater than 2500 Ohm-cm are used. Si passivation layers affect the transmission line attenuation; however, measured results demonstrate that passivation layers do not necessarily increase attenuation. If standard, low resistivity Si wafers must be used, alternative transmission lines such as thin film microstrip and Co-Planar Waveguide (CPW) on thick polyimide layers must be used. Measured results presented here show that low loss per unit length is achievable with these transmission lines.

  6. Transmission Line Security Monitor: Final Report

    SciTech Connect

    John Svoboda

    2011-04-01

    The Electric Power Transmission Line Security Monitor System Operational Test is a project funded by the Technical Support Working Group (TSWG). TSWG operates under the Combating Terrorism Technical Support Office that functions under the Department of Defense. The Transmission Line Security Monitor System is based on technology developed by Idaho National Laboratory. The technology provides a means for real-time monitoring of physical threats and/or damage to electrical transmission line towers and conductors as well as providing operational parameters to transmission line operators to optimize transmission line operation. The end use is for monitoring long stretches of transmission lines that deliver electrical power from remote generating stations to cities and industry. These transmission lines are generally located in remote transmission line corridors where security infrastructure may not exist. Security and operational sensors in the sensor platform on the conductors take power from the transmission line and relay security and operational information to operations personnel hundreds of miles away without relying on existing infrastructure. Initiated on May 25, 2007, this project resulted in pre-production units tested in realistic operational environments during 2010. A technology licensee, Lindsey Manufacturing of Azusa California, is assisting in design, testing, and ultimately production. The platform was originally designed for a security monitoring mission, but it has been enhanced to include important operational features desired by electrical utilities.

  7. Extraordinary acoustic transmission through annuluses in air and its applications in acoustic beam splitter and concentrator.

    PubMed

    Ge, Yong; Sun, Hong-Xiang; Liu, Shu-Sen; Yuan, Shou-Qi; Xia, Jian-Ping; Guan, Yi-Jun; Zhang, Shu-Yi

    2016-08-01

    We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications. PMID:27587144

  8. Extraordinary acoustic transmission through annuluses in air and its applications in acoustic beam splitter and concentrator

    NASA Astrophysics Data System (ADS)

    Ge, Yong; Sun, Hong-xiang; Liu, Shu-sen; Yuan, Shou-qi; Xia, Jian-ping; Guan, Yi-jun; Zhang, Shu-yi

    2016-08-01

    We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications.

  9. Micromachined silicon acoustic delay line with 3D-printed micro linkers and tapered input for improved structural stability and acoustic directivity

    NASA Astrophysics Data System (ADS)

    Cho, Y.; Kumar, A.; Xu, S.; Zou, J.

    2016-10-01

    Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. To achieve deeper imaging depth and wider field of view, a longer delay time and therefore delay length are required. However, as the length of the delay line increases, it becomes more vulnerable to structural instability due to reduced mechanical stiffness. In this paper, we report the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, the improvement of the acoustic acceptance angle of the silicon acoustic delay lines was also investigated to better suppress the reception of unwanted ultrasound signals outside of the imaging plane. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays.

  10. ACOUSTIC DETECTING AND LOCATING GAS PIPE LINE INFRINGEMENT

    SciTech Connect

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Patrick Browning

    2004-10-31

    The extensive network of high-pressure natural gas transmission pipelines covering the United States provides an important infrastructure for our energy independence. Early detection of pipeline leaks and infringements by construction equipment, resulting in corrosion fractures, presents an important aspect of our national security policy. The National Energy Technology Laboratory Strategic Center for Natural Gas (SCVG) is and has been funding research on various applicable techniques. The WVU research team has focused on monitoring pipeline background acoustic signals generated and transmitted by gas flowing through the gas inside the pipeline. In case of a pipeline infringement, any mechanical impact on the pipe wall, or escape of high-pressure gas, generates acoustic signals traveling both up and down stream through the gas. Sudden changes in flow noise are detectable with a Portable Acoustic Monitoring Package (PAMP), developed under this contract. It incorporates a pressure compensating microphone and a signal- recording device. Direct access to the gas inside the line is obtained by mounting such a PAMP, with a 1/2 inch NPT connection, to a pipeline pressure port found near most shut-off valves. An FFT of the recorded signal subtracted by that of the background noise recorded one-second earlier appears to sufficiently isolate the infringement signal to allow source interpretation. Using cell phones for data downloading might allow a network of such 1000-psi rated PAMP's to acoustically monitor a pipeline system and be trained by neural network software to positively identify and locate any pipeline infringement.

  11. ACOUSTIC DETECTING AND LOCATING GAS PIPE LINE INFRINGEMENT

    SciTech Connect

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Patrick Browning

    2004-12-01

    The extensive network of high-pressure natural gas transmission pipelines covering the United States provides an important infrastructure for our energy independence. Early detection of pipeline leaks and infringements by construction equipment, resulting in corrosion fractures, presents an important aspect of our national security policy. The National Energy Technology Laboratory Strategic Center for Natural Gas (SCVG) is and has been funding research on various applicable techniques. The WVU research team has focused on monitoring pipeline background acoustic signals generated and transmitted by gas flowing through the gas inside the pipeline. In case of a pipeline infringement, any mechanical impact on the pipe wall, or escape of high-pressure gas, generates acoustic signals traveling both up and down stream through the gas. Sudden changes in flow noise are detectable with a Portable Acoustic Monitoring Package (PAMP), developed under this contract. It incorporates a pressure compensating microphone and a signal- recording device. Direct access to the gas inside the line is obtained by mounting such a PAMP, with a 1/2 inch NPT connection, to a pipeline pressure port found near most shut-off valves. An FFT of the recorded signal subtracted by that of the background noise recorded one-second earlier appears to sufficiently isolate the infringement signal to allow source interpretation. Using cell phones for data downloading might allow a network of such 1000-psi rated PAMP's to acoustically monitor a pipeline system and be trained by neural network software to positively identify and locate any pipeline infringement.

  12. Transmission Characteristics of Primate Vocalizations: Implications for Acoustic Analyses

    PubMed Central

    Maciej, Peter; Fischer, Julia; Hammerschmidt, Kurt

    2011-01-01

    Acoustic analyses have become a staple method in field studies of animal vocal communication, with nearly all investigations using computer-based approaches to extract specific features from sounds. Various algorithms can be used to extract acoustic variables that may then be related to variables such as individual identity, context or reproductive state. Habitat structure and recording conditions, however, have strong effects on the acoustic structure of sound signals. The purpose of this study was to identify which acoustic parameters reliably describe features of propagated sounds. We conducted broadcast experiments and examined the influence of habitat type, transmission height, and re-recording distance on the validity (deviation from the original sound) and reliability (variation within identical recording conditions) of acoustic features of different primate call types. Validity and reliability varied independently of each other in relation to habitat, transmission height, and re-recording distance, and depended strongly on the call type. The smallest deviations from the original sounds were obtained by a visually-controlled calculation of the fundamental frequency. Start- and end parameters of a sound were most susceptible to degradation in the environment. Because the recording conditions can have appreciable effects on acoustic parameters, it is advisable to validate the extraction method of acoustic variables from recordings over longer distances before using them in acoustic analyses. PMID:21829682

  13. Experimental realization of extraordinary acoustic transmission using Helmholtz resonators

    SciTech Connect

    Crow, Brian C.; Cullen, Jordan M.; McKenzie, William W.; Koju, Vijay; Robertson, William M.

    2015-02-15

    The phenomenon of extraordinary acoustic transmission through a solid barrier with an embedded Helmholtz resonator (HR) is demonstrated. The Helmholtz resonator consists of an embedded cavity and two necks that protrude, one on each side of the barrier. Extraordinary transmission occurs for a narrow spectral range encompassing the resonant frequency of the Helmholtz resonator. We show that an amplitude transmission of 97.5% is achieved through a resonator whose neck creates an open area of 6.25% of the total barrier area. In addition to the enhanced transmission, we show that there is a smooth, continuous phase transition in the transmitted sound as a function of frequency. The frequency dependent phase transition is used to experimentally realize slow wave propagation for a narrow-band Gaussian wave packet centered at the maximum transmission frequency. The use of parallel pairs of Helmholtz resonators tuned to different resonant frequencies is experimentally explored as a means of increasing the transmission bandwidth. These experiments show that because of the phase transition, there is always a frequency between the two Helmholtz resonant frequencies at which destructive interference occurs whether the resonances are close or far apart. Finally, we explain how the phase transition associated with Helmholtz-resonator-mediated extraordinary acoustic transmission can be exploited to produce diffractive acoustic components including sub-wavelength thickness acoustic lenses.

  14. Single transmission line data acquisition system

    DOEpatents

    Fasching, George E.

    1984-01-01

    A single transmission line interrogated multiple channel data acquisition system is provided in which a plurality of remote station/sensors monitor specific process variables and transmit measurement values over the single transmission line to a master station when addressed by the master station. Power for all remote stations (up to 980) is provided by driving the line with constant voltage supplied from the master station and automatically maintained independent of the number of remote stations directly connected to the line. The transmission line can be an RG-62 coaxial cable with lengths up to about 10,000 feet with branches up to 500 feet. The remote stations can be attached randomly along the line. The remote stations can be scanned at rates up to 980 channels/second.

  15. Electrical Transmission Line Diametrical Retention Mechanism

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David; Dahlgren, Scott; Sneddon, Cameron; Briscoe, Michael; Fox, Joe

    2006-01-03

    The invention is a mechanism for retaining an electrical transmission line. In one embodiment of the invention it is a system for retaining an electrical transmission line within downhole components. The invention allows a transmission line to be attached to the internal diameter of drilling components that have a substantially uniform drilling diameter. In accordance with one aspect of the invention, the system includes a plurality of downhole components, such as sections of pipe in a drill string, drill collars, heavy weight drill pipe, and jars. The system also includes a coaxial cable running between the first and second end of a drill pipe, the coaxial cable having a conductive tube and a conductive core within it. The invention allows the electrical transmission line to withstand the tension and compression of drill pipe during routine drilling cycles.

  16. Transmission Line Series Compensation for Wind Energy Transmission

    NASA Astrophysics Data System (ADS)

    Palanichamy, Dr C., Prof; Wong, Y. C.

    2015-04-01

    Wind energy has demonstrated to be a clean, copious and absolutely renewable source of energy, and the large penetration of it into the power grid indicates that wind energy is considered an effective means of power generation, Transmission of wind energy from remote locations to load centers necessitates long transmission lines. Series compensation is a proven and economical transmission solution to address system power transfer strength, grid stability, and voltage profile issues of long transmission lines. In this paper, a programmable approach to determine the capacitive reactance of series capacitor and optimum location for its placement to achieve maximum power transfer gas been presented. The respective program with sample solutions has been provided for real-time applications.

  17. Waveform-preserved unidirectional acoustic transmission based on impedance-matched acoustic metasurface and phononic crystal

    NASA Astrophysics Data System (ADS)

    Song, Ai-Ling; Chen, Tian-Ning; Wang, Xiao-Peng; Wan, Le-Le

    2016-08-01

    The waveform distortion happens in most of the unidirectional acoustic transmission (UAT) devices proposed before. In this paper, a novel type of waveform-preserved UAT device composed of an impedance-matched acoustic metasurface (AMS) and a phononic crystal (PC) structure is proposed and numerically investigated. The acoustic pressure field distributions and transmittance are calculated by using the finite element method. The subwavelength AMS that can modulate the wavefront of the transmitted wave at will is designed and the band structure of the PC structure is calculated and analyzed. The sound pressure field distributions demonstrate that the unidirectional acoustic transmission can be realized by the proposed UAT device without changing the waveforms of the output waves, which is the distinctive feature compared with the previous UAT devices. The physical mechanism of the unidirectional acoustic transmission is discussed by analyzing the refraction angle changes and partial band gap map. The calculated transmission spectra show that the UAT device is valid within a relatively broad frequency range. The simulation results agree well with the theoretical predictions. The proposed UAT device provides a good reference for designing waveform-preserved UAT devices and has potential applications in many fields, such as medical ultrasound, acoustic rectifiers, and noise insulation.

  18. Effect of tornado loads on transmission lines

    SciTech Connect

    Ishac, M.F.; White, H.B.

    1994-12-31

    Of all the populated areas in Canada, southwestern Ontario has experienced the highest tornado incidence and faces the greatest tornado damage. About 1 or 2 tornadoes per 10,000 km{sup 2} can be expected there annually. The probability of a tornado strike at a given point is very small but the probability of a transmission line being crossed by a tornado is significant. The purpose of this paper is to review the literature related to tornadoes in Ontario and to investigate the effect of tornado loads on transmission lines. Based on this investigation a design basis tornado loading for transmission towers is proposed.

  19. Effect of tornado loads on transmission lines

    SciTech Connect

    Ishac, M.F.; White, H.B.

    1995-01-01

    Of all the populated areas in Canada, southwestern Ontario has experienced the highest tornado incidence and faces the greatest tornado damage. About 1 or 2 tornadoes per 10,000 km{sup 2} can be expected there annually. The probability of a tornado strike at a given point is very small but the probability of a transmission line being crossed by a tornado is significant. The purpose of this paper is to review the literature related to tornadoes in Ontario and to investigate the effect of tornado loads on transmission lines. Based on this investigation a design basis tornado loading for transmission towers is proposed.

  20. 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.

  1. Bird streamer flashovers on FPL transmission lines

    SciTech Connect

    Burnham, J.T.

    1995-04-01

    FPL transmission lines with excessive unknown cause outages were investigated and determined to have experiences bird streamer flashovers. Findings are extended to similar lines and the frequency of bird streamer occurrences are estimated. Outage patterns associated with bird streamer flashovers are presented.

  2. Upgrading a 24-in. gas transmission line

    SciTech Connect

    Stiles, R.E.

    1986-10-01

    Because of increasing population density, Texas Eastern Transmission Corp. removed an existing 24-in. gas line and replaced it with a higher yield line pipe with a greater wall thickness. Work was through exclusive lake subdivisions and across a golf course and required special construction techniques.

  3. Load-resistant coaxial transmission line

    DOEpatents

    Hall, David R.; Fox, Joe

    2006-01-03

    A transmission line for downhole tools that make up all or part of a tool string for drilling and production of oil, gas, and geothermal wells that can withstand the dynamic gravitational forces and other accelerations associated with downhole excavations. The transmission line has a metal tube, or outer conductor, that houses a coaxial wire inner conductor. A non-metallic dielectric material is interposed between the inner and outer conductors. The outer and inner conductors and the dielectric are sufficiently compressed together so that independent motion between them is abated. Compression of the components of the transmission line may be achieved by drawing the transmission through one or more dies in order to draw down the outer conductor onto the dielectric, or by expanding the inner conductor against the dielectric using a mandrel or hydraulic pressure. Non-metallic bead segments may be used in aid of the compression necessary to resist the dynamic forces and accelerations of drilling.

  4. Impedance matched joined drill pipe for improved acoustic transmission

    DOEpatents

    Moss, William C.

    2000-01-01

    An impedance matched jointed drill pipe for improved acoustic transmission. A passive means and method that maximizes the amplitude and minimize the temporal dispersion of acoustic signals that are sent through a drill string, for use in a measurement while drilling telemetry system. The improvement in signal transmission is accomplished by replacing the standard joints in a drill string with joints constructed of a material that is impedance matched acoustically to the end of the drill pipe to which it is connected. Provides improvement in the measurement while drilling technique which can be utilized for well logging, directional drilling, and drilling dynamics, as well as gamma-ray spectroscopy while drilling post shot boreholes, such as utilized in drilling post shot boreholes.

  5. Acoustic transmission loss and structureborne noise transmission tests on a LASCOR and a reference steel panel

    NASA Astrophysics Data System (ADS)

    Norwood, C. J.

    1993-09-01

    LASCOR is a laser welded corrugated steel sandwich developed as a lightweight construct for ship superstructures. Tests were performed to measure acoustic transmission loss and structureborne noise transmission for both a LASCOR panel and a reference conventional rib-stiffened steel panel. This report outlines the test methods used and compares the results for the two panels.

  6. Advanced Nacelle Acoustic Lining Concepts Development

    NASA Technical Reports Server (NTRS)

    Bielak, G.; Gallman, J.; Kunze, R.; Murray, P.; Premo, J.; Kosanchick, M.; Hersh, A.; Celano, J.; Walker, B.; Yu, J.; Parrott, Tony L. (Technical Monitor)

    2002-01-01

    The work reported in this document consisted of six distinct liner technology development subtasks: 1) Analysis of Model Scale ADP Fan Duct Lining Data (Boeing): An evaluation of an AST Milestone experiment to demonstrate 1995 liner technology superiority relative to that of 1992 was performed on 1:5.9 scale model fan rig (Advanced Ducted Propeller) test data acquired in the NASA Glenn 9 x 15 foot wind tunnel. The goal of 50% improvement was deemed satisfied. 2) Bias Flow Liner Investigation (Boeing, VCES): The ability to control liner impedance by low velocity bias flow through liner was demonstrated. An impedance prediction model to include bias flow was developed. 3) Grazing Flow Impedance Testing (Boeing): Grazing flow impedance tests were conducted for comparison with results achieved at four different laboratories. 4) Micro-Perforate Acoustic Liner Technology (BFG, HAE, NG): Proof of concept testing of a "linear liner." 5) Extended Reaction Liners (Boeing, NG): Bandwidth improvements for non-locally reacting liner were investigated with porous honeycomb core test liners. 6) Development of a Hybrid Active/Passive Lining Concept (HAE): Synergism between active and passive attenuation of noise radiated by a model inlet was demonstrated.

  7. 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.

  8. Reflection and Transmission of Acoustic Waves at Semiconductor - Liquid Interface

    NASA Astrophysics Data System (ADS)

    Sharma, J. N.; Sharma, A.

    2011-09-01

    The study of reflection and transmission characteristics of acoustic waves at the interface of a semiconductor halfspace underlying an inviscid liquid has been carried out. The reflection and transmission coefficients of reflected and transmitted waves have been obtained for quasi-longitudinal (qP) wave incident at the interface from fluid to semiconductor. The numerical computations of reflection and transmission coefficients have been carried out with the help of Gauss elimination method by using MATLAB programming for silicon (Si), germanium (Ge) and silicon nitride (Si3N4) semiconductors. In order to interpret and compare, the computer simulated results are plotted graphically. The study may be useful in semiconductors, seismology and surface acoustic wave (SAW) devices in addition to engines of the space shuttles.

  9. Application of transmission-line super theory to classical transmission lines with risers

    NASA Astrophysics Data System (ADS)

    Rambousky, R.; Nitsch, J.; Tkachenko, S.

    2015-11-01

    By applying the Transmission-Line Super Theory (TLST) to a practical transmission-line configuration (two risers and a horizontal part of the line parallel to the ground plane) it is elaborated under which physical and geometrical conditions the horizontal part of the transmission-line can be represented by a classical telegrapher equation with a sufficiently accurate description of the physical properties of the line. The risers together with the part of the horizontal line close to them are treated as separate lines using the TLST. Novel frequency and local dependent reflection coefficients are introduced to take into account the action of the bends and their radiation. They can be derived from the matrizant elements of the TLST solution. It is shown that the solution of the resulting network and the TLST solution of the entire line agree for certain line configurations. The physical and geometrical parameters for these corresponding configurations are determined in this paper.

  10. EC Transmission Line Risk Identification and Analysis

    SciTech Connect

    Bigelow, Tim S

    2012-04-01

    The purpose of this document is to assist in evaluating and planning for the cost, schedule, and technical project risks associated with the delivery and operation of the EC (Electron cyclotron) transmission line system. In general, the major risks that are anticipated to be encountered during the project delivery phase associated with the implementation of the Procurement Arrangement for the EC transmission line system are associated with: (1) Undefined or changing requirements (e.g., functional or regulatory requirements) (2) Underperformance of prototype, first unit, or production components during testing (3) Unavailability of qualified vendors for critical components Technical risks associated with the design and operation of the system are also identified.

  11. Flux Cloning in Josephson Transmission Lines

    SciTech Connect

    Gulevich, D.R.; Kusmartsev, F.V.

    2006-07-07

    We describe a novel effect related to the controlled birth of a single Josephson vortex. In this phenomenon, the vortex is created in a Josephson transmission line at a T-shaped junction. The 'baby' vortex arises at the moment when a 'mother' vortex propagating in the adjacent transmission line passes the T-shaped junction. In order to give birth to a new vortex, the mother vortex must have enough kinetic energy. Its motion can also be supported by an externally applied driving current. We determine the critical velocity and the critical driving current for the creation of the baby vortices and briefly discuss the potential applications of the found effect.

  12. Asymmetric wave transmission in a diatomic acoustic/elastic metamaterial

    NASA Astrophysics Data System (ADS)

    Li, Bing; Tan, K. T.

    2016-08-01

    Asymmetric acoustic/elastic wave transmission has recently been realized using nonlinearity, wave diffraction, or bias effects, but always at the cost of frequency distortion, direction shift, large volumes, or external energy. Based on the self-coupling of dual resonators, we propose a linear diatomic metamaterial, consisting of several small-sized unit cells, to realize large asymmetric wave transmission in low frequency domain (below 1 kHz). The asymmetric transmission mechanism is theoretically investigated, and numerically verified by both mass-spring and continuum models. This passive system does not require any frequency conversion or external energy, and the asymmetric transmission band can be theoretically predicted and mathematically controlled, which extends the design concept of unidirectional transmission devices.

  13. 18 CFR 2.2 - Transmission lines.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Transmission lines. 2.2 Section 2.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES GENERAL POLICY AND INTERPRETATIONS Statements of General Policy and...

  14. 18 CFR 2.2 - Transmission lines.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Transmission lines. 2.2 Section 2.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES GENERAL POLICY AND INTERPRETATIONS Statements of General Policy and...

  15. 18 CFR 2.2 - Transmission lines.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Transmission lines. 2.2 Section 2.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES GENERAL POLICY AND INTERPRETATIONS Statements of General Policy and...

  16. Fluxon propagation on a Josephson transmission line

    SciTech Connect

    Matsuda, A.; Kawakami, T.

    1983-08-22

    Fluxon propagation profiles for Josephson transmission lines have been directly measured. Single--input-pulse dissociation into multifluxon as well as velocity-dependent wave forms have actually been observed. The experimental results agree well with the theoretical results if a large rf loss term is assumed.

  17. Determining Transmission Loss from Measured External and Internal Acoustic Environments

    NASA Technical Reports Server (NTRS)

    Scogin, Tyler; Smith, A. M.

    2012-01-01

    An estimate of the internal acoustic environment in each internal cavity of a launch vehicle is needed to ensure survivability of Space Launch System (SLS) avionics. Currently, this is achieved by using the noise reduction database of heritage flight vehicles such as the Space Shuttle and Saturn V for liftoff and ascent flight conditions. Marshall Space Flight Center (MSFC) is conducting a series of transmission loss tests to verify and augment this method. For this test setup, an aluminum orthogrid curved panel representing 1/8th of the circumference of a section of the SLS main structure was mounted in between a reverberation chamber and an anechoic chamber. Transmission loss was measured across the panel using microphones. Data measured during this test will be used to estimate the internal acoustic environments for several of the SLS launch vehicle internal spaces.

  18. Transport composite fuselage technology: Impact dynamics and acoustic transmission

    NASA Technical Reports Server (NTRS)

    Jackson, A. C.; Balena, F. J.; Labarge, W. L.; Pei, G.; Pitman, W. A.; Wittlin, G.

    1986-01-01

    A program was performed to develop and demonstrate the impact dynamics and acoustic transmission technology for a composite fuselage which meets the design requirements of a 1990 large transport aircraft without substantial weight and cost penalties. The program developed the analytical methodology for the prediction of acoustic transmission behavior of advanced composite stiffened shell structures. The methodology predicted that the interior noise level in a composite fuselage due to turbulent boundary layer will be less than in a comparable aluminum fuselage. The verification of these analyses will be performed by NASA Langley Research Center using a composite fuselage shell fabricated by filament winding. The program also developed analytical methodology for the prediction of the impact dynamics behavior of lower fuselage structure constructed with composite materials. Development tests were performed to demonstrate that the composite structure designed to the same operating load requirement can have at least the same energy absorption capability as aluminum structure.

  19. Transmission of acoustic emission in bones, implants and dental materials.

    PubMed

    Ossi, Zannar; Abdou, Wael; Reuben, Robert L; Ibbetson, Richard J

    2013-11-01

    There is considerable interest in using acoustic emission (AE) and ultrasound to assess the quality of implant-bone interfaces and to monitor for micro-damage leading to loosening. However, remarkably little work has been done on the transmission of ultrasonic waves though the physical and biological structures involved. The aim of this in vitro study is to assess any differences in transmission between various dental materials and bovine rib bones with various degrees of hydration. Two types of tests have been carried out using pencil lead breaks as a standard AE source. The first set of tests was configured to assess the surface propagation of AE on various synthetic materials compared with fresh bovine rib bone. The second is a set of transmission tests on fresh, dried and hydrated bones each fitted with dental implants with various degrees of fixity, which includes components due to bone and interface transmission. The results indicate that transmission through glass ionomer cement is closest to the bone. This would suggest that complete osseointegration could potentially be simulated using such cement. The transmission of AE energy through bone was found to be dependent on its degree of hydration. It was also found that perfusing samples of fresh bone with water led to an increase in transmitted energy, but this appeared to affect transmission across the interface more than transmission through the bone. These findings have implications not only for implant interface inspection but also for passive AE monitoring of implants.

  20. Transmission line environmental assessment guidance document

    SciTech Connect

    Jackson, J.; Pentecost, E.; Muzzarelli, J.

    1994-01-01

    Since 1939, U.S. utility companies have been required to obtain a Presidential Permit to construct electric transmission lines that cross a U.S. border and connect with a foreign utility. The purpose of this document is to provide Presidential Permit applicants with two types of guidance: (1) on the type of environmental and project descriptive information needed to assess the potential impacts of the proposed and alternative actions and (2) on compliance with applicable federal and state regulations. The main three chapters present information on the purpose and content of this document (Chapter 1); legislative, regulatory, and consultation requirements for transmission line interconnect projects (Chapter 2); and identification of basic transmission system design parameters and environmental data requirements for analysis of potential impacts of the proposed action (Chapter 3). Chapter 3 also includes information on possible techniques or measures to mitigate impacts. Appendix A presents an overview of NEPA requirements and DOE`s implementing procedures. Appendix B summarizes information on legislation that may be applicable to transmission line projects proposed in Presidential Permit applications.

  1. Theoretical vibro-acoustic modeling of acoustic noise transmission through aircraft windows

    NASA Astrophysics Data System (ADS)

    Aloufi, Badr; Behdinan, Kamran; Zu, Jean

    2016-06-01

    In this paper, a fully vibro-acoustic model for sound transmission across a multi-pane aircraft window is developed. The proposed model is efficiently applied for a set of window models to perform extensive theoretical parametric studies. The studied window configurations generally simulate the passenger window designs of modern aircraft classes which have an exterior multi-Plexiglas pane, an interior single acrylic glass pane and a dimmable glass ("smart" glass), all separated by thin air cavities. The sound transmission loss (STL) characteristics of three different models, triple-, quadruple- and quintuple-paned windows identical in size and surface density, are analyzed for improving the acoustic insulation performances. Typical results describing the influence of several system parameters, such as the thicknesses, number and spacing of the window panes, on the transmission loss are then investigated. In addition, a comparison study is carried out to evaluate the acoustic reduction capability of each window model. The STL results show that the higher frequencies sound transmission loss performance can be improved by increasing the number of window panels, however, the low frequency performance is decreased, particularly at the mass-spring resonances.

  2. 7 CFR 1726.77 - Substation and transmission line construction.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Substation and transmission line construction. 1726... and Transmission Facilities § 1726.77 Substation and transmission line construction. (a) Contract... substation and transmission line construction (including minor modifications or improvements), exclusive...

  3. 7 CFR 1726.77 - Substation and transmission line construction.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Substation and transmission line construction. 1726... and Transmission Facilities § 1726.77 Substation and transmission line construction. (a) Contract... substation and transmission line construction (including minor modifications or improvements), exclusive...

  4. 7 CFR 1726.77 - Substation and transmission line construction.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Substation and transmission line construction. 1726... and Transmission Facilities § 1726.77 Substation and transmission line construction. (a) Contract... substation and transmission line construction (including minor modifications or improvements), exclusive...

  5. 7 CFR 1726.77 - Substation and transmission line construction.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Substation and transmission line construction. 1726... and Transmission Facilities § 1726.77 Substation and transmission line construction. (a) Contract... substation and transmission line construction (including minor modifications or improvements), exclusive...

  6. Accelerator power concepts using isolated transmission lines

    SciTech Connect

    Nunnally, W.C.

    1981-05-01

    This report outlines the rationale and the advantages of using multiple transmission-line sections isolated by transit time and inductance in accelerating high-current (approx. = 10 -kA), short-pulse (less than or equal to 100-ns) particle beams to the multimegavolt level. The main advantages of this system include reducing the number of output switches required per output pulse by nearly an order of magnitude over conventional systems and increasing the system capability for repetition-rate operation. The isolated transmission-line concept is developed, and possible modes of operation are outlined. In addition, a point design of a 10-kA short-pulse accelerator is presented.

  7. Application of composite insulators to transmission lines

    SciTech Connect

    Cherney, E.A.; Brown, R.L.; Karady, G.; Nicholls, J.L.; Orbeck, T.; Pargamin, L.

    1983-05-01

    The paper provides guidelines for the application of composite insulators to transmission lines. These guidelines are based on utility field experiences, results of research laboratory tests and manufacturers' recommendations. Discussed are interchangeability with porcelain and glass insulators, application in contaminated environments, material ageing, insulator icing, the use of grease, resistance to vandalism, temperature extremes, and the need for grading rings. Clarification is provided on the mechanical rating of composite insulators because there is not yet general agreement by various industry groups.

  8. Microstrip transmission line for soil moisture measurement

    NASA Astrophysics Data System (ADS)

    Chen, Xuemin; Li, Jing; Liang, Renyue; Sun, Yijie; Liu, C. Richard; Rogers, Richard; Claros, German

    2004-12-01

    Pavement life span is often affected by the amount of voids in the base and subgrade soils, especially moisture content in pavement. Most available moisture sensors are based on the capacitive sensing using planar blades. Since the planar sensor blades are fabricated on the same surface to reduce the overall size of the sensor, such structure cannot provide very high accuracy for moisture content measurement. As a consequence, a typical capacitive moisture sensor has an error in the range of 30%. A more accurate measurement is based on the time domain refelctometer (TDR) measurement. However, typical TDR system is fairly expensive equipment, very large in size, and difficult to operate, the moisture content measurement is limited. In this paper, a novel microstrip transmission line based moisture sensor is presented. This sensor uses the phase shift measurement of RF signal going through a transmission line buried in the soil to be measured. Since the amplitude of the transmission measurement is a strong function of the conductivity (loss of the media) and the imaginary part of dielectric constant, and the phase is mainly a strong function of the real part of the dielectric constant, measuring phase shift in transmission mode can directly obtain the soil moisture information. This sensor was designed and implemented. Sensor networking was devised. Both lab and field data show that this sensor is sensitive and accurate.

  9. The factorization method for the acoustic transmission problem

    NASA Astrophysics Data System (ADS)

    Anagnostopoulos, Konstantinos A.; Charalambopoulos, Antonios; Kleefeld, Andreas

    2013-11-01

    In this work, the shape reconstruction problem of acoustically penetrable bodies from the far-field data corresponding to time-harmonic plane wave incidence is investigated within the framework of the factorization method. Although the latter technique has received considerable attention in inverse scattering problems dealing with impenetrable scatterers and it has not been elaborated for inverse transmission problems with the only exception being a work by the first two authors and co-workers. We aim to bridge this gap in the field of acoustic scattering; the paper on one hand focuses on establishing rigorously the necessary theoretical framework for the application of the factorization method to the inverse acoustic transmission problem. The main outcome of the investigation undertaken is the derivation of an explicit formula for the scatterer's characteristic function, which depends solely on the far-field data feeding the inverse scattering scheme. Extended numerical examples in three dimensions are also presented, where a variety of different surfaces are successfully reconstructed by the factorization method, thus, complementing the method's validation from the computational point of view.

  10. Dispersion-free radial transmission lines

    DOEpatents

    Caporaso, George J.; Nelson, Scott D.

    2011-04-12

    A dispersion-free radial transmission line ("DFRTL") preferably for linear accelerators, having two plane conductors each with a central hole, and an electromagnetically permeable material ("EPM") between the two conductors and surrounding a channel connecting the two holes. At least one of the material parameters of relative magnetic permeability, relative dielectric permittivity, and axial width of the EPM is varied as a function of radius, so that the characteristic impedance of the DFRTL is held substantially constant, and pulse transmission therethrough is substantially dispersion-free. Preferably, the EPM is divided into concentric radial sections, with the varied material parameters held constant in each respective section but stepwise varied between sections as a step function of the radius. The radial widths of the concentric sections are selected so that pulse traversal time across each section is the same, and the varied material parameters of the concentric sections are selected to minimize traversal error.

  11. View facing north, Structure 162 in foreground, as Transmission Line ...

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

    View facing north, Structure 16-2 in foreground, as Transmission Line turns at intersection of Powerline Road and US 87 - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  12. View facing south, near Structure 515, of Transmission Line rising ...

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

    View facing south, near Structure 51-5, of Transmission Line rising out of Marias River Valley - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  13. 3. DETAIL, LIGHTNING ARRESTER ON SAR TRANSMISSION LINE. EEC print ...

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

    3. DETAIL, LIGHTNING ARRESTER ON SAR TRANSMISSION LINE. EEC print no. S-C-01-00478, no date. Photographer unknown. - Santa Ana River Hydroelectric System, Transmission Lines, Redlands, San Bernardino County, CA

  14. Transmission line including support means with barriers

    DOEpatents

    Cookson, Alan H.

    1982-01-01

    A gas insulated transmission line includes an elongated outer sheath, a plurality of inner conductors disposed within and extending along the outer sheath, and an insulating gas which electrically insulates the inner conductors from the outer sheath. A support insulator insulatably supports the inner conductors within the outer sheath, with the support insulator comprising a main body portion including a plurality of legs extending to the outer sheath, and barrier portions which extend between the legs. The barrier portions have openings therein adjacent the main body portion through which the inner conductors extend.

  15. Transmission line icing measurement on photogrammetry method

    NASA Astrophysics Data System (ADS)

    Huang, Huan; Ma, Xiaohong; Zhao, Lijin; Du, Hao; Luo, Hong; Mao, Xianyin; Tang, Min; Liu, Yawen

    2015-12-01

    Icing thickness parameter is the basic data for power sector to make decision for icing accident prevention. In this paper, a transmission line icing measurement method is proposed. It used the photogrammetry method to realize icing parameters measurement through the integration of high resolution camera, laser range finder and inertial measurement unit. Compared with traditional icing measurement method, this method is flexible and is the effective supplement of the fixed icing detection terminal. And its high accuracy measurement guarantees the reliability of the icing thickness parameters.

  16. SMILE transmission line adder for RADLAC II

    SciTech Connect

    Mazarakis, M.G.; Poukey, J.W.; Shope, S.L.; Frost, C.A.; Turman, B.N.; Ramirez, J.J.; Prestwich, K.R.; Pankuch, P.J.

    1991-12-31

    SMILE is a coaxial Self Magnetically Insulated Transmission Line voltage adder. It replaces the original beam line of the RADLAC II accelerator by a 12.5 m long cathode electrode. The anode electrode remains practically the same, consisting of the original eight insulating stacks or feeds which are connected with equal diameter stainless steel cylinders. The beam is produced at the end of the accelerator and is free of all the possible instabilities associated with accelerating gaps and magnetic vacuum transport. Annular beams with {beta}{perpendicular} {le} 0.1 and radius r{sub b} {le} 1 cm were routinely obtained and extracted from a small magnetically-immersed foilless electron diode. Results of the experimental evaluation are presented and compared with design parameters and numerical simulation predictions. 4 refs.

  17. SMILE transmission line adder for RADLAC II

    SciTech Connect

    Mazarakis, M.G.; Poukey, J.W.; Shope, S.L.; Frost, C.A.; Turman, B.N.; Ramirez, J.J.; Prestwich, K.R. ); Pankuch, P.J. . Special Projects)

    1991-01-01

    SMILE is a coaxial Self Magnetically Insulated Transmission Line voltage adder. It replaces the original beam line of the RADLAC II accelerator by a 12.5 m long cathode electrode. The anode electrode remains practically the same, consisting of the original eight insulating stacks or feeds which are connected with equal diameter stainless steel cylinders. The beam is produced at the end of the accelerator and is free of all the possible instabilities associated with accelerating gaps and magnetic vacuum transport. Annular beams with {beta}{perpendicular} {le} 0.1 and radius r{sub b} {le} 1 cm were routinely obtained and extracted from a small magnetically-immersed foilless electron diode. Results of the experimental evaluation are presented and compared with design parameters and numerical simulation predictions. 4 refs.

  18. Giant vacuum forces via transmission lines

    PubMed Central

    Shahmoon, Ephraim; Mazets, Igor; Kurizki, Gershon

    2014-01-01

    Quantum electromagnetic fluctuations induce forces between neutral particles, known as the van der Waals and Casimir interactions. These fundamental forces, mediated by virtual photons from the vacuum, play an important role in basic physics and chemistry and in emerging technologies involving, e.g., microelectromechanical systems or quantum information processing. Here we show that these interactions can be enhanced by many orders of magnitude upon changing the character of the mediating vacuum modes. By considering two polarizable particles in the vicinity of any standard electric transmission line, along which photons can propagate in one dimension, we find a much stronger and longer-range interaction than in free space. This enhancement may have profound implications on many-particle and bulk systems and impact the quantum technologies mentioned above. The predicted giant vacuum force is estimated to be measurable in a coplanar waveguide line. PMID:25002503

  19. 49 CFR 192.719 - Transmission lines: Testing of repairs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Testing of repairs. 192.719... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.719 Transmission lines: Testing of repairs. (a) Testing of replacement pipe. If a segment of transmission line...

  20. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valve maintenance: Transmission lines. 192.745... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.745 Valve maintenance: Transmission lines. (a) Each transmission line valve that might be required during any...

  1. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Valve maintenance: Transmission lines. 192.745... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.745 Valve maintenance: Transmission lines. (a) Each transmission line valve that might be required during any...

  2. 49 CFR 192.179 - Transmission line valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission line valves. 192.179 Section 192.179... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.179 Transmission line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing...

  3. 49 CFR 192.179 - Transmission line valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission line valves. 192.179 Section 192.179... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.179 Transmission line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing...

  4. 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...

  5. 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...

  6. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Valve maintenance: Transmission lines. 192.745 Section 192.745 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... maintenance: Transmission lines. (a) Each transmission line valve that might be required during any...

  7. 49 CFR 192.719 - Transmission lines: Testing of repairs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Testing of repairs. 192.719 Section 192.719 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Testing of repairs. (a) Testing of replacement pipe. If a segment of transmission line...

  8. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Valve maintenance: Transmission lines. 192.745 Section 192.745 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... maintenance: Transmission lines. (a) Each transmission line valve that might be required during any...

  9. 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...

  10. 49 CFR 192.719 - Transmission lines: Testing of repairs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Testing of repairs. 192.719 Section 192.719 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Testing of repairs. (a) Testing of replacement pipe. If a segment of transmission line...

  11. 49 CFR 192.719 - Transmission lines: Testing of repairs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Testing of repairs. 192.719 Section 192.719 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Testing of repairs. (a) Testing of replacement pipe. If a segment of transmission line...

  12. 49 CFR 192.719 - Transmission lines: Testing of repairs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Testing of repairs. 192.719 Section 192.719 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Testing of repairs. (a) Testing of replacement pipe. If a segment of transmission line...

  13. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Valve maintenance: Transmission lines. 192.745 Section 192.745 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... maintenance: Transmission lines. (a) Each transmission line valve that might be required during any...

  14. 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...

  15. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  16. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  17. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  18. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  19. 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...

  20. ACOUSTIC DETECTING AND LOCATING GAS PIPE LINE INFRINGEMENT

    SciTech Connect

    John L Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Deepak Mehra

    2003-04-01

    The West Virginia University natural gas transmission line leak detection research is only considering using readily available 1/2 inch pipeline access ports for the detection of leak generated signals. The main problem with leak signals is the low signal to noise ratio. One of the acoustic signals associated with gas escaping through a leak is only temporary and is in the form of a rarefaction wave originating when the leak is formed. Due to pipeline friction, over distance such a step function transitions to a ramp function. The ability to identify a leak by pipeline monitoring and signal processing depends a great deal on the quality and signal to noise ratio of the characteristics of the detectors used. Combinations of sensing devices are being used for the WVU sensor package and are contained in a removable sensor housing. The four sensors currently installed are a 1/2 inch 3 Hz-40 Khz microphone, an audible range moving coil sensor, a piezo-electric pressure transducer, and the WVU designed floating 3 inch diameter diaphragm to detect flow transient induced pressure ramp type signals. The WVU diaphragm sensor, which is currently under development, uses the same diaphragm principle as a high quality capacitance type microphone, but utilizes aerodynamic signal amplification. This type of amplification only amplifies the ramp-signal itself, not the random pipeline noise.

  1. A radial transmission line material measurement apparatus

    SciTech Connect

    Warne, L.K.; Moyer, R.D.; Koontz, T.E.; Morris, M.E.

    1993-05-01

    A radial transmission line material measurement sample apparatus (sample holder, offset short standards, measurement software, and instrumentation) is described which has been proposed, analyzed, designed, constructed, and tested. The purpose of the apparatus is to obtain accurate surface impedance measurements of lossy, possibly anisotropic, samples at low and intermediate frequencies (vhf and low uhf). The samples typically take the form of sections of the material coatings on conducting objects. Such measurements thus provide the key input data for predictive numerical scattering codes. Prediction of the sample surface impedance from the coaxial input impedance measurement is carried out by two techniques. The first is an analytical model for the coaxial-to-radial transmission line junction. The second is an empirical determination of the bilinear transformation model of the junction by the measurement of three full standards. The standards take the form of three offset shorts (and an additional lossy Salisbury load), which have also been constructed. The accuracy achievable with the device appears to be near one percent.

  2. Subwavelength acoustic focusing by surface-wave-resonance enhanced transmission in doubly negative acoustic metamaterials

    SciTech Connect

    Zhou, Xiaoming; Badreddine Assouar, M. Oudich, Mourad

    2014-11-21

    We present analytical and numerical analyses of a yet unseen lensing paradigm that is based on a solid metamaterial slab in which the wave excitation source is attached. We propose and demonstrate sub-diffraction-limited acoustic focusing induced by surface resonant states in doubly negative metamaterials. The enhancement of evanescent waves across the metamaterial slab produced by their resonant coupling to surface waves is evidenced and quantitatively determined. The effect of metamaterial parameters on surface states, transmission, and wavenumber bandwidth is clearly identified. Based on this concept consisting of a wave source attached on the metamaterial, a high resolution of λ/28.4 is obtained with the optimum effective physical parameters, opening then an exciting way to design acoustic metamaterials for ultrasonic focused imaging.

  3. Acoustic Wave Propagation in Pressure Sense Lines

    NASA Technical Reports Server (NTRS)

    Vitarius, Patrick; Gregory, Don A.; Wiley, John; Korman, Valentin

    2003-01-01

    Sense lines are used in pressure measurements to passively transmit information from hostile environments to areas where transducers can be used. The transfer function of a sense line can be used to obtain information about the measured environment from the protected sensor. Several properties of this transfer function are examined, including frequency dependence, Helmholtz resonance, and time of flight delay.

  4. Method for bonding a transmission line to a downhole tool

    SciTech Connect

    Hall, David R.; Fox, Joe

    2007-11-06

    An apparatus for bonding a transmission line to the central bore of a downhole tool includes a pre-formed interface for bonding a transmission line to the inside diameter of a downhole tool. The pre-formed interface includes a first surface that substantially conforms to the outside contour of a transmission line and a second surface that substantially conforms to the inside diameter of a downhole tool. In another aspect of the invention, a method for bonding a transmission line to the inside diameter of a downhole tool includes positioning a transmission line near the inside wall of a downhole tool and placing a mold near the transmission line and the inside wall. The method further includes injecting a bonding material into the mold and curing the bonding material such that the bonding material bonds the transmission line to the inside wall.

  5. One-dimensional pressure transfer models for acoustic-electric transmission channels

    NASA Astrophysics Data System (ADS)

    Wilt, K. R.; Lawry, T. J.; Scarton, H. A.; Saulnier, G. J.

    2015-09-01

    A method for modeling piezoelectric-based ultrasonic acoustic-electric power and data transmission channels is presented. These channels employ piezoelectric disk transducers to convey signals across a series of physical layers using ultrasonic waves. This model decomposes the mechanical pathway of the signal into individual ultrasonic propagation layers which are generally independent of the layer's adjacent domains. Each layer is represented by a two-by-two traveling pressure wave transfer matrix which relates the forward and reverse pressure waves on one side of the layer to the pressure waves on the opposite face, where each face is assumed to be in contact with a domain of arbitrary reference acoustic impedance. A rigorous implementation of ultrasonic beam spreading is introduced and implemented within applicable domains. Compatible pressure-wave models for piezoelectric transducers are given, which relate the electric voltage and current interface of the transducer to the pressure waves on one mechanical interface while also allowing for passive acoustic loading of the secondary mechanical interface. It is also shown that the piezoelectric model's electrical interface is compatible with transmission line parameters (ABCD-parameters), allowing for connection of electronic components and networks. The model is shown to be capable of reproducing the behavior of realistic physical channels.

  6. Nonlinear transmission line based electron beam driver

    SciTech Connect

    French, David M.; Hoff, Brad W.; Tang Wilkin; Heidger, Susan; Shiffler, Don; Allen-Flowers, Jordan

    2012-12-15

    Gated field emission cathodes can provide short electron pulses without the requirement of laser systems or cathode heating required by photoemission or thermionic cathodes. The large electric field requirement for field emission to take place can be achieved by using a high aspect ratio cathode with a large field enhancement factor which reduces the voltage requirement for emission. In this paper, a cathode gate driver based on the output pulse train from a nonlinear transmission line is experimentally demonstrated. The application of the pulse train to a tufted carbon fiber field emission cathode generates short electron pulses. The pulses are approximately 2 ns in duration with emission currents of several mA, and the train contains up to 6 pulses at a frequency of 100 MHz. Particle-in-cell simulation is used to predict the characteristic of the current pulse train generated from a single carbon fiber field emission cathode using the same technique.

  7. Networks of nonlinear superconducting transmission line resonators

    NASA Astrophysics Data System (ADS)

    Leib, M.; Deppe, F.; Marx, A.; Gross, R.; Hartmann, M. J.

    2012-07-01

    We investigate a network of coupled superconducting transmission line resonators, each of them made nonlinear with a capacitively shunted Josephson junction coupling to the odd flux modes of the resonator. The resulting eigenmode spectrum shows anticrossings between the plasma mode of the shunted junction and the odd resonator modes. Notably, we find that the combined device can inherit the complete nonlinearity of the junction, allowing for a description as a harmonic oscillator with a Kerr nonlinearity. Using a dc SQUID instead of a single junction, the nonlinearity can be tuned between 10 kHz and 4 MHz while maintaining resonance frequencies of a few gigahertz for realistic device parameters. An array of such nonlinear resonators can be considered a scalable superconducting quantum simulator for a Bose-Hubbard Hamiltonian. The device would be capable of accessing the strongly correlated regime and be particularly well suited for investigating quantum many-body dynamics of interacting particles under the influence of drive and dissipation.

  8. New transmission line analogy applied to single and multilayered piezoelectric transducers.

    PubMed

    Dion, J L

    1993-01-01

    It is shown that a piezoelectric element vibrating in an extensional or shear mode can be modeled rigorously by systematic use of the transmission line analogy and the superposition theorem. A schematic representation of such an element which is in a way more intuitive than others representations is introduced. The stresses on the electroded faces are considered as sources of stress applied at the two ends of an acoustic transmission line, since the acoustical perturbations may be considered as originating on these faces. Using transmission line theory, a complete set of expressions is found for electrical impedance, acoustic stresses, and velocities. Computed results are exactly the same as those given by the classical method, even if the computation sequence is almost entirely different. An intuitive graphical model for a piezoelectric element is proposed. It is also shown that the acoustic velocities on opposite faces of an asymmetrical loaded piezoelectric plate are exactly equal at the antiresonance frequency when internal losses are neglected. The programs developed can be used efficiently for practical multilayered transducer design. PMID:18263222

  9. 49 CFR 192.705 - Transmission lines: Patrolling.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Patrolling. 192.705 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.705 Transmission... adjacent to the transmission line right-of-way for indications of leaks, construction activity, and...

  10. 49 CFR 192.709 - Transmission lines: Record keeping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Record keeping. 192.709... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.709 Transmission lines: Record keeping. Each operator shall maintain the following records for transmission...

  11. 49 CFR 192.709 - Transmission lines: Record keeping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Record keeping. 192.709 Section 192.709 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Record keeping. Each operator shall maintain the following records for transmission...

  12. 7 CFR 1726.77 - Substation and transmission line construction.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Substation and transmission line construction. 1726... UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES Substation and Transmission Facilities § 1726.77 Substation and transmission line construction. (a)...

  13. 49 CFR 192.709 - Transmission lines: Record keeping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Record keeping. 192.709 Section 192.709 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Record keeping. Each operator shall maintain the following records for transmission...

  14. 49 CFR 192.705 - Transmission lines: Patrolling.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Patrolling. 192.705 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.705 Transmission... adjacent to the transmission line right-of-way for indications of leaks, construction activity, and...

  15. 49 CFR 192.709 - Transmission lines: Record keeping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Record keeping. 192.709 Section 192.709 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Record keeping. Each operator shall maintain the following records for transmission...

  16. 49 CFR 192.709 - Transmission lines: Record keeping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Record keeping. 192.709 Section 192.709 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Transmission lines: Record keeping. Each operator shall maintain the following records for transmission...

  17. 49 CFR 192.705 - Transmission lines: Patrolling.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Patrolling. 192.705 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.705 Transmission... adjacent to the transmission line right-of-way for indications of leaks, construction activity, and...

  18. 49 CFR 192.705 - Transmission lines: Patrolling.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Patrolling. 192.705 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.705 Transmission... adjacent to the transmission line right-of-way for indications of leaks, construction activity, and...

  19. 49 CFR 192.705 - Transmission lines: Patrolling.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Patrolling. 192.705 Section... lines: Patrolling. (a) Each operator shall have a patrol program to observe surface conditions on and adjacent to the transmission line right-of-way for indications of leaks, construction activity, and...

  20. 49 CFR 192.179 - Transmission line valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission line valves. 192.179 Section 192.179... line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing block valves spaced as follows, unless in a particular case the Administrator finds that alternative...

  1. 49 CFR 192.179 - Transmission line valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... be equipped with valves or other components to shut off the flow of gas to an offshore platform in an... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission line valves. 192.179 Section 192.179... line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing...

  2. Big Creek Hydroelectric System, East & West Transmission Line, 241mile ...

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

    Big Creek Hydroelectric System, East & West Transmission Line, 241-mile transmission corridor extending between the Big Creek Hydroelectric System in the Sierra National Forest in Fresno County and the Eagle Rock Substation in Los Angeles, California, Visalia, Tulare County, CA

  3. Multiplex transmission system for gate drive signals of inverter circuit using surface acoustic wave filters

    NASA Astrophysics Data System (ADS)

    Suzuki, Akifumi; Ueda, Kensuke; Goka, Shigeyoshi; Wada, Keiji; Kakio, Shoji

    2016-07-01

    We propose and fabricate a multiplexed transmission system based on frequency-division multiple access (FDMA) with surface acoustic wave (SAW) filters. SAW filters are suitable for use in wide-gap switching devices and multilevel inverters because of their capability to operate at high temperatures, good electrical isolation, low cost, and high reliability. Our proposed system reduces the number of electrical signal wires needed to control each switching device and eliminates the need for isolation circuits, simplifying the transmission system and gate drive circuits. We successfully controlled two switching devices with a single coaxial line and confirmed the operation of a single-phase half-bridge inverter at a supply voltage of 100 V, and the total delay time to control the switching devices was less than 2.5 µs. Our experimental results validated our proposed system.

  4. Measurement of transmission loss characteristics using acoustic intensity techniques at the KU-FRL Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Roskam, J.

    1983-01-01

    The transmission loss characteristics of panels using the acoustic intensity technique is presented. The theoretical formulation, installation of hardware, modifications to the test facility, and development of computer programs and test procedures are described. A listing of all the programs is also provided. The initial test results indicate that the acoustic intensity technique is easily adapted to measure transmission loss characteristics of panels. Use of this method will give average transmission loss values. The fixtures developed to position the microphones along the grid points are very useful in plotting the intensity maps of vibrating panels.

  5. 49 CFR 192.707 - Line markers for mains and transmission lines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Line markers for mains and transmission lines. 192... § 192.707 Line markers for mains and transmission lines. (a) Buried pipelines. Except as provided in paragraph (b) of this section, a line marker must be placed and maintained as close as practical over...

  6. 49 CFR 192.707 - Line markers for mains and transmission lines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Line markers for mains and transmission lines. 192... § 192.707 Line markers for mains and transmission lines. (a) Buried pipelines. Except as provided in paragraph (b) of this section, a line marker must be placed and maintained as close as practical over...

  7. 49 CFR 192.707 - Line markers for mains and transmission lines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Line markers for mains and transmission lines. 192... § 192.707 Line markers for mains and transmission lines. (a) Buried pipelines. Except as provided in paragraph (b) of this section, a line marker must be placed and maintained as close as practical over...

  8. Radio frequency communication system utilizing radiating transmission lines

    DOEpatents

    Struven, Warren C.

    1984-01-01

    A radio communication system for use in tunnels, mines, buildings or other shielded locations in which a pair of radiating transmission lines (30), (31) extend through such location in spaced coextensive relation to each other. Each transmission line (30), (31) has at least one unidirectional amplifier (32), (33) interposed therein with the sense of the unidirectional amplifier (32) of one transmission line (30) being opposite to the sense of the unidirectional amplifier (33) of the other transmission line (31). Each of the amplifiers (32), (33) has a gain which is less than the coupling loss between the transmission lines (30), (31). Two or more mobile transceivers (35) in the location served by the system are coupled to the transmission lines (30), (31) by electromagnetic wave propagation in space in order to communicate directly with each other at a given radio frequency within the frequency range of the system.

  9. Experimental verification of manipulating propagation directions of transmitted waves in asymmetric acoustic transmission

    NASA Astrophysics Data System (ADS)

    Sun, Hong-xiang; Zhang, Shu-yi; Yuan, Shou-qi; Xia, Jian-ping

    2016-04-01

    The manipulation of the propagation directions of the transmitted waves in an acoustic system with asymmetric acoustic transmission is investigated numerically and experimentally, in which the system consists of a brass plate and a periodical grating immersed in water. It is experimentally demonstrated that the propagation angles of the transmitted waves are close to those of ±1-order diffractions in the pass-band of the asymmetric acoustic transmission, and thus, the manipulation of the propagation directions of the transmitted waves is realized by adjusting the grating period and plate thickness. Our scheme may open up an avenue to the design of tunable unidirectional acoustic devices.

  10. Numerical study of acoustic instability in a partly lined flow duct using the full linearized Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Xin, Bo; Sun, Dakun; Jing, Xiaodong; Sun, Xiaofeng

    2016-07-01

    Lined ducts are extensively applied to suppress noise emission from aero-engines and other turbomachines. The complex noise/flow interaction in a lined duct possibly leads to acoustic instability in certain conditions. To investigate the instability, the full linearized Navier-Stokes equations with eddy viscosity considered are solved in frequency domain using a Galerkin finite element method to compute the sound transmission in shear flow in the lined duct as well as the flow perturbation over the impedance wall. A good agreement between the numerical predictions and the published experimental results is obtained for the sound transmission, showing that a transmission peak occurs around the resonant frequency of the acoustic liner in the presence of shear flow. The eddy viscosity is an important influential factor that plays the roles of both providing destabilizing and making coupling between the acoustic and flow motions over the acoustic liner. Moreover, it is shown from the numerical investigation that the occurrence of the sound amplification and the magnitude of transmission coefficient are closely related to the realistic velocity profile, and we find it essential that the actual variation of the velocity profile in the axial direction over the liner surface be included in the computation. The simulation results of the periodic flow patterns possess the proper features of the convective instability over the liner, as observed in Marx et al.'s experiment. A quantitative comparison between numerical and experimental results of amplitude and phase of the instability is performed. The corresponding eigenvalues achieve great agreement.

  11. 49 CFR 192.485 - Remedial measures: Transmission lines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.485 Remedial measures: Transmission lines. (a) General corrosion. Each segment of transmission line with general corrosion and with a remaining wall thickness less than that required for...

  12. 49 CFR 192.485 - Remedial measures: Transmission lines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.485 Remedial measures: Transmission lines. (a) General corrosion. Each segment of transmission line with general corrosion and with a remaining wall thickness less than that required for...

  13. 49 CFR 192.485 - Remedial measures: Transmission lines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.485 Remedial measures: Transmission lines. (a) General corrosion. Each segment of transmission line with general corrosion and with a remaining wall thickness less than that required for...

  14. 49 CFR 192.485 - Remedial measures: Transmission lines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.485 Remedial measures: Transmission lines. (a) General corrosion. Each segment of transmission line with general corrosion and with a remaining wall thickness less than that required for...

  15. Algorithm for predictive control implementation on fiber optic transmission lines

    NASA Astrophysics Data System (ADS)

    Andreev, Vladimir A.; Burdin, Vladimir A.; Voronkov, Andrey A.

    2014-04-01

    This paper presents the algorithm for predictive control implementation on fiber-optic transmission lines. In order to improve the maintenance of fiber optic communication lines, the algorithm prediction uptime optic communication cables have been worked out. It considers the results of scheduled preventive maintenance and database of various works on the track cable line during maintenance.

  16. Quantitative measurement of acoustic pressure in the focal zone of acoustic lens-line focusing using the Schlieren method.

    PubMed

    Jiang, Xueping; Cheng, Qian; Xu, Zheng; Qian, Menglu; Han, Qingbang

    2016-04-01

    This paper proposes a theory and method for quantitative measurement of the acoustic lens-line focusing ultrasonic (ALLFU) field in its focal spot size and acoustic pressure using the Schlieren imaging technique. Using Fourier transformation, the relationship between the brightness of the Schlieren image and the acoustic pressure was introduced. The ALLFU field was simulated using finite element method and compared with the Schlieren acoustic field image. The measurement of the focal spot size was performed using the Schlieren method. The acoustic pressure in the focal zone of the ALLFU field and the transducer-transmitting voltage response were quantitatively determined by measuring the diffraction light fringe intensity. The results show that the brightness of the Schlieren image is a linear function of the acoustic intensity when the acousto-optic interaction length remains constant and the acoustic field is weak. PMID:27139646

  17. Underwater asymmetric acoustic transmission structure using the medium with gradient change of impedance

    NASA Astrophysics Data System (ADS)

    Bo, Hu; Jie, Shi; Sheng-Guo, Shi; Yu, Sun; Zhong-Rui, Zhu

    2016-02-01

    We propose an underwater asymmetric acoustic transmission structure comprised of two media each with a gradient change of acoustic impedance. By gradually increasing the acoustic impedances of the media, the propagating direction of the acoustic wave can be continuously bent, resulting in allowing the acoustic wave to pass through along the positive direction and blocking acoustic waves from the negative one. The main advantages of this structure are that the asymmetric transmission effect of this structure can be realized and enhanced more easily in water. We investigate both numerically and experimentally the asymmetric transmission effect. The experimental results show that a highly efficient asymmetric acoustic transmission can be yielded within a remarkable broadband frequency range, which agrees well with the numerical prediction. It is of potential practical significance for various underwater applications such as reducing vibration and noise. Project supported by the National Natural Science Foundation of China (Grant Nos. 11204049 and 11204050), the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (Grant No. IRT1228), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant Nos. 20122304120023 and 20122304120011).

  18. Citizens, farmers fight huge transmission lines

    SciTech Connect

    Brummer, J.

    1982-02-01

    Opposition to high tension power lines with a 20-story towers is growing as coalitions of farmers and advocates of safe energy respond with legal intervention and sabotage, and sometimes with success. Examples of citizen action are the efforts opposing a 450 kilovolt direct current line connecting the US with Quebec Hydro and another opposing a 500 kilovolt alternating current line from Georgia Power Co.'s nuclear plants to Florida. The opposition derives partly from evidence of health hazards to humans and adverse effects on livestock. High voltage lines are felt to symbolize a utility and regulatory failure to assess the recent decline in power demand. It is stated that administration efforts to outlaw organized resistence will not deter the opposition, which cites instances of ground shock, aborted and stillborn cattle, physical irritants, and other phenomena. The General Assembly to Stop the Powerline (GASP) objects to the guinea pig position forced upon residents by the utilities. 6 references. (DCK)

  19. Performance robustness of a noise-assisted transmission line

    NASA Astrophysics Data System (ADS)

    Ibáñez, S. A.; Fierens, P. I.; Perazzo, R. P. J.; Grosz, D. F.

    2009-11-01

    In this paper we analyze the stochastic-resonant behavior of a chain of forward-coupled bistable overdamped oscillators used as a transmission line with possible applications to neurophysiology, information transmission and storage. We drive the line with a random sequence of non-return-to-zero bits and each oscillator is independently perturbed by noise. The line is analyzed for varying coupling strengths that lead to different regimes, ranging from noise-supported to coupling-supported transmission. We characterize the transmission performance by parameters such as output bit error rate and delivered signal-to-noise ratio, and show them to improve and remain flat for a broad range of noise intensities in all coupling regimes. In particular, we found that this system exhibits an enhanced robustness as compared to a linear transmission channel impaired only by additive noise.

  20. Single transmission line interrogated multiple channel data acquisition system

    DOEpatents

    Fasching, George E.; Keech, Jr., Thomas W.

    1980-01-01

    A single transmission line interrogated multiple channel data acquisition system is provided in which a plurality of remote station/sensor circuits each monitors a specific process variable and each transmits measurement values over a single transmission line to a master interrogating station when addressed by said master interrogating station. Typically, as many as 330 remote stations may be parallel connected to the transmission line which may exceed 7,000 feet. The interrogation rate is typically 330 stations/second. The master interrogating station samples each station according to a shared, charging transmit-receive cycle. All remote station address signals, all data signals from the remote stations/sensors and all power for all of the remote station/sensors are transmitted via a single continuous terminated coaxial cable. A means is provided for periodically and remotely calibrating all remote sensors for zero and span. A provision is available to remotely disconnect any selected sensor station from the main transmission line.

  1. 10. TRANSMISSION LINES BETWEEN DIABLO AND GORGE; CONSTRUCTION DETAIL OF ...

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

    10. TRANSMISSION LINES BETWEEN DIABLO AND GORGE; CONSTRUCTION DETAIL OF TOWER STRUCTURE, 1989. - Skagit Power Development, Gorge High Dam, On Skagit River, 2.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  2. Electrical and Biological Effects of Transmission Lines: A Review.

    SciTech Connect

    Lee, Jack M.

    1989-06-01

    This review describes the electrical properties of a-c and d-c transmission lines and the resulting effects on plants, animals, and people. Methods used by BPA to mitigate undesirable effects are also discussed. Although much of the information in this review pertains to high-voltage transmission lines, information on distribution lines and electrical appliances is included. The electrical properties discussed are electric and magnetic fields and corona: first for alternating-current (a-c) lines, then for direct current (d-c).

  3. Comparison of Computational Aeroacoustics Prediction of Acoustic Transmission Through a 3D Stator with Experiment

    NASA Technical Reports Server (NTRS)

    Hixon, Ray; Envia, Edmane; Dahl, Milo; Sutliff, Daniel

    2014-01-01

    In this paper, numerical predictions of acoustic transmission through a 3D stator obtained using the NASA BASS code are compared with experimentally measured data. The influence of vane count and stagger as well as frequency and mode order on the transmission loss is investigated. The data-theory comparisons indicate that BASS can predict all the important trends observed in the experimental data.

  4. Comparison of Computational Aeroacoustics Prediction of Acoustic Transmission Through a 3D Stator With Experiment

    NASA Technical Reports Server (NTRS)

    Hixon, Ray; Envia, Edmane; Dahl, Milo; Sutliff, Daniel L.

    2014-01-01

    In this paper, numerical predictions of acoustic transmission through a 3D stator obtained using the NASA BASS code are compared with experimentally measured data. The influence of vane count and stagger as well as frequency and mode order on the transmission loss is investigated. The data-theory comparisons indicate that BASS can predict all the important trends observed in the experimental data.

  5. Acoustic transmission through a 2-D orthotropic multi-layered infinite cylindrical shell

    NASA Astrophysics Data System (ADS)

    Blaise, A.; Lesueur, C.

    1992-05-01

    An investigation is presented of the transmission loss of two-dimensional orthotropic multilayered infinite cylindrical shells. Equations of motion are established by using a variational displacement formulation; these equations remain unchanged in form whatever the number of layers. Numerical results are presented illustrating the influence of acoustic and structural parameters on the transmission loss.

  6. Gas insulated transmission line having tapered particle trapping ring

    DOEpatents

    Cookson, Alan H.

    1982-01-01

    A gas-insulated transmission line includes an outer sheath, an inner conductor, insulating supports and an insulating gas. A particle-trapping ring is secured to each insulating support, and it is comprised of a central portion and two tapered end portions. The ends of the particle trapping ring have a smaller diameter than the central portion of the ring, so as to enable the use of the particle trapping ring in a curved transmission line.

  7. Corrugated outer sheath gas-insulated transmission line

    DOEpatents

    Kemeny, George A.; Cookson, Alan H.

    1981-01-01

    A gas-insulated transmission line includes two transmission line sections each of which are formed of a corrugated outer housing enclosing an inner high-voltage conductor disposed therein, with insulating support means supporting the inner conductor within the outer housing and an insulating gas providing electrical insulation therebetween. The outer housings in each section have smooth end sections at the longitudinal ends thereof which are joined together by joining means which provide for a sealing fixed joint.

  8. Multimode circuit quantum electrodynamics with hybrid metamaterial transmission lines.

    PubMed

    Egger, D J; Wilhelm, F K

    2013-10-18

    Quantum transmission lines are central to superconducting and hybrid quantum computing. In this work we show how coupling them to a left-handed transmission line allows circuit QED to reach a new regime: multimode ultrastrong coupling. Out of the many potential applications of this novel device, we discuss the preparation of multipartite entangled states and the simulation of the spin-boson model where a quantum phase transition is reached up to finite size effects.

  9. High aspect ratio transmission line circuits micromachined in silicon

    NASA Astrophysics Data System (ADS)

    Todd, Shane Truman

    The performance of complimentary metal-oxide-semiconductor (CMOS) monolithic microwave integrated circuits (MMICs) fabricated on silicon has improved dramatically. The scaling down of silicon transistors has increased the maximum frequency of transistors to the point where silicon MMICs have become a viable alternative to compound semiconductor MMICs in certain applications. A fundamental problem still exists in silicon MMICs however in that transmission lines fabricated on silicon can suffer from high loss due to the finite conductivity of the silicon substrate. A novel approach for creating low-loss transmission lines on silicon is presented in this work. Low-loss transmission lines are created on low resistivity silicon by using a micromachining method that combines silicon deep reactive ion etching (DRIE), thermal oxidation, electroplating, and planarization. Two types of high aspect ratio transmission lines are created with this method including high aspect ratio coplanar waveguide (hicoplanar) and semi-rectangular coaxial (semicoaxial). Transmission lines with impedances ranging from 20--80 O have been fabricated with minimum measured loss lower than 1 dB/cm at 67 GHz. Low-loss dielectrics are created for the high aspect ratio transmission lines using the mesa merging method. The mesa merging method works by creating silicon mesa arrays using DRIE and then converting and merging the mesa arrays into a solid oxide dielectric using thermal oxidation. The transmission lines are designed so that the fields penetrate the low-loss oxide dielectric and are isolated from the lossy silicon substrate. The mesa merging method has successfully created large volume oxide with depth up to 65 microm and width up to 240 microm in short oxidation times. Other advantages of the high aspect ratio transmission lines are demonstrated including low-loss over a wide impedance range, high isolation, and high coupling for coupled-line circuits. Transmission line models have been

  10. Multi-band asymmetric acoustic transmission in a bended waveguide with multiple mechanisms

    NASA Astrophysics Data System (ADS)

    Huang, Yu-lei; Sun, Hong-xiang; Xia, Jian-ping; Yuan, Shou-qi; Ding, Xin-lei

    2016-07-01

    We report the realization of a multi-band device of the asymmetric acoustic transmission by placing a phononic crystal inside a bended waveguide immersed in water, as determined both experimentally and numerically. The asymmetric acoustic transmission exists in three frequency bands below 500 kHz induced by multiple mechanisms. Besides the band gap of the phononic crystal, we also introduce the deaf mode and interaction between the phononic crystal and waveguide. More importantly, this asymmetric transmission can be systematically controlled by mechanically rotating the square rods of the phononic crystal. The device has the advantages of multiple band, broader bandwidth, and adjustable property, showing promising applications in ultrasonic devices.

  11. Five Mass Power Transmission Line of a Ship Computer Modelling

    NASA Astrophysics Data System (ADS)

    Kazakoff, Alexander Borisoff; Marinov, Boycho Ivanov

    2016-03-01

    The work, presented in this paper, appears to be a natural continuation of the work presented and reported before, on the design of power transmission line of a ship, but with different multi-mass model. Some data from the previous investigations are used as a reference data, mainly from the analytical investigations, for the developed in the previ- ous study, frequency and modal analysis of a five mass model of a power transmission line of a ship. In the paper, a profound dynamic analysis of a concrete five mass dynamic model of the power transmission line of a ship is performed using Finite Element Analysis (FEA), based on the previously recommended model, investigated in the previous research and reported before. Thus, the partially validated by frequency analysis five mass model of a power transmission line of a ship is subjected to dynamic analysis. The objective of the work presented in this paper is dynamic modelling of a five mass transmission line of a ship, partial validation of the model and von Mises stress analysis calculation with the help of Finite Element Analysis (FEA) and comparison of the derived results with the analytically calculated values. The partially validated five mass power transmission line of a ship can be used for definition of many dy- namic parameters, particularly amplitude of displacement, velocity and acceleration, respectively in time and frequency domain. The frequency behaviour of the model parameters is investigated in frequency domain and it corresponds to the predicted one.

  12. A Generalized Lossy Transmission-Line Model for Tunable Graphene-Based Transmission Lines with Attenuation Phenomenon

    PubMed Central

    Wu, Yongle; Qu, Meijun; Liu, Yuanan

    2016-01-01

    To investigate the frequency shift phenomenon by inserting graphene, a generalized lossy transmission-line model and the related electrical parameter-extraction theory are proposed in this paper. Three kinds of graphene-based transmission lines with attenuation phenomenon including microstrip line, double-side parallel strip line, and uniplanar coplanar waveguide are analyzed under the common conditions where different chemical potentials are loaded on graphene. The values of attenuation constant and phase constant, and the real and imaginary parts of the characteristic impedance of transmission lines are extracted to analyze in details. When the attenuation constant and the reactance part of the characteristic impedance are approximately equal to zero, this kind of transmission line has low or zero insertion loss. On the contrary, the transmission line is under the radiation mode with obvious insertion loss. The phase constant changes linearly under the transmission mode and can be varied with changing of chemical potentials which attributes to the property of frequency tunability. Furthermore, a bandwidth reconfigurable uniplanar coplanar waveguide power divider is simulated to demonstrate that this theory can be applied to the design of three-port devices. In summary, this work provides a strong potential approach and design theory to help design other kinds of terahertz and mid-infrared reconfigurable devices. PMID:27553759

  13. A Generalized Lossy Transmission-Line Model for Tunable Graphene-Based Transmission Lines with Attenuation Phenomenon.

    PubMed

    Wu, Yongle; Qu, Meijun; Liu, Yuanan

    2016-01-01

    To investigate the frequency shift phenomenon by inserting graphene, a generalized lossy transmission-line model and the related electrical parameter-extraction theory are proposed in this paper. Three kinds of graphene-based transmission lines with attenuation phenomenon including microstrip line, double-side parallel strip line, and uniplanar coplanar waveguide are analyzed under the common conditions where different chemical potentials are loaded on graphene. The values of attenuation constant and phase constant, and the real and imaginary parts of the characteristic impedance of transmission lines are extracted to analyze in details. When the attenuation constant and the reactance part of the characteristic impedance are approximately equal to zero, this kind of transmission line has low or zero insertion loss. On the contrary, the transmission line is under the radiation mode with obvious insertion loss. The phase constant changes linearly under the transmission mode and can be varied with changing of chemical potentials which attributes to the property of frequency tunability. Furthermore, a bandwidth reconfigurable uniplanar coplanar waveguide power divider is simulated to demonstrate that this theory can be applied to the design of three-port devices. In summary, this work provides a strong potential approach and design theory to help design other kinds of terahertz and mid-infrared reconfigurable devices. PMID:27553759

  14. A Generalized Lossy Transmission-Line Model for Tunable Graphene-Based Transmission Lines with Attenuation Phenomenon

    NASA Astrophysics Data System (ADS)

    Wu, Yongle; Qu, Meijun; Liu, Yuanan

    2016-08-01

    To investigate the frequency shift phenomenon by inserting graphene, a generalized lossy transmission-line model and the related electrical parameter-extraction theory are proposed in this paper. Three kinds of graphene-based transmission lines with attenuation phenomenon including microstrip line, double-side parallel strip line, and uniplanar coplanar waveguide are analyzed under the common conditions where different chemical potentials are loaded on graphene. The values of attenuation constant and phase constant, and the real and imaginary parts of the characteristic impedance of transmission lines are extracted to analyze in details. When the attenuation constant and the reactance part of the characteristic impedance are approximately equal to zero, this kind of transmission line has low or zero insertion loss. On the contrary, the transmission line is under the radiation mode with obvious insertion loss. The phase constant changes linearly under the transmission mode and can be varied with changing of chemical potentials which attributes to the property of frequency tunability. Furthermore, a bandwidth reconfigurable uniplanar coplanar waveguide power divider is simulated to demonstrate that this theory can be applied to the design of three-port devices. In summary, this work provides a strong potential approach and design theory to help design other kinds of terahertz and mid-infrared reconfigurable devices.

  15. Engineering the electrical characteristics of resonant type metamaterial transmission lines

    NASA Astrophysics Data System (ADS)

    Martin, F.; Bonache, J.; Gil, M.; Sisó, G.

    2008-04-01

    This paper is focused on the control of the electrical characteristics of resonant type metamaterial transmission lines, that is, transmission lines loaded with complementary split ring resonators (CSRRs). The key parameters of metamaterial transmission lines for microwave and millimetre wave circuit design are the characteristic impedance and the phase constant (rather than the effective magnetic permeability or dielectric permittivity). Thanks to the presence of reactive elements loading the host line, metamaterial transmission lines exhibit a major design flexibility that can be useful for circuit design purposes. Specifically, we can tailor the dispersion diagram and the characteristic impedance to some extent. By virtue of this, it is possible the design of microwave and millimetre wave components with superior performance in terms of bandwidth, or the design of multi-band components, both of interest in modern wireless communication systems. Thanks to the small electrical size of the unit cell of such lines, the resulting metamaterial-based components are also very small and fully compatible with planar technology (that is, no lumped elements are used). Different examples are provided to illustrate the possibilities of resonant type metamaterial transmission lines. This includes hybrid couplers, power dividers and phase shifters, among others. The paper includes also the theoretical foundations of the approach.

  16. Stand-off transmission lines and method for making same

    DOEpatents

    Tuckerman, D.B.

    1991-05-21

    Standoff transmission lines in an integrated circuit structure are formed by etching away or removing the portion of the dielectric layer separating the microstrip metal lines and the ground plane from the regions that are not under the lines. The microstrip lines can be fabricated by a subtractive process of etching a metal layer, an additive process of direct laser writing fine lines followed by plating up the lines or a subtractive/additive process in which a trench is etched over a nucleation layer and the wire is electrolytically deposited. Microstrip lines supported on freestanding posts of dielectric material surrounded by air gaps are produced. The average dielectric constant between the lines and ground plane is reduced, resulting in higher characteristic impedance, less crosstalk between lines, increased signal propagation velocities, and reduced wafer stress. 16 figures.

  17. Stand-off transmission lines and method for making same

    DOEpatents

    Tuckerman, David B.

    1991-01-01

    Standoff transmission lines in an integrated circuit structure are formed by etching away or removing the portion of the dielectric layer separating the microstrip metal lines and the ground plane from the regions that are not under the lines. The microstrip lines can be fabricated by a subtractive process of etching a metal layer, an additive process of direct laser writing fine lines followed by plating up the lines or a subtractive/additive process in which a trench is etched over a nucleation layer and the wire is electrolytically deposited. Microstrip lines supported on freestanding posts of dielectric material surrounded by air gaps are produced. The average dielectric constant between the lines and ground plane is reduced, resulting in higher characteristic impedance, less crosstalk between lines, increased signal propagation velocities, and reduced wafer stress.

  18. Transmission line inversion and synthesis from the point of view of transient response

    NASA Technical Reports Server (NTRS)

    Sondhi, M. M.

    1972-01-01

    The transmission line inversion problem is applied to the speech communication process. The problem involves acquiring information necessary for synthesis of speech and for making models of the speech production mechanism. Formulation for the problem is derived from an analysis of the human vocal tract functions. It is known that speech sounds are produced by acoustic excitation of the tract by means of quasi-periodic pulses from the vocal cords during vowel sounds and turbulent air flow at various points along the tract during fricative sounds. By assuming plane wave propagation, differential equations are obtained relating the cross sectional area of the tract, the pressure, and the volume velocity. By replacing the pressure factor with a voltage factor and the volume velocity by current, the problem becomes a transmission line problem.

  19. NOVEL SIGNAL PROCESSING WITH NONLINEAR TRANSMISSION LINES

    SciTech Connect

    D. REAGOR; ET AL

    2000-08-01

    Nonlinear dielectrics offer uniquely strong and tunable nonlinearities that make them attractive for current devices (for example, frequency-agile microwave filters) and for future signal-processing technologies. The goal of this project is to understand pulse propagation on nonlinear coplanar waveguide prototype devices. We have performed time-domain and frequency-domain experimental studies of simple waveguide structures and pursued a theoretical understanding of the propagation of signals on these nonlinear waveguides. To realistically assess the potential applications, we used a time-domain measurement and analysis technique developed during this project to perform a broadband electrodynamics characterization in terms of nonlinear, dispersive, and dissipative effects. We completed a comprehensive study of coplanar waveguides made from high-temperature superconducting thin-film YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} electrodes on nonlinear dielectric single-crystal SrTiO{sub 3} substrates. By using parameters determined from small-signal (linear) transmission characteristics of the waveguides, we develop a model equation that successfully predicts and describes large-signal (nonlinear) behavior.

  20. Direct measurement of transmission loss of aircraft structures using the acoustic intensity approach

    NASA Technical Reports Server (NTRS)

    Wang, Y. S.; Crocker, M. J.

    1982-01-01

    A measurement technique is developed in order to obtain the sound transmission loss of an aircraft fuselage which obviates the need for the two-room transmission suite. The sound transmission paths were determined in tests on a light aircraft fuselage using a two-microphone acoustic intensity method for measuring the acoustic intensity transmitted to the interior when the fuselage was exposed to an external random incidence sound-field. The intensity transmitted through different sections of the fuselage can be estimated accurately using this new technique. Results of these tests show that the plexiglass window is the major transmission path in the high frequency range. In addition, the transmission losses through a single and a double layer window were predicted theoretically by using the Statistical Energy Analysis Model. Very good agreement is found between the predictions and the measurements.

  1. Transmission line icing prediction based on DWT feature extraction

    NASA Astrophysics Data System (ADS)

    Ma, T. N.; Niu, D. X.; Huang, Y. L.

    2016-08-01

    Transmission line icing prediction is the premise of ensuring the safe operation of the network as well as the very important basis for the prevention of freezing disasters. In order to improve the prediction accuracy of icing, a transmission line icing prediction model based on discrete wavelet transform (DWT) feature extraction was built. In this method, a group of high and low frequency signals were obtained by DWT decomposition, and were fitted and predicted by using partial least squares regression model (PLS) and wavelet least square support vector model (w-LSSVM). Finally, the final result of the icing prediction was obtained by adding the predicted values of the high and low frequency signals. The results showed that the method is effective and feasible in the prediction of transmission line icing.

  2. Quasi-Optical Transmission Line for 94-GHz Radar

    NASA Technical Reports Server (NTRS)

    Perez, Raul M.; Veruttipong, Watt

    2008-01-01

    A quasi-optical transmission line (QOTL) has been developed as a low-loss transmission line for a spaceborne cloudobserving radar instrument that operates at a nominal frequency of 94 GHz. This QOTL could also readily be redesigned for use in terrestrial millimeter-wave radar systems and millimeter-wave imaging systems. In the absence of this or another lowloss transmission line, it would be necessary to use a waveguide transmission line in the original radar application. Unfortunately, transmission losses increase and power-handling capacities of waveguides generally decrease with frequency, such that at 94 GHz, the limitation on transmitting power and the combined transmission and reception losses (greater than 5 dB) in a waveguide transmission line previously considered for the original application would be unacceptable. The QOTL functions as a very-lowloss, three-port circulator. The QOTL includes a shaped input mirror that can be rotated to accept 94-GHz transmitter power from either of two high-power amplifiers. Inside the QOTL, the transmitter power takes the form of a linearly polarized beam radiated from a feed horn. This beam propagates through a system of mirrors, each of which refocuses the beam to minimize diffraction losses. A magnetically biased ferrite disc is placed at one of the foci to utilize the Faraday effect to rotate the polarization of the beam by 45 degrees. The beam is then transmitted via an antenna system. The radar return (scatter from clouds, and/or reflections from other objects) is collected by the same antenna and propagates through the Faraday rotator in the reverse of the direction of propagation of the transmitted beam. In the Faraday rotator, the polarization of the received signal is rotated a further 45 degrees, so that upon emerging from the Faraday rotator, the received beam is polarized at 90 with respect to the transmitted beam. The transmitted and received signals are then separated by a wire-grid polarizer.

  3. Call transmission efficiency in native and invasive anurans: competing hypotheses of divergence in acoustic signals.

    PubMed

    Llusia, Diego; Gómez, Miguel; Penna, Mario; Márquez, Rafael

    2013-01-01

    Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. Here we compare for the first time the transmission efficiency of the advertisement calls of native and invasive species, searching for competitive advantages for acoustic communication and reproduction of introduced taxa, and providing insights into competing hypotheses in evolutionary divergence of acoustic signals: acoustic adaptation vs. morphological constraints. Using sound propagation experiments, we measured the attenuation rates of pure tones (0.2-5 kHz) and playback calls (Lithobates catesbeianus and Pelophylax perezi) across four distances (1, 2, 4, and 8 m) and over two substrates (water and soil) in seven Iberian localities. All factors considered (signal type, distance, substrate, and locality) affected transmission efficiency of acoustic signals, which was maximized with lower frequency sounds, shorter distances, and over water surface. Despite being broadcast in nonindigenous habitats, the advertisement calls of invasive L. catesbeianus were propagated more efficiently than those of the native species, in both aquatic and terrestrial substrates, and in most of the study sites. This implies absence of optimal relationship between native environments and propagation of acoustic signals in anurans, in contrast to what predicted by the acoustic adaptation hypothesis, and it might render these vertebrates particularly vulnerable to intrusion of invasive species producing low frequency signals, such as L. catesbeianus. Our findings suggest that mechanisms optimizing sound transmission in native habitat can play a less

  4. Noise transmission from a curved panel into a cylindrical enclosure: analysis of structural acoustic coupling.

    PubMed

    Henry, J K; Clark, R L

    2001-04-01

    Much of the research on sound transmission through the aircraft fuselage into the interior of aircraft has considered coupling of the entire cylinder to the acoustic modes of the enclosure. Yet, much of the work on structural acoustic control of sound radiation has focused on reducing sound radiation from individual panels into an acoustic space. Research by the authors seeks to bridge this gap by considering the transmission of sound from individual panels on the fuselage to the interior of the aircraft. As part of this research, an analytical model of a curved panel, with attached piezoelectric actuators, subjected to a static pressure load was previously developed. In the present work, the analytical model is extended to consider the coupling of a curved panel to the interior acoustics of a rigid-walled cylinder. Insight gained from an accurate analytical model of the dynamics of the noise transmission from the curved panels of the fuselage into the cylindrical enclosure of an aircraft is essential to the development of feedback control systems for the control of stochastic inputs, such as turbulent boundary layer excitation. The criteria for maximal structural acoustic coupling between the modes of the curved panel and the modes of the cylindrical enclosure are studied. For panels with aspect ratios typical of those found in aircraft, results indicate that predominately axial structural modes couple most efficiently to the acoustic modes of the enclosure. The effects of the position of the curved panel on the cylinder are also studied. Structural acoustic coupling is found to not be significantly affected by varying panel position. The impact of the findings of this study on structural acoustic control design is discussed. PMID:11325117

  5. Call Transmission Efficiency in Native and Invasive Anurans: Competing Hypotheses of Divergence in Acoustic Signals

    PubMed Central

    Llusia, Diego; Gómez, Miguel; Penna, Mario; Márquez, Rafael

    2013-01-01

    Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. Here we compare for the first time the transmission efficiency of the advertisement calls of native and invasive species, searching for competitive advantages for acoustic communication and reproduction of introduced taxa, and providing insights into competing hypotheses in evolutionary divergence of acoustic signals: acoustic adaptation vs. morphological constraints. Using sound propagation experiments, we measured the attenuation rates of pure tones (0.2–5 kHz) and playback calls (Lithobates catesbeianus and Pelophylax perezi) across four distances (1, 2, 4, and 8 m) and over two substrates (water and soil) in seven Iberian localities. All factors considered (signal type, distance, substrate, and locality) affected transmission efficiency of acoustic signals, which was maximized with lower frequency sounds, shorter distances, and over water surface. Despite being broadcast in nonindigenous habitats, the advertisement calls of invasive L. catesbeianus were propagated more efficiently than those of the native species, in both aquatic and terrestrial substrates, and in most of the study sites. This implies absence of optimal relationship between native environments and propagation of acoustic signals in anurans, in contrast to what predicted by the acoustic adaptation hypothesis, and it might render these vertebrates particularly vulnerable to intrusion of invasive species producing low frequency signals, such as L. catesbeianus. Our findings suggest that mechanisms optimizing sound transmission in native habitat can play a

  6. On the selection of transmission range in underwater acoustic sensor networks.

    PubMed

    Gao, Mingsheng; Foh, Chuan Heng; Cai, Jianfei

    2012-01-01

    Transmission range plays an important role in the deployment of a practical underwater acoustic sensor network (UWSN), where sensor nodes equipping with only basic functions are deployed at random locations with no particular geometrical arrangements. The selection of the transmission range directly influences the energy efficiency and the network connectivity of such a random network. In this paper, we seek analytical modeling to investigate the tradeoff between the energy efficiency and the network connectivity through the selection of the transmission range. Our formulation offers a design guideline for energy-efficient packet transmission operation given a certain network connectivity requirement.

  7. Conductor design for the VLHC transmission line magnet

    SciTech Connect

    Foster, G.W.; Kashikhin, V.; McAshan, M.; Mazur, P.O.; Piekarz, H.; Volk, J.T.; Walker, R.

    1999-03-01

    The transmission line magnet [1] is under development for the Very Large Hadron Collider (VLHC) at Fermilab with the expectation that it’s cost will be several times less (per Tesla-meter) than conventional superconducting magnets. It is a dual-aperture warm-iron superferric magnet built around an 80kA superconducting transmission line. The superconductor consists of 8 Rutherford (SSC Outer) cables in an Invar pipe jacket. The conductor design requirements and development program is described. A 100kA conductor test facility based on inductive coupling is described.

  8. Gates to Gregg High Voltage Transmission Line Study. [California

    NASA Technical Reports Server (NTRS)

    Bergis, V.; Maw, K.; Newland, W.; Sinnott, D.; Thornbury, G.; Easterwood, P.; Bonderud, J.

    1982-01-01

    The usefulness of LANDSAT data in the planning of transmission line routes was assessed. LANDSAT digital data and image processing techniques, specifically a multi-date supervised classification aproach, were used to develop a land cover map for an agricultural area near Fresno, California. Twenty-six land cover classes were identified, of which twenty classes were agricultural crops. High classification accuracies (greater than 80%) were attained for several classes, including cotton, grain, and vineyards. The primary products generated were 1:24,000, 1:100,000 and 1:250,000 scale maps of the classification and acreage summaries for all land cover classes within four alternate transmission line routes.

  9. Self-monitoring high voltage transmission line suspension insulator

    DOEpatents

    Stemler, Gary E.; Scott, Donald N.

    1981-01-01

    A high voltage transmission line suspension insulator (18 or 22) which monitors its own dielectric integrity. A dielectric rod (10) has one larger diameter end fitting attachable to a transmission line and another larger diameter end fitting attachable to a support tower. The rod is enclosed in a dielectric tube (14) which is hermetically sealed to the rod's end fittings such that a liquidtight space (20) is formed between the rod and the tube. A pressurized dielectric liquid is placed within that space. A discoloring dye placed within this space is used to detect the loss of the pressurized liquid.

  10. Reconfigurable Wave Velocity Transmission Lines for Phased Arrays

    NASA Technical Reports Server (NTRS)

    Host, Nick; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix

    2013-01-01

    Phased array antennas showcase many advantages over mechanically steered systems. However, they are also more complex, heavy and most importantly costly. This presentation paper presents a concept which overcomes these detrimental attributes by eliminating all of the phase array backend (including phase shifters). Instead, a wave velocity reconfigurable transmission line is used in a series fed array arrangement to allow phase shifting with one small (100mil) mechanical motion. Different configurations of the reconfigurable wave velocity transmission line are discussed and simulated and experimental results are presented.

  11. Investigation of Transmission Line Models for Switching Overvoltages Studies

    NASA Astrophysics Data System (ADS)

    Sadeghkhani, Iman; Ketabi, Abbas; Feuillet, Rene

    2013-06-01

    Overvoltages caused by switching operation of power system equipments might damage some equipment and delay power system restoration. This paper presents a comparison between transmission line (TL) models for overvoltages study and investigates which TL model is most proper for every case study. Both simulation time and accuracy factors of TL models are considered for selecting best TL model. Various cases of switching of transformer, shunt reactor, capacitor bank, and transmission line are investigated and simulation results for a partial of 39-bus New England test system, show that the proposed TL model evaluation increase accuracy and reduce simulation time (accelerate power system restoration) properly.

  12. Effects of electromagnetic fields produced by high voltage transmission lines

    NASA Astrophysics Data System (ADS)

    Young, T.

    1984-06-01

    The potential impacts of higher transmission line voltages on people, animals, and plants were determined. The differences among various studies are reviewed. Although there are some obvious dangers posed by transmission line operation, construction, and maintenance, most of these concerns are addressed by safety measures taken by utility companies. The indirect effects of power transission is reported. Three major categories of field effects are covered: (1) corona effects due to the electric field at the conductor's surface; (2) indirect coupling effects, arising from induced currents in nearby conducting objects; and (3) direct coupling effects, caused by induced currents in organisms.

  13. Role of superconductivity in superconducting transmission line resonator

    NASA Astrophysics Data System (ADS)

    Qin, Xiao-Ke

    2016-06-01

    In order to understand the role of superconductivity in superconducting transmission line resonator, we derive the mode equations using the macroscopic wavefunction of the Cooper pairs. We make an appropriate scaling to obtain the dimensionless form of equations and establish the validity of good conductor approximation under most circumstances. Quantization of superconducting transmission line resonator is realized by the black-box principle. We also briefly discuss that the deviation from good conductor behavior would result in the observable effects, such as the considerable decrease of phase velocity and the soliton.

  14. Simultaneous backward data transmission and power harvesting in an ultrasonic transcutaneous energy transfer link employing acoustically dependent electric impedance modulation.

    PubMed

    Ozeri, Shaul; Shmilovitz, Doron

    2014-09-01

    The advancement and miniaturization of body implanted medical devices pose several challenges to Ultrasonic Transcutaneous Energy Transfer (UTET), such as the need to reduce the size of the piezoelectric resonator, and the need to maximize the UTET link power-transfer efficiency. Accordingly, the same piezoelectric resonator that is used for energy harvesting at the body implant, may also be used for ultrasonic backward data transfer, for instance, through impedance modulation. This paper presents physical considerations and design guidelines of the body implanted transducer of a UTET link with impedance modulation for a backward data transfer. The acoustic matching design procedure was based on the 2×2 transfer matrix chain analysis, in addition to the Krimholtz Leedom and Matthaei KLM transmission line model. The UTET power transfer was carried out at a frequency of 765 kHz, continuous wave (CW) mode. The backward data transfer was attained by inserting a 9% load resistance variation around its matched value (550 Ohm), resulting in a 12% increase in the acoustic reflection coefficient. A backward data transmission rate of 1200 bits/s was experimentally demonstrated using amplitude shift keying, simultaneously with an acoustic power transfer of 20 mW to the implant. PMID:24861424

  15. Simultaneous backward data transmission and power harvesting in an ultrasonic transcutaneous energy transfer link employing acoustically dependent electric impedance modulation.

    PubMed

    Ozeri, Shaul; Shmilovitz, Doron

    2014-09-01

    The advancement and miniaturization of body implanted medical devices pose several challenges to Ultrasonic Transcutaneous Energy Transfer (UTET), such as the need to reduce the size of the piezoelectric resonator, and the need to maximize the UTET link power-transfer efficiency. Accordingly, the same piezoelectric resonator that is used for energy harvesting at the body implant, may also be used for ultrasonic backward data transfer, for instance, through impedance modulation. This paper presents physical considerations and design guidelines of the body implanted transducer of a UTET link with impedance modulation for a backward data transfer. The acoustic matching design procedure was based on the 2×2 transfer matrix chain analysis, in addition to the Krimholtz Leedom and Matthaei KLM transmission line model. The UTET power transfer was carried out at a frequency of 765 kHz, continuous wave (CW) mode. The backward data transfer was attained by inserting a 9% load resistance variation around its matched value (550 Ohm), resulting in a 12% increase in the acoustic reflection coefficient. A backward data transmission rate of 1200 bits/s was experimentally demonstrated using amplitude shift keying, simultaneously with an acoustic power transfer of 20 mW to the implant.

  16. Study of the cavity-magnon-polariton transmission line shape

    NASA Astrophysics Data System (ADS)

    Harder, Michael; Bai, LiHui; Match, Christophe; Sirker, Jesko; Hu, CanMing

    2016-11-01

    We experimentally and theoretically investigate the microwave transmission line shape of the cavity-magnon-polariton (CMP) created by inserting a low damping magnetic insulator into a high quality 3D microwave cavity. While fixed field measurements are found to have the expected Lorentzian characteristic, at fixed frequencies the field swept line shape is in general asymmetric. Such fixed frequency measurements demonstrate that microwave transmission can be used to access magnetic characteristics of the CMP, such as the field line width Δ H. By developing an effective oscillator model of the microwave transmission we show that these line shape features are general characteristics of harmonic coupling. At the same time, at the classical level the underlying physical mechanism of the CMP is electrodynamic phase correlation and a second model based on this principle also accurately reproduces the experimental line shape features. In order to understand the microscopic origin of the effective coupled oscillator model and to allow for future studies of CMP phenomena to extend into the quantum regime, we develop a third, microscopic description, based on a Green's function formalism. Using this method we calculate the transmission spectra and find good agreement with the experimental results.

  17. Resonant transmission and mode modulation of acoustic waves in H-shaped metallic gratings

    SciTech Connect

    Deng, Yu-Qiang; Fan, Ren-Hao; Zhang, Kun; Peng, Ru-Wen E-mail: dongxiang87@gmail.com; Qi, Dong-Xiang E-mail: dongxiang87@gmail.com

    2015-04-15

    In this work, we demonstrate that resonant full transmission of acoustic waves exists in subwavelength H-shaped metallic gratings, and transmission peaks can be efficiently tuned by adjusting the grating geometry. We investigate this phenomenon through both numerical simulations and theoretical calculations based on rigorous-coupled wave analysis. The transmission peaks are originated from Fabry-Perot resonances together with the couplings between the diffractive wave on the surface and the multiple guided modes in the slits. Moreover, the transmission modes can be efficiently tuned by adjusting the cavity geometry, without changing the grating thickness. The mechanism is analyzed based on an equivalent circuit model and verified by both the theoretical calculations and the numerical simulations. This research has potential application in acoustic-device miniaturization over a wide range of wavelengths.

  18. Exploiting the leaky-wave properties of transmission-line metamaterials for single-microphone direction finding.

    PubMed

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

    2016-06-01

    A transmission-line acoustic metamaterial is an engineered, periodic arrangement of relatively small unit-cells, the acoustic properties of which can be manipulated to achieve anomalous physical behaviours. These exotic properties open the door to practical applications, such as an acoustic leaky-wave antenna, through the implementation of radiating channels along the metamaterial. In the transmitting mode, such a leaky-wave antenna is capable of steering sound waves in frequency-dependent directions. Used in reverse, the antenna presents a well defined direction-frequency behaviour. In this paper, an acoustic leaky-wave structure is presented in the receiving mode. It is shown that it behaves as a sound source direction-finding device using only one sensor. After a general introduction of the acoustic leaky-wave antenna concept, its radiation pattern and radiation efficiency are expressed in closed form. Then, numerical simulations and experimental assessments of the proposed transmission-line based structure, implementing only one sensor at one termination, are presented. It is shown that such a structure is capable of finding the direction of an incoming sound wave, from backward to forward, based on received sound power spectra. This introduces the concept of sound source localization without resorting to beam-steering techniques based on multiple sensors.

  19. Exploiting the leaky-wave properties of transmission-line metamaterials for single-microphone direction finding.

    PubMed

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

    2016-06-01

    A transmission-line acoustic metamaterial is an engineered, periodic arrangement of relatively small unit-cells, the acoustic properties of which can be manipulated to achieve anomalous physical behaviours. These exotic properties open the door to practical applications, such as an acoustic leaky-wave antenna, through the implementation of radiating channels along the metamaterial. In the transmitting mode, such a leaky-wave antenna is capable of steering sound waves in frequency-dependent directions. Used in reverse, the antenna presents a well defined direction-frequency behaviour. In this paper, an acoustic leaky-wave structure is presented in the receiving mode. It is shown that it behaves as a sound source direction-finding device using only one sensor. After a general introduction of the acoustic leaky-wave antenna concept, its radiation pattern and radiation efficiency are expressed in closed form. Then, numerical simulations and experimental assessments of the proposed transmission-line based structure, implementing only one sensor at one termination, are presented. It is shown that such a structure is capable of finding the direction of an incoming sound wave, from backward to forward, based on received sound power spectra. This introduces the concept of sound source localization without resorting to beam-steering techniques based on multiple sensors. PMID:27369150

  20. Analytical models for use in fan inflow control structure design. Inflow distortion and acoustic transmission models

    NASA Technical Reports Server (NTRS)

    Gedge, M. R.

    1979-01-01

    Analytical models were developed to study the effect of flow contraction and screening on inflow distortions to identify qualitative design criteria. Results of the study are that: (1) static testing distortions are due to atmospheric turbulence, nacelle boundary layer, exhaust flow reingestion, flow over stand, ground plane, and engine casing; (2) flow contraction suppresses, initially, turbulent axial velocity distortions and magnifies turbulent transverse velocity distortions; (3) perforated plate and gauze screens suppress axial components of velocity distortions to a degree determined by the screen pressure loss coefficient; (4) honeycomb screen suppress transverse components of velocity distortions to a degree determined by the length to diameter ratio of the honeycomb; (5) acoustic transmission loss of perforated plate is controlled by the reactance of its acoustic impedance; (6) acoustic transmission loss of honeycomb screens is negligible; and (7) a model for the direction change due to a corner between honeycomb panels compares favorably with measured data.

  1. 49 CFR 192.707 - Line markers for mains and transmission lines.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance... buried main and transmission line: (1) At each crossing of a public road and railroad; and (2)...

  2. Tunable broadband unidirectional acoustic transmission based on a waveguide with phononic crystal

    NASA Astrophysics Data System (ADS)

    Song, Ailing; Chen, Tianning; Wang, Xiaopeng; Wan, Lele

    2016-08-01

    In this paper, a tunable broadband unidirectional acoustic transmission (UAT) device composed of a bended tube and a superlattice with square columns is proposed and numerically investigated by using finite element method. The UAT is realized in the proposed UAT device within two wide frequency ranges. And the effectiveness of the UAT device is demonstrated by analyzing the sound pressure distributions when the acoustic waves are incident from different directions. The unidirectional band gaps can be effectively tuned by mechanically rotating the square columns, which is a highlight of this paper. Besides, a bidirectional acoustic isolation (BAI) device is obtained by placing two superlattices in the bended tube, in which the acoustic waves cannot propagate along any directions. The physical mechanisms of the proposed UAT device and BAI device are simply discussed. The proposed models show potential applications in some areas, such as unidirectional sonic barrier or noise insulation.

  3. Enhanced and reduced transmission of acoustic waves with bubble meta-screens

    NASA Astrophysics Data System (ADS)

    Bretagne, Alice; Tourin, Arnaud; Leroy, Valentin

    2011-11-01

    We present a class of sonic meta-screens for manipulating air-borne acoustic waves at ultrasonic or audible frequencies. Our screens consist of periodic arrangements of air bubbles in water or possibly embedded in a soft elastic matrix. They can be used for soundproofing but also for exalting transmission at an air/water interface or even to achieve enhanced absorption.

  4. Spin Start Line Effects on the J2X Gas Generator Chamber Acoustics

    NASA Technical Reports Server (NTRS)

    Kenny, R. Jeremy

    2011-01-01

    The J2X Gas Generator engine design has a spin start line connected near to the turbine inlet vanes. This line provides helium during engine startup to begin turbomachinery operation. The spin start line also acts as an acoustic side branch which alters the chamber's acoustic modes. The side branch effectively creates 'split modes' in the chamber longitudinal modes, in particular below the first longitudinal mode and within the frequency range associated with the injection-coupled response of the Gas Generator. Interaction between the spin start-modified chamber acoustics and the injection-driven response can create a higher system response than without the spin start attached to the chamber. This work reviews the acoustic effects of the spin start line as seen throughout the workhorse gas generator test program. A simple impedance model of the spin start line is reviewed. Tests were run with no initial spin start gas existing in the line, as well as being initially filled with nitrogen gas. Tests were also run with varying spin start line lengths from 0" to 40". Acoustic impedance changes due to different spin start gas constituents and line lengths are shown. Collected thermocouple and static pressure data in the spin start line was used to help estimate the fluid properties along the line length. The side branch impedance model was coupled to a chamber impedance model to show the effects on the overall chamber response. Predictions of the spin start acoustic behavior for helium operation are shown and compared against available data.

  5. Transmission Lines: An Overview of Electrical Properties and Environmental Effects.

    SciTech Connect

    United States. Bonneville Power Administration. Biological Studies Task Team.

    1982-03-01

    A brief overview is provided of environmental and biological effects of high-voltage power transmission lines. Paragraph length descriptions of electric fields, induced voltage and currents, biological effects, magnetic fields, corona, radio and television interference, and ozone are given. 13 figs.

  6. High voltage gas insulated transmission line with continuous particle trapping

    DOEpatents

    Cookson, Alan H.; Dale, Steinar J.

    1983-01-01

    This invention provides a novel high voltage gas insulated transmission line utilizing insulating supports spaced at intervals with snap-in means for supporting a continuous trapping apparatus and said trapping apparatus having perforations and cutouts to facilitate trapping of contaminating particles and system flexibility.

  7. 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.

  8. 77 FR 35366 - Albany-Eugene Transmission Line Rebuild Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... Administration (BPA), Department of Energy (DOE). ACTION: Notice of Availability of Record of Decision (ROD..., based on the Albany-Eugene Transmission Line Rebuild Project (DOE/EIS-0457, March 2012). BPA has decided... will continue to operate at 115 kV. ADDRESSES: Copies of the ROD and EIS may be obtained by calling...

  9. 34. DETAIL OF SIGNAL TRANSMISSION LINES AND CIRCUIT BREAKERS ON ...

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

    34. DETAIL OF SIGNAL TRANSMISSION LINES AND CIRCUIT BREAKERS ON TOP OF BRIDGE, CATENARY ANCHOR BRIDGE 524, NEAR SOUTHWALK SWITCH TOWER - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  10. Flow Impedance in a Uniform Magnetically-Insulated Transmission Line

    SciTech Connect

    Mendel, C.W.

    1999-03-23

    In two recent publications relativistic electron flow in cylindrical magnetically-insulated transmission lines (MITL) was analyzed and modeled under the assumption of negligible electron pressure. Cylindrical MITLs were used because of their common occurrence, and because they are the simplest case of finite width. The authors show in this report that the models apply equally to MITLs of any cross section.

  11. Integrated micromachined transmission lines and endfire slotline antennas

    NASA Astrophysics Data System (ADS)

    Gearhart, Steven S.; Willke, Theodore L.; Onggosanusi, Eko N.

    1997-09-01

    An entirely new class of micromachined 3D microwave and millimeter-wave integrated circuits and antennas are being developed at the University of Wisconsin-Madison using a subset o the LIGA micromachining process. The deep x-ray lithography and metal plating portions of the LIGA process are used to precisely form tall metal structures on semiconductor and dielectric substrates. This micromachining process allows metal height to be included as a parameter in the design of integrated circuits, which will permit several important advancements in high frequency waveguiding circuits and integrated antennas. With appropriate thick- metal cross-sectional geometry, transmission line losses and dispersion may both be reduced on a given substrate. Vertical-walled metal structures allow increased control over element-to-element coupling for integrated coupled-line filters and couplers and result in very significant reductions in ohmic loss. It will be demonstrated that the first single-level coupled-line 3dB coupler can be fabricated using the LIGA process. In addition, the mechanical properties of the thick metal structures will be utilized in the fabrication of integrated antennas and transmission lines that are unsupported by a dielectric substrate. The elimination of the substrate beneath antennas reduces losses to substrate modes, and the elimination o the substrate beneath transmission line filters is necessary for extremely high Q integrated filters. This paper will present simulated loss results that demonstrate the advantages of thick metal transmission lines, measured results of a coupled-line bandpass filter, and a recently fabricated thick-metal tapered slotline antenna which extends nearly a centimeter off of the edge of a GaAs wafer.

  12. Airplane Ice Detector Based on a Microwave Transmission Line

    NASA Technical Reports Server (NTRS)

    Ngo, Phong; Arndt, G. Dickey; Carl, James R.

    2004-01-01

    An electronic instrument that could detect the potentially dangerous buildup of ice on an airplane wing is undergoing development. The instrument is based on a microwave transmission line configured as a capacitance probe: at selected spots, the transmission-line conductors are partly exposed to allow any ice and/or liquid water present at those spots to act as predominantly capacitive electrical loads on the transmission line. These loads change the input impedance of the transmission line, as measured at a suitable excitation frequency. Thus, it should be possible to infer the presence of ice and/or liquid water from measurements of the input impedance and/or electrical parameters related to the input impedance. The sensory transmission line is of the microstrip type and thus thin enough to be placed on an airplane wing without unduly disturbing airflow in flight. The sensory spots are small areas from which the upper layer of the microstrip has been removed to allow any liquid water or ice on the surface to reach the transmission line. The sensory spots are spaced at nominal open-circuit points, which are at intervals of a half wavelength (in the transmission line, not in air) at the excitation frequency. The excitation frequency used in the experiments has been 1 GHz, for which a half wavelength in the transmission line is .4 in. (.10 cm). The figure depicts a laboratory prototype of the instrument. The impedance-related quantities chosen for use in this version of the instrument are the magnitude and phase of the scattering parameter S11 as manifested in the in-phase (I ) and quadrature (Q) outputs of the phase detector. By careful layout of the transmission line (including the half-wavelength sensor spacing), one can ensure that the amplitude and phase of the input to the phase detector keep shifting in the same direction as ice forms on one or more of the sensor areas. Although only one transmission-line sensor strip is used in the laboratory version, in a

  13. Asymmetric acoustic transmission through near-zero-index and gradient-index metasurfaces

    NASA Astrophysics Data System (ADS)

    Shen, Chen; Xie, Yangbo; Li, Junfei; Cummer, Steven A.; Jing, Yun

    2016-05-01

    We present a design of acoustic metasurfaces yielding asymmetric transmission within a certain frequency band. The design consists of a layer of gradient-index metasurface and a layer of low refractive index metasurface. Incident waves are controlled in a wave vector dependent manner to create strong asymmetric transmission. Numerical simulations show that the approach provides high transmission contrast between the two incident directions within the designed frequency band. This is further verified by experiments. Compared to previous designs, the proposed approach yields a compact and planar device. Our design may find applications in various scenarios such as noise control and therapeutic ultrasound.

  14. Asymmetric transmission of acoustic waves in a layer thickness distribution gradient structure using metamaterials

    NASA Astrophysics Data System (ADS)

    Chen, Jung-San; Chang, I.-Ling; Huang, Wan-Ting; Chen, Lien-Wen; Huang, Guan-Hua

    2016-09-01

    This research presents an innovative asymmetric transmission design using alternate layers of water and metamaterial with complex mass density. The directional transmission behavior of acoustic waves is observed numerically inside the composite structure with gradient layer thickness distribution and the rectifying performance of the present design is evaluated. The layer thickness distributions with arithmetic and geometric gradients are considered and the effect of gradient thickness on asymmetric wave propagation is systematically investigated using finite element simulation. The numerical results indicate that the maximum pressure density and transmission through the proposed structure are significantly influenced by the wave propagation direction over a wide range of audible frequencies. Tailoring the thickness of the layered structure enables the manipulation of asymmetric wave propagation within the desired frequency range. In conclusion, the proposed design offers a new possibility for developing directional-dependent acoustic devices.

  15. Acoustic transmission matrix of a variable area duct or nozzle carrying a compressible subsonic flow

    NASA Technical Reports Server (NTRS)

    Miles, J. H.

    1980-01-01

    The differential equations governing the propagation of sound in a variable area duct or nozzle carrying a one dimensional subsonic compressible fluid flow are derived and put in state variable form using acoustic pressure and particle velocity as the state variables. The duct or nozzle is divided into a number of regions. The region size is selected so that in each region the Mach number can be assumed constant and the area variation can be approximated by an exponential area variation. Consequently, the state variable equation in each region has constant coefficients. The transmission matrix for each region is obtained by solving the constant coefficient acoustic state variable differential equation. The transmission matrix for the duct or nozzle is the product of the individual transmission matrices of each region. Solutions are presented for several geometries with and without mean flow.

  16. Wireless Sensor Network for Electric Transmission Line Monitoring

    SciTech Connect

    Alphenaar, Bruce

    2009-06-30

    Generally, federal agencies tasked to oversee power grid reliability are dependent on data from grid infrastructure owners and operators in order to obtain a basic level of situational awareness. Since there are many owners and operators involved in the day-to-day functioning of the power grid, the task of accessing, aggregating and analyzing grid information from these sources is not a trivial one. Seemingly basic tasks such as synchronizing data timestamps between many different data providers and sources can be difficult as evidenced during the post-event analysis of the August 2003 blackout. In this project we investigate the efficacy and cost effectiveness of deploying a network of wireless power line monitoring devices as a method of independently monitoring key parts of the power grid as a complement to the data which is currently available to federal agencies from grid system operators. Such a network is modeled on proprietary power line monitoring technologies and networks invented, developed and deployed by Genscape, a Louisville, Kentucky based real-time energy information provider. Genscape measures transmission line power flow using measurements of electromagnetic fields under overhead high voltage transmission power lines in the United States and Europe. Opportunities for optimization of the commercial power line monitoring technology were investigated in this project to enable lower power consumption, lower cost and improvements to measurement methodologies. These optimizations were performed in order to better enable the use of wireless transmission line monitors in large network deployments (perhaps covering several thousand power lines) for federal situational awareness needs. Power consumption and cost reduction were addressed by developing a power line monitor using a low power, low cost wireless telemetry platform known as the ''Mote''. Motes were first developed as smart sensor nodes in wireless mesh networking applications. On such a platform

  17. Refinement and application of acoustic impulse technique to study nozzle transmission characteristics

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Brown, W. H.; Ramakrishnan, R.; Tanna, H. K.

    1983-01-01

    An improved acoustic impulse technique was developed and was used to study the transmission characteristics of duct/nozzle systems. To accomplish the above objective, various problems associated with the existing spark-discharge impulse technique were first studied. These included (1) the nonlinear behavior of high intensity pulses, (2) the contamination of the signal with flow noise, (3) low signal-to-noise ratio at high exhaust velocities, and (4) the inability to control or shape the signal generated by the source, specially when multiple spark points were used as the source. The first step to resolve these problems was the replacement of the spark-discharge source with electroacoustic driver(s). These included (1) synthesizing on acoustic impulse with acoustic driver(s) to control and shape the output signal, (2) time domain signal averaging to remove flow noise from the contaminated signal, (3) signal editing to remove unwanted portions of the time history, (4) spectral averaging, and (5) numerical smoothing. The acoustic power measurement technique was improved by taking multiple induct measurements and by a modal decomposition process to account for the contribution of higher order modes in the power computation. The improved acoustic impulse technique was then validated by comparing the results derived by an impedance tube method. The mechanism of acoustic power loss, that occurs when sound is transmitted through nozzle terminations, was investigated. Finally, the refined impulse technique was applied to obtain more accurate results for the acoustic transmission characteristics of a conical nozzle and a multi-lobe multi-tube supressor nozzle.

  18. Transmission capability of asymmetric digital subscriber lines in Taiwan

    NASA Astrophysics Data System (ADS)

    Wei, Shyue-Win; Leu, Shyue-Tzong; Wei, Che-Ho

    1995-04-01

    The transmission capacity of discrete multitone (DMT) modulation system for Taiwan's subscriber loops is evaluated in this study. Based on the characteristics of Taiwan's local loops, the transmission capacity is estimated to be 1.544 Mb/s and 6 Mb/s in Taiwan. Simulation results also show how many percents of users in Taiwan may have 1.544 Mb/s or 6 Mb/s of asymmetric digital subscriber lines (ADSL) services. Self far-end crosstalk (FEXT) and additive white Gaussian noise (AWGN) are considered to be the dominant noise sources in the work.

  19. Low-power digital communication with unterminated transmission lines

    NASA Astrophysics Data System (ADS)

    Cooperman, Michael; Sieber, Richard W.; Moolenbeek, Rob

    1988-06-01

    Conventional telecommunication techniques are optimized to communicate over long distances (greater than 1 mi), subject to high attenuation, high crosstalk, and other deteriorations in transmission. A trend in telecommunication system architectures is to disperse the previously centralized switching centers, thereby providing switching within a few hundred feet of the subscriber. This creates an opportunity for great improvements in cost and performance for short distance communication links. A technique for low-power digital communication over short transmission lines that exploits this possibility is described. The typical power is more than an order of magnitude lower than the power required with conventional circuits. Associated with this technique are a tenfold reduction in the chip area occupied by the transmission line drivers and the elimination of coupling transformers. The power and chip-area reductions result from terminating the line at the transmitter and maintaining an open circuit at the receiver. These advantages make this line-driving technique particularly suitable for single-chip VLSI systems.

  20. Progress in Acoustic Transmission of Power through Walls

    NASA Technical Reports Server (NTRS)

    Sherrit,Stewart; Coty, Benjamin; Bao, Xiaoqi; Bar-Cohen, Yoseph; Badescu, Mircea; Chang, Zensheu

    2008-01-01

    A document presents updated information on implementation of the wireless acoustic-electric feed-through (WAEF) concept, which was reported in Using Piezoelectric Devices To Transmit Power Through Walls (NPO-41157), NASA Tech Briefs, Vol. 32, No. 6 (June 2008), page 70. To recapitulate: In a basic WAEF setup, a transmitting piezoelectric transducer on one side of a wall is driven at resonance to excite ultrasonic vibrations in the wall. A receiving piezoelectric transducer on the opposite side of the wall converts the vibrations back to an ultrasonic AC electric signal, which is then detected and otherwise processed in a manner that depends on the modulation (if any) applied to the signal and whether the signal is used to transmit power, data, or both. The present document expands upon the previous information concerning underlying physical principles, advantages, and potential applications of WAEF. It discusses the design and construction of breadboard prototype piezoelectric transducers for WAEF. It goes on to present results of computational simulations of performance and results of laboratory tests of the prototypes. In one notable test, a 100-W light bulb was lit by WAEF to demonstrate the feasibility of powering a realistic load.

  1. Resonant coupling of Rayleigh waves through a narrow fluid channel causing extraordinary low acoustic transmission.

    PubMed

    Garcia-Chocano, Victor M; Nagaraj; Lòpez-Rios, Tomàs; Gumen, Lyudmila; Sànchez-Dehesa, Josè; Krokhin, Arkadii

    2012-10-01

    Coupling of Rayleigh waves propagating along two metal surfaces separated by a narrow fluid channel is predicted and experimentally observed. Although the coupling through a fluid (water) is weak, a strong synchronization in propagation of Rayleigh waves even for the metals with sufficiently high elastic contrast (brass and aluminum) is observed. Dispersion equation for two polarizations of the coupled Rayleigh waves is derived and experimentally confirmed. Excitation of coupled Rayleigh waves in a channel of finite length leads to anomalously low transmission of acoustic energy at discrete set of resonant frequencies. This effect may find useful applications in the design of acoustic metamaterial screens and reflectors.

  2. Coherent reflection from surface gravity water waves during reciprocal acoustic transmissions.

    PubMed

    Badiey, Mohsen; Song, Aijun; Smith, Kevin B

    2012-10-01

    During a recent experiment in Kauai, Hawaii, reciprocal transmissions were conducted between two acoustic transceivers mounted on the seafloor at a depth of 100 m. The passage of moving surface wave crests was shown to generate focused and intense coherent acoustic returns, which had increasing or decreasing delay depending on the direction of propagation relative to the direction of surface wave crests. It is shown that a rough surface two-dimensional parabolic equation model with an evolving sea surface can produce qualitative agreement with data for the dynamic surface returns.

  3. A comparison of digital subscriber line transmission systems employing different line codes

    NASA Astrophysics Data System (ADS)

    Brosio, A.; Dejulio, U.; Lazzari, V.; Ravaglia, R.; Tofanelli, A.

    1981-12-01

    The main characteristics and the performance of two systems implemented for two wire digital transmission on subscriber lines are presented. Both systems utilize different time intervals to transit bursts of bits in the two directions with an information bit rate of 80 kbit/s and a line bit rate in the bursts of 256 kbit/s. One system employing WAL2 as the line code, exhibits extreme circuitry simplicity and low power consumption. The other system, which employs CMI as the line code, shows better performance in the presence of line disturbances.

  4. Enhanced acoustic transmission into dissipative solid materials through the use of inhomogeneous plane waves

    NASA Astrophysics Data System (ADS)

    Woods, D. C.; Bolton, J. S.; Rhoads, J. F.

    2016-09-01

    A number of applications, for instance ultrasonic imaging and nondestructive testing, involve the transmission of acoustic energy across fluid-solid interfaces into dissipative solids. However, such transmission is generally hindered by the large impedance mismatch at the interface. In order to address this problem, inhomogeneous plane waves were investigated in this work for the purpose of improving the acoustic energy transmission. To this end, under the assumption of linear hysteretic damping, models for fluid-structure interaction were developed that allow for both homogeneous and inhomogeneous incident waves. For low-loss solids, the results reveal that, at the Rayleigh angle, a unique value of the wave inhomogeneity can be found which minimizes the reflection coefficient, and consequently maximizes the transmission. The results also reveal that with sufficient dissipation levels in the solid material, homogeneous incident waves yield lower reflection values than inhomogeneous waves, due to the large degrees of inhomogeneity inherent in the transmitted waves. Analytical conditions have also been derived which predict the dependence of the optimal incident wave type on the dissipation level and wave speeds in the solid medium. Finally, implications related to the use of acoustic beams of limited spatial extent are discussed.

  5. Recent Enhancements to the NASA Langley Structural Acoustics Loads and Transmission (SALT) Facility

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A.; Cabell, Randolph H.; Allen, Albert R.

    2013-01-01

    The Structural Acoustics Loads and Transmission (SALT) facility at the NASA Langley Research Center is comprised of an anechoic room and a reverberant room, and may act as a transmission loss suite when test articles are mounted in a window connecting the two rooms. In the latter configuration, the reverberant room acts as the noise source side and the anechoic room as the receiver side. The noise generation system used for qualification testing in the reverberant room was previously shown to achieve a maximum overall sound pressure level of 141 dB. This is considered to be marginally adequate for generating sound pressure levels typically required for launch vehicle payload qualification testing. Recent enhancements to the noise generation system increased the maximum overall sound pressure level to 154 dB, through the use of two airstream modulators coupled to 35 Hz and 160 Hz horns. This paper documents the acoustic performance of the enhanced noise generation system for a variety of relevant test spectra. Additionally, it demonstrates the capability of the SALT facility to conduct transmission loss and absorption testing in accordance with ASTM and ISO standards, respectively. A few examples of test capabilities are shown and include transmission loss testing of simple unstiffened and built up structures and measurement of the diffuse field absorption coefficient of a fibrous acoustic blanket.

  6. Sound transmission through triple-panel structures lined with poroelastic materials

    NASA Astrophysics Data System (ADS)

    Liu, Yu

    2015-03-01

    In this paper, previous theories on the prediction of sound transmission loss for a double-panel structure lined with poroelastic materials are extended to address the problem of a triple-panel structure. Six typical configurations are considered for a triple-panel structure based on the method of coupling the porous layers to the facing panels which determines critically the sound insulation performance of the system. The transfer matrix method is employed to solve the system by applying appropriate types of boundary conditions for these configurations. The transmission loss of the triple-panel structures in a diffuse sound field is calculated as a function of frequency and compared with that of corresponding double-panel structures. Generally, the triple-panel structure with poroelastic linings has superior acoustic performance to the double-panel counterpart, remarkably in the mid-high frequency range and possibly at low frequencies, by selecting appropriate configurations in which those with two air gaps in the structure exhibit the best overall performance over the entire frequency range. The poroelastic lining significantly lowers the cut-on frequency above which the triple-panel structure exhibits noticeably higher transmission loss. Compared with a double-panel structure, the wider range of system parameters for a triple-panel structure due to the additional partition provides more design space for tuning the sound insulation performance. Despite the increased structural complexity, the triple-panel structure lined with poroelastic materials has the obvious advantages in sound transmission loss while without the penalties in weight and volume, and is hence a promising replacement for the widely used double-panel sandwich structure.

  7. Tunable Transmission-Line Metamaterials Mimicking Electromagnetically Induced Transparency

    NASA Astrophysics Data System (ADS)

    Feng, T. H.; Han, H. P.

    2016-11-01

    Tunable transmission-line (TL) metamaterials mimicking electromagnetically induced transparency (EIT) have been studied. Firstly, two types of tunable TL EIT-like metamaterial, based on the double split-ring resonator (DSRR) and single split-ring resonator (SSRR), were fabricated and their transmission properties carefully compared. The results showed that the transmittance maximum was almost invariable with shift of the transparency window for the tunable DSRR-based TL EIT-like metamaterial, but for the tunable SSRR-based TL EIT-like metamaterial, the transmittance maximum gradually diminished with shift of the transparency window toward the center of the absorption band. Moreover, the reason for these different transmission properties was explored, revealing that the reduction of the transmittance maximum of the transparency window for the tunable SSRR-based TL EIT-like metamaterial is mainly due to energy loss caused by the resistance of the loaded varactor diodes.

  8. Tunable Transmission-Line Metamaterials Mimicking Electromagnetically Induced Transparency

    NASA Astrophysics Data System (ADS)

    Feng, T. H.; Han, H. P.

    2016-08-01

    Tunable transmission-line (TL) metamaterials mimicking electromagnetically induced transparency (EIT) have been studied. Firstly, two types of tunable TL EIT-like metamaterial, based on the double split-ring resonator (DSRR) and single split-ring resonator (SSRR), were fabricated and their transmission properties carefully compared. The results showed that the transmittance maximum was almost invariable with shift of the transparency window for the tunable DSRR-based TL EIT-like metamaterial, but for the tunable SSRR-based TL EIT-like metamaterial, the transmittance maximum gradually diminished with shift of the transparency window toward the center of the absorption band. Moreover, the reason for these different transmission properties was explored, revealing that the reduction of the transmittance maximum of the transparency window for the tunable SSRR-based TL EIT-like metamaterial is mainly due to energy loss caused by the resistance of the loaded varactor diodes.

  9. Beam coupling impedances of fast transmission-line kickers.

    SciTech Connect

    Kurennoy, S.

    2002-01-01

    Fast transmission-line kickers contain no ferrite and consist of two long metallic parallel plates supported by insulators inside a beam pipe. A beam is deflected by both the electric and magnetic fields of a TEM wave created by a pulse propagating along the strips in the direction opposite to the beam. Computations of the beam coupling impedances for such structures are difficult because of their length. In the paper, the beam coupling impedances of transmission-line kickers are calculated by combining analytical and numerical methods: the wake potentials computed in short models are extended analytically to obtain the wakes for the long kickers, and then the corresponding beam impedances are derived. At very low frequencies the results are compared with simple analytical expressions for the coupling impedances of striplines in beam position monitors.

  10. HTS DC Transmission Line for Megalopolis Grid Development

    NASA Astrophysics Data System (ADS)

    Kopylov, S.; Sytnikov, V.; Bemert, S.; Ivanov, Yu; Krivetskiy, I.; Romashov, M.; Shakaryan, Yu; Keilin, V.; Shikov, A.; Patrikeev, V.; Lobyntsev, V.; Shcherbakov, V.

    2014-05-01

    Using of HTS AC and DC cables in electric power grids allows increasing of the transferred power, losses diminishing, decreasing of exclusion zone areas, the enhancement of the environmental conditions and fire/explosion safety of electric power systems. However, the use of DC superconducting cable lines together with converters brings additional advantages as reduction of losses in cables and suitable lowering of refrigerating plant capacity, as well as the realization of the function of short-circuit currents limitation by means of the appropriate setting of converter equipment. Russian Federal Grid Company and its R&D Center started the construction of the DC HTS power transmission line which includes the cable itself, cryogenic equipment, AC/DC converters, terminals and cable coupling boxes. This line will connect two substations in Saint-Petersburg - 330 kV "Centralnaya" and 220 kV "RP-9". The length of this HTS transmission line will be about 2500 meters. Nowadays are developed all the elements of the line and technologies of the cable manufacturing. Two HTS cable samples, each 30 m length, have been made. This paper describes the results of cables tests.

  11. Reconfigurable Wave Velocity Transmission Lines for Phased Arrays

    NASA Technical Reports Server (NTRS)

    Host, Nicholas Keith; Chen, Chi-Chih; Volakis, John L.

    2012-01-01

    This presentation discussed a novel phased array with an emphasis to simplify the array feed. Specifically, we will demonstrate a simple, low cost feeding approach by mechanically controlling the substrate thickness. The array feed lines are constructed from parallel plate transmission lines whose thickness are adjusted to control their effective dielectric constant (Epsilon_eff). As a result the phase delay/excitation at each array element will be adjusted per desired beam direction. The proposed antenna elements will be overlapping dipoles operating over a 2:1 bandwidth in the Ku-Band spectrum. Preliminary simulation and experimental demonstration of such an array will be presented.

  12. Transmission Line for 258 GHz Gyrotron DNP Spectrometry

    NASA Astrophysics Data System (ADS)

    Bogdashov, Alexandr A.; Belousov, Vladimir I.; Chirkov, Alexey V.; Denisov, Gregory G.; Korchagin, Vyacheslav V.; Kornishin, Sergey Yu.; Tai, Evgeny M.

    2011-06-01

    We describe the design and test results of the transmission line for liquid-state (LS) and solid-state (SS) DNP spectrometers with the second-harmonic 258.6 GHz gyrotron at the Institute of the Biophysical Chemistry Center of Goethe University (Frankfurt). The 13-meter line includes a mode converter, HE11 waveguides, 4 mitre bends, a variable polarizer-attenuator, directional couplers, a water-flow calorimeter and a mechanical switch. A microwave power of about 15 W was obtained in the pure HE11 mode at the spectrometer inputs.

  13. Flow impedance in a uniform magnetically insulated transmission line

    SciTech Connect

    Mendel, C.W. Jr.; Seidel, D.B.

    1999-12-01

    In two recent publications [C. W. Mendel, Jr. and S. E. Rosenthal, Phys. of Plasmas {bold 2}, 1332 (1995), C. W. Mendel, Jr. and S. E. Rosenthal, Phys. of Plasmas {bold 3}, 4207 (1996)] relativistic electron flow in cylindrical magnetically insulated transmission lines was analyzed and modeled under the assumption of negligible electron pressure. The model allows power flow in these lines to be accurately calculated under most conditions. The model was developed for coaxial right circular cylindrical electrodes. It is shown here that the model applies equally well to arbitrary cylindrical systems, i.e., systems consisting of electrodes of arbitrary cross section. {copyright} {ital 1999 American Institute of Physics.}

  14. Flow impedance in a uniform magnetically insulated transmission line

    NASA Astrophysics Data System (ADS)

    Mendel, C. W.; Seidel, D. B.

    1999-12-01

    In two recent publications [C. W. Mendel, Jr. and S. E. Rosenthal, Phys. of Plasmas 2, 1332 (1995), C. W. Mendel, Jr. and S. E. Rosenthal, Phys. of Plasmas 3, 4207 (1996)] relativistic electron flow in cylindrical magnetically insulated transmission lines was analyzed and modeled under the assumption of negligible electron pressure. The model allows power flow in these lines to be accurately calculated under most conditions. The model was developed for coaxial right circular cylindrical electrodes. It is shown here that the model applies equally well to arbitrary cylindrical systems, i.e., systems consisting of electrodes of arbitrary cross section.

  15. Gas insulated transmission line with insulators having field controlling recesses

    DOEpatents

    Cookson, Alan H.; Pederson, Bjorn O.

    1984-01-01

    A gas insulated transmission line having a novel insulator for supporting an inner conductor concentrically within an outer sheath. The insulator has a recess contiguous with the periphery of one of the outer and inner conductors. The recess is disposed to a depth equal to an optimum gap for the dielectric insulating fluid used for the high voltage insulation or alternately disposed to a large depth so as to reduce the field at the critical conductor/insulator interface.

  16. Nonlinear waves propagating in the electrical transmission line

    NASA Astrophysics Data System (ADS)

    Duan, W.-S.

    2004-04-01

    A coupled Zakharov-Kuznetsov (ZK) equation is derived for a nonlinear transmission line in which the nonlinear capacitance C is of a general form C = C0(1 + k1V + k2V2 + ...). For a solitary-wave solution of the ZK equation, there is an instability region which is given numerically in this paper. It is in agreement with the analytical results for special cases.

  17. Frequency-Preserved Acoustic Diode Model with High Forward-Power-Transmission Rate

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Du, Zongliang; Sun, Zhi; Gao, Huajian; Guo, Xu

    2015-06-01

    The acoustic diode (AD) can provide brighter and clearer ultrasound images by eliminating acoustic disturbances caused by sound waves traveling in two directions at the same time and interfering with each other. Such an AD could give designers new flexibility in making ultrasonic sources like those used in medical imaging or nondestructive testing. However, current AD designs, based on nonlinear effects, only partially fill this role by converting sound to a new frequency and blocking any backward flow of the original frequency. In this work, an AD model that preserves the frequencies of acoustic waves and has a relatively high forward-power-transmission rate is proposed. Theoretical analysis indicates that the proposed AD has forward, reverse, and breakdown characteristics very similar to electrical diodes. The significant rectifying effect of the proposed AD is verified numerically through a one-dimensional example. Possible schemes for experimental realization of this model as well as more complex and efficient AD designs are also discussed.

  18. The effect of habitat acoustics on common marmoset vocal signal transmission.

    PubMed

    Morrill, Ryan J; Thomas, A Wren; Schiel, Nicola; Souto, Antonio; Miller, Cory T

    2013-09-01

    Noisy acoustic environments present several challenges for the evolution of acoustic communication systems. Among the most significant is the need to limit degradation of spectro-temporal signal structure in order to maintain communicative efficacy. This can be achieved by selecting for several potentially complementary processes. Selection can act on behavioral mechanisms permitting signalers to control the timing and occurrence of signal production to avoid acoustic interference. Likewise, the signal itself may be the target of selection, biasing the evolution of its structure to comprise acoustic features that avoid interference from ambient noise or degrade minimally in the habitat. Here, we address the latter topic for common marmoset (Callithrix jacchus) long-distance contact vocalizations, known as phee calls. Our aim was to test whether this vocalization is specifically adapted for transmission in a species-typical forest habitat, the Atlantic forests of northeastern Brazil. We combined seasonal analyses of ambient habitat acoustics with experiments in which pure tones, clicks, and vocalizations were broadcast and rerecorded at different distances to characterize signal degradation in the habitat. Ambient sound was analyzed from intervals throughout the day and over rainy and dry seasons, showing temporal regularities across varied timescales. Broadcast experiment results indicated that the tone and click stimuli showed the typically inverse relationship between frequency and signaling efficacy. Although marmoset phee calls degraded over distance with marked predictability compared with artificial sounds, they did not otherwise appear to be specially designed for increased transmission efficacy or minimal interference in this habitat. We discuss these data in the context of other similar studies and evidence of potential behavioral mechanisms for avoiding acoustic interference in order to maintain effective vocal communication in common marmosets.

  19. The Effect of Habitat Acoustics on Common Marmoset Vocal Signal Transmission

    PubMed Central

    MORRILL, RYAN J.; THOMAS, A. WREN; SCHIEL, NICOLA; SOUTO, ANTONIO; MILLER, CORY T.

    2013-01-01

    Noisy acoustic environments present several challenges for the evolution of acoustic communication systems. Among the most significant is the need to limit degradation of spectro-temporal signal structure in order to maintain communicative efficacy. This can be achieved by selecting for several potentially complementary processes. Selection can act on behavioral mechanisms permitting signalers to control the timing and occurrence of signal production to avoid acoustic interference. Likewise, the signal itself may be the target of selection, biasing the evolution of its structure to comprise acoustic features that avoid interference from ambient noise or degrade minimally in the habitat. Here, we address the latter topic for common marmoset (Callithrix jacchus) long-distance contact vocalizations, known as phee calls. Our aim was to test whether this vocalization is specifically adapted for transmission in a species-typical forest habitat, the Atlantic forests of northeastern Brazil. We combined seasonal analyses of ambient habitat acoustics with experiments in which pure tones, clicks, and vocalizations were broadcast and rerecorded at different distances to characterize signal degradation in the habitat. Ambient sound was analyzed from intervals throughout the day and over rainy and dry seasons, showing temporal regularities across varied timescales. Broadcast experiment results indicated that the tone and click stimuli showed the typically inverse relationship between frequency and signaling efficacy. Although marmoset phee calls degraded over distance with marked predictability compared with artificial sounds, they did not otherwise appear to be specially designed for increased transmission efficacy or minimal interference in this habitat. We discuss these data in the context of other similar studies and evidence of potential behavioral mechanisms for avoiding acoustic interference in order to maintain effective vocal communication in common marmosets. PMID

  20. Application of High Order Acoustic Finite Elements to Transmission Losses and Enclosure Problems

    NASA Technical Reports Server (NTRS)

    Craggs, A.; Stevenson, G.

    1985-01-01

    A family of acoustic finite elements was developed based on C continuity (acoustic pressure being the nodal variable) and the no-flow condition. The family include triangular, quadrilateral and hexahedral isoparametric elements with linear quadratic and cubic variation in modelling and distortion. Of greatest use in problems with irregular boundaries are the cubic isoparametric elements: the 32 node hexahedral element for three-dimensional systems; and the twelve node quadrilateral and ten node triangular elements for two-dimensional/axisymmetric applications. These elements were applied to problems involving cavity resonances, transmission loss in silencers and the study of end effects, using a Floating Point Systems 164 attached array processor accessed through an Amdahl 5860 mainframe. The elements are presently being used to study the end effects associated with duct terminations within finite enclosures. The transmission losses with various silencers and sidebranches in ducts is also being studied using the same elements.

  1. Mitigation of bird collisions with transmission lines: Final report

    SciTech Connect

    Beaulaurier, D.L.

    1981-09-11

    In this study removal of overhead groundwires was evaluated as a technique for mitigating bird collisions with transmission lines. Groundwires were removed by BPA from a 500 kV double circuit line at Bybee Lake in Portland, Oregon. Earlier studies at these sites had documented small but measurable collision rates (i.e., No. collisions/No. flights) attributed primarily to collisions with groundwires. Observations of bird flights and searches for dead birds in the vicinity of the lines constituted the primary methods of data collection during pre- and post-removal studies. Field work was conducted from October 1980 through March 1981. A total of seven dead birds and eight feather spots were found after groundwire removal. Species found were green-winged teal, pintail, greater scaup, American wigeon, glaucous-winged gull, starling, red-winged blackbird and song sparrow. No collisions with transmission lines were observed. During pre-removal studies at these two sites, a total of 53 dead birds and 22 feather spots were found over two years of study. It was necessary to document flight intensity (No. flights/day) during pre- and post-removal studies, in order to determine if the number of dead birds found changed because of groundwire removal or simply because of changes in flight intensity. 41 refs., 18 figs., 22 tabs.

  2. Dynamic modeling of magnetically insulated transmission line systems

    SciTech Connect

    Mendel, C.W. Jr.; Rosenthal, S.E.

    1996-11-01

    Negative conductors in vacuum transmission lines used in multiterrawatt applications emit electrons freely. These lines are efficient only because the self-magnetic field of the power flow forces the electrons to flow parallel to the electrodes. Excepting numerical simulations, dynamic modeling of systems of these transmission lines has generally either ignored electron flow, or has included only those electrons that cross immediately to the anode at the front of the forward wave. In this paper we describe an analytic model that includes flowing electrons and the effects of these flows on line voltage and on the reduction of magnetic flux. Axial electron currents are modeled using simple, measurable, and calculable parameters. Transverse electron currents are modeled using general patterns found empirically from simulation data. These currents are in turn related by an expanded set of Telegrapher equations. An example of the use of the model is compared to two-dimensional, time-dependent particle-in-cell simulations. {copyright} {ital 1996 American Institute of Physics.}

  3. Characterization of the Reverberation Chamber at the NASA Langley Structural Acoustics Loads and Transmission (SALT) Facility

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.

    2013-01-01

    In 2011 the noise generating capabilities in the reverberation chamber of the Structural Acoustic Loads and Transmission (SALT) facility at NASA Langley Research Center were enhanced with two fiberglass reinforced polyester resin exponential horns, each coupled to Wyle Acoustic Source WAS-3000 airstream modulators. This report describes the characterization of the reverberation chamber in terms of the background noise, diffusivity, sound pressure levels, the reverberation times and the related overall acoustic absorption in the empty chamber and with the acoustic horn(s) installed. The frequency range of interest includes the 80 Hz to 8000 Hz one-third octave bands. Reverberation time and sound pressure level measurements were conducted and standard deviations from the mean were computed. It was concluded that a diffuse field could be produced above the Schroeder frequency in the 400 Hz one-third octave band and higher for all applications. This frequency could be lowered by installing panel diffusers or moving vanes to improve the acoustic modal overlap in the chamber. In the 80 Hz to 400 Hz one-third octave bands a successful measurement will be dependent on the type of measurement, the test configuration, the source and microphone locations and the desired accuracy. It is recommended that qualification measurements endorsed in the International Standards be conducted for each particular application.

  4. Acoustic contributions of a sound absorbing blanket placed in a double panel structure: absorption versus transmission.

    PubMed

    Doutres, Olivier; Atalla, Noureddine

    2010-08-01

    The objective of this paper is to propose a simple tool to estimate the absorption vs. transmission loss contributions of a multilayered blanket unbounded in a double panel structure and thus guide its optimization. The normal incidence airborne sound transmission loss of the double panel structure, without structure-borne connections, is written in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The method is applied to four different blankets frequently used in automotive and aeronautic applications: a non-symmetric multilayer made of a screen in sandwich between two porous layers and three symmetric porous layers having different pore geometries. It is shown that the absorption behavior of the blanket controls the acoustic behavior of the treatment at low and medium frequencies and its transmission loss at high frequencies. Acoustic treatment having poor sound absorption behavior can affect the performance of the double panel structure.

  5. Integral measurements of mass transport and heat content in the Strait of Gibraltar from acoustic transmissions

    NASA Astrophysics Data System (ADS)

    Send, Uwe; Worcester, Peter F.; Cornuelle, Bruce D.; Tiemann, Christopher O.; Baschek, Burkard

    Three 2 kHz acoustic transceivers were deployed on either side of the eastern entrance of the Strait of Gibraltar during April-May 1996 to determine the feasibility of using acoustic methods to make routine, rapidly repeated, horizontally integrated measurements of flow and temperature in straits. Reciprocal transmissions between the transceivers were used to test the feasibility of using traditional ray differential travel times to monitor the component of flow along the acoustic paths. Transmissions directly across the Strait were used to test the feasibility of using horizontal arrival angle fluctuations and acoustic intensity scintillations to monitor the flow perpendicular to the acoustic path. The geometry was selected to provide ray paths that only sample the lower-layer Mediterranean water, so that the feasibility of monitoring the Mediterranean outflow using the various methods could be evaluated. The acoustic scintillation method did not yield useful current estimates, but the experimental parameters were not optimized for this approach. Since the low-frequency variability in log-amplitude was found to be highly correlated at receivers 228 m apart, it is possible that acoustic scintillation measurements using different receiver spacings and more rapid sampling might yield better results. The horizontal deflection method gave encouraging results at the time of neap tides, but less so during spring tides. For this approach, both theoretical estimates and measured phase differences between the horizontally separated receivers suggest that internal-wave-induced horizontal arrival angle fluctuations may fundamentally limit the precision with which arrival angles can be measured. Further work is needed to determine if a smaller horizontal spacing and higher signal-to-noise ratios would yield better results. Reciprocal travel time measurements diagonally across the Strait performed the best of the three methods, giving absolute flow estimates consistent with

  6. Radiofrequency transmission line for bioluminescent Vibrio sp. irradiation

    NASA Astrophysics Data System (ADS)

    Nassisi, V.; Alifano, P.; Talà, A.; Velardi, L.

    2012-07-01

    We present the study and the analyses of a transmission line for radiofrequency (RF) irradiation of bacteria belonging to Vibrio harveyi-related strain PS1, a bioluminescent bacterium living in symbiosis with many marine organisms. The bioluminescence represents a new biologic indicator which is useful for studying the behaviour of living samples in the presence of RF waves due to the modern communication systems. A suitable transmission line, used as an irradiating cell and tested up to the maximum frequency used by the global system for mobile communications and universal mobile telecommunications system transmissions, was characterized. In this experiment, the RF voltage applied to the transmission line was 1 V. Due to short dimensions of the line and the applied high frequencies, standing waves were produced in addition to progressing waves and the electric field strength varies particularly along the longitudinal direction. The magnetic field map was not strongly linked to the electric one due to the presence of standing waves and of the outgoing irradiation. RF fields were measured by two homemade suitable probes able to diagnostic fields of high frequency. The field measurements were performed without any specimens inside the line. Being our sample made of living matter, the real field was modified and its value was estimated by a simulation code. The bioluminescence experiments were performed only at 900 MHz for two different measured electric fields, 53 and 140 V/m. The light emission was measured right from the beginning and after 7 and 25 h. Under RF irradiation, we found that the bioluminescence activity decreased. Compared with the control sample, the diminution was 6.8% and 44% after 7 and 25 h of irradiation, respectively, both with the low or high field. No changes of the survival factor for all the samples were observed. Besides, to understand the emission processes, we operated the deconvolution of the spectra by two Gaussian curves. The Gaussian

  7. A Numerical Investigation of Turbine Noise Source Hierarchy and Its Acoustic Transmission Characteristics: Proof-of-Concept Progress

    NASA Technical Reports Server (NTRS)

    VanZante, Dale; Envia, Edmane

    2008-01-01

    A CFD-based simulation of single-stage turbine was done using the TURBO code to assess its viability for determining acoustic transmission through blade rows. Temporal and spectral analysis of the unsteady pressure data from the numerical simulations showed the allowable Tyler-Sofrin modes that are consistent with expectations. This indicated that high-fidelity acoustic transmission calculations are feasible with TURBO.

  8. View facing north (30°) of Transmission Line entering Teton River ...

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

    View facing north (30°) of Transmission Line entering Teton River Valley, near Structure 40-7 - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  9. View facing south (210°) of Transmission Line going over hill, ...

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

    View facing south (210°) of Transmission Line going over hill, Structure 46-12 in foreground, near Collins School - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  10. View facing northeast (60°) of Structure 259, other transmission lines ...

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

    View facing northeast (60°) of Structure 25-9, other transmission lines and small farmstead visible in background - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  11. HendersonMead Transmission Line 2 southwest of Boulder City Substation, view ...

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

    Henderson-Mead Transmission Line 2 southwest of Boulder City Substation, view southwest - Hoover Dam, Henderson-Mead Transmission Line 2, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  12. Sound transmission through double cylindrical shells lined with porous material under turbulent boundary layer excitation

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Bhaskar, Atul; Zhang, Xin

    2015-11-01

    This paper investigates sound transmission through double-walled cylindrical shell lined with poroelastic material in the core, excited by pressure fluctuations due to the exterior turbulent boundary layer (TBL). Biot's model is used to describe the sound wave propagating in the porous material. Three types of constructions, bonded-bonded, bonded-unbonded and unbonded-unbonded, are considered in this study. The power spectral density (PSD) of the inner shell kinetic energy is predicted for two turbulent boundary layer models, different air gap depths and three types of polyimide foams, respectively. The peaks of the inner shell kinetic energy due to shell resonance, hydrodynamic coincidence and acoustic coincidence are discussed. The results show that if the frequency band over the ring frequency is of interest, an air gap, even if very thin, should exist between the two elastic shells for better sound insulation. And if small density foam has a high flow resistance, a superior sound insulation can still be maintained.

  13. On-Line Acoustic and Semantic Interpretation of Talker Information

    ERIC Educational Resources Information Center

    Creel, Sarah C.; Tumlin, Melanie A.

    2011-01-01

    Recent work demonstrates that listeners utilize talker-specific information in the speech signal to inform real-time language processing. However, there are multiple representational levels at which this may take place. Listeners might use acoustic cues in the speech signal to access the talker's identity and information about what they tend to…

  14. WaveQ3D: Fast and accurate acoustic transmission loss (TL) eigenrays, in littoral environments

    NASA Astrophysics Data System (ADS)

    Reilly, Sean M.

    This study defines a new 3D Gaussian ray bundling acoustic transmission loss model in geodetic coordinates: latitude, longitude, and altitude. This approach is designed to lower the computation burden of computing accurate environmental effects in sonar training application by eliminating the need to transform the ocean environment into a collection of Nx2D Cartesian radials. This approach also improves model accuracy by incorporating real world 3D effects, like horizontal refraction, into the model. This study starts with derivations for a 3D variant of Gaussian ray bundles in this coordinate system. To verify the accuracy of this approach, acoustic propagation predictions of transmission loss, time of arrival, and propagation direction are compared to analytic solutions and other models. To validate the model's ability to predict real world phenomena, predictions of transmission loss and propagation direction are compared to at-sea measurements, in an environment where strong horizontal refraction effect have been observed. This model has been integrated into U.S. Navy active sonar training system applications, where testing has demonstrated its ability to improve transmission loss calculation speed without sacrificing accuracy.

  15. Field quality measurements of a 2-Tesla transmission line magnet

    SciTech Connect

    Velev, G.V.; Foster, W.; Kashikhin, V.; Mazur, P.; Oleck, A.; Piekarz, H.; Schlabach, P.; Sylvester, C.; Wake, M.; /KEK, Tsukuba

    2005-09-01

    A prototype 2-Tesla superconducting transmission line magnet for future hadron colliders was designed, built and tested at Fermilab. The 1.5 m long, combined-function gradient-dipole magnet has a vertical pole aperture of 20 mm. To measure the magnetic field quality in such a small magnet aperture, a specialized rotating coil of 15.2 mm diameter, 0.69 m long was fabricated. Using this probe, a program of magnetic field quality measurements was successfully performed. Results of the measurements are presented and discussed.

  16. LineCast: line-based distributed coding and transmission for broadcasting satellite images.

    PubMed

    Wu, Feng; Peng, Xiulian; Xu, Jizheng

    2014-03-01

    In this paper, we propose a novel coding and transmission scheme, called LineCast, for broadcasting satellite images to a large number of receivers. The proposed LineCast matches perfectly with the line scanning cameras that are widely adopted in orbit satellites to capture high-resolution images. On the sender side, each captured line is immediately compressed by a transform-domain scalar modulo quantization. Without syndrome coding, the transmission power is directly allocated to quantized coefficients by scaling the coefficients according to their distributions. Finally, the scaled coefficients are transmitted over a dense constellation. This line-based distributed scheme features low delay, low memory cost, and low complexity. On the receiver side, our proposed line-based prediction is used to generate side information from previously decoded lines, which fully utilizes the correlation among lines. The quantized coefficients are decoded by the linear least square estimator from the received data. The image line is then reconstructed by the scalar modulo dequantization using the generated side information. Since there is neither syndrome coding nor channel coding, the proposed LineCast can make a large number of receivers reach the qualities matching their channel conditions. Our theoretical analysis shows that the proposed LineCast can achieve Shannon's optimum performance by using a high-dimensional modulo-lattice quantization. Experiments on satellite images demonstrate that it achieves up to 1.9-dB gain over the state-of-the-art 2D broadcasting scheme and a gain of more than 5 dB over JPEG 2000 with forward error correction.

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Maintenance § 192.713 Transmission lines: Permanent field repair of imperfections and damages. (a) Each imperfection or damage that impairs the serviceability of pipe in a steel transmission line operating at or... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Permanent field repair...

  2. Estimating Magnetic Fields of Homes Near Transmission Lines in the California Power Line Study

    PubMed Central

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

    2015-01-01

    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. PMID:26005950

  3. Inverse estimation of the acoustic impedance of a porous woven hose from measured transmission coefficients.

    PubMed

    Park, Chul-Min; Ih, Jeong-Guon; Nakayama, Yoshio; Takao, Hideo

    2003-01-01

    A porous tube, comprised of a resin-coated woven fabric has recently been used as an effective component for use in intake systems of internal combustion engines to reduce the intake noise. For the prediction of the acoustic performance of an engine intake system with a porous woven hose, the acoustic wall impedance of the hose must be known. However, the accurate measurement of the wall impedance of a porous woven hose is not easy because of its peculiar acoustical and structural characteristics. A new measurement technique is proposed herein, that is valid over the low to mid frequency ranges. The acoustics impedance is inversely estimated from an overdetermined set of measured pressure transmission coefficients for specimens of different lengths and the reflection coefficient of end termination. The method involves only one measurement setup, and, as a result, it is very simple. A variation of the proposed method, an inverse estimation method using one of the four-pole parameters is also proposed. An error sensitivity analysis was performed to investigate the effect of measurement error on the accuracy of the final result. The measured TL for samples with arbitrary lengths and arbitrary porous frequency are in reasonably good agreement with values predicted from curve-fitted impedance data. PMID:12558253

  4. Inverse estimation of the acoustic impedance of a porous woven hose from measured transmission coefficients.

    PubMed

    Park, Chul-Min; Ih, Jeong-Guon; Nakayama, Yoshio; Takao, Hideo

    2003-01-01

    A porous tube, comprised of a resin-coated woven fabric has recently been used as an effective component for use in intake systems of internal combustion engines to reduce the intake noise. For the prediction of the acoustic performance of an engine intake system with a porous woven hose, the acoustic wall impedance of the hose must be known. However, the accurate measurement of the wall impedance of a porous woven hose is not easy because of its peculiar acoustical and structural characteristics. A new measurement technique is proposed herein, that is valid over the low to mid frequency ranges. The acoustics impedance is inversely estimated from an overdetermined set of measured pressure transmission coefficients for specimens of different lengths and the reflection coefficient of end termination. The method involves only one measurement setup, and, as a result, it is very simple. A variation of the proposed method, an inverse estimation method using one of the four-pole parameters is also proposed. An error sensitivity analysis was performed to investigate the effect of measurement error on the accuracy of the final result. The measured TL for samples with arbitrary lengths and arbitrary porous frequency are in reasonably good agreement with values predicted from curve-fitted impedance data.

  5. Single-wire radio frequency transmission lines in biological tissue

    NASA Astrophysics Data System (ADS)

    Besnoff, Jordan S.; Reynolds, Matthew S.

    2015-05-01

    We present an approach for implanting radio frequency transmission lines in biological tissue, using a single insulated wire surrounded by tissue as a variant of the Goubau single-wire transmission line (SWTL) in air. We extend the Goubau SWTL model to include SWTLs surrounded by lossy dielectrics such as tissue by assuming a propagating mode component in the tissue. We show that a thin wire of radius 63.5 μ m , coated with biocompatible fluorinated ethylene propylene dielectric, exhibits a measured loss of only 1 dB/cm at a frequency of 915 MHz. The model fit to the measured insertion loss is within ±0.3 dB/cm across the 100 MHz to 3 GHz band. This SWTL presents excellent impedance matching to 50 Ω as evidenced by a measured median return loss better than 10 dB across the 100 MHz to 3 GHz range. This approach represents an alternative to near-field magnetic coupling for implanted systems where tissue displacement by a single, thin wire can be tolerated.

  6. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V.

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  7. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes.

  8. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  9. Quad Cities Unit 2 Main Steam Line Acoustic Source Identification and Load Reduction

    SciTech Connect

    DeBoo, Guy; Ramsden, Kevin; Gesior, Roman

    2006-07-01

    The Quad Cities Units 1 and 2 have a history of steam line vibration issues. The implementation of an Extended Power Up-rate resulted in significant increases in steam line vibration as well as acoustic loading of the steam dryers, which led to equipment failures and fatigue cracking of the dryers. This paper discusses the results of extensive data collection on the Quad Cities Unit 2 replacement dryer and the Main Steam Lines. This data was taken with the intent of identifying acoustic sources in the steam system. Review of the data confirmed that vortex shedding coupled column resonance in the relief and safety valve stub pipes were the principal sources of large magnitude acoustic loads in the main steam system. Modifications were developed in sub-scale testing to alter the acoustic properties of the valve standpipes and add acoustic damping to the system. The modifications developed and installed consisted of acoustic side branches that were attached to the Electromatic Relief Valve (ERV) and Main Steam Safety Valve (MSSV) attachment pipes. Subsequent post-modification testing was performed in plant to confirm the effectiveness of the modifications. The modifications have been demonstrated to reduce vibration loads at full Extended Power Up-rate (EPU) conditions to levels below those at Original Licensed Thermal Power (OLTP). (authors)

  10. Acoustic Quality of the 40- by 80- Foot Wind Tunnel Test Section After Installation of a Deep Acoustic Lining

    NASA Technical Reports Server (NTRS)

    Soderman, Paul T.; Jaeger, Stephen M.; Hayes, Julie A.; Allen, Christopher S.

    2002-01-01

    A recessed, 42-inch deep acoustic lining has been designed and installed in the 40- by 80- Foot Wind Tunnel (40x80) test section to greatly improve the acoustic quality of the facility. This report describes the test section acoustic performance as determined by a detailed static calibration-all data were acquired without wind. Global measurements of sound decay from steady noise sources showed that the facility is suitable for acoustic studies of jet noise or similar randomly generated sound. The wall sound absorption, size of the facility, and averaging effects of wide band random noise all tend to minimize interference effects from wall reflections. The decay of white noise with distance was close to free field above 250 Hz. However, tonal sound data from propellers and fans, for example, will have an error band to be described that is caused by the sensitivity of tones to even weak interference. That error band could be minimized by use of directional instruments such as phased microphone arrays. Above 10 kHz, air absorption began to dominate the sound field in the large test section, reflections became weaker, and the test section tended toward an anechoic environment as frequency increased.

  11. Sound Transmission Loss Through a Corrugated-Core Sandwich Panel with Integrated Acoustic Resonators

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Allen, Albert R.; Zalewski, Bart F; Beck, Benjamin S.

    2014-01-01

    The goal of this study is to better understand the effect of structurally integrated resonators on the transmission loss of a sandwich panel. The sandwich panel has facesheets over a corrugated core, which creates long aligned chambers that run parallel to the facesheets. When ports are introduced through the facesheet, the long chambers within the core can be used as low-frequency acoustic resonators. By integrating the resonators within the structure they contribute to the static load bearing capability of the panel while also attenuating noise. An analytical model of a panel with embedded resonators is derived and compared with numerical simulations. Predictions show that acoustic resonators can significantly improve the transmission loss of the sandwich panel around the natural frequency of the resonators. In one configuration with 0.813 m long internal chambers, the diffuse field transmission loss is improved by more than 22 dB around 104 Hz. The benefit is achieved with no added mass or volume relative to the baseline structure. The embedded resonators are effective because they radiate sound out-of-phase with the structure. This results in destructive interference, which leads to less transmitted sound power.

  12. [Quantification and improvement of speech transmission performance using headphones in acoustic stimulated functional magnetic resonance imaging].

    PubMed

    Yamamura, Ken ichiro; Takatsu, Yasuo; Miyati, Tosiaki; Kimura, Tetsuya

    2014-10-01

    Functional magnetic resonance imaging (fMRI) has made a major contribution to the understanding of higher brain function, but fMRI with auditory stimulation, used in the planning of brain tumor surgery, is often inaccurate because there is a risk that the sounds used in the trial may not be correctly transmitted to the subjects due to acoustic noise. This prompted us to devise a method of digitizing sound transmission ability from the accuracy rate of 67 syllables, classified into three types. We evaluated this with and without acoustic noise during imaging. We also improved the structure of the headphones and compared their sound transmission ability with that of conventional headphones attached to an MRI device (a GE Signa HDxt 3.0 T). We calculated and compared the sound transmission ability of the conventional headphones with that of the improved model. The 95 percent upper confidence limit (UCL) was used as the threshold for accuracy rate of hearing for both headphone models. There was a statistically significant difference between the conventional model and the improved model during imaging (p < 0.01). The rate of accuracy of the improved model was 16 percent higher. 29 and 22 syllables were accurate at a 95% UCL in the improved model and the conventional model, respectively. This study revealed the evaluation system used in this study to be useful for correctly identifying syllables during fMRI.

  13. Smaller-loss planar SPP transmission line than conventional microstrip in microwave frequencies

    PubMed Central

    Zhang, Hao Chi; Zhang, Qian; Liu, Jun Feng; Tang, Wenxuan; Fan, Yifeng; Cui, Tie Jun

    2016-01-01

    Transmission line is a basic component in all passive devices, integrated circuits, and systems. Microstrip is the most popular transmission line in the microwave and millimeter-wave frequencies, and has been widely used in current electronic devices, circuits, and systems. One of the important issues to be solved in such applications is the relatively large transmission loss of microstrip. Here, we propose a method to reduce the loss of microwave transmission line based on the designable wavenumber of spoof surface plasmon polaritons (SPPs). Using this characteristic, we analyze and experimentally demonstrate the low-loss feature of the SPP transmission line through the perturbation method and S-parameter measurements, respectively. Both simulation and experimental results show that the SPP transmission line has much smaller transmission loss than traditional microstrip with the same size in the microwave frequencies. Hence, the spoof SPP transmission line may make a big step forward in the low-loss circuits and systems. PMID:26983911

  14. Wild Horse 69-kV transmission line environmental assessment

    SciTech Connect

    1996-12-01

    Hill County Electric Cooperative Inc. (Hill County) proposes to construct and operate a 69-kV transmission line from its North Gildford Substation in Montana north to the Canadian border. A vicinity project area map is enclosed as a figure. TransCanada Power Corporation (TCP), a Canadian power-marketing company, will own and construct the connecting 69-kV line from the international border to Express Pipeline`s pump station at Wild Horse, Alberta. This Environmental Assessment is prepared for the Department of Energy (DOE) as lead federal agency to comply with the requirements of the National Environmental Policy Act (NEPA), as part of DOE`s review and approval process of the applications filed by Hill County for a DOE Presidential Permit and License to Export Electricity to a foreign country. The purpose of the proposed line is to supply electric energy to a crude oil pump station in Canada, owned by Express Pipeline Ltd. (Express). The pipeline would transport Canadian-produced oil from Hardisty, Alberta, Canada, to Caster, Wyoming. The Express Pipeline is scheduled to be constructed in 1996--97 and will supply crude oil to refineries in Wyoming and the midwest.

  15. Material selection of a ferrimagnetic loaded coaxial delay line for phasing gyromagnetic nonlinear transmission lines.

    PubMed

    Johnson, J M; Reale, D V; Cravey, W H; Garcia, R S; Barnett, D H; Neuber, A A; Dickens, J C; Mankowski, J J

    2015-08-01

    Implementing nonlinear transmission line (NLTL) technology in the design of a high power microwave source has the benefits of producing a comparatively small and lightweight solid-state system where the emission frequency is easily tuned. Usually, smaller in physical size, single NLTLs may produce significantly less power than its vacuum based counterparts. However, combining individual NLTL outputs electrically or in free-space is an attractive solution to achieve greater output power. This paper discusses a method for aligning a four element NLTL antenna array with coaxial geometry using easily adjustable temporal delay lines. These delay lines, sometimes referred to as pulse shock lines or pulse sharpening lines, are placed serially in front of the main NLTL line. The propagation velocity in each delay line is set by the voltage amplitude of an incident pulse as well as the magnetic field bias. Each is adjustable although for the system described in this paper, the voltage is held constant while the bias is changed through applying an external DC magnetic field of varying magnitude. Three different ferrimagnetic materials are placed in the temporal delay line to evaluate which yields the greatest range of electrical delay with the least amount of variability from consecutive shots. PMID:26329216

  16. Fuzzy logic based on-line fault detection and classification in transmission line.

    PubMed

    Adhikari, Shuma; Sinha, Nidul; Dorendrajit, Thingam

    2016-01-01

    This study presents fuzzy logic based online fault detection and classification of transmission line using Programmable Automation and Control technology based National Instrument Compact Reconfigurable i/o (CRIO) devices. The LabVIEW software combined with CRIO can perform real time data acquisition of transmission line. When fault occurs in the system current waveforms are distorted due to transients and their pattern changes according to the type of fault in the system. The three phase alternating current, zero sequence and positive sequence current data generated by LabVIEW through CRIO-9067 are processed directly for relaying. The result shows that proposed technique is capable of right tripping action and classification of type of fault at high speed therefore can be employed in practical application. PMID:27398278

  17. Fuzzy logic based on-line fault detection and classification in transmission line.

    PubMed

    Adhikari, Shuma; Sinha, Nidul; Dorendrajit, Thingam

    2016-01-01

    This study presents fuzzy logic based online fault detection and classification of transmission line using Programmable Automation and Control technology based National Instrument Compact Reconfigurable i/o (CRIO) devices. The LabVIEW software combined with CRIO can perform real time data acquisition of transmission line. When fault occurs in the system current waveforms are distorted due to transients and their pattern changes according to the type of fault in the system. The three phase alternating current, zero sequence and positive sequence current data generated by LabVIEW through CRIO-9067 are processed directly for relaying. The result shows that proposed technique is capable of right tripping action and classification of type of fault at high speed therefore can be employed in practical application.

  18. A computer code to calculate line by line atmospheric transmission spectra on a microcomputer

    NASA Astrophysics Data System (ADS)

    Safren, H. G.

    1987-07-01

    A computer program is described which calculates line by line atmospheric transmission spectra on a microcomputer. Radiance calculations are not included. The program is written in FORTRAN and could be modified to run on a microcomputer other than the one on which it was implemented, except that the plotting routine would have to be replaced. The program is based on the 1978 Air Force Geophysics Laboratory LASER routine, and uses absorption line data from the 1982 update of the AFGL Atmospheric Absorption Line Parameters Compilation; segments of needed line data are taken from the tape, preprocessed into the form used by the program and stored on floppy disks. The program calculates transmission spectra over a variety of paths and spanning an arbitrarily chosen wavelength or frequency range; the path may be chosen to be horizontal, vertical or slanted at any zenith angle, and may extend between any two altitudes between 0 and 15 km. Aerosol effects are included, presently based on the 1976 Shettle and Fenn models, plus some molecular continuum effects and Rayleigh scattering.

  19. Fuel Line Based Acoustic Flame-Out Detection System

    NASA Technical Reports Server (NTRS)

    Puster, Richard L. (Inventor); Franke, John M. (Inventor)

    1997-01-01

    An acoustic flame-out detection system that renders a large high pressure combustor safe in the event of a flame-out and possible explosive reignition. A dynamic pressure transducer is placed in the fuel and detects the stabilizing fuel pressure oscillations, caused by the combustion process. An electric circuit converts the signal from the combustion vortices, and transmitted to the fuel flow to a series of pulses. A missing pulse detector counts the pulses and continuously resets itself. If three consecutive pulses are missing, the circuit closes the fuel valve. With fuel denied the combustor is shut down or restarted under controlled conditions.

  20. Gas insulated transmission line having low inductance intercalated sheath

    DOEpatents

    Cookson, Alan H.

    1978-01-01

    A gas insulated transmission line including an outer sheath, an inner conductor disposed within the outer sheath, and an insulating gas between the inner conductor and the outer sheath. The outer sheath comprises an insulating tube having first and second ends, and having interior and exterior surfaces. A first electrically conducting foil is secured to the interior surface of the insulating tube, is spirally wound from one tube end to the second tube end, and has a plurality of overlapping turns. A second electrically conducting foil is secured to the exterior surface of the insulating tube, and is spirally wound in the opposite direction from the first electrically conducting foil. By winding the foils in opposite directions, the inductances within the intercalated sheath will cancel each other out.

  1. Monolithic high voltage nonlinear transmission line fabrication process

    DOEpatents

    Cooper, Gregory A.

    1994-01-01

    A process for fabricating sequential inductors and varactor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varactor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process.

  2. Monolithic high voltage nonlinear transmission line fabrication process

    DOEpatents

    Cooper, G.A.

    1994-10-04

    A process for fabricating sequential inductors and varistor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varistor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process. 6 figs.

  3. Terahertz Quantum-Cascade Transmission-Line Metamaterials

    NASA Astrophysics Data System (ADS)

    Tavallaee, Amir Ali

    Terahertz quantum-cascade (QC) lasers operating at 0.6 - 5 THz (λ ˜ 60 - 500 µm) are poised to become the dominant solid-state sources of continuous-wave (cw) far-infrared radiation enabling applications in terahertz spectroscopy, imaging, and sensing. QC-lasers are the longest wavelength semiconductor laser sources in which terahertz gain is obtained from electronic intersubband radiative transitions in GaAs/AlGaAs heterostructure quantum wells. Since their invention in 2001, rapid development has enabled demonstration of cw powers greater than 100 mW. However, challenges still remain in the areas of operating temperature, laser efficiency and power, and beam quality to name a few. The highest-temperature operation of terahertz quantum-cascade lasers (200 K pulsed, 117 K cw) depends on the use of a low-loss "metal-metal" waveguide where the active gain material is sandwiched between two metal cladding layers; a technique similar, in concept, to microstrip transmission line technology at microwave frequencies. Due to the subwavelength transverse dimensions of the metal-metal waveguide, however, obtaining a directive beam pattern and efficient out-coupling of THz power is non-trivial. This thesis reports the demonstration of a one-dimensional waveguide for terahertz quantum-cascade lasers that acts as a leaky-wave antenna and tailors laser radiation in one dimension to a directional beam. This scheme adapts microwave transmission-line metamaterial concepts to a planar structure realized in terahertz metal-metal waveguide technology and is fundamentally different from distributed feedback/photonic crystal structures that work based on Bragg scattering of propagating modes. The leaky-wave metamaterial antenna operates based on a propagating mode with an effective phase index smaller than unity such that it radiates in the surface direction via a leaky-wave mechanism. Surface emission (˜ 40° from broadside) with a single directive beam (FWHM ˜ 15°) at 2.74 THz

  4. Nonlinear galloping of internally resonant iced transmission lines considering eccentricity

    NASA Astrophysics Data System (ADS)

    Yan, Zhimiao; Yan, Zhitao; Li, Zhengliang; Tan, Ting

    2012-07-01

    Based on the curved-beam theory, a nonlinear galloping model considering three displacement (normal, bi-normal and tangential) components and twist is formulated. According to the property of transmission line, one reduced (normal and bi-normal) galloping model, with regard of bending, rotation and eccentricity of cross section, is obtained. Moreover, the initial rotation angle is also introduced in galloping and aerodynamic models. Additionally, based on the reduced model, the bifurcation and stability of the two cases (1:1 resonance and 2:1 resonance) are analyzed. The results turn out that the importance of ice eccentricity needs to be highlighted. Finally, multiple stabilities are found through the analyses of bifurcation and stability and proved by the reduced model and Reduced Amplitude Modulation Equations (RAME) numerically integrated in time history.

  5. Microwave transmission line dielectric probe to detect biomolecular surface interactions.

    PubMed

    Chen, Qin; McMurdie, Joey; Roitman, Daniel; Knoesen, Andre

    2004-01-01

    A probe was developed to detect biomolecular binding events at a liquid-solid interface in the microwave regime in real time and without using fluorescence labels. The probe consists of a coplanar transmission line (CTL) fabricated on a glass slide that can detect dielectric changes in close proximity of the interface. The CTL geometry concentrates the electric flux density in the gap region between the signal and ground electrodes and makes it very sensitive to permittivity changes at the liquid-solid interface. The probe operation was demonstrated by immobilizing protein A on the glass surface and detecting rabbit IgG molecules in a flow channel. The sensitivity was conservatively estimated to be 100 pg/mm(2).

  6. Transmission line corona losses under hoar frost conditions

    SciTech Connect

    Lahti, K.; Nousiainen, K.; Lahtinen, M.

    1997-04-01

    Transmission line corona losses under hoar frost conditions were studied in the climate room of the high voltage laboratory of Tampere University of Technology. The measurements were performed using a coaxial measurement arrangement with different bundle and conductor types. The effects of conductor and bundle type, temperature, applied voltage and hoar frost thickness on corona losses were investigated. A two-conductor bundle had corona losses about 2.5--5 times higher than a three-conductor bundle. Relatively thin hoar frosts were used in the tests. Even the thinnest hoar frost resulted in remarkable corona losses and the losses were very sensitive to changes in the hoar frost thickness. The ambient temperature had a strong influence on the measured losses.

  7. Tailoring of electron flow current in magnetically insulated transmission lines

    NASA Astrophysics Data System (ADS)

    Martin, J. P.; Savage, M. E.; Pointon, T. D.; Gilmore, M. A.

    2009-03-01

    It is desirable to optimize (minimizing both the inductance and electron flow) the magnetically insulated vacuum sections of low impedance pulsed-power drivers. The goal of low inductance is understandable from basic efficiency arguments. The goal of low electron flow results from two observations: (1) flowing electrons generally do not deliver energy to (or even reach) most loads, and thus constitute a loss mechanism; (2) energetic electrons deposited in a small area can cause anode damage and anode plasma formation. Low inductance and low electron flow are competing goals; an optimized system requires a balance of the two. While magnetically insulated systems are generally forgiving, there are times when optimization is crucial. For example, in large pulsed-power drivers used to energize high energy density physics loads, the electron flow as a fraction of total current is small, but that flow often reaches the anode in relatively small regions. If the anode temperature becomes high enough to desorb gas, the resulting plasma initiates a gap closure process that can impact system performance. Magnetic-pressure driven (z pinches and material equation of state) loads behave like a fixed inductor for much of the drive pulse. It is clear that neither fixed gap nor constant-impedance transmission lines are optimal for driving inductive loads. This work shows a technique for developing the optimal impedance profile for the magnetically insulated section of a high-current driver. Particle-in-cell calculations are used to validate the impedance profiles developed in a radial disk magnetically insulated transmission line geometry. The input parameters are the spacing and location of the minimum gap, the effective load inductance, and the desired electron flow profile. The radial electron flow profiles from these simulations are in good agreement with theoretical predictions when driven at relatively high voltage (i.e., V≥2MV).

  8. Modeling graphite anodes with serial and transmission line models

    NASA Astrophysics Data System (ADS)

    Illig, J.; Ender, M.; Weber, A.; Ivers-Tiffée, E.

    2015-05-01

    Electrochemical impedance spectroscopy (EIS) is an indispensable technique for the investigation of polarization processes in Lithium-ion Batteries. These cause performance limitation or degradation. A physically meaningful impedance model is key when drawing conclusions on further cell improvement. This study introduces an in-depth impedance analysis of a commercial high-power graphite anode. The impedance spectra measured between 0 °C and 30 °C and 0%-100% SOC were analyzed by the distribution of relaxation times (DRT-method), enabling a separation of loss processes by their individual time constants. Using this method, we separated charge transfer resistance and solid electrolyte interface resistance at medium frequencies (10 Hz-200 Hz) and the contact resistance anode/current collector in the at high frequency range (5 kHz-100 kHz). Two fundamentally different model structures were set up, either (i) two modifications of a serial model connecting RQ-elements and a Warburg element for solid state diffusion, or (ii) three modifications of a transmission line model with one-path or two-path design. The suitability of all serial and TLM model structures was tested, and the fitting procedure was supported using microstructure parameters gained from x-ray tomography. The favored one-path transmission line model reveals that the lithium-ion transport in the electrolyte contributes more to polarization than expected. Impediment of lithium-ion transport is caused by the pore structure and the tortuosity of the high-power graphite anode, and has to be considered for meaningful interpretation of impedance spectra.

  9. Tunability of acoustic phonon transmission and thermal conductance in three dimensional quasi-periodically stubbed waveguides

    NASA Astrophysics Data System (ADS)

    Xie, Zhong-Xiang; Liu, Jing-Zhong; Yu, Xia; Wang, Hai-Bin; Deng, Yuan-Xiang; Li, Ke-Min; Zhang, Yong

    2015-03-01

    We investigate acoustic phonon transmission and thermal conductance in three dimensional (3D) quasi-periodically stubbed waveguides according to the Fibonacci sequence. Results show that the transmission coefficient exhibits the periodic oscillation upon varying the length of stub/waveguide at low frequency, and the period of such oscillation is tunably decreased with increasing the Fibonacci number N. Interestingly, there also exist some anti-resonant dips that gradually develop into wide stop-frequency gaps with increasing N. As the temperature goes up, a transition of the thermal conductance from the decrease to the increase occurs in these systems. When N is increased, the thermal conductance is approximately decreased with a linear trend. Moreover, the decreasing degree sensitively depends on the variation of temperature. A brief analysis of these results is given.

  10. Vibro-acoustic response and sound transmission loss analysis of functionally graded plates

    NASA Astrophysics Data System (ADS)

    Chandra, N.; Raja, S.; Nagendra Gopal, K. V.

    2014-10-01

    This paper presents analytical studies on the vibro-acoustic and sound transmission loss characteristics of functionally graded material (FGM) plates using a simple first-order shear deformation theory. The material properties of the plate are assumed to vary according to power law distribution of the constituent materials in terms of volume fraction. The sound radiation due to sinusoidally varying point load, uniformly distributed load and obliquely incident sound wave is computed by solving the Rayleigh integral with a primitive numerical scheme. Displacement, velocity, acceleration, radiated sound power level, radiated sound pressure level and radiation efficiency of FGM plate for varying power law index are examined. The sound transmission loss of the FGM plate for several incidence angles and varying power law index is studied in detail. It has been found that, for the plate being considered, the sound power level increases monotonically with increase in power law index at lower frequency range (0-500 Hz) and a non-monotonic trend is appeared towards higher frequencies for both point and distributed force excitations. Increased vibration and acoustic response is observed for ceramic-rich FGM plate at higher frequency band; whereas a similar trend is seen for metal-rich FGM plate at lower frequency band. The dBA values are found to be decreasing with increase in power law index. The radiation efficiency of ceramic-rich FGM plate is noticed to be higher than that of metal and metal-rich FGM plates. The transmission loss below the first resonance frequency is high for ceramic-rich FGM plate and low for metal-rich FGM plate and further depends on the specific material property. The study has found that increased transmission loss can be achieved at higher frequencies with metal-rich FGM plates.

  11. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Permanent field repair of... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable under § 192.241(c) must be repaired as follows: (a) If it is feasible to take the segment of transmission...

  12. 49 CFR 192.711 - Transmission lines: General requirements for repair procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Maintenance § 192.711 Transmission lines: General requirements for repair procedures. (a) Temporary repairs... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: General requirements for..., imperfection, or damage that impairs its serviceability is found in a segment of steel transmission...

  13. 49 CFR 192.711 - Transmission lines: General requirements for repair procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: General requirements for... Maintenance § 192.711 Transmission lines: General requirements for repair procedures. (a) Temporary repairs..., imperfection, or damage that impairs its serviceability is found in a segment of steel transmission...

  14. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Permanent field repair of... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable under § 192.241(c) must be repaired as follows: (a) If it is feasible to take the segment of transmission...

  15. Polar On-Line Acquisition Relay and Transmission System (POLARATS)

    SciTech Connect

    Yuracko, K.

    2004-07-15

    POLARATS (Polar On-Line Acquisition Relay And Transmission System) is being developed by YAHSGS LLC (YAHSGS) and Oak Ridge National Laboratory (ORNL) to provide remote, unattended monitoring of environmental parameters under harsh environmental conditions. In particular, instrumental design and engineering is oriented towards protection of human health in the Arctic, and with the additional goal of advancing Arctic education and research. POLARATS will obtain and transmit environmental data from hardened monitoring devices deployed in locations important to understanding atmospheric and aquatic pollutant migration as it is biomagnified in Arctic food chains. An Internet- and personal computer (PC)-based educational module will provide real time sensor data, on-line educational content, and will be integrated with workbooks and textbooks for use in middle and high school science programs. The educational elements of POLARATS include an Internet-based educational module that will instruct students in the use of the data and how those data fit into changing Arctic environments and food chains. POLARATS will: (1) Enable students, members of the community, and scientific researchers to monitor local environmental conditions in real time over the Internet; and (2) Provide additional educational benefits through integration with middle- and high-school science curricula. Information will be relayed from POLARATS devices to classrooms and libraries along with custom-designed POLARATS teaching materials that will be integrated into existing curricula to enhance the educational benefits realized from the information obtained.

  16. A Study in Wedge Waves with Applications in Acoustic Delay- line

    NASA Astrophysics Data System (ADS)

    Tung, Po-Hsien; Wang, Wen-Chi; Yang, Che-Hua

    The acoustic delay line is usually used to supply protection from dangerous environment, to enhance signal intensity by fit geometry of analyte, or to achieve specific angle/focusing by Snell's law, but rarely to avoid noise from coupling agent and to raise spatial resolution by reducing contact area. This study is focused on wedge waves with applications in delay-line to solve the knot of traditionally transducer measurement. Wedge waves are guided acoustic waves propagating along the tip of a wedge. The advantages of wedge being used in acoustic delay line are wedge waves has large motion amplitude of anti-symmetric flexural (ASF) mode, low energy attenuation and the velocity of ASF more is regular weather frequency varied or not. According the characteristic of wedge wave and vibration direction of particle, the acoustical wedge delay line with high signal- noise-ratio, approximate point-like contact area, without coupling agent and in/out vibration measurement by specific experimental setup is developed.

  17. A collimated focused ultrasound beam of high acoustic transmission and minimum diffraction achieved by using a lens with subwavelength structures

    SciTech Connect

    Lin, Zhou; Tu, Juan; Cheng, Jianchun; Guo, Xiasheng E-mail: dzhang@nju.edu.cn; Wu, Junru; Huang, Pingtong; Zhang, Dong E-mail: dzhang@nju.edu.cn

    2015-09-14

    An acoustic focusing lens incorporated with periodically aligned subwavelength grooves corrugated on its spherical surface has been developed. It is demonstrated theoretically and experimentally that acoustic focusing achieved by using the lens can suppress the relative side-lobe amplitudes, enhance the focal gain, and minimize the shifting of the focus. Use of the lens coupled with a planar ultrasound transducer can generate an ultrasound beam with enhanced acoustic transmission and collimation effect, which offers the capability of improving the safety, efficiency, and accuracy of targeted surgery implemented by high intensity focused ultrasound.

  18. Gas density does not affect pulmonary acoustic transmission in normal men.

    PubMed

    Mahagnah, M; Gavriely, N

    1995-03-01

    Fremitus, the transmission of sound and vibration from the mouth to the chest wall, has long been used clinically to examine the pulmonary system. Recently, modern technology has become available to measure the acoustic transfer function (TF) and transit times (TT) of the pulmonary system. Because sound speed is inversely proportional to the square root of gas density in free gas, but not in porous media, we measured the effect of air and Heliox (80% He-20% O2) breathing on pulmonary sound transmission in six healthy subjects to investigate the mechanism of sound transmission. Wide-band noise (75-2,000 Hz) was "injected" into the mouth and picked up over the trachea and chest wall. The averaged power spectra, TF, phase, and coherence were calculated using a fast Fourier transform-based algorithm. The phase data were used to calculate TT as a function of frequency. TF was found to consist of a low-pass filter property with essentially flat transmitted energy to 300 Hz and exponential decline to 600 Hz at the anterior right upper lobe (CR) and flat transmission to 100 Hz with exponential decline to 150 Hz at the right posterior base (BR). TF was not affected by breathing Heliox. The average TT values, calculated from the slopes of the averaged phase, were 1.5 +/- 0.5 ms for trachea to CR and 5.2 +/- 0.5 ms for trachea to BR transmission during air breathing. During Heliox breathing, the values of TT were 1.5 +/- 0.5 ms and 4.9 +/- 0.5 ms from the trachea to CR and from the trachea to BR locations, respectively. These results suggest that sound transmission in the respiratory system is dominated by wave propagation through the parenchymal porous structure. PMID:7775338

  19. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

    SciTech Connect

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Patrick Browning

    2004-07-20

    The Portable Acoustic Monitoring Package (PAMP) has been designed to record and monitor the acoustic signal in natural gas transmission lines. In particular the three acoustic signals associated with a line leak. The system is portable ({approx}30 lbs) and is designed for line pressures up to 1000 psi. It has become apparent that cataloging of the various background acoustic signals in natural gas transmission line is very important if a system to identify leak signals is to be developed. The low-pressure (0-200 psig) laboratory test phase has been completed and a number of field trials have been conducted. Before the cataloging phase could begin, a few problems identified in field trials identified had to be corrected such as: (1) Decreased microphone sensitivity at line pressures above 250 psig. (2) The inability to deal with large data sets collected when cataloging the variety of signals in a transmission line. (3) The lack of an available online acoustic calibration system. These problems have been solved and the WVU PAMP is now fully functional over the entire pressure range found in the Natural Gas transmission lines in this region. Field portability and reliability have been greatly improved. Data collection and storage have also improved to the point were the full acoustic spectrum of acoustic signals can be accurately cataloged, recorded and described.

  20. 49 CFR 236.73 - Open-wire transmission line; clearance to other circuits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Open-wire transmission line; clearance to other... line; clearance to other circuits. Open-wire transmission line operating at voltage of 750 volts or... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS,...

  1. Effects of high-voltage transmission lines on honeybees

    SciTech Connect

    Greenberg, B.; Bindokas, V.P.; Gauger, J.R.

    1985-05-01

    When shielded and exposed colonies were placed at incremental distances at a right angle from a 760-kV transmission line different thresholds for biologic effects were obtained. Hive exposures were controlled (E-field: 7, 5.5, 4.1, 1.8, and 0.65 to 0.85 kV/m) by variable height current collectors; shielded hives under the line behave normally. Exposure to 7 kV/m can produce the following sequence of events: (1) increased motor activity and transient hive temperature increase; (2) abnormal propolization; (3) retarded hive weight gain; (4) excess queen cell production with queen loss; (5) reduction of sealed brood area; and (6) poor winter survival. No biological effects were detected below 4.1 kV/m, thus the ''biological effects corridor'' is limited to approximately 23 m beyond a ground projection of each outer phase wire. Hive architecture enhances E-fields and creates shock hazards for bees. Intra-hive E-fields (15 to 100+ kV/m) were measured with a displacement current sensor and fiber optic telemetry link. Step-potential-induced currents up to 0.5 uA were measured with a bee model in hives at 7 kV/m. To investigate further the role of shock versus electric field exposure the study was continued to develop hive entrance extensions (porches), which produce controlled bee exposure to E-field or shock, and to test the feasibility of using these porches in such a study. Biological effects (e.g., abnormal propolization, retarded hive weight, queen loss) found in colonies with total-hive exposure were produced by entrance-only exposure of adult bees. We now have an exposure system in which E-field and shock can be separately controlled to reproduce the biological effects. 10 refs.

  2. A Numerical Investigation of Turbine Noise Source Hierarchy and Its Acoustic Transmission Characteristics

    NASA Technical Reports Server (NTRS)

    VanZante, Dale; Envia, Edmane

    2008-01-01

    Understanding the relative importance of the various turbine noise generation mechanisms and the characteristics of the turbine acoustic transmission loss are essential ingredients in developing robust reduced-order models for predicting the turbine noise signature. A computationally based investigation has been undertaken to help guide the development of a turbine noise prediction capability that does not rely on empiricism. The investigation relies on highly detailed numerical simulations of the unsteady flowfield inside a modern high-pressure turbine (HPT). The simulations are developed using TURBO, which is an unsteady Reynolds-averaged Navier-Stokes (URANS) code capable of multi-stage simulations. The purpose of this study is twofold. First, to determine an estimate of the relative importance of the contributions to the coherent part of the acoustic signature of a turbine from the three potential sources of turbine noise generation, namely, blade-row viscous interaction, potential field interaction, and entropic source associated with the interaction of the blade rows with the temperature nonuniformities caused by the incomplete mixing of the hot fluid and the cooling flow. Second, to develop an understanding of the turbine acoustic transmission characteristics and to assess the applicability of existing empirical and analytical transmission loss models to realistic geometries and flow conditions for modern turbine designs. The investigation so far has concentrated on two simulations: (1) a single-stage HPT and (2) a two-stage HPT and the associated inter-turbine duct/strut segment. The simulations are designed to resolve up to the second harmonic of the blade passing frequency tone in accordance with accepted rules for second order solvers like TURBO. The calculations include blade and vane cooling flows and a radial profile of pressure and temperature at the turbine inlet. The calculation can be modified later to include the combustor pattern factor at the

  3. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... encirclement welded split sleeve of appropriate design, unless the transmission line is joined by mechanical... method that reliable engineering tests and analyses show can permanently restore the serviceability...

  4. Requirements for self-magnetically insulated transmission lines

    SciTech Connect

    VanDevender, J. Pace; Pointon, Timothy D.; Seidel, David B.; Struve, Kenneth W.; Jennings, Christopher; Oliver, Bryan V.; Schneider, Larry X.

    2015-03-01

    Self-magnetically insulated transmission lines (MITLs) connect pulsed-power drivers with a load. Although the technology was originally developed in the 1970s and is widely used today in super power generators, failure of the technology is the principal limitation on the power that can be delivered to an experiment. We address issues that are often overlooked, rejected after inadequate simulations, or covered by overly conservative assumptions: (i) electron retrapping in coupling MITLs to loads, (ii) the applicability of collisionless versus collisional electron flow, (iii) power transport efficiency as a function of the geometry at the beginning of the MITL, (iv) gap closure and when gap closure can be neglected, and (v) the role of negative ions in causing anode plasmas and enhancing current losses. We suggest a practical set of conservative design requirements for self-magnetically insulated electron flow based on the results discussed in this paper and on previously published results. The requirements are not necessarily severe constraints in all MITL applications; however, each of the 18 suggested requirements should be examined in the design of a MITL and in the investigation of excessive losses.

  5. Precision electron flow measurements in a disk transmission line.

    SciTech Connect

    Clark, Waylon T.; Pelock, Michael D.; Martin, Jeremy Paul; Jackson, Daniel Peter Jr.; Savage, Mark Edward; Stoltzfus, Brian Scott; Mendel, Clifford Will, Jr.; Pointon, Timothy David

    2008-01-01

    An analytic model for electron flow in a system driving a fixed inductive load is described and evaluated with particle in cell simulations. The simple model allows determining the impedance profile for a magnetically insulated transmission line given the minimum gap desired, and the lumped inductance inside the transition to the minimum gap. The model allows specifying the relative electron flow along the power flow direction, including cases where the fractional electron flow decreases in the power flow direction. The electrons are able to return to the cathode because they gain energy from the temporally rising magnetic field. The simulations were done with small cell size to reduce numerical heating. An experiment to compare electron flow to the simulations was done. The measured electron flow is {approx}33% of the value from the simulations. The discrepancy is assumed to be due to a reversed electric field at the cathode because of the inductive load and falling electron drift velocity in the power flow direction. The simulations constrain the cathode electric field to zero, which gives the highest possible electron flow.

  6. Radial transmission line analysis of multi-layer structures

    SciTech Connect

    Hahn, H.; Hammons, L.

    2011-03-28

    The analysis of multi-layer beam tubes is a standard problem and involves axially propagating waves. This treatment is ill suited to a short multi-layer structure such as the present example of a ferrite covered ceramic break in the beam tube at the ERL photo-cathode electron gun. This paper demonstrates that such structure can better be treated by radial wave propagation. The theoretical method is presented and numerical results are compared with measured network analyser data and Microwave Studio generated simulations. The results confirm the concept of radial transmission lines as a valid analytical method. An Energy Recovery Linac (ERL) is being constructed at this laboratory for the purpose of research towards an envisioned Electron Ion Collider. One of the pertinent topics is damping of Higher Order Modes (HOM). In this ERL, the damping is provided by ferrite absorbers in the beam tube. A modified version thereof, a ceramic break surrounded by ferrite, is planed for the superconducting electron gun. The damper here is located at room temperature just outside of the gun. If used in a cavity chain, the ceramic break is in the vacuum tube at helium temperature whereas the ferrite is moved into the cryostat insulating vacuum allowing higher temperatures. The general properties of the ferrite HOM dampers have been published but are more detailed in this paper.

  7. Requirements for self-magnetically insulated transmission lines

    DOE PAGES

    VanDevender, J. Pace; Pointon, Timothy D.; Seidel, David B.; Struve, Kenneth W.; Jennings, Christopher; Oliver, Bryan V.; Schneider, Larry X.

    2015-03-01

    Self-magnetically insulated transmission lines (MITLs) connect pulsed-power drivers with a load. Although the technology was originally developed in the 1970s and is widely used today in super power generators, failure of the technology is the principal limitation on the power that can be delivered to an experiment. We address issues that are often overlooked, rejected after inadequate simulations, or covered by overly conservative assumptions: (i) electron retrapping in coupling MITLs to loads, (ii) the applicability of collisionless versus collisional electron flow, (iii) power transport efficiency as a function of the geometry at the beginning of the MITL, (iv) gap closuremore » and when gap closure can be neglected, and (v) the role of negative ions in causing anode plasmas and enhancing current losses. We suggest a practical set of conservative design requirements for self-magnetically insulated electron flow based on the results discussed in this paper and on previously published results. The requirements are not necessarily severe constraints in all MITL applications; however, each of the 18 suggested requirements should be examined in the design of a MITL and in the investigation of excessive losses.« less

  8. Choice of transmission line for operation in the millimeter-wave range

    NASA Astrophysics Data System (ADS)

    Kazantsev, V. I.; Kharitonov, A. I.

    1989-10-01

    The paper presents requirements for millimeter-wave transmission lines, including low losses, high electrical strength, wide operating band, weak dispersion, good manufacturability, electrohermeticity, low weight and small size, and low cost. Lines that fully satisfy these requirements are described.

  9. 78 FR 44586 - Draft Environmental Assessment and Proposed Cross Valley Transmission Line Habitat Conservation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... Habitat Conservation Plan, Tulare County, California AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice of availability; receipt of permit application, draft environmental assessment, proposed habitat... prepared the draft Cross Valley Transmission Line Habitat Conservation Plan (Cross Valley Line HCP)...

  10. ``Multifractals in Transmission of Off-line & On-line E-Voting Systems''

    NASA Astrophysics Data System (ADS)

    Maksoed, Wh-

    An e-voting systems is a voting system in which the election data is recorded, stored & processed primarily as digital information. Those are 2 type of e-voting systems: off-line & on-line systems[Alaguvel & Gnanavel, 2013]. ``Using transfer matrix method & multifractal theory, we studied the transmission properties of 1D generalized Fibonacci structures GF(m.n) in which m & n different intervals are integer according to a substitution rule[Yuannong Zhang, et.al,:Multifractal properties of 1D quasi-period Photonic Crystal''. ``Transmission spectra of 1D fractal multilayer structures are found to exhibit self-similar properties'' says Zhukovsky & Lavrinenko in ``Spectral self-similarity in fractal 1D photonic structures'',Photonics & Nanostructures, 2005 whereas Jacob Trevino, et.al studies `structural properties, photonic density of state & bandedge modes of Vogel spiral arrays of dielectric cylinders in air'. Acknowledgment to HE. Mr. AUGUST PARENGKUAN if accepts 1995-2005 Invoicing & Fulfillments to ``KOMPAS'' cq the Prodi of Physics ITB.

  11. Novel Micromachined Coplanar Waveguide Transmission Lines for Application in Millimeter-Wave Circuits

    NASA Astrophysics Data System (ADS)

    Park, Jae-Hyoung; Baek, Chang-Wook; Jung, Sanghwa; Kim, Hong-Teuk; Kwon, Youngwoo; Kim, Yong-Kweon

    2000-12-01

    In this paper, novel micromachined coplanar waveguide(CPW) transmission lines for application in millimeter-wave circuits are proposed. Two types of transmission lines with the length of 1 cm are fabricated and the measured characteristics are compared with those of the conventional CPW transmission line. One is the elevated CPW(ECPW) transmission line and the other is the overlay CPW(OCPW) line. These transmission lines are composed of 3-μm-thick electroplated gold lines with overhanging parts. By elevating the metal lines from the substrate using micromachining technology, the conductor and substrate dielectric loss can be reduced and easily integrated with conventional monolithic microwave integrated circuits. Compared with the conventional CPW line showing 2.65 dB/cm insertion loss at 50 GHz, the loss can be reduced to 1.9 dB/cm and 1.25 dB/cm at 50 GHz in the case of the ECPW and OCPW transmission lines, respectively. Also, the OCPW transmission line shows that the insertion loss does not vary with the change of the characteristic impedance. As shown in the measured and simulated results, the insertion loss is maintained below 1.4 dB/cm over wide impedance ranges.

  12. Cascading multi-hop reservation and transmission in underwater acoustic sensor networks.

    PubMed

    Lee, Jae-Won; Cho, Ho-Shin

    2014-01-01

    The long propagation delay in an underwater acoustic channel makes designing an underwater media access control (MAC) protocol more challenging. In particular, handshaking-based MAC protocols widely used in terrestrial radio channels have been known to be inappropriate in underwater acoustic channels, because of the inordinately large latency involved in exchanging control packets. Furthermore, in the case of multi-hop relaying in a hop-by-hop handshaking manner, the end-to-end delay significantly increases. In this paper, we propose a new MAC protocol named cascading multi-hop reservation and transmission (CMRT). In CMRT, intermediate nodes between a source and a destination may start handshaking in advance for the next-hop relaying before handshaking for the previous node is completed. By this concurrent relaying, control packet exchange and data delivery cascade down to the destination. In addition, to improve channel utilization, CMRT adopts a packet-train method where multiple data packets are sent together by handshaking once. Thus, CMRT reduces the time taken for control packet exchange and accordingly increases the throughput. The performance of CMRT is evaluated and compared with that of two conventional MAC protocols (multiple-access collision avoidance for underwater (MACA-U) and MACA-U with packet trains (MACA-UPT)). The results show that CMRT outperforms other MAC protocols in terms of both throughput and end-to-end delay.

  13. Cascading multi-hop reservation and transmission in underwater acoustic sensor networks.

    PubMed

    Lee, Jae-Won; Cho, Ho-Shin

    2014-01-01

    The long propagation delay in an underwater acoustic channel makes designing an underwater media access control (MAC) protocol more challenging. In particular, handshaking-based MAC protocols widely used in terrestrial radio channels have been known to be inappropriate in underwater acoustic channels, because of the inordinately large latency involved in exchanging control packets. Furthermore, in the case of multi-hop relaying in a hop-by-hop handshaking manner, the end-to-end delay significantly increases. In this paper, we propose a new MAC protocol named cascading multi-hop reservation and transmission (CMRT). In CMRT, intermediate nodes between a source and a destination may start handshaking in advance for the next-hop relaying before handshaking for the previous node is completed. By this concurrent relaying, control packet exchange and data delivery cascade down to the destination. In addition, to improve channel utilization, CMRT adopts a packet-train method where multiple data packets are sent together by handshaking once. Thus, CMRT reduces the time taken for control packet exchange and accordingly increases the throughput. The performance of CMRT is evaluated and compared with that of two conventional MAC protocols (multiple-access collision avoidance for underwater (MACA-U) and MACA-U with packet trains (MACA-UPT)). The results show that CMRT outperforms other MAC protocols in terms of both throughput and end-to-end delay. PMID:25275349

  14. Analysis of the Transient Response of a Dual-Fed RC Transmission Line

    PubMed Central

    Dorraki, Mohsen; Cambrell, Gregory K.; Abbott, Derek

    2015-01-01

    The transient analysis of a uniform transmission line of finite length is considered in this paper. For the first time this paper provides an analytical expression for the time-domain response of an RC transmission line, which is stimulated by a step function that is fed into both ends of the transmission line. In particular, we find an analytical expression for the step response at the center of the transmission line, in order to determine the worst-case rise time. This is of interest, for example, in large charge-coupled device (CCD) arrays, where long polysilicon lines are dual-fed in order to mitigate degradation in rise time. The analytical expressions for the RC transmission line are supported by computer-simulated lumped RC models. PMID:25679379

  15. Transmission in nonuniform ducts - A comparative evaluation of finite element and weighted residuals computational schemes. [acoustic propagation

    NASA Technical Reports Server (NTRS)

    Eversman, W.; Astley, R. J.; Thanh, V. P.

    1977-01-01

    The Method of Weighted Residuals (MWR) and the Finite Element Method (FEM) are considered as computational schemes in the problem of acoustic transmission in nonuniform ducts. MWR is presented in an improved form which includes the interaction of acoustic modes (irrotational) and hydrodynamic modes (rotational). FEM is based on a weighted residuals formulation using eight noded isoparametric elements. Both are applicable to two-dimensional and axially symmetric problems. Calculations are made for several sample problems to demonstrate accuracy and relative efficiency. One test case has implications in the phenomenon of subsonic acoustic choking and it is found that a large transmission loss is not an automatic consequence of propagation against a high subsonic mean flow.

  16. Electric Utility Transmission and Distribution Line Engineering Program

    SciTech Connect

    Peter McKenny

    2010-08-31

    Economic development in the United States depends on a reliable and affordable power supply. The nation will need well educated engineers to design a modern, safe, secure, and reliable power grid for our future needs. An anticipated shortage of qualified engineers has caused considerable concern in many professional circles, and various steps are being taken nationwide to alleviate the potential shortage and ensure the North American power system's reliability, and our world-wide economic competitiveness. To help provide a well-educated and trained workforce which can sustain and modernize the nation's power grid, Gonzaga University's School of Engineering and Applied Science has established a five-course (15-credit hour) Certificate Program in Transmission and Distribution (T&D) Engineering. The program has been specifically designed to provide working utility engineering professionals with on-line access to advanced engineering courses which cover modern design practice with an industry-focused theoretical foundation. A total of twelve courses have been developed to-date and students may select any five in their area of interest for the T&D Certificate. As each course is developed and taught by a team of experienced engineers (from public and private utilities, consultants, and industry suppliers), students are provided a unique opportunity to interact directly with different industry experts over the eight weeks of each course. Course material incorporates advanced aspects of civil, electrical, and mechanical engineering disciplines that apply to power system design and are appropriate for graduate engineers. As such, target students for the certificate program include: (1) recent graduates with a Bachelor of Science Degree in an engineering field (civil, mechanical, electrical, etc.); (2) senior engineers moving from other fields to the utility industry (i.e. paper industry to utility engineering or project management positions); and (3) regular working

  17. Recent progress of the improved magnetically insulated transmission line oscillator.

    PubMed

    Fan, Yu-Wei; Zhong, Hui-Huang; Li, Zhi-Qiang; Shu, Ting; Zhang, Jian-De; Liu, Jin-Liang; Yang, Jian-Hua; Zhang, Jun; Yuan, Cheng-Wei; Luo, Ling

    2008-03-01

    The improved magnetically insulated transmission line oscillator (MILO) is a gigawatt-class L-band high power microwave tube driven by a 550 kV, 57 kA, 50 ns electron beam. It has allowed us to generate 2.4 GW pulse of 22 ns duration. The recent progress of the improved MILO is presented in this paper. First, a field shaper cathode is introduced into the improved MILO to avoid the cathode flares in the triple point region. The experimental results show that the cathode flares are avoided, so the lifetime of the velvet cathode is longer than that of the taper cathode. Furthermore, the shot-to-shot reproducibility is better than that of the taper cathode. Second, In order to prolong the pulse duration and increase the radiated microwave power, a self-built 600 kV, 10 Omega, 80 ns pulser: SPARK-03 is employed to drive the improved MILO. Simulation and experimental investigation are performed. In simulation, when the improved MILO is driven by a 600 kV, 57 kA electron beam, high-power microwave is generated with output power of 4.15 GW, frequency of 1.76 GHz, and relevant power conversion efficiency of 12.0%. In experiments, when the diode voltage is 550 kV and current is 54 kA, the measured results are that the radiated microwave power is above 3.1 GW, the pulse duration is above 40 ns, the microwave frequency is about 1.755 GHz, and the power conversion efficiency is about 10.4%.

  18. 76 FR 21338 - Reopening of Scoping Period for the Northern Pass Transmission Line Project Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-15

    ... Reopening of Scoping Period for the Northern Pass Transmission Line Project Environmental Impact Statement... (DOE) is reopening the public scoping period for the Northern Pass Transmission Line Project Environmental Impact Statement (EIS) (DOE/EIS-0463). The scoping period now ends on June 14, 2011. DOE...

  19. 76 FR 34969 - Extension of Scoping Period for the Northern Pass Transmission Line Project Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-15

    ... Extension of Scoping Period for the Northern Pass Transmission Line Project Environmental Impact Statement... Register (76 FR 7828) its intention to prepare an EIS to assess the potential environmental impacts from... (DOE) is reopening the public scoping period for the Northern Pass Transmission Line...

  20. 78 FR 57372 - Northern Pass Transmission Line Project Environmental Impact Statement: Announcement of Change in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-18

    ... Northern Pass Transmission Line Project Environmental Impact Statement: Announcement of Change in Public... amended Notice of Intent (NOI) to modify the scope of the Northern Pass Transmission Line Project Environmental Impact Statement (EIS) (DOE/EIS-0463) and to conduct additional public scoping meetings (78...

  1. A calibration technique for measuring the complex permittivity of materials with planar transmission lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple two-standard calibration procedure for determining the permittivity of a material from the propagation constant measured with planar transmission lines is presented. The suitability of this procedure is demonstrated by using a coplanar waveguide transmission-line sensor to measure the permi...

  2. View facing east (70°) of Transmission Line crossing Marias River, ...

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

    View facing east (70°) of Transmission Line crossing Marias River, near Structure 47-9, grain elevators in town of Loma visible in background - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  3. Context view of RyantoRainbow 100kv Transmission Line showing copper wire ...

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

    Context view of Ryan-to-Rainbow 100kv Transmission Line showing copper wire conductors leaving roof of Ryan Powerhouse. View to east - Ryan Hydroelectric Facility, Ryan-to-Rainbow 100 kV Transmission Line, West bank of Missouri River, northeast of Great Falls, Great Falls, Cascade County, MT

  4. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak on a transmission line must be made by— (a) Removing the leak by cutting out and replacing...

  5. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak on a transmission line must be made by— (a) Removing the leak by cutting out and replacing...

  6. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak on a transmission line must be made by— (a) Removing the leak by cutting out and replacing...

  7. Some Little-Known Facts about Transmission Lines and Some New Results

    ERIC Educational Resources Information Center

    Dutta Roy, Suhash C.

    2010-01-01

    The study of transmission lines forms an integral part of any curriculum in electrical engineering. This paper presents some little-known but interesting facts about transmission lines, which are generally not found in textbooks, along with some new facts, which arose as extensions of these little-known ones. The facts highlighted in this paper…

  8. Explanation of the inverse Doppler effect observed in nonlinear transmission lines.

    PubMed

    Kozyrev, Alexander B; van der Weide, Daniel W

    2005-05-27

    The theory of the inverse Doppler effect recently observed in magnetic nonlinear transmission lines is developed. We explain the crucial role of the backward spatial harmonic in the occurrence of an inverse Doppler effect and draw analogies of the magnetic nonlinear transmission line to the backward wave oscillator.

  9. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Permanent field repair of welds. 192.715 Section 192.715 Transportation Other Regulations Relating to Transportation (Continued... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable...

  10. 75 FR 56051 - Bemidji to Grand Rapids Minnesota 230 kV Transmission Line Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-15

    ...; ] DEPARTMENT OF AGRICULTURE Rural Utilities Service Bemidji to Grand Rapids Minnesota 230 kV Transmission Line... Rapids, Minnesota 230 kV Transmission Line Project (``Project'') in Minnesota. The Final EIS was prepared... application of Minnkota Power Cooperative, Inc. for RUS financing to construct a 230 kilovolt...

  11. Determination of near-surface material properties by line-focus acoustic microscopy

    SciTech Connect

    Achenbach, J.D.; Li, W.

    1996-12-31

    A line-focus acoustic microscope is used in conjunction with a multiple wave-mode method to determine elastic constants from a single V(z) measurement. V(z) curves which include contributions from different wave modes, measured using the line-focus acoustic microscope at 225 MHz, have been compared with theoretical results predicted by a V(z) measurement model. The determination of elastic constants has been achieved numerically by seeking a set of elastic constants that leads to the best fit, in the least square sense, of the theoretical results to the experimental ones. The method has been applied to isotropic materials in bulk, and plate and thin-film configurations. Elastic constants for each of these cases have been determined. The consistency, convergence, sensitivity and accuracy of the procedure have been investigated.

  12. Acoustic Reflection and Transmission of 2-Dimensional Rotors and Stators, Including Mode and Frequency Scattering Effects

    NASA Technical Reports Server (NTRS)

    Hanson, Donald B.

    1999-01-01

    A reduced order modeling scheme has been developed for the unsteady acoustic and vortical coupling between blade rows of a turbomachine. The essential behavior of the system is governed by modal scattering coefficients (i.e., reflection and transmission coefficients) of the rotor, stator, inlet and nozzle, which are calculated as if they were connected to non-reflecting ducts. The objective of this report is to identify fundamental behavior of these scattering coefficients for a better understanding of the role of blade row reflection and transmission in noise generation. A 2D flat plate unsteady cascade model is used for the analysis with the expectation that the general behavior presented herein will carry over to models that include more realistic flow and geometry. It is shown that stators scatter input waves into many modes at the same frequency whereas rotors scatter on frequency, or harmonic order. Important cases are shown here the rotor reflection coefficient is greater than unity; a mode at blade passing frequency (BPF) traveling from the stator with unit sound power is reflected by the rotor with more than unit power at 2xBPF and 3xBPE Analysis is presented to explain this unexpected phenomenon. Scattering curves are presented in a format chosen for design use and for physical interpretation. To aid in interpretation of the curves, formulas are derived for special condition where waveforms are parallel to perpendicular to the rotor.

  13. Acoustic echo cancellation for full-duplex voice transmission on fading channels

    NASA Astrophysics Data System (ADS)

    Park, Sangil; Messer, Dion D.

    This paper discusses the implementation of an adaptive acoustic echo canceler for a hands-free cellular phone operating on a fading channel. The adaptive lattice structure, which is particularly known for faster convergence relative to the conventional tapped-delay-line (TDL) structure, is used in the initialization stage. After convergence, the lattice coefficients are converted into the coefficients for the TDL structure which can accommodate a larger number of taps in real-time operation due to its computational simplicity. The conversion method of the TDL coefficients from the lattice coefficients is derived and the DSP56001 assembly code for the lattice and TDL structure is included, as well as simulation results and the schematic diagram for the hardware implementation.

  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. Computation of transient electromagnetic fields radiated by transmission line: An exact model

    SciTech Connect

    Shi, R.S.; Darcherif, A.; Sabonnadiere, J.C.

    1995-07-01

    A novel time domain analytical method for predicting electromagnetic field transients resulting from power line switching operations is presented in this paper. This method, which is directly derived from electromagnetic field theory of a power transmission line, allows the field transients to be accurately and efficiently calculated. It will be shown that conventional numerical methods for computing transmission line transient electromagnetic fields are in fact degenerative approximate models for this analytical method.

  16. 1KW Power Transmission Using Wireless Acoustic-Electric Feed-Through (WAEF)

    NASA Technical Reports Server (NTRS)

    Sherrit, S.; Bao, X.; Badescu, M.; Aldrich, J.; Bar-Cohen, Y.; Biederman, W.

    2008-01-01

    A variety of space applications require the delivery of power into sealed structures. Since the structural integrity can be degraded by holes for cabling we present an alternative method of delivering power and information using stress waves to the internal space of a sealed structure. One particular application of this technology is in sample return missions where it is critical to preserve the sample integrity and to prevent earth contamination. Therefore, the container has to be hermetically sealed and the integrity of the seal must be monitored in order to insure to a high degree of reliability the integrity of the sample return vessel. In this study we investigated the use of piezoelectric acoustic-electric power feed-through devices to transfer electric power wirelessly through a solid wall by using elastic or acoustic waves. The technology is applicable to a range of space and terrestrial applications where power is required by electronic equipment inside sealed containers, vacuum or pressure vessels, etc., where holes in the wall are prohibitive or may result in significant structural performance degradation or unnecessarily complex designs. To meet requirements of higher power applications, the feasibility to transfer kilowatts level power was investigated. Pre-stressed longitudinal piezoelectric feed-through devices were analyzed by finite element models and an equivalent circuit model was developed to predict the power transfer characteristics to different electric loads. Based on the results of the analysis a prototype device was designed, fabricated and a demonstration of the transmission of electric power up to 1.068-kW was successfully conducted. Efficiencies in the 80-90% range were also demonstrated and methods to increase the efficiency further are currently being considered.

  17. Transmission characteristics and transmission line model of a metal-insulator-metal waveguide with a stub modified by cuts.

    PubMed

    Shen, Xinru; Wang, Yueke; Yan, Xin; Yuan, Lin; Sang, Tian

    2016-08-10

    We propose a structure of a metal-insulator-metal (MIM) waveguide with a stub modified by cuts. Our simulation results, conducted by the finite element method, show that the wavelengths of transmission dip vary with the position of the cuts and form the zigzag lines. A transmission line model is also presented, and it agrees with simulation results well. It is believed that our findings provide a smart way to design a plasmonic waveguide filter at the communication region based on MIM structures. PMID:27534492

  18. The effect of external mean flow on sound transmission through double-walled cylindrical shells lined with poroelastic material

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Bhaskar, Atul; Zhang, Xin

    2014-03-01

    Sound transmission through a system of double shells, lined with poroelastic material in the presence of external mean flow, is studied. The porous material is modeled as an equivalent fluid because shear wave contributions are known to be insignificant. This is achieved by accounting for the energetically most dominant wave types in the calculations. The transmission characteristics of the sandwich construction are presented for different incidence angles and Mach numbers over a wide frequency range. It is noted that the transmission loss exhibits three dips on the frequency axis as opposed to flat panels where there are only two such frequencies—results are discussed in the light of these observations. Flow is shown to decrease the transmission loss below the ring frequency, but increase this above the ring frequency due to the negative stiffness and the damping effect added by the flow. In the absence of external mean flow, porous material provides superior insulation for most part of the frequency band of interest. However, in the presence of external flow, this is true only below the ring frequency—above this frequency, the presence of air gap in sandwich constructions is the dominant factor that determines the acoustic performance. In the absence of external flow, an air gap always improves sound insulation.

  19. Sound transmission through a double-panel construction lined with poroelastic material in the presence of mean flow

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Bhaskar, Atul; Zhang, Xin

    2013-08-01

    This paper investigates the sound transmission characteristics through a system of double-panel lined with poroelastic material in the core. The panels are surrounded by external and internal fluid media where a uniform external mean flow exists on one side. Biot's theory is used to model the porous material. Three types of constructions—bonded-bonded, bonded-unbonded and unbonded-unbonded—are considered. The effect of Mach number of the external flow on the sound transmission over a wide frequency range in a diffuse sound field is examined. External mean flow is shown to give a modest increase in transmission loss at low frequency, but a significant increase at high frequency. It is brought out that calculations based on static air on the incidence side provide a conservative estimate of sound transmission through the sandwich structure. The acoustic performance of the sandwich panel for different configurations is presented. The effect of curvature of the panel is also brought out by using shallow shell theory.

  20. Sensor, method and system of monitoring transmission lines

    SciTech Connect

    Syracuse, Steven J.; Clark, Roy; Halverson, Peter G.; Tesche, Frederick M.; Barlow, Charles V.

    2012-10-02

    An apparatus, method, and system for measuring the magnetic field produced by phase conductors in multi-phase power lines. The magnetic field measurements are used to determine the current load on the conductors. The magnetic fields are sensed by coils placed sufficiently proximate the lines to measure the voltage induced in the coils by the field without touching the lines. The x and y components of the magnetic fields are used to calculate the conductor sag, and then the sag data, along with the field strength data, can be used to calculate the current load on the line and the phase of the current. The sag calculations of this invention are independent of line voltage and line current measurements. The system applies a computerized fitter routine to measured and sampled voltages on the coils to accurately determine the values of parameters associated with the overhead phase conductors.

  1. 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

  2. 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. PMID:25105157

  3. 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.

  4. A planar transmission-line sensor for measuring microwave permittivity of liquid and semisolid biological materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An accurate technique for determining the permittivity of biological materials with coplanar waveguide transmission line is presented. The technique utilizes closed-form approximations that relate the material permittivity to the line propagation constant. A thru-reflect-line calibration procedure i...

  5. Research on UAV Intelligent Obstacle Avoidance Technology During Inspection of Transmission Line

    NASA Astrophysics Data System (ADS)

    Wei, Chuanhu; Zhang, Fei; Yin, Chaoyuan; Liu, Yue; Liu, Liang; Li, Zongyu; Wang, Wanguo

    Autonomous obstacle avoidance of unmanned aerial vehicle (hereinafter referred to as UAV) in electric power line inspection process has important significance for operation safety and economy for UAV intelligent inspection system of transmission line as main content of UAV intelligent inspection system on transmission line. In the paper, principles of UAV inspection obstacle avoidance technology of transmission line are introduced. UAV inspection obstacle avoidance technology based on particle swarm global optimization algorithm is proposed after common obstacle avoidance technologies are studied. Stimulation comparison is implemented with traditional UAV inspection obstacle avoidance technology which adopts artificial potential field method. Results show that UAV inspection strategy of particle swarm optimization algorithm, adopted in the paper, is prominently better than UAV inspection strategy of artificial potential field method in the aspects of obstacle avoidance effect and the ability of returning to preset inspection track after passing through the obstacle. An effective method is provided for UAV inspection obstacle avoidance of transmission line.

  6. Acoustic transmission analysis on cavity resonance sound in a cylindrical cavity system: application to a Korean bell.

    PubMed

    Jeong, Won Tae; Kang, Yeon June; Kim, Seock Hyun

    2012-02-01

    This paper presents an analytical model for acoustic transmission characteristics of a cylindrical cavity system representing the acoustic resonance conditions of a Korean bell. The cylindrical cavity system consists of an internal cavity, a gap, an auxiliary cavity, and a rigid base. Since the internal cavity is connected to the external field through a gap, determination of the acoustic transmission characteristics becomes a coupling problem between the internal cavity and external field. The acoustic field of the internal cavity is considered by expanding the solution method of the mixed boundary problem, and the external field is addressed by modifying the radiation impedance model of a finite cylinder. The analytical model is validated by comparison with both experiment and a boundary element method. Using the analytical model, the resonance conditions are determined to maximize the resonance effect. Thus, the resonance frequencies of the bell cavity system are investigated according to the gap size and auxiliary cavity depth. By adjusting gap size or auxiliary cavity depth, the cavity resonance frequency is tuned to resonate partial tones of the bell sound. Finally, the optimal combination of gap size and auxiliary cavity depth is determined. PMID:22352524

  7. Self-Characterization of Commercial Ultrasound Probes in Transmission Acoustic Inverse Scattering: Transducer Model and Volume Integral Formulation

    PubMed Central

    Haynes, Mark; Verweij, Sacha A. M.; Moghaddam, Mahta; Carson, Paul L.

    2014-01-01

    A self-contained source characterization method for commercial ultrasound probes in transmission acoustic inverse scattering is derived and experimentally tested. The method is based on modified scattered field volume integral equations that are linked to the source-scattering transducer model. The source-scattering parameters are estimated via pair-wise transducer measurements and the nonlinear inversion of an acoustic propagation model that is derived. This combination creates a formal link between the transducer characterization and the inverse scattering algorithm. The method is tested with two commercial ultrasound probes in a transmission geometry including provisions for estimating the probe locations and aligning a robotic rotator. The transducer characterization results show that the nonlinear inversion fit the measured data well. The transducer calibration and inverse scattering algorithm are tested on simple targets. Initial images show that the recovered contrasts are physically consistent with expected values. PMID:24569251

  8. A planar transmission-line sensor for measuring the microwave permittivity of liquid and semisolid biological materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A planar transmission-line configuration for rapid, nondestructive, wideband permittivity measurements of liquid and semisolid materials at microwave frequencies is described. The transmission-line propagation constant of the proposed configuration is determined with the multiline technique from sca...

  9. Hayden-Blue River 345-kV transmission line project, Colorado

    SciTech Connect

    Not Available

    1982-09-01

    Tri-State Generation and Transmission Association, Inc., Colorado-Ute Electric Association, Inc., Platte River Power Authority, and Western Area Power Administration propose to construct and operate approximately 90 miles of 345-kilovolt (kV) transmission line between Hayden and the Blue River Valley in Colorado. The project would involve expansion of existing substation facilities at Hayden and construction of two new substations. The line would be operated at 230 kV initially. Estimated cost of the project is $37.8 million. The new line and substation facilities would provide a backup transmission path, satisfy the long-term needs in meeting the energy requirements, improve system reliability, improve system stability for the Craig and Hayden generating stations, and leave the existing 115-kV and 138-kV lines in operation to provide additional transmission capacity that would function as backup transmission during an outage on another line. Minute amounts of lands would be displaced. Construction activities would disturb critical ranges for elk and mule deer, elk calving areas, and the mating and nesting areas of greater sandhill cranes, great blue herons, sage grouse, golden eagles, and prairie falcons. Management of timberland would damage natural vegetation. The line would traverse 3.1 miles of flood-prone area, and as many as three transmission towers would lie within the floodplain of the Colorado River. The visual quality of land crossed by the line would be degraded somewhat.

  10. 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

    This report provides 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 on alternatives in environmental documents. EMF strengths at 0 {+-} 200 ft from centerline were calculated for ac overhead lines, and for 345 and 230-kV ac underground line and for a {+-}450-kV dc overhead line. Compacting and height sensitivity factors were computed for the variation in EMFs when line conductors are moved closer or raised. Estimated costs for the lines are presented and discussed so that the impact of using alternative strategies for reducing EMF strengths and the implications of implementing the strategies can be better appreciated.

  11. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

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

  12. Coyote Pumping Plant 115-kV transmission line project, Santa Clara County, California: Environmental assessment

    SciTech Connect

    Not Available

    1985-01-01

    Environmental impacts expected from the design and siting of transmission lines and the associated pumping plant station are addressed with alternative routes and actions considered, in compliance with environmental laws. (PSB)

  13. PennsylvaniaNew Jersey Interconnection Bushkill to Roseland Transmission Line, From Roseland ...

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

    Pennsylvania-New Jersey Interconnection Bushkill to Roseland Transmission Line, From Roseland Borough, Essex County, through Morris County and Sussex County to Hardwick Township, Warren County, Roseland, Essex County, NJ

  14. A unique method to study acoustic transmission through ducts using signal synthesis and averaging of acoustic pulses

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Ramakrishnan, R.; Ahuja, K. K.; Brown, W. H.

    1981-01-01

    An acoustic impulse technique using a loudspeaker driver is developed to measure the acoustic properties of a duct/nozzle system. A signal synthesis method is used to generate a desired single pulse with a flat spectrum. The convolution of the desired signal and the inverse Fourier transform of the reciprocal of the driver's response are then fed to the driver. A signal averaging process eliminates the jet mixing noise from the mixture of jet noise and the internal noise, thereby allowing very low intensity signals to be measured accurately, even for high velocity jets. A theoretical analysis is carried out to predict the incident sound field; this is used to help determine the number and locations of the induct measurement points to account for the contributions due to higher order modes present in the incident tube method. The impulse technique is validated by comparing experimentally determined acoustic characteristics of a duct-nozzle system with similar results obtained by the impedance tube method. Absolute agreement in the comparisons was poor, but the overall shapes of the time histories and spectral distributions were much alike.

  15. First structure on MoronytoRainbow 100kV Transmission Line below Morony Dam ...

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

    First structure on Morony-to-Rainbow 100kV Transmission Line below Morony Dam and Power House. Three-pole H-frame structure with historic porcelain suspension insulators, jumper supports insulators, overhead ground wires, and pole stubs. View to east-northeast - Morony Hydroelectric Facility, Morony-to-Rainbow 100 kV Transmission Line, West bank of the Missouri River, Great Falls, Cascade County, MT

  16. Optimized Minimal Inductance Transmission Line Configuration for Z-Pinch Experiments

    SciTech Connect

    Hurricane, O

    2003-10-16

    Successful dynamic Z-pinch experiments generally require good current delivery to the target load. Power flow losses through highly inductive transmission line configurations reduce the current available to the load. In this Brief Report, a variational calculus technique is used to determine the transmission line configuration that produces the least possible inductance and therefore the best possible current delivery for Z-pinch experiments.

  17. TE sub r azimuthal modes for a biconic transmission line in the small-gap limit

    SciTech Connect

    Johnson, W.A.; Mendel, C.W. Jr.; Seidel, D.B. )

    1992-04-15

    Azimuthally asymmetric modes in a biconic transmission line with a small-gap angle may be approximated by transmission-line-like'' modes. It is shown that the errors in these approximations are second order in the gap angle and approximate error bounds are provided. As an example demonstrating the application of this analysis in biconic structures, an analysis to characterize of the electromagnetic waves in the vacuum feed of the Particle Beam Fusion Accelerator II is provided.

  18. Multisection transmission line scatter function theory for measurements of soil dielectric properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vector network analyzers measure both reflection (S11) and transmission (S21) functions, but S21 has not been used to estimate soil dielectric permittivity independently. The objectives of this study were to: (1) derive the mathematical model for S21 of a multisection transmission line, and (2) tes...

  19. 33 CFR 165.T01-0992 - Safety Zone; repair of high voltage transmission lines to Logan International Airport; Saugus...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... voltage transmission lines to Logan International Airport; Saugus River, Saugus, MA. 165.T01-0992 Section... high voltage transmission lines to Logan International Airport; Saugus River, Saugus, MA. (a) General... high voltage transmission lines to Logan International Airport; Saugus River, Saugus, MA. (i)...

  20. Analysis of optimum diameter of orbit of transmission line source in positron emission tomograph

    SciTech Connect

    Yamamoto, S.; Amano, M.; Hirose, Y.; Muira, S.; Kanno, I.

    1989-02-01

    Accurate attenuation correction is one of the most important factors to achieve quantitative measurements in positron emission tomography (PET). A transmission scan is most commonly used technique for the attenuation correction in PET. A difficulty in transmission scan is relatively long period to obtain a data with good signal-to-noise ratio. Insufficient signal-to-noise ratio of the transmission data limits that of emission data. Several approaches were reported to improve the transmission data. Those were (1) optimizing of detector threshold, (2) processing delayed coincidence sinogram before subtraction, filtering of transmission sinogram before performing attenuation correction, and (3) rejection of random and scatter coincidence by using rotating line source and information of its position. In some of these methods, additional calculation time or processing hardware is needed. The authors have estimated a relationship between ring diameter of a transmission line source and signal to noise ratio of the transmission dat. This paper aimes to analyze optimum diameter of the orbit of transmission line source in concerning to signal to noise ratio in transmission data.

  1. Sound propagation in and radiation from acoustically lined flow ducts: A comparison of experiment and theory

    NASA Technical Reports Server (NTRS)

    Plumblee, H. E., Jr.; Dean, P. D.; Wynne, G. A.; Burrin, R. H.

    1973-01-01

    The results of an experimental and theoretical study of many of the fundamental details of sound propagation in hard wall and soft wall annular flow ducts are reported. The theory of sound propagation along such ducts and the theory for determining the complex radiation impedance of higher order modes of an annulus are outlined, and methods for generating acoustic duct modes are developed. The results of a detailed measurement program on propagation in rigid wall annular ducts with and without airflow through the duct are presented. Techniques are described for measuring cut-on frequencies, modal phase speed, and radial and annular mode shapes. The effects of flow velocity on cut-on frequencies and phase speed are measured. Comparisons are made with theoretical predictions for all of the effects studies. The two microphone method of impedance is used to measure the effects of flow on acoustic liners. A numerical study of sound propagation in annular ducts with one or both walls acoustically lined is presented.

  2. Parabolic equation modeling of high frequency acoustic transmission with an evolving sea surface.

    PubMed

    Senne, J; Song, A; Badiey, M; Smith, K B

    2012-09-01

    The present paper examines the temporal evolution of acoustic fields by modeling forward propagation subject to sea surface dynamics with time scales of less than a second to tens of seconds. A time-evolving rough sea surface model is combined with a rough surface formulation of a parabolic equation model for predicting time-varying acoustic fields. Surface waves are generated from surface wave spectra, and stepped in time using a Runge-Kutta integration technique applied to linear evolution equations. This evolving, range-dependent surface information is combined with other environmental parameters and input to the acoustic model, giving an approximation of the time-varying acoustic field. The wide-angle parabolic equation model manages the rough sea surfaces by molding them into the boundary conditions for calculations of the near-surface acoustic field. This merged acoustic model is validated using concurrently-collected acoustic and environmental information, including surface wave spectra. Data to model comparisons demonstrate that the model is able to approximate the ensemble-averaged acoustic intensity at ranges of about a kilometer for acoustic signals of around 15 kHz. Furthermore, the model is shown to capture variations due to surface fluctuations occurring over time scales of less than a second to tens of seconds.

  3. The physical meaning of transmission-line parameters in a full-wave theory

    NASA Astrophysics Data System (ADS)

    Rambousky, Ronald; Nitsch, Jürgen; Tkachenko, Sergey

    2016-09-01

    In the potential-current representation, transmission-line parameters in the Transmission-Line Super Theory (TLST) do not have a direct physical meaning - they are gauge dependent, i.e.: they are different in the Lorenz and Coulomb gauge. However, they retain traces of their classical origin: They are constituted of capacitances and inductances for forward and backward running waves along the lines. Therefore their corresponding matrices are not symmetrical as in the case of classical transmission-line theory. In the charge-current representation the parameter matrices have a physical meaning: their elements consist of damping functions due to the non-uniformities of the lines and of the propagation functions along the lines, incorporating conductor and radiation losses. The transmission line parameters also contribute to the total radiated power of the lines. The attempt to quantize radiation locally, fails because radiation describes a long-range (integral) interaction, and therefore affects all conductor parts of all lines. However, it can be stated that at stronger inhomogeneities the local contributions to radiation increase, and are particularly recognizable along the risers.

  4. Millikelvin thermal and electrical performance of lossy transmission line filters

    SciTech Connect

    Slichter, Daniel; Naaman, Ofer; Siddiqi, Irfan

    2009-03-11

    We report on the scattering parameters and Johnson noise emission of low-pass stripline filters employing a magnetically loaded silicone dielectric down to 25 mK. The transmission characteristic of a device with f-3dB=1.3 GHz remains essentially unchanged upon cooling. Another device with f-edB=0.4 GHz, measured in its stopband, exhibits a steady state noise power emission consistent with a temperature difference of a few mK relative to a well-anchored cryogenic microwave attenuator at temperatures down to 25 mK, thus presenting a matched thermal load.

  5. Acoustic emission and magnification of atomic lines resolution for laser breakdown of salt water in ultrasound field

    SciTech Connect

    Bulanov, Alexey V.; Nagorny, Ivan G.

    2015-10-28

    Researches of the acoustic effects accompanying optical breakdown in a water, generated by the focused laser radiation with power ultrasound have been carried out. Experiments were performed by using 532 nm pulses from Brilliant B Nd:YAG laser. Acoustic radiation was produced by acoustic focusing systems in the form hemisphere and ring by various resonance frequencies of 10.7 kHz and 60 kHz. The experimental results are obtained, that show the sharply strengthens effects of acoustic emission from a breakdown zone by the joint influence of a laser and ultrasonic irradiation. Essentially various thresholds of breakdown and character of acoustic emission in fresh and sea water are found out. The experimental result is established, testifying that acoustic emission of optical breakdown of sea water at presence and at absence of ultrasound essentially exceeds acoustic emission in fresh water. Atomic lines of some chemical elements like a Sodium, Magnesium and so on were investigated for laser breakdown of water with ultrasound field. The effect of magnification of this lines resolution for salt water in ultrasound field was obtained.

  6. Numerical and experimental analysis of unidirectional meander-line coil electromagnetic acoustic transducers.

    PubMed

    Wang, Shujuan; Su, Riliang; Chen, Xiaoyang; Kang, Lei; Zhai, Guofu

    2013-12-01

    The elastic waves generated by traditional meander-line coil electromagnetic acoustic transducers (EMATs) propagate in two directions, overlapping the echo signals from defects with the same distances, and the defect echo signal is hard to distinguish from the edge-reflected signal when the EMATs are near the edge of a specimen. In this paper, a unidirectional EMAT with two meander-line coils is proposed. A finite element model is used to simulate the directivity of the Rayleigh and shear vertical waves generated by these EMATs. Six transducers are fabricated using the printed circuit technique. The unidirectional Rayleigh wave and shear vertical wave are tested, and the results agree well with the simulation.

  7. An additional channel for FM signal transmission in standard fiber-optic AM communication lines

    NASA Astrophysics Data System (ADS)

    Lebedev, V. V.; Anufriev, K. M.; Toguzov, N. V.; Il'ichev, I. V.; Shamray, A. V.

    2015-11-01

    A paradigm has been developed according to which an additional FM signal transfer channel is formed in a standard optical fiber transmission line without violating the main AM channel operation. Using the proposed approach, an RS-232 interface signal has been experimentally transferred via a standard intraobject 100-Mbit Ethernet line based on an SMF-28 single-mode optical fiber.

  8. Measuring the complex permittivity of poultry meat with a planar transmission-line sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A planar transmission-line sensor is used to measure the complex permittivity of chicken breast meat over the frequency range 0.5 – 5 GHz. Results for the permittivity of nine samples of chicken breast meat are compared to results obtained with a commercially available open-ended coaxial-line probe....

  9. Reflection of an acoustic line source by an impedance surface with uniform flow

    NASA Astrophysics Data System (ADS)

    Brambley, E. J.; Gabard, G.

    2014-10-01

    An exact analytic solution is derived for the 2D acoustic pressure field generated by a time-harmonic line mass source located above an impedance surface with uniform grazing flow. Closed-form asymptotic solutions in the far field are also provided. The analysis is valid for both locally-reacting and nonlocally-reacting impedances, as is demonstrated by analyzing a nonlocally reacting effective impedance representing the presence of a thin boundary layer over the surface. The analytic solution may be written in a form suggesting a generalization of the method of images to account for the impedance surface. The line source is found to excite surface waves on the impedance surface, some of which may be leaky waves which contradict the assumption of decay away from the surface predicted in previous analyses of surface waves with flow. The surface waves may be treated either (correctly) as unstable waves or (artificially) as stable waves, enabling comparison with previous numerical or mathematical studies which make either of these assumptions. The computer code for evaluating the analytic solution and far-field asymptotics is provided in the supplementary material. It is hoped this work will provide a useful benchmark solution for validating 2D numerical acoustic codes.

  10. Line-focusing electromagnetic acoustic transducers for the detection of slit defects.

    PubMed

    Ogi, H; Hirao, M; Ohtani, T

    1999-01-01

    This paper describes the design principles of a line-focusing electromagnetic acoustic transducer (LF-EMAT) and the results of a feasibility test for detecting slit-type defects in metals. The LF-EMAT excites shear vertical (SV) elastic waves and focuses them to a line in a metal body. It consists of a permanent magnet block and a meanderline coil, whose spacing is continuously varied so that the excited SV waves become coherent on a focal line after traveling oblique paths. The measured directivity of generation and reception show a sharp peak at the designed focal line. The LF-EMATs are then applied to detecting slit defects in the bottom surface of steel blocks, on which the focal lines are located. Portions of the scattered defect signals are received by the same EMAT. When operated at 4 MHz, the LF-EMATs are capable of detecting slits deeper than 0.05 mm. The sensitivity decreases with liftoff and the LF-EMATs are usable with liftoff up to 0.6 mm. PMID:18238430

  11. An on-line acoustic fluorocarbon coolant mixture analyzer for the ATLAS silicon tracker

    SciTech Connect

    Bates, R.; Battistin, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Bousson, N.; Boyd, G.; Botelho-Direito, J.; DiGirolamo, B.; Doubek, M.; Egorov, K.; Godlewski, J.; Hallewell, G.; Katunin, S.; Mathieu, M.; McMahon, S.; Nagai, K.; Perez-Rodriguez, E.; Rozanov, A.; Vacek, V.; Vitek, M.

    2011-07-01

    The ATLAS silicon tracker community foresees an upgrade from the present octafluoro-propane (C{sub 3}F{sub 8}) evaporative cooling fluid - to a composite fluid with a probable 10-20% admixture of hexafluoro-ethane (C{sub 2}F{sub 6}). Such a fluid will allow a lower evaporation temperature and will afford the tracker silicon substrates a better safety margin against leakage current-induced thermal runaway caused by cumulative radiation damage as the luminosity profile at the CERN Large Hadron Collider increases. Central to the use of this new fluid is a new custom-developed speed-of-sound instrument for continuous real-time measurement of the C{sub 3}F{sub 8}/C{sub 2}F{sub 6} mixture ratio and flow. An acoustic vapour mixture analyzer/flow meter with new custom electronics allowing ultrasonic frequency transmission through gas mixtures has been developed for this application. Synchronous with the emission of an ultrasound 'chirp' from an acoustic transmitter, a fast readout clock (40 MHz) is started. The clock is stopped on receipt of an above threshold sound pulse at the receiver. Sound is alternately transmitted parallel and anti-parallel with the vapour flow for volume flow measurement from transducers that can serve as acoustic transmitters or receivers. In the development version, continuous real-time measurement of C{sub 3}F{sub 8}/C{sub 2}F{sub 6} flow and calculation of the mixture ratio is performed within a graphical user interface developed in PVSS-II, the Supervisory, Control and Data Acquisition standard chosen for LHC and its experiments at CERN. The described instrument has numerous potential applications - including refrigerant leak detection, the analysis of hydrocarbons, vapour mixtures for semiconductor manufacture and anesthetic gas mixtures. (authors)

  12. Measurement of the Stochastic Electromagnetic Field Coupling into Transmission Lines in a Reverberation Chamber

    NASA Astrophysics Data System (ADS)

    Magdowski, M.; Siddiqui, S.; Vick, R.

    2012-05-01

    The coupling of stochastic electromagnetic fields to a straight and uniform transmission line was measured in a reverberation chamber. Such stochastic fields also appear in large and complex overmoded cavities like aircraft fuse- lages and satellite enclosures. The measurements were carried out with different line lengths over a large frequency range. The results are analyzed with respect to the statistical distribution of the characteristics of the coupled voltage and compared to simulated values. The simulation is based on a transmission line model and a plane wave representation of the field.

  13. Political efficacy and familiarity as predictors of attitudes towards electric transmission lines in the United States

    DOE PAGES

    Joe, Jeffrey C.; Hendrickson, Kelsie; Wong, Maria; Kane, Stephanie L.; Solan, David; Carlisle, Juliet E.; Koehler, David; Ames, Daniel P.; Beazer, Robert

    2016-05-18

    Public opposition to the construction (i.e., siting) of new high voltage overhead transmission lines is not a new or isolated phenomenon. Past research has posited a variety of reasons, applied general theories, and has provided empirical evidence to explain public opposition. The existing literature, while clarifying many elements of the issue, does not yet fully explain the complexities underlying this public opposition phenomenon. As a result, the current study demonstrated how two overlooked factors, people’s sense of political efficacy and their familiarity (i.e., prior exposure) with transmission lines, explained attitudes of support and opposition to siting new power lines.

  14. 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.

  15. Terawatt power division and combination using self-magnetically insulated transmission lines

    SciTech Connect

    Crow, J.T.; Peterson, G.D.

    1980-01-01

    Self-magnetically insulated transmission lines are necessary for the efficient transport of the terawatt pulses used in electron and ion accelerators. For some applications it is desirable to divide one transmission line into two, or to combine outputs of two or more lines into one, by means of self-magnetically insulated convolutes. Tests have been made on a coaxial-to-triaxial convolute in which connections between negative inner and outer lines are made by pins passing through holes in the intermediate positive conductor. Measurements in the 2 MV, 400 kA, 40 ns pulse Mite facility indicate virtually 100% current transport through the convolute and the ability to vary the division of current between the inner and outer lines of the triax by choice of inner line impedance. These measurements, and results obtained with this convolute connected to the ion diode for which it was designed, will be presented.

  16. Fiber Optic Picosecond Laser Pulse Transmission Line for Hydrogen Ion Beam Profile Measurement

    SciTech Connect

    Liu, Yun; Huang, Chunning; Aleksandrov, Alexander V

    2013-01-01

    We present a fiber optic laser pulse transmission line for non-intrusive longitudinal profile measurement of the hydrogen ion (H-) beam at the front-end of the Spallation Neutron Source (SNS) accelerator. The 80.5 MHz, 2.5 ps, multi-killowatt optical pulses are delivered to the accelerator beam line through a large mode area polarization maintaining optical fiber to ensure a high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter and pulse width broadening over a 100-ft fiber line are experimentally investigated. A successful measurement of the H- beam microbunch (~130 ps) profile is obtained. Our experiment is the first demonstration of particle beam profile diagnostics using fiber optic laser pulse transmission line.

  17. Fiber optic picosecond laser pulse transmission line for hydrogen ion beam longitudinal profile measurement.

    PubMed

    Huang, Chunning; Liu, Yun; Aleksandrov, Alexander

    2013-07-01

    We present a fiber optic laser pulse transmission line for nonintrusive longitudinal profile measurement of the hydrogen ion (H(-)) beam at the front-end of the Spallation Neutron Source accelerator. The 80.5 MHz, 2.5 ps, multikilowatt optical pulses are delivered to the accelerator beam line through a large-mode-area polarization-maintaining optical fiber to ensure high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter, and pulse width broadening over a 30 m long fiber line are experimentally investigated. A successful measurement of the H(-) beam microbunch (~130 ps) profile is obtained. The experiment is the first demonstration to our knowledge of particle beam profile diagnostics using a fiber optic laser pulse transmission line.

  18. Flashover vulnerability of transmission and distribution lines to high-altitude electromagnetic pulse (HEMP)

    SciTech Connect

    Kruse, V.J.; Liu, T.K.; Tesche, F.M.; Barnes, P.R.

    1989-01-01

    This paper estimates the vulnerability of transmission and distribution lines to flashover from the electromagnetic pulse generated by a nuclear detonation 400 kilometers above the earth. The analysis consists of first determining the cumulative probability of induced-voltage on three-phase lines, including shield and neutral conductors, for four operating voltages and then comparing these stresses to estimates of line insulation strength. 11 refs., 9 figs., 5 tabs.

  19. Assessment of Fecundity and Germ Line Transmission in Two Transgenic Pig Lines Produced by Sleeping Beauty Transposition

    PubMed Central

    Garrels, Wiebke; Holler, Stephanie; Cleve, Nicole; Niemann, Heiner; Ivics, Zoltan; Kues, Wilfried A.

    2012-01-01

    Recently, we described a simplified injection method for producing transgenic pigs using a non-autonomous Sleeping Beauty transposon system. The founder animals showed ubiquitous expression of the Venus fluorophore in almost all cell types. To assess, whether expression of the reporter fluorophore affects animal welfare or fecundity, we analyzed reproductive parameters of two founder boars, germ line transmission, and organ and cell specific transgene expression in animals of the F1 and F2 generation. Molecular analysis of ejaculated sperm cells suggested three monomeric integrations of the Venus transposon in both founders. To test germ line transmission of the three monomeric transposon integrations, wild-type sows were artificially inseminated. The offspring were nursed to sexual maturity and hemizygous lines were established. A clear segregation of the monomeric transposons following the Mendelian rules was observed in the F1 and F2 offspring. Apparently, almost all somatic cells, as well as oocytes and spermatozoa, expressed the Venus fluorophore at cell-type specific levels. No detrimental effects of Venus expression on animal health or fecundity were found. Importantly, all hemizygous lines expressed the fluorophore in comparable levels, and no case of transgene silencing or variegated expression was found after germ line transmission, suggesting that the insertions occurred at transcriptionally permissive loci. The results show that Sleeping Beauty transposase-catalyzed transposition is a promising approach for stable genetic modification of the pig genome. PMID:24705079

  20. Acoustic dispersive prism

    PubMed Central

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

    2016-01-01

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

  1. Marys Lake 69/115-kV transmission line upgrade and substation expansion projects

    SciTech Connect

    1996-05-01

    Western Area Power Administration (Western) and the Platte River Power Authority (Platte River) propose to upgrade portions of the existing electric transmission and substation system that serves the Town of Estes Park, Colorado. The existing transmission lines between the Estes Power Plant Switchyard and the Marys Lake Substation include a 115,000 volt (115-kV) line and 69,000 volt (69-kV) line. Approximately one mile is a double-circuit 115/69-kV line on steel lattice structures, and approximately two miles consists of separate single-circuit 115-kV and a 69-kV lines, constructed on wood H-Frame structures. Both lines were constructed in 1951 by the US Bureau of Reclamation. The existing transmission lines are on rights-of-way (ROW) that vary from 75 feet to 120 feet and are owned by Western. There are 48 landowners adjacent to the existing ROW. All of the houses were built adjacent to the existing ROW after the transmission lines were constructed. Upgrading the existing 69-kV transmission line between the Marys Lake Substation and the Estes Power Plant Switchyard to 115-kV and expanding the Marys Lake Substation was identified as the most effective way in which to improve electric service to Estes Park. The primary purpose and need of the proposed project is to improve the reliability of electric service to the Town of Estes Park. Lack of reliability has been a historical concern, and reliability will always be less than desired until physical improvements are made to the electrical facilities serving Estes Park.

  2. Photoacoustic and ultrasound imaging with a gas-coupled laser acoustic line detector

    NASA Astrophysics Data System (ADS)

    Johnson, Jami L.; van Wijk, Kasper; Caron, James N.; Timmerman, Miriam

    2016-03-01

    Conventional contacting transducers are highly sensitive and readily available for ultrasonic and photoacoustic imaging. On the other hand, optical detection can be advantageous when a small sensor footprint, large bandwidth and no contact are essential. However, most optical methods utilizing interferometry or Doppler vibrometry rely on the reflection of light from the object. We present a non-contact detection method for photoacoustic and ultrasound imaging--termed Gas-Coupled Laser Acoustic Detection (GCLAD)--that does not involve surface reflectivity. GCLAD measures the displacement along a line in the air parallel to the object. Information about point displacements along the line is lost with this method, but resolution is increased over techniques that utilize finite point-detectors when used as an integrating line detector. In this proceeding, we present a formula for quantifying surface displacement remotely with GCLAD. We will validate this result by comparison with a commercial vibrometer. Finally, we will present two-dimensional imaging results using GCLAD as a line detector for photoacoustic and laser-ultrasound imaging.

  3. Study of transmission line attenuation in broad band millimeter wave frequency range

    SciTech Connect

    Pandya, Hitesh Kumar B.; Austin, M. E.; Ellis, R. F.

    2013-10-15

    Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

  4. Preliminary evaluation of space station transmission line in a ring configuration

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen

    1990-01-01

    The results of a preliminary evaluation of a space station type transmission line and commercial transmission lines in a ring configuration, are reported. In a ring configuration, each node has two paths for the return current of each wire. The additional path can create an unbalanced condition, where the magnetic fields created by the forward and return currents do not cancel. This evaluation was to quantify the effects of the unbalanced case upon the external fields. The transmission lines evaluated were standard commercial coaxial cables, RG59 and RG213, and a space station designed flat Litz transmission line. Each was evaluated in a balanced and unbalanced mode of operation. Currents and their harmonic content were recorded and compared. As expected, the harmonic content of the different current (I delta) was substantial for the unbalanced case as compared to the balanced case. For the balanced case, very little difference was noted among the various transmission lines evaluated. The evaluation is discussed, and the test circuit, the measurements, and the resulting data are described.

  5. Development of an Acoustic Sensor for On-Line Gas Temperature Measurement in Gasifiers

    SciTech Connect

    Peter Ariessohn; Hans Hornung

    2006-01-15

    This project was awarded under U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) Program Solicitation DE-PS26-02NT41422 and specifically addresses Technical Topical Area 2-Gasification Technologies. The project team includes Enertechnix, Inc. as the main contractor and ConocoPhillips Company as a technical partner, who also provides access to the SG Solutions Gasification Facility (formerly Wabash River Energy Limited), host for the field-testing portion of the research. Since 1989 the U.S. Department of Energy has supported development of advanced coal gasification technology. The Wabash River and TECO IGCC demonstration projects supported by the DOE have demonstrated the ability of these plants to achieve high levels of energy efficiency and extremely low emissions of hazardous pollutants. However, a continuing challenge for this technology is the tradeoff between high carbon conversion which requires operation with high internal gas temperatures, and limited refractory life which is exacerbated by those high operating temperatures. Attempts to control internal gas temperature so as to operate these gasifiers at the optimum temperature have been hampered by the lack of a reliable technology for measuring internal gas temperatures. Thermocouples have serious survival problems and provide useful temperature information for only a few days or weeks after startup before burning out. For this reason, the Department of Energy has funded several research projects to develop more robust and reliable temperature measurement approaches for use in coal gasifiers. Enertechnix has developed a line of acoustic gas temperature sensors for use in coal-fired electric utility boilers, kraft recovery boilers, cement kilns and petrochemical process heaters. Acoustic pyrometry provides several significant advantages for gas temperature measurement in hostile process environments. First, it is non-intrusive so survival of the measurement components is not a

  6. Acoustic one-way mode conversion and transmission by sonic crystal waveguides

    NASA Astrophysics Data System (ADS)

    Ouyang, Shiliang; He, Hailong; He, Zhaojian; Deng, Ke; Zhao, Heping

    2016-09-01

    We proposed a scheme to achieve one-way acoustic propagation and even-odd mode switching in two mutually perpendicular sonic crystal waveguides connected by a resonant cavity. The even mode in the entrance waveguide is able to switch to the odd mode in the exit waveguide through a symmetry match between the cavity resonant modes and the waveguide modes. Conversely, the odd mode in the exit waveguide is unable to be converted into the even mode in the entrance waveguide as incident waves and eigenmodes are mismatched in their symmetries at the waveguide exit. This one-way mechanism can be applied to design an acoustic diode for acoustic integration devices and can be used as a convertor of the acoustic waveguide modes.

  7. Empirical dependence of acoustic transmission scintillation statistics on bandwidth, frequency, and range in New Jersey continental shelf.

    PubMed

    Andrews, Mark; Chen, Tianrun; Ratilal, Purnima

    2009-01-01

    The scintillation statistics of broadband acoustic transmissions are determined as a function of signal bandwidth B, center frequency f(c), and range with experimental data in the New Jersey continental shelf. The received signal intensity is shown to follow the Gamma distribution implying that the central limit theorem has led to a fully saturated field from independent multimodal propagation contributions. The Gamma distribution depends on the mean intensity and the number of independent statistical fluctuations or coherent cells micro of the received signal. The latter is calculated for the matched filter, the Parseval sum, and the bandpassed center frequency, all of which are standard ocean acoustic receivers. The number of fluctuations mu of the received signal is found to be an order of magnitude smaller than the time-bandwidth product TB of the transmitted signal, and to increase monotonically with relative bandwidth Bfc. A computationally efficient numerical approach is developed to predict the mean intensity and the corresponding broadband transmission loss of a fluctuating, range-dependent ocean waveguide by range and depth averaging the output of a time-harmonic stochastic propagation model. This model enables efficient and accurate estimation of transmission loss over wide areas, which has become essential in wide-area sonar imaging applications.

  8. Calculation of transmission line impedances using the ANSYS finite element program

    SciTech Connect

    Johnson, M.E.

    1984-06-29

    This paper describes numerical techniques for calculating the capacitance of an arbitrary two conductor structure. For two dimensional structures the capacitance per unit length can be easily related to the characteristic impedance of a transmission line with the same cross section. Note that this is true for lines operated below their cut off frequency, i.e., TEM mode only. Thus, one can compute the impedance of an arbitrarily shaped line. The method using the ANSYS finite element program is being used to design the high voltage transmission line for the Yale streamer chamber. This line has a transition piece between two different cross sections. It is being modeled by taking several slices throughout the transition region.

  9. Wireless acoustic-electric feed-through for power and signal transmission

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Bar-Cohen, Yoseph (Inventor); Bao, Xiaoqi (Inventor); Doty, Benjamin (Inventor); Badescu, Mircea (Inventor); Chang, Zensheu (Inventor)

    2011-01-01

    An embodiment provides electrical energy from a source on one side of a medium to a load on the other side of the medium, the embodiment including a first piezoelectric to generate acoustic energy in response to electrical energy from the source, and a second piezoelectric to convert the received acoustic energy to electrical energy used by the load. Other embodiments are described and claimed.

  10. Dynamic responses and vibration control of the transmission tower-line system: a state-of-the-art review.

    PubMed

    Chen, Bo; Guo, Wei-hua; Li, Peng-yun; Xie, Wen-ping

    2014-01-01

    This paper presented an overview on the dynamic analysis and control of the transmission tower-line system in the past forty years. The challenges and future developing trends in the dynamic analysis and mitigation of the transmission tower-line system under dynamic excitations are also put forward. It also reviews the analytical models and approaches of the transmission tower, transmission lines, and transmission tower-line systems, respectively, which contain the theoretical model, finite element (FE) model and the equivalent model; shows the advances in wind responses of the transmission tower-line system, which contains the dynamic effects under common wind loading, tornado, downburst, and typhoon; and discusses the dynamic responses under earthquake and ice loads, respectively. The vibration control of the transmission tower-line system is also reviewed, which includes the magnetorheological dampers, friction dampers, tuned mass dampers, and pounding tuned mass dampers. PMID:25105161

  11. Dynamic Responses and Vibration Control of the Transmission Tower-Line System: A State-of-the-Art Review

    PubMed Central

    Chen, Bo; Guo, Wei-hua; Li, Peng-yun; Xie, Wen-ping

    2014-01-01

    This paper presented an overview on the dynamic analysis and control of the transmission tower-line system in the past forty years. The challenges and future developing trends in the dynamic analysis and mitigation of the transmission tower-line system under dynamic excitations are also put forward. It also reviews the analytical models and approaches of the transmission tower, transmission lines, and transmission tower-line systems, respectively, which contain the theoretical model, finite element (FE) model and the equivalent model; shows the advances in wind responses of the transmission tower-line system, which contains the dynamic effects under common wind loading, tornado, downburst, and typhoon; and discusses the dynamic responses under earthquake and ice loads, respectively. The vibration control of the transmission tower-line system is also reviewed, which includes the magnetorheological dampers, friction dampers, tuned mass dampers, and pounding tuned mass dampers. PMID:25105161

  12. Lumped-element model of a tapered transmission line for impedance matching in a pulsed power system

    NASA Astrophysics Data System (ADS)

    Lee, Kun-A.; Ko, Kwang-Cheol

    2016-07-01

    In a pulsed power system, impedance matching is one of the significant factors for increasing the efficiency of the system. One of the most general methods for impedance matching is to use a tapered transmission line. Because the characteristics of a tapered transmission line are changed continuously according to its position, modeling the tapered transmission line by using lumped elements is difficult. In this study, we investigated a tapered transmission line to match the impedance of power supply to that of a load by using lumped elements especially in a pulsed power system. In modeling the tapered transmission line, we used the concept of a transmission, and we introduced an efficient modeling method. We propose a simulation model based on the investigation results. The results of the study will be useful for research on tapered transmission lines.

  13. Dynamic responses and vibration control of the transmission tower-line system: a state-of-the-art review.

    PubMed

    Chen, Bo; Guo, Wei-hua; Li, Peng-yun; Xie, Wen-ping

    2014-01-01

    This paper presented an overview on the dynamic analysis and control of the transmission tower-line system in the past forty years. The challenges and future developing trends in the dynamic analysis and mitigation of the transmission tower-line system under dynamic excitations are also put forward. It also reviews the analytical models and approaches of the transmission tower, transmission lines, and transmission tower-line systems, respectively, which contain the theoretical model, finite element (FE) model and the equivalent model; shows the advances in wind responses of the transmission tower-line system, which contains the dynamic effects under common wind loading, tornado, downburst, and typhoon; and discusses the dynamic responses under earthquake and ice loads, respectively. The vibration control of the transmission tower-line system is also reviewed, which includes the magnetorheological dampers, friction dampers, tuned mass dampers, and pounding tuned mass dampers.

  14. 75 FR 32940 - Request for Proposals for New or Upgraded Transmission Line Projects Under Section 1222 of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-10

    ... several states. Southwestern operates and maintains 1,380 miles of high voltage transmission lines in... Dakota, Texas, Utah, and Wyoming. Western's 17,000-mile high-voltage transmission system carries... Transmission Line Projects under section 1222 of EPAct (73 FR 70636 and 70638 respectively)....

  15. Effects of high-voltage transmission lines on honey bees

    SciTech Connect

    Greenberg, B.; Bindokas, V.P.

    1981-04-01

    Data are reported on the effect of hive height and current distribution on honey bees hived under a 765 kV line (E-field ca. 7 kV/m). Hive height was standardized with adjustable collectors to 1 meter (59 ..mu..A total hive current) or 1.5 meter (85 ..mu..A) equivalents; controls were shielded. A 1.5 meter group with completely painted supers was included. After 8 or 16 weeks of exposure there was no effect on honey moisture content or weight of young workers in any group. Worker capped brood was not affected in 1 m hives but declined significantly in 1.5 m hives after 4 weeks of exposure and this was associated with queen loss, abnormal queen cell production, and colony failure. Weight gain was depressed in all hives after 2 weeks of exposure and was dose related, with the taller hives more severely affected. Only the exposed hives propolized entrances but the amount and time of onset were not dose related. The 1.5 m hives with painted interiors behaved like the 1 m hives with unpainted interiors in all respects, although their total hive current approximated the other group of 1.5 m hives. Reversal of treatments at midseason resulted in reversal of colony behavior, manifested most clearly with respect to hive weight, less with respect to brood. When first exposed, colonies exhibit pronounced but transient elevations in hive temperature. Bio-effects were more severe during the first period when hives had fewer bees. Total hive current was greater in wet than in dry periods. All these factors influence observed bioeffects.

  16. Kinetic inductance driven nanoscale 2D and 3D THz transmission lines

    NASA Astrophysics Data System (ADS)

    Mousavi, S. Hossein; Williamson, Ian A. D.; Wang, Zheng

    2016-05-01

    We examine the unusual dispersion and attenuation of transverse electromagnetic waves in the few-THz regime on nanoscale graphene and copper transmission lines. Conventionally, such propagation has been considered to be highly dispersive, due to the RC time constant-driven voltage diffusion below 1 THz and plasmonic effects at higher optical frequencies. Our numerical modeling across the microwave, THz, and optical frequency ranges reveals that the conductor kinetic inductance creates an ultra-broadband linear-dispersion and constant-attenuation region in the THz regime. This so-called LC region is an ideal characteristic that is known to be absent in macro-scale transmission lines. The kinetic-LC frequency range is dictated by the structural dimensionality and the free-carrier scattering rate of the conductor material. Moreover, up to 40x wavelength reduction is observed in graphene transmission lines.

  17. Kinetic inductance driven nanoscale 2D and 3D THz transmission lines

    PubMed Central

    Mousavi, S. Hossein; Williamson, Ian A. D.; Wang, Zheng

    2016-01-01

    We examine the unusual dispersion and attenuation of transverse electromagnetic waves in the few-THz regime on nanoscale graphene and copper transmission lines. Conventionally, such propagation has been considered to be highly dispersive, due to the RC time constant-driven voltage diffusion below 1 THz and plasmonic effects at higher optical frequencies. Our numerical modeling across the microwave, THz, and optical frequency ranges reveals that the conductor kinetic inductance creates an ultra-broadband linear-dispersion and constant-attenuation region in the THz regime. This so-called LC region is an ideal characteristic that is known to be absent in macro-scale transmission lines. The kinetic-LC frequency range is dictated by the structural dimensionality and the free-carrier scattering rate of the conductor material. Moreover, up to 40x wavelength reduction is observed in graphene transmission lines. PMID:27137628

  18. Computer simulation of multiple coupled transmission lines in electronic packaging application

    SciTech Connect

    Liao, Jenchyi.

    1989-01-01

    A method for simulating the transient responses of networks containing lossless transmission lines and lumped parameter elements of circuits, both linear and nonlinear, has been developed and investigated. The method combines the technique of network analysis and that of modal decomposition of transmission lines. A prototype computer simulation program, called UANTL, based on the developed algorithm has been implemented. Several example networks have been simulated using this program. The results have been compared with those generated by the well known circuit simulator program called SPICE. UANTL has shown several advantages over SPICE in simulating the transient responses of networks containing transmission lines. A description of the prototype version of UANTL and a summary of the results of numerical experiments are included.

  19. Transmission Line Jobs and Economic Development Impact (JEDI) Model User Reference Guide

    SciTech Connect

    Goldberg, M.; Keyser, D.

    2013-10-01

    The Jobs and Economic Development Impact (JEDI) models, developed through the National Renewable Energy Laboratory (NREL), are freely available, user-friendly tools that estimate the potential economic impacts of constructing and operating power generation projects for a range of conventional and renewable energy technologies. The Transmission Line JEDI model can be used to field questions about the economic impacts of transmission lines in a given state, region, or local community. This Transmission Line JEDI User Reference Guide was developed to provide basic instruction on operating the model and understanding the results. This guide also provides information on the model's underlying methodology, as well as the parameters and references used to develop the cost data contained in the model.

  20. Kinetic inductance driven nanoscale 2D and 3D THz transmission lines.

    PubMed

    Mousavi, S Hossein; Williamson, Ian A D; Wang, Zheng

    2016-05-03

    We examine the unusual dispersion and attenuation of transverse electromagnetic waves in the few-THz regime on nanoscale graphene and copper transmission lines. Conventionally, such propagation has been considered to be highly dispersive, due to the RC time constant-driven voltage diffusion below 1 THz and plasmonic effects at higher optical frequencies. Our numerical modeling across the microwave, THz, and optical frequency ranges reveals that the conductor kinetic inductance creates an ultra-broadband linear-dispersion and constant-attenuation region in the THz regime. This so-called LC region is an ideal characteristic that is known to be absent in macro-scale transmission lines. The kinetic-LC frequency range is dictated by the structural dimensionality and the free-carrier scattering rate of the conductor material. Moreover, up to 40x wavelength reduction is observed in graphene transmission lines.

  1. Kinetic inductance driven nanoscale 2D and 3D THz transmission lines.

    PubMed

    Mousavi, S Hossein; Williamson, Ian A D; Wang, Zheng

    2016-01-01

    We examine the unusual dispersion and attenuation of transverse electromagnetic waves in the few-THz regime on nanoscale graphene and copper transmission lines. Conventionally, such propagation has been considered to be highly dispersive, due to the RC time constant-driven voltage diffusion below 1 THz and plasmonic effects at higher optical frequencies. Our numerical modeling across the microwave, THz, and optical frequency ranges reveals that the conductor kinetic inductance creates an ultra-broadband linear-dispersion and constant-attenuation region in the THz regime. This so-called LC region is an ideal characteristic that is known to be absent in macro-scale transmission lines. The kinetic-LC frequency range is dictated by the structural dimensionality and the free-carrier scattering rate of the conductor material. Moreover, up to 40x wavelength reduction is observed in graphene transmission lines. PMID:27137628

  2. Non-Linear Transmission Line (NLTL) Microwave Source Lecture Notes the United States Particle Accelerator School

    SciTech Connect

    Russell, Steven J.; Carlsten, Bruce E.

    2012-06-26

    We will quickly go through the history of the non-linear transmission lines (NLTLs). We will describe how they work, how they are modeled and how they are designed. Note that the field of high power, NLTL microwave sources is still under development, so this is just a snap shot of their current state. Topics discussed are: (1) Introduction to solitons and the KdV equation; (2) The lumped element non-linear transmission line; (3) Solution of the KdV equation; (4) Non-linear transmission lines at microwave frequencies; (5) Numerical methods for NLTL analysis; (6) Unipolar versus bipolar input; (7) High power NLTL pioneers; (8) Resistive versus reactive load; (9) Non-lineaer dielectrics; and (10) Effect of losses.

  3. Development of an accurate transmission line fault locator using the global positioning system satellites

    NASA Technical Reports Server (NTRS)

    Lee, Harry

    1994-01-01

    A highly accurate transmission line fault locator based on the traveling-wave principle was developed and successfully operated within B.C. Hydro. A transmission line fault produces a fast-risetime traveling wave at the fault point which propagates along the transmission line. This fault locator system consists of traveling wave detectors located at key substations which detect and time tag the leading edge of the fault-generated traveling wave as if passes through. A master station gathers the time-tagged information from the remote detectors and determines the location of the fault. Precise time is a key element to the success of this system. This fault locator system derives its timing from the Global Positioning System (GPS) satellites. System tests confirmed the accuracy of locating faults to within the design objective of +/-300 meters.

  4. Onset of dispersion in Nb microstrip transmission lines at submillimeter wave frequencies

    NASA Technical Reports Server (NTRS)

    Javadi, H. H. S.; Mcgrath, William R.; Bumble, B.; Leduc, Henry G.

    1992-01-01

    We have measured the dispersion in phase velocity of a Nb-SiO(x)-Nb microstrip transmission line resonator over a frequency range from 50 GHz to 800 GHz. A submicron Nb/Al-AlO(x)/Nb Josephson junction was used as a voltage-controlled oscillator to excite the high order modes in the resonator. The same junction is used as a direct detector resulting in a series of step-like structures in the DC current-voltage characteristic at the position of each mode frequency. The transmission line is dispersionless up to about 500 GHz where the phase velocity begins to decrease. This is well below the gap frequency f(sub g) approx. equals 700 GHz. Results agree qualitatively with the expected theoretical behavior near f(sub g). This onset of dispersion and loss in Nb transmission lines will have a significant impact on the design of submillimeter wave RF circuits.

  5. A test of a 2 Tesla superconducting transmission line magnet system

    SciTech Connect

    Piekarz, Henryk; Carcagno, Ruben; Claypool, Brad; Foster, George W.; Hays, Steven L.; Huang, Yuenian; Kashikhin, Vladimir; Malamud, Ernest; Mazur, Peter O.; Nehring, Roger; Oleck, Andrew; Rabehl, Roger; Schlabach, Phil; Sylvester, Cosmore; Velev, Gueorgui; Volk, James; Wake, Masayoshi; /KEK, Tsukuba

    2005-09-01

    Superconducting transmission line magnet test system for an injector accelerator of a staged VLHC proton-proton colliding beam accelerator has been built and operated at Fermilab. The 1.5 m long, twin-aperture, combined function dipole magnet of 2 Tesla field is excited by a single turn 100 kA transmission line superconductor. The 100 kA dc current is generated using dc-dc switching converters powered by a bulk 240 kW supply. A pair of horizontally placed conventional leads facilitates transfer of this current to the magnet transmission line superconductor operating at liquid helium temperature. Fabrication of magnet components and magnet assembly work are described. The magnet test system and its operation are presented, and the performance is summarized.

  6. A comparison of matrix methods for calculating eigenvalues in acoustically lined ducts

    NASA Technical Reports Server (NTRS)

    Watson, W.; Lansing, D. L.

    1976-01-01

    Three approximate methods - finite differences, weighted residuals, and finite elements - were used to solve the eigenvalue problem which arises in finding the acoustic modes and propagation constants in an absorptively lined two-dimensional duct without airflow. The matrix equations derived for each of these methods were solved for the eigenvalues corresponding to various values of wall impedance. Two matrix orders, 20 x 20 and 40 x 40, were used. The cases considered included values of wall admittance for which exact eigenvalues were known and for which several nearly equal roots were present. Ten of the lower order eigenvalues obtained from the three approximate methods were compared with solutions calculated from the exact characteristic equation in order to make an assessment of the relative accuracy and reliability of the three methods. The best results were given by the finite element method using a cubic polynomial. Excellent accuracy was consistently obtained, even for nearly equal eigenvalues, by using a 20 x 20 order matrix.

  7. Simple Correctors for Elimination of High-Order Modes in Corrugated Waveguide Transmission Lines

    PubMed Central

    Kowalski, Elizabeth J.; Shapiro, Michael A.; Temkin, Richard J.

    2014-01-01

    When using overmoded corrugated waveguide transmission lines for high power applications, it is necessary to control the mode content of the system. Ideally, overmoded corrugated transmission lines operate in the fundamental HE11 mode and provide low losses for long distances. Unwanted higher order modes (HOMs), particularly LP11 and HE12, are often excited in the experimental systems due to practical misalignments in the transmission line system. This paper discusses how the unwanted modes propagate along with the fundamental mode in the transmission line system by formulating an equation that relates the center of power offset and angle of propagation of a beam (for the HE11 and LP11 modes) or the waist size and phase front radius of curvature of a beam (for the HE11 and HE12 modes). By introducing two miter bend correctors into the transmission system—miter bends that have slightly angled or ellipsoidal mirrors—the HOMs can be precisely manipulated in the system. This technique can be used to eliminate small quantities of unwanted modes, thereby creating a nearly pure fundamental mode beam with minimal losses. Examples of these applications are calculated and show the theoretical conversion of up to 10% HOM content into the fundamental HE11 mode with minimal losses. PMID:25067859

  8. Measurement of RF Mode Purity in EC Transmission Test Line for ITER

    SciTech Connect

    Oda, Yasuhisa; Kajiwara, Ken; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi

    2009-11-26

    The transmission mode purity was measured at the ITER relevant transmission line for 170 GHz ECH and CD system. The measured purity of HE{sub 11} in transmission power was 73% and the other was higher order modes. The dominant higher order mode was LP{sub 11} mode (HE{sub 21}+TE{sub 01}). To improve the mode purity, the RF beam coupling in MOU was aligned because LP{sub 11} mode is generated the offset and the tilt angle of RF beam at the waveguide inlet. After the alignment, HE{sub 11} mode purity was increased to 87%.

  9. Quantum transducers: Integrating transmission lines and nanomechanical resonators via charge qubits

    SciTech Connect

    Sun, C. P.; Wei, L. F.; Liu Yuxi; Nori, Franco

    2006-02-15

    We propose a mechanism to interface a transmission line resonator (TLR) with a nanomechanical resonator (NAMR) by commonly coupling them to a charge qubit, a Cooper-pair box with a controllable gate voltage. Integrated in this quantum transducer or simple quantum network, the charge qubit plays the role of a controllable quantum node coherently exchanging quantum information between the TLR and NAMR. With such an interface, a quasiclassical state of the NAMR can be created by controlling a single-mode classical current in the TLR. Alternatively, a 'Cooper pair' coherent output through the transmission line can be driven by a single-mode classical oscillation of the NAMR.

  10. Design Considerations of Fast-cycling Synchrotrons Based on Superconducting Transmission Line Magnets

    SciTech Connect

    Piekarz, H.; Hays, S.; Huang, Y.; Shiltsev, V.; /Fermilab

    2008-06-01

    Fast-cycling synchrotrons are key instruments for accelerator based nuclear and high-energy physics programs. We explore a possibility to construct fast-cycling synchrotrons by using super-ferric, {approx}2 Tesla B-field dipole magnets powered with a superconducting transmission line. We outline both the low temperature (LTS) and the high temperature (HTS) superconductor design options and consider dynamic power losses for an accelerator with operation cycle of 0.5 Hz. We also briefly outline possible power supply system for such accelerator, and discuss the quench protection system for the magnet string powered by a transmission line conductor.

  11. Sound transmission through lined, composite panel structures: Transversely isotropic poro-elastic model

    NASA Astrophysics Data System (ADS)

    Kim, Jeong-Woo

    A joint experimental and analytical investigation of the sound transmission loss (STL) and two-dimensional free wave propagation in composite sandwich panels is presented here. An existing panel, a Nomex honeycomb sandwich panel, was studied in detail. For the purpose of understanding the typical behavior of sandwich panels, a composite structure comprising two aluminum sheets with a relatively soft, poro-elastic foam core was also constructed and studied. The cores of both panels were modeled using an anisotropic (transversely isotropic) poro-elastic material theory. Several estimation methods were used to obtain the material properties of the honeycomb core and the skin plates to be used in the numerical calculations. Appropriate values selected from among the estimates were used in the STL and free wave propagation models. The prediction model was then verified in two ways: first, the calculated wave speeds and STL of a single poro-elastic layer were numerically verified by comparison with the predictions of a previously developed isotropic model. Secondly, to physically validate the transversely isotropic model, the measured STL and the phase speeds of the sandwich panels were compared with their predicted values. To analyze the actual treatment of a fuselage structure, multi-layered configurations, including a honeycomb panel and several layers such as air gaps, acoustic blankets and membrane partitions, were formulated. Then, to find the optimal solution for improving the sound barrier performance of an actual fuselage system, air layer depth and glass fiber lining effects were investigated by using these multi-layer models. By using the free wave propagation model, the first anti-symmetric and symmetric modes of the sandwich panels were characterized to allow the identification of the coincidence frequencies of the sandwich panel. The behavior of the STL could then be clearly explained by comparison with the free wave propagation solutions. By performing a

  12. The use of acoustically tuned resonators to improve the sound transmission loss of double-panel partitions

    NASA Astrophysics Data System (ADS)

    Mason, J. M.; Fahy, F. J.

    1988-07-01

    Double-leaf partitions are often utilized in situations requiring low weight structures with high transmission loss, an example of current interest being the fuselage walls of propeller-driven aircraft. In this case, acoustic excitation is periodic and, if one of the frequencies of excitation lies in the region of the fundamental mass-air-mass frequency of the partition, insulation performance is considerably less than desired. The potential effectiveness of tuned Helmholtz resonators connected to the partition cavity is investigated as a method of improving transmission loss. This is demonstrated by a simple theoretical model and then experimentally verified. Results show that substantial improvements may be obtained at and around the mass-air-mass frequency for a total resonator volume 15 percent of the cavity volume.

  13. Weld-Windsor 115-kV Transmission Line Project, Weld County, Colorado

    SciTech Connect

    1996-05-01

    The Western Area Power Administration is proposing to rebuild a 3.0 mile segment of the existing Flatiron-Weld 115-kV transmission line in Weld County. The line would be reconductored with new conductor on new wood pole double circuit structures. The new structures would support a double circuit transmission line configuration. The first circuit would be owned by Western and the second by Public Service Company of Colorado (PSCO). Alternatives considered included no action, constructing PSCO`s circuit on new right-of-way, and reconductoring Western`s existing line on the same structures. The proposed action was selected because it provided an opportunity to share structures with PSCO and, overall, would minimize costs and environmental impacts. The environmental assessment identifies minor effects on existing natural or human resources and minor benefits for agricultural operations.

  14. Electrical and mechanical design criteria for EHV and UHV: overhead transmission lines

    SciTech Connect

    Not Available

    1980-06-01

    The results are presented of a program devoted to the selection of electrical and mechanical design criteria and parameters for overhead power transmission lines for ac systems rated at from 345 to 1100 kV and for dc systems rated at from 600 to 1200 kV. Information is included on the environmental effects, i.e., audible noise and electric fields, of the lines, mechanical and economic requirements, safety, failures, grounding, and lightning protection. (LCL)

  15. Generation of Acoustic Gravity Waves by Periodic Radio Transmissions from a High-Power Ionospheric Heater

    NASA Astrophysics Data System (ADS)

    Frolov, Vladimir; Chernogor, Leonid; Rozumenko, Victor

    The Radiophysical Research Institute (Nizhny Novgorod, Russia) and Kharkiv V. N. Karazin National University (Kharkiv, Ukraine) have studied opportunities for the effective generation of acoustic gravity waves (AGWs) in 3 - 180-min period range. The excitation of such waves was conducted for the last several years using the SURA heating facility (Nizhny Novgorod). The detection of the HF-induced AGWs was carried out in the Radiophysical Observatory located near Kharkiv City at a distance of about 960 km from the SURA. A coherent radar for vertical sounding, an ionosonde, and magnetometer chains were used in our measurements. The main results are the following (see [1-5]): 1. Infrasound oscillation trains with a period of 6 min are detected during periodic SURA heater turn-on and -off. Similar oscillation trains are detected after long time pumping, during periodic transmissions with a period of 20 s, as well as after pumping turn-off. The train recordings begin 28 - 54 min after the heater turn-on or -off, and the train propagation speeds are about 300 - 570 m/s, the value of which is close to the sound speed at upper atmospheric altitudes. The amplitude of the Doppler shift frequency is of 10 - 40 mHz, which fits to the 0.1 - 0.3% electron density disturbances at ionospheric altitudes. The amplitude of the infrasound oscillations depends on the SURA mode of operation and the state of the upper atmosphere and ionosphere. 2. High-power radio transmissions stimulate the generation (or enhancement) of waves at ionospheric altitudes in the range of internal gravity wave periods. The HF-induced waves propagate with speeds of 360 - 460 m/s and produce changes in electron density with amplitudes of 2 - 3%. The generation of such periodic perturbations is more preferable with periods of 10 - 60 minutes. Their features depend significantly on the heater mode of operation. It should be stressed that perturbation intensity increases when a pumping wave frequency approaches

  16. Grand Coulee - Bell 500-kV Transmission Line Project, Draft Environmental Impact Statement

    SciTech Connect

    N /A

    2002-08-09

    BPA is proposing to construct a 500-kilovolt (kV) transmission line that would extend approximately 84 miles between the Grand Coulee 500-kV Switchyard, near Grand Coulee Dam, and the Bell Substation, in Mead just north of Spokane. The new line would cross portions of Douglas, Grant, Lincoln, and Spokane counties. In addition to the transmission line, new equipment would be installed at the substations at each end of the new line and at other facilities. The proposed action would remove an existing 115-kV transmission line and replace it with the new 500-kV line on existing right-of-way for most of its length. Additional right-of-way would be needed in the first 3.5 miles out of the Grand Coulee Switchyard to connect to the existing 115-kV right-of-way. Since the mid-1990s, the transmission path west of Spokane, called the West of Hatwai transmission pathway, has grown increasingly constrained. To date, BPA has been able to manage operation of the path through available operating practices, and customer needed have been met while maintaining the reliability of the path. however, in early 2001, operations showed that the amount of electricity that needs to flow from east to west along this path creates severe transmission congestion. Under these conditions, the system is at risk of overloads and violation of industry safety and reliability standards. The problem is particularly acute in the spring and summer months because of the large amount of power generated by dams east of the path. Large amounts of water cannot be spilled during that time in order for BPA to fulfill its obligation to protect threatened and endangered fish. The amount of power that needs to move through this area during these months at times could exceed the carrying capacity of the existing transmission lines. In additional capacity is not added, BPA will run a significant risk that it will not be able to continue to meet its contractual obligations to deliver power and maintain reliability

  17. Decoding method for T1 line format for ccitt 32K bit per second adpcm clear channel transmission and 64 KBPS clear channel transmission

    SciTech Connect

    Blondeau, E.E. Jr.; Czarnecki, S.J.

    1988-05-24

    In a data transmission system having first and second digital switching systems connected via T1 line transmission facilities for bidirectional data transmissions, a decoding method for T1 line zero bit suppression is described comprising the steps of: receiving an encoded T1 line frame including bundled channels; testing indicator bits of the received T1 line frame to determine whether any channel of the T1 line frame has been altered for the transmission; first transferring the received T1 line frame as received, performed in response to the indicated bits showing that no alteration have been made to the received T1 line frame; decoding mapping bits of the received T1 line frame to determine which channels of the bundle of the received T1 line frame have been altered for the encoded transmission; replacing the contents of each of the altered channel of the bundle with zeroes; iterating the steps of decoding and replacing for each of the bundles of the received T1 line frame; and second transferring the received T1 line frame with the altered channels being replaced with zeroes.

  18. On-chip sub-terahertz surface plasmon polariton transmission lines in CMOS

    PubMed Central

    Liang, Yuan; Yu, Hao; Zhang, Hao Chi; Yang, Chang; Cui, Tie Jun

    2015-01-01

    A low-loss and low-crosstalk surface-wave transmission line (T-line) is demonstrated at sub-THz in CMOS. By introducing periodical sub-wavelength structures onto the metal transmission line, surface plasmon polaritons (SPP) are excited and propagate signals via a strongly localized surface wave. Two coupled SPP T-lines and two quasi-TEM T-lines are both fabricated on-chip, each with a separation distance of 2.4 μm using standard 65 nm CMOS technology. Measurement results show that the SPP T-lines achieve wideband reflection coefficient lower than −14 dB and crosstalk ratio better than −24 dB, which is 19 dB lower on average than the traditional T-lines from 220 GHz to 325 GHz. The demonstrated compact and wideband SPP T-lines have shown great potential for future realization of highly dense on-chip sub-THz communications in CMOS. PMID:26445889

  19. Canby Area Service Project : Substation and Associated Transmission Line : Environmental Assessment.

    SciTech Connect

    United States. Bonneville Power Administration.

    1992-02-01

    Bonneville Power Administration (BPA) provides power to Surprise Valley Electrification Corporation (SVEC) in Modoc County, California. BPA uses PacificCorp's substation and transmission facilities between Alturas and Canby, California to transfer power to SVEC's Canby Substation. In the next year, SVEC expects increased industrial, agricultural, and residential electric loads on their 69-kV transmission system south of Canby. SVEC's substation can accommodate only about 10 percent of the expected additional electric load. BPA's proposed action is intended to meet SVEC's increasing electric load. BPA proposes to meet SVEC's increasing energy load by tapping into BPA's existing BPA Malin-Warner 230-kV transmission line, and building an 7.9-mile transmission line to a new BPA substation. BPA proposes to build the new substation next to the west side of SVEC's Canby Substation (Figure 1). This new substation will allow SVEC to move the additional power over their existing transmission or distribution lines. This report is the environmental assessment of the potential impact of the proposed project. The assessment determined that no environmental impact statement'' is not required.

  20. Canby Area Service Project substation and associated transmission line. Environmental Assessment

    SciTech Connect

    Not Available

    1992-02-01

    Bonneville Power Administration (BPA) provides power to Surprise Valley Electrification Corporation (SVEC) in Modoc County, California. BPA uses PacificCorp`s substation and transmission facilities between Alturas and Canby, California to transfer power to SVEC`s Canby Substation. In the next year, SVEC expects increased industrial, agricultural, and residential electric loads on their 69-kV transmission system south of Canby. SVEC`s substation can accommodate only about 10 percent of the expected additional electric load. BPA`s proposed action is intended to meet SVEC`s increasing electric load. BPA proposes to meet SVEC`s increasing energy load by tapping into BPA`s existing BPA Malin-Warner 230-kV transmission line, and building an 7.9-mile transmission line to a new BPA substation. BPA proposes to build the new substation next to the west side of SVEC`s Canby Substation (Figure 1). This new substation will allow SVEC to move the additional power over their existing transmission or distribution lines. This report is the environmental assessment of the potential impact of the proposed project. The assessment determined that no ``environmental impact statement`` is not required.

  1. Sound Transmission Through Multi-Panel Structures Lined with Elastic Porous Materials

    NASA Astrophysics Data System (ADS)

    Bolton, J. S.; Shiau, N.-M.; Kang, Y. J.

    1996-04-01

    Theory and measurements related to sound transmission through double panels lined with elastic porous media are presented. The information has application to the design of noise control barriers and to the optimization of aircraft fuselage transmission loss, for example. The major difference between the work described here and earlier research in this field relates to the treatment of the porous material that is used to line the cavity between the two panels of the double panel structure. Here we have used the porous material theory proposed by Biot since it takes explicit account of all the wave types known to propagate in elastic porous materials. As a result, it is possible to use the theory presented here to calculate the transmission loss of lined double panels at arbitrary angles of incidence; results calculated over a range of incidence angles may then be combined to yield the random incidence transmission loss. In this paper, the equations governing wave propagation in an elastic porous material are first considered briefly and then the general forms for the stresses and displacements within the porous material are given. Those solutions are expressed in terms of a number of constants that can be determined by application of appropriate boundary conditions. The boundary conditions required to model double panels having linings that are either directly attached to the facing panels or separated?!from them by air gaps are presented and discussed. Measurements of the random incidence transmission loss of aluminium double-panel structures lined with polyurethane foam are presented and have been found to be in good agreement with theoretical predictions. Both the theoretical predictions and the measured results have shown that the method by which an elastic porous lining material is attached to the facing panels can have a profound influence on the transmission loss of the panel system. It has been found, for example, that treatments in which the lining material

  2. Compact test method for the evaluation of acoustical transmission loss and insertion loss of new helmet material samples

    NASA Astrophysics Data System (ADS)

    Maher, Matthew G.; Collier, Robert D.; Ray, Laura E.

    2005-09-01

    There is a need to establish a simple and accurate measurement technique for determining the transmission loss of sample materials for helmets over a frequency range of 300-3 kHz. Standard methods, e.g., ASTM E 90-02, for measuring transmission loss of building materials and structures, based on adjacent reverberation chambers, are too costly and impractical. A 1.22-m-long double-wall tube, packed with Owens Corning R13 insulation, has been fabricated using QUIK-TUBETM cardboard concrete forms of 200 and 300 mm diameters. A circular sample of material, also 300 mm in diameter, is placed on the end of the tube and subjected to an external sound field. Transmission loss is established by external and internal microphones. This paper describes the measurement and analysis procedures and examines the associated variables and error terms. Results are presented for 16 material samples with surface weights covering a range from 0.3 to 14.7 kg/m2 and compared with analytical predictions including mass law models. The acoustical characteristics of commercial helmet materials and liners are evaluated in the context of hearing protection systems. The transmission loss measurement procedure has the potential for meeting standardization objectives.

  3. Measuring the complex permittivity tensor of uniaxial biological materials with coplanar waveguide transmission line

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple and accurate technique is described for measuring the uniaxial permittivity tensor of biological materials with a coplanar waveguide transmission-line configuration. Permittivity tensor results are presented for several chicken and beef fresh meat samples at 2.45 GHz....

  4. Multiwavelet packet entropy and its application in transmission line fault recognition and classification.

    PubMed

    Liu, Zhigang; Han, Zhiwei; Zhang, Yang; Zhang, Qiaoge

    2014-11-01

    Multiwavelets possess better properties than traditional wavelets. Multiwavelet packet transformation has more high-frequency information. Spectral entropy can be applied as an analysis index to the complexity or uncertainty of a signal. This paper tries to define four multiwavelet packet entropies to extract the features of different transmission line faults, and uses a radial basis function (RBF) neural network to recognize and classify 10 fault types of power transmission lines. First, the preprocessing and postprocessing problems of multiwavelets are presented. Shannon entropy and Tsallis entropy are introduced, and their difference is discussed. Second, multiwavelet packet energy entropy, time entropy, Shannon singular entropy, and Tsallis singular entropy are defined as the feature extraction methods of transmission line fault signals. Third, the plan of transmission line fault recognition using multiwavelet packet entropies and an RBF neural network is proposed. Finally, the experimental results show that the plan with the four multiwavelet packet energy entropies defined in this paper achieves better performance in fault recognition. The performance with SA4 (symmetric antisymmetric) multiwavelet packet Tsallis singular entropy is the best among the combinations of different multiwavelet packets and the four multiwavelet packet entropies.

  5. 49 CFR 192.476 - Internal corrosion control: Design and construction of transmission line.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Internal corrosion control: Design and construction of transmission line. 192.476 Section 192.476 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION...

  6. 76 FR 15970 - Central Ferry to Lower Monumental 500-kilovolt Transmission Line Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-22

    ... AGENCY: Bonneville Power Administration (BPA), Department of Energy (DOE). ACTION: Notice of Availability..., and Walla Walla counties, Washington. BPA has decided to implement the Combination A Alternative... single- circuit transmission line from BPA's new Central Ferry Substation near the Port of Central...

  7. Exact Solutions for a Local Fractional DDE Associated with a Nonlinear Transmission Line

    NASA Astrophysics Data System (ADS)

    Aslan, İsmail

    2016-09-01

    Of recent increasing interest in the area of fractional calculus and nonlinear dynamics are fractional differential-difference equations. This study is devoted to a local fractional differential-difference equation which is related to a nonlinear electrical transmission line. Explicit traveling wave solutions (kink/antikink solitons, singular, periodic, rational) are obtained via the discrete tanh method coupled with the fractional complex transform.

  8. Effect of discontinuities on the group delay of a microwave transmission line

    NASA Technical Reports Server (NTRS)

    Beatty, R. W.; Otoshi, T. Y.

    1975-01-01

    The problem is considered of the effect of reflections from discontinuities at each end of a transmission line on the group delay at microwave frequencies. Previous work is briefly reviewed and a general analysis is made. Graphical data are presented based upon the formulas developed. Experimental results are given which confirm the theory.

  9. Position-momentum-entangled photon pairs in nonlinear waveguides and transmission lines

    NASA Astrophysics Data System (ADS)

    Sherkunov, Y.; Whittaker, David M.; Fal'ko, Vladimir

    2016-04-01

    We analyze the correlation properties of light in nonlinear waveguides and transmission lines, predict the position-momentum realization of the Einstein-Podolsky-Rosen paradox for photon pairs in Kerr-type nonlinear photonic circuits, and we show how two-photon entangled states can be generated and detected.

  10. Efficient design of multituned transmission line NMR probes: the electrical engineering approach.

    PubMed

    Frydel, J A; Krzystyniak, M; Pienkowski, D; Pietrzak, M; de Sousa Amadeu, N; Ratajczyk, T; Idzik, K; Gutmann, T; Tietze, D; Voigt, S; Fenn, A; Limbach, H H; Buntkowsky, G

    2011-01-01

    Transmission line-based multi-channel solid state NMR probes have many advantages regarding the cost of construction, number of RF-channels, and achievable RF-power levels. Nevertheless, these probes are only rarely employed in solid state-NMR-labs, mainly owing to the difficult experimental determination of the necessary RF-parameters. Here, the efficient design of multi-channel solid state MAS-NMR probes employing transmission line theory and modern techniques of electrical engineering is presented. As technical realization a five-channel ((1)H, (31)P, (13)C, (2)H and (15)N) probe for operation at 7 Tesla is described. This very cost efficient design goal is a multi port single coil transmission line probe based on the design developed by Schaefer and McKay. The electrical performance of the probe is determined by measuring of Scattering matrix parameters (S-parameters) in particular input/output ports. These parameters are compared to the calculated parameters of the design employing the S-matrix formalism. It is shown that the S-matrix formalism provides an excellent tool for examination of transmission line probes and thus the tool for a rational design of these probes. On the other hand, the resulting design provides excellent electrical performance. From a point of view of Nuclear Magnetic Resonance (NMR), calibration spectra of particular ports (channels) are of great importance. The estimation of the π/2 pulses length for all five NMR channels is presented.

  11. Determination of complex permittivity from propagation constant measurement with planar transmission lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new two-standard calibration procedure is outlined for determining the complex permittivity of materials from the propagation constant measured with planar transmission lines. Once calibrated, a closed-form expression for the material permittivity is obtained. The effects of radiation and conducto...

  12. Frequency considerations in evaluation of geomagnetically induced currents in transmission lines

    NASA Astrophysics Data System (ADS)

    Trichtchenko, Larisa

    2016-04-01

    Significant impacts of large geomagnetically induced currents on power transmission systems lead to the necessity to properly evaluate the size of these currents. Several simplified assumptions which are used for the modelling of these currents would be clarified in the presentations. The following two classes of possible sources of errors will be discussed: 1. "Geophysical" uncertainties in the evaluation of the earth geoelectric field, such as a) influence of geomagnetic sampling rate on the "true" waveform of the geomagnetic disturbance and b) influence of the uncertainties in the 1-dimensional layered earth models; 2. Assumptions in the power network modelling, such as a) DC-approximation of the response of transmission line and b) not taking into accounts the impacts of the conducting system (transmission lines) on the ambient (geophysical) electric field. The results of presented research will help in proper evaluations of the GIC and, therefore, in preparing the adequate mitigation measures to counteract the space weather impacts on critical infrastructure.

  13. Advances in fibers and transmission line technology for long haul submarine systems

    NASA Astrophysics Data System (ADS)

    Peckham, David W.; Kim, Jinkee; Sun, Yi; Lingle, Robert L., Jr.; Levring, Ole

    2007-11-01

    The 7.1-magnitude earthquake on December 26, 2006 in the Strait of Luzon resulted in the failure of several submarine cable systems. Seven of the nine cables that pass through the strait were damaged, disrupting communications to China, Taiwan, Japan, Korea and Singapore. This recent event highlighted the dependence of international communications on submarine fiber optic transmission systems. This paper will review the evolution of optical fiber transmission line technology that has been deployed in the long haul undersea telecommunications network. It will start with a discussion of the chronological evolution of the optical fiber transmission line architecture in section one, then give more detail regarding the technology that is still being deployed today.

  14. Theoretical limit of repeater spacing in an optical transmission line utilizing Raman amplification

    NASA Astrophysics Data System (ADS)

    Nakashima, T.; Seikai, S.; Nakazawa, M.; Negishi, Y.

    1986-08-01

    The limit of repeater spacing is investigated theoretically for optical transmission lines utilizing stimulated Raman scattering to amplify the signal light. Achievable repeater spacing is numerically estimated on the basis of coupled power equations and measured fiber characteristics for various signal wavelengths and relative index differences. Three types of transmission line configurations are considered, i.e., utilization of forward only, backward only, and bidirectional amplification. In the third case, a transmission distance of more than 400 km is predicted for an input signal light power of 100 microW, a signal wavelength of 1.57 microns, and a pump power of 0.5 W using a fiber with a relative index difference of 1 percent for signal light amplification.

  15. Identification and characterization of populations living near high-voltage transmission lines: a pilot study.

    PubMed Central

    Wartenberg, D; Greenberg, M; Lathrop, R

    1993-01-01

    Populations living close to high-voltage transmission lines often have residential magnetic field exposures in excess of 1 microT, and sometimes over 2 microT. Yet, populations studied in most epidemiologic investigations of the association between residential magnetic field exposure and cancer typically have exposures below 1 microT and frequently below 0.5 microT. To improve statistical power and precision, it would be useful to compare high exposure populations with low exposure populations rather than only studying small differences within low exposure populations. Toward this end, we have developed an automated method for identifying populations living near high-voltage transmission lines. These populations likely have more highly exposed individuals than the population at large. The method uses a geographic information system (GIS) to superimpose digitized transmission line locations on U.S. Census block location data and then extract relevant demographic data. Analysis of data from a pilot study of the populations residing within 100 m of a 29-km segment of one 230-kV line in New Jersey shows that when compared to populations in the surrounding census blocks farther than 100 m from this line, those populations close to the line have similar demographics but differ in terms of perceived housing value variables. We believe that the approach we have developed will enable investigators to rapidly identify and characterize populations living near high-voltage transmission lines on a statewide basis for considering the impact of exposures and for public policy and that these populations also can be used for epidemiologic study. Images p626-a Figure 1. Figure 2. Figure 3. PMID:8143596

  16. Analysis and Experimental Evaluation of Power Line Transmission Parameters for Power Line Communication

    NASA Astrophysics Data System (ADS)

    Mlynek, P.; Misurec, J.; Koutny, M.; Fujdiak, R.; Jedlicka, T.

    2015-04-01

    The article describes a way of evaluating the power line channel frequency response and input impedance by means of the linear time-invariant (LTI) power line generator. Two possible methods are introduced for the calculation of primary parameters: the first method depends on the physical realization and physical dimension of the cable, and the second method is derived from the data provided by typical electrical cable manufacturers. Based on these methods, a comparison of transfer functions was made. This is followed by measurement evaluation and numerical verification on a simple topology

  17. Results of TLMRC research on x-bracing strength in lattice transmission towers. [Transmission Line Mechanical Research Center

    SciTech Connect

    Cannon, D.D. Jr.; Nickerson, R. )

    1993-01-01

    The generally accepted procedures for designing lattice transmission towers in the US are those given in the American Society of Civil Engineers (ASCE) guide, Guide for Design of Steel Transmission Towers (ASCE Manual 52). When the ASCE Task Committee on updating Manual 52 was active prior to publishing the second edition, a topic of discussion and disagreement was the calculation of the strength of X-bracing members. The primary point of disagreement was the effect of the tension member load on the support offered to the compression member and how this should be accounted for in calculating the capacity of the compression member. To clarify the design of X-bracing, EPRI's Transmission Line Mechanical Research Center (TLMRC) initiated a research program to study the strength of X-bracing, with particular emphasis on the effect of the tension member load on the capacity of the compression member. A two-dimensional test frame was used to test X-braces constructed of equal leg angles, unequal leg angles framed either on the long le or on the short leg.

  18. Theory and simulation of high-power microwave generation in a magnetically insulated transmission line oscillator

    NASA Astrophysics Data System (ADS)

    Lemke, Raymond W.; Clark, Collins M.

    1987-10-01

    The magnetically insulated transmission line (MITE-LINE) oscillator is an electron beam diode comprised of a field emitting cathode and a corrugated anode. The device is similar to a linear magnetron except that the insulating magnetic field is self-generated. The self-insulating property makes this device a robust high-power microwave tube. Using the thin-beam approximation a dispersion relation for a cylindrical MITE-LINE oscillator is derived. The dispersion relation is used to predict frequency and growth rate of the microwave generating instability. Analytical results are compared with CCUBE particle simulations.

  19. Sidney-North Yuma 230-kV Transmission Line Project, Colorado and Nebraska

    SciTech Connect

    Not Available

    1991-06-01

    This report describes the need for a 230-kV overhead transmission line to supply power from Sidney, Nebraska to eastern Colorado. The alternative scenario compared to construction of the line is No Action. Rejected alternatives include underground lines and different routing paths, with a possible extension to the Sterling area. Both scenarios are evaluated for environmental effects, cost, and consequences for the eastern Colorado region. The proposed route is determined to be the environmentally preferred choice. 120 refs., 6 figs., 13 tabs. (MHB)

  20. Space charge drift from a +/- 400-kV direct current transmission line.

    PubMed

    Hendrickson, R C

    1986-01-01

    The Minnesota Environmental Quality Board completed a 3-year study of the space charge plume outside the right of way of a bipolar (+/- 400 kV) direct current transmission line in rural west central Minnesota. The purpose of the study was to determine the levels of DC potential gradient and small airs ions in the downwind plume to which humans and animals may be exposed. Potential gradient measurements show that a space charge plume is detectable downwind at least 1600 m from the transmission line. Plume relaxation rates indicate that under certain conditions one could detect the plume at twice that distance or more. Net charge in the plume assumes the polarity of the downwind energized transmission line conductor. The bipolar DC line thus electrically bisects the land through which it passes; on one side of the line there is a net positive space charge, on the other side a net negative space charge. Electric charge in the plume resides on aerosols and small air ions. Polar conductivity data substantiate the fact that small air ions of one polarity in the plume are elevated while those of opposite polarity are suppressed compared to background concentrations found in the rural environment. The resulting charge imbalance persists downwind at least 1600 m, though the median small air ion concentrations of plume polarity have adjusted to within the background range by that time with perpendicular wind speed components between 1 and 6 m/sec.

  1. 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. PMID:25136653

  2. Data-Mining-Based Intelligent Differential Relaying for Transmission Lines Including UPFC and Wind Farms.

    PubMed

    Jena, Manas Kumar; Samantaray, Subhransu Ranjan

    2016-01-01

    This paper presents a data-mining-based intelligent differential relaying scheme for transmission lines, including flexible ac transmission system device, such as unified power flow controller (UPFC) and wind farms. Initially, the current and voltage signals are processed through extended Kalman filter phasor measurement unit for phasor estimation, and 21 potential features are computed at both ends of the line. Once the features are extracted at both ends, the corresponding differential features are derived. These differential features are fed to a data-mining model known as decision tree (DT) to provide the final relaying decision. The proposed technique has been extensively tested for single-circuit transmission line, including UPFC and wind farms with in-feed, double-circuit line with UPFC on one line and wind farm as one of the substations with wide variations in operating parameters. The test results obtained from simulation as well as in real-time digital simulator testing indicate that the DT-based intelligent differential relaying scheme is highly reliable and accurate with a response time of 2.25 cycles from the fault inception.

  3. 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

  4. Titanium honeycomb acoustic lining structural and thermal test report. [for acoustic tailpipe for JT8D engine

    NASA Technical Reports Server (NTRS)

    Joynes, D.; Balut, J. P.

    1974-01-01

    The results are presented of static, fatigue and thermal testing of titanium honeycomb acoustic panels representing the acoustic tailpipe for the Pratt and Whitney Aircraft JT8D Refan engine which is being studied for use on the Boeing 727-200 airplane. Test specimens represented the engine and tailpipe flange joints, the rail to which the thrust reverser is attached and shear specimens of the tailpipe honeycomb. Specimens were made in four different batches with variations in configuration, materials and processes in each. Static strength of all test specimens exceeded the design ultimate load requirements. Fatigue test results confirmed that aluminum brazed titanium, as used in the Refan tailpipe design, meets the fatigue durability objectives. Quality of welding was found to be critical to life, with substandard welding failing prematurely, whereas welding within the process specification exceeded the panel skin life. Initial fatigue testing used short grip length bolts which failed prematurely. These were replaced with longer bolts and subsequent testing demonstrated the required life. Thermal tests indicate that perforated skin acoustic honeycomb has approximately twice the heat transfer of solid skin honeycomb.

  5. Broad frequency-band characterizations of electromagnetic energy propagation in planar thin-film transmission lines

    NASA Astrophysics Data System (ADS)

    Kim, Dongchul; Eo, Yungseon

    2014-04-01

    Thin-film transmission lines are experimentally characterized in the frequency range from 10 MHz to 110 GHz. Scattering (S-) parameters for several test lines are measured. Then, two important transmission line parameters ( i.e., the propagation constant and characteristic impedance) are determined in the measured frequency range. The resonances, which are inevitable in a practical experimental environment, are carefully eliminated by de-embedding parasitic effects and by determining the frequency-variant dielectric permittivity based on the Debye model. Based on the experimental work, we showed that the conventional skin-effect model may not be accurate for high-frequencies. Further, the 3-dimensional (3D) numerical field solver does not reflect the radiation loss at high-frequency. Finally, in the millimeter (mm)-wave region, all the three loss mechanisms due to the skin-effect, dielectric polarization, and electromagnetic radiation have to be taken into account.

  6. Rolled-up transmission line structure for a radiofrequency integrated circuit (RFIC)

    SciTech Connect

    Li, Xiuling; Huang, Wen

    2015-04-28

    A rolled-up transmission line structure for a radiofrequency integrated circuit (RFIC) comprises a multilayer sheet in a rolled configuration comprising multiple turns about a longitudinal axis, where the multilayer sheet comprises a conductive pattern layer on a strain-relieved layer. The conductive pattern layer comprises a first conductive film and a second conductive film separated from the first conductive film in a rolling direction. In the rolled configuration, the first conductive film surrounds the longitudinal axis, and the second conductive film surrounds the first conductive film. The first conductive film serves as a signal line and the second conductive film serves as a conductive shield for the rolled-up transmission line structure.

  7. A high transmission broadband gradient index lens using elastic shell acoustic metamaterial elements.

    PubMed

    Titovich, Alexey S; Norris, Andrew N; Haberman, Michael R

    2016-06-01

    The use of cylindrical elastic shells as elements in acoustic metamaterial devices is demonstrated through simulations and underwater measurements of a cylindrical-to-plane wave lens. Transformation acoustics of a circular region to a square dictate that the effective density in the lens remain constant and equal to that of water. Piecewise approximation to the desired effective compressibility is achieved using a square array with elements based on the elastic shell metamaterial concept developed by Titovich and Norris [J. Acoust. Soc. Am. 136(4), 1601-1609 (2014)]. The sizes of the elements are chosen based on availability of shells, minimizing fabrication difficulties. The tested device is neutrally buoyant comprising 48 elements of nine different types of commercial shells made from aluminum, brass, copper, and polymers. Simulations indicate a broadband range in which the device acts as a cylindrical to plane wave lens. The experimental findings confirm the broadband quadropolar response from approximately 20 to 40 kHz, with positive gain of the radiation pattern in the four plane wave directions. PMID:27369162

  8. [Acoustic characteristics of classrooms].

    PubMed

    Koszarny, Zbigniew; Chyla, Andrzej

    2003-01-01

    Quality and usefulness of school rooms for transmission of verbal information depends on the two basic parameters: form and quantity of the reverberation time, and profitable line measurements of school rooms from the acoustic point of view. An analysis of the above-mentioned parameters in 48 class rooms and two gymnasiums in schools, which were built in different periods, shows that the most important problem is connected with too long reverberation time and inappropriate acoustic proportions. In schools built in the 1970s, the length of reverberation time is mostly within a low frequency band, while in schools built contemporarily, the maximum length of disappearance time takes place in a quite wide band of 250-2000 Hz. This exceeds optimal values for that kind of rooms at least twice, and five times in the newly built school. A long reverberation time is connected with a low acoustic absorption of school rooms. Moreover, school rooms are characterised by inappropriate acoustic proportions. The classrooms, in their relation to the height, are too long and too wide. It is connected with deterioration of the transmission of verbal information. The data show that this transmission is unequal. Automatically, it leads to a speech disturbance and difficulties with understanding. There is the need for adaptation of school rooms through increase of an acoustic absorption.

  9. Transgenerational transmission of anxiety induced by neonatal exposure to lipopolysaccharide: implications for male and female germ lines.

    PubMed

    Walker, Adam K; Hawkins, Guy; Sominsky, Luba; Hodgson, Deborah M

    2012-08-01

    Neonatal lipopolysaccharide (LPS) exposure increases anxiety-like behaviour and alters neuroendocrine responses to stress in adult rats. The current study assessed whether this anxiety-related phenotype observed in rats neonatally exposed to LPS is transferable to subsequent generations. Wistar rats were exposed to LPS (0.05 mg/kg, Salmonella enteritidis) or non-pyrogenic saline (equivolume) on postnatal days 3 and 5. In adulthood, animals were subjected to restraint and isolation stress or no stress, and subsequently evaluated for anxiety-like behaviours on the elevated plus maze, acoustic startle response, and holeboard apparatus. Blood was collected to examine corticosterone responses to stress and behavioural testing in adulthood. Animals from both treatment groups which exhibited the anxiety-like phenotype were bred with untreated partners. Maternal care of the second generation (F2) was monitored over the first week of life. In adulthood, the F2 generation underwent identical testing procedures as the parental (F1) generation. The F2 offspring of females exposed to LPS as neonates exhibited an anxiety-like phenotype in adulthood and a potentiated corticosterone response to stress (p<.05). F2 offspring of males exposed to LPS as neonates also exhibited an anxiety-like phenotype (p<.05), however, no differences in corticosterone responses were observed. To determine the impact of maternal care on the anxiety-like phenotype, a cross-fostering study was conducted in which offspring of LPS-treated females were fostered to saline-treated mothers and vice versa, which was found to reverse the behavioural and endocrine phenotypes of the F2 generation. These data indicate that a neonatally bacterially induced anxiety phenotype is transferable across generations in both sexes. Maternal care is the mediating mechanism along the maternal line. We suggest that transmission may be dependent upon heritable epigenetic phenomena for the paternal line. The implications of this

  10. Lightning Surge Analysis for 500-kV Transmission Lines using Grounding Model with Dynamic Characteristics

    NASA Astrophysics Data System (ADS)

    Yasuda, Yoh; Kondo, Shuhei; Hara, Takehisa; Ikeda, Keiichi; Sonoi, Yasuo; Furuoka, Yoshihiro

    It is well known that grounding resistance under huge lightning current injection has current-dependent characteristics, whose mathematical model was already proposed by Liew and Darveniza in 1974. In this paper, where our final goal is reasonable design for lightning protection of 500-kV transmission tower, we adopt the dynamic grounding-resistance model to MODELS-ATP simulation. The effect of the model for the lightning surge analysis on 500-kV transmission line systems is discussed in detail.

  11. A Novel Transient Fault Current Sensor Based on the PCB Rogowski Coil for Overhead Transmission Lines

    PubMed Central

    Liu, Yadong; Xie, Xiaolei; Hu, Yue; Qian, Yong; Sheng, Gehao; Jiang, Xiuchen

    2016-01-01

    The accurate detection of high-frequency transient fault currents in overhead transmission lines is the basis of malfunction detection and diagnosis. This paper proposes a novel differential winding printed circuit board (PCB) Rogowski coil for the detection of transient fault currents in overhead transmission lines. The interference mechanism of the sensor surrounding the overhead transmission line is analyzed and the guideline for the interference elimination is obtained, and then a differential winding printed circuit board (PCB) Rogowski coil is proposed, where the branch and return line of the PCB coil were designed to be strictly symmetrical by using a joining structure of two semi-rings and collinear twisted pair differential windings in each semi-ring. A serial test is conducted, including the frequency response, linearity, and anti-interference performance as well as a comparison with commercial sensors. Results show that a PCB Rogowski coil has good linearity and resistance to various external magnetic field interferences, thus enabling it to be widely applied in fault-current-collecting devices. PMID:27213402

  12. Study on galloping behavior of iced eight bundle conductor transmission lines

    NASA Astrophysics Data System (ADS)

    Zhou, Linshu; Yan, Bo; Zhang, Liang; Zhou, Song

    2016-02-01

    Wind tunnel test was carried out to obtain the aerodynamic coefficients of an eight bundle conductor accreted with crescent-shaped ice. A user-defined cable element with torsional degree of freedom is developed in ABAQUS software to capture the torsional deformation of the iced conductors during galloping. By means of the user-defined cable element, different damping ratios in in-plane, out-of-plane and torsional directions of the conductors can be defined and the aerodynamic forces varying with their motion status can be exerted on the conductors conveniently when ABAQUS is used to simulate galloping of transmission lines. A wind tunnel test to model galloping of an iced eight bundle conductor segment was carried out, and the validity of the numerical simulation method is demonstrated by the agreement of the galloping orbit of the bundle conductor segment model recorded in the test and that by the numerical simulation. Furthermore, galloping behavior, including dynamic responses, galloping orbits, frequencies, vibration modes and amplitudes, of typical iced eight bundle conductor transmission lines in the cases of different span lengths, initial tensions in sub-conductors, wind velocities, angles of wind attack and damping ratios is studied, and the galloping behavior of the lines with internal resonance conditions is discussed. The obtained results may provide a fundamental tool for the development of anti-galloping techniques of eight bundle conductor transmission lines.

  13. A Novel Transient Fault Current Sensor Based on the PCB Rogowski Coil for Overhead Transmission Lines.

    PubMed

    Liu, Yadong; Xie, Xiaolei; Hu, Yue; Qian, Yong; Sheng, Gehao; Jiang, Xiuchen

    2016-05-21

    The accurate detection of high-frequency transient fault currents in overhead transmission lines is the basis of malfunction detection and diagnosis. This paper proposes a novel differential winding printed circuit board (PCB) Rogowski coil for the detection of transient fault currents in overhead transmission lines. The interference mechanism of the sensor surrounding the overhead transmission line is analyzed and the guideline for the interference elimination is obtained, and then a differential winding printed circuit board (PCB) Rogowski coil is proposed, where the branch and return line of the PCB coil were designed to be strictly symmetrical by using a joining structure of two semi-rings and collinear twisted pair differential windings in each semi-ring. A serial test is conducted, including the frequency response, linearity, and anti-interference performance as well as a comparison with commercial sensors. Results show that a PCB Rogowski coil has good linearity and resistance to various external magnetic field interferences, thus enabling it to be widely applied in fault-current-collecting devices.

  14. TRIFL: A design tool for modeling complex magnetically insulated transmission line geometries

    SciTech Connect

    Mix, L.P.; Mendel, C.W. Jr.; Seidel, D.B.; Rosenthal, S.E.

    1996-12-31

    Vacuum power flow in modern high-power pulsed accelerator transmission lines requires field stresses at the conductors that are so high that negative surfaces become space-charge-limited electron emitters. The performance of these lines can be calculated using two- and three-dimensional, time-dependent, particle-in-cell electromagnetic codes such a TWOQUICK and QUICKSILVER. Extensive design of complex systems using these simulation codes would be extremely expensive and, perhaps, impossible for many of the new pulsed power systems being planned. An analytic model has been developed which predicts the behavior of magnetically insulated transmission lines. The model uses flow impedance parameters with an expanded set of Telegrapher`s equations to calculate radial currents in the transmission lines. This model has been implemented in a code, TRIFL (TRIple-equation-FLow model), on workstations and PC`s and allows one to do detailed designed studies on systems far too complex for similar treatment using a PIC code. TRIFL has been used to design hardware for the PBFA-X accelerator and to analyze PBFA-X data.

  15. High frequency acoustic transmission loss of perforated plates at normal incidence.

    PubMed

    Phong, Vincent; Papamoschou, Dimitri

    2013-08-01

    A study has been conducted on the transmission loss of perforated plates at normal incidence. The investigation includes a theoretical analysis of the problem with validation through experimentation. The experiments comprised microphone measurements of transmission loss for 11 perforated plates with variable thickness, hole size, and porosity. The theoretical model is based on planar wave propagation through a single contraction/expansion chamber with modifications to account for hole interaction effects. The resulting formula for transmission loss yields superior predictions over past theories for the range of properties investigated. Deviations between experimental measurements and theoretical predictions of transmission loss are less than about 1.5 dB for dimensionless hole diameter d/λ < 0.5. The accuracy of the model does not show a strong dependence on plate thickness-to-diameter ratio or porosity. PMID:23927109

  16. A transmission-line model of back-cavity dynamics for in-plane pressure-differential microphones.

    PubMed

    Kim, Donghwan; Kuntzman, Michael L; Hall, Neal A

    2014-11-01

    Pressure-differential microphones inspired by the hearing mechanism of a special parasitoid fly have been described previously. The designs employ a beam structure that rotates about two pivots over an enclosed back volume. The back volume is only partially enclosed due to open slits around the perimeter of the beam. The open slits enable incoming sound waves to affect the pressure profile in the microphone's back volume. The goal of this work is to study the net moment applied to pressure-differential microphones by an incoming sound wave, which in-turn requires modeling the acoustic pressure distribution within the back volume. A lumped-element distributed transmission-line model of the back volume is introduced for this purpose. It is discovered that the net applied moment follows a low-pass filter behavior such that, at frequencies below a corner frequency depending on geometrical parameters of the design, the applied moment is unaffected by the open slits. This is in contrast to the high-pass filter behavior introduced by barometric pressure vents in conventional omnidirectional microphones. The model accurately predicts observed curvature in the frequency response of a prototype pressure-differential microphone 2 mm × 1 mm × 0.5 mm in size and employing piezoelectric readout.

  17. A transmission-line model of back-cavity dynamics for in-plane pressure-differential microphones.

    PubMed

    Kim, Donghwan; Kuntzman, Michael L; Hall, Neal A

    2014-11-01

    Pressure-differential microphones inspired by the hearing mechanism of a special parasitoid fly have been described previously. The designs employ a beam structure that rotates about two pivots over an enclosed back volume. The back volume is only partially enclosed due to open slits around the perimeter of the beam. The open slits enable incoming sound waves to affect the pressure profile in the microphone's back volume. The goal of this work is to study the net moment applied to pressure-differential microphones by an incoming sound wave, which in-turn requires modeling the acoustic pressure distribution within the back volume. A lumped-element distributed transmission-line model of the back volume is introduced for this purpose. It is discovered that the net applied moment follows a low-pass filter behavior such that, at frequencies below a corner frequency depending on geometrical parameters of the design, the applied moment is unaffected by the open slits. This is in contrast to the high-pass filter behavior introduced by barometric pressure vents in conventional omnidirectional microphones. The model accurately predicts observed curvature in the frequency response of a prototype pressure-differential microphone 2 mm × 1 mm × 0.5 mm in size and employing piezoelectric readout. PMID:25373956

  18. Extraction of acoustic normal mode depth functions using vertical line array data

    NASA Astrophysics Data System (ADS)

    Neilsen, Tracianne B.; Westwood, Evan K.

    2002-02-01

    A method for extracting the normal modes of acoustic propagation in the shallow ocean from sound recorded on a vertical line array (VLA) of hydrophones as a source travels nearby is presented. The mode extraction is accomplished by performing a singular value decomposition (SVD) of individual frequency components of the signal's temporally averaged, spatial cross-spectral density matrix. The SVD produces a matrix containing a mutually orthogonal set of basis functions, which are proportional to the depth-dependent normal modes, and a diagonal matrix containing the singular values, which are proportional to the modal source excitations and mode eigenvalues. The conditions under which the method is expected to work are found to be (1) sufficient depth sampling of the propagating modes by the VLA receivers; (2) sufficient source-VLA range sampling, and (3) sufficient range interval traversed by the source. The mode extraction method is applied to data from the Area Characterization Test II, conducted in September 1993 in the Hudson Canyon Area off the New Jersey coast. Modes are successfully extracted from cw tones recorded while (1) the source traveled along a range-independent track with constant bathymetry and (2) the source traveled up-slope with gradual changes in bathymetry. In addition, modes are successfully extracted at multiple frequencies from ambient noise.

  19. Acoustical standards in engineering acoustics

    NASA Astrophysics Data System (ADS)

    Burkhard, Mahlon D.

    2001-05-01

    The Engineering Acoustics Technical Committee is concerned with the evolution and improvement of acoustical techniques and apparatus, and with the promotion of new applications of acoustics. As cited in the Membership Directory and Handbook (2002), the interest areas include transducers and arrays; underwater acoustic systems; acoustical instrumentation and monitoring; applied sonics, promotion of useful effects, information gathering and transmission; audio engineering; acoustic holography and acoustic imaging; acoustic signal processing (equipment and techniques); and ultrasound and infrasound. Evident connections between engineering and standards are needs for calibration, consistent terminology, uniform presentation of data, reference levels, or design targets for product development. Thus for the acoustical engineer standards are both a tool for practices, for communication, and for comparison of his efforts with those of others. Development of many standards depends on knowledge of the way products are put together for the market place and acoustical engineers provide important input to the development of standards. Acoustical engineers and members of the Engineering Acoustics arm of the Society both benefit from and contribute to the Acoustical Standards of the Acoustical Society.

  20. Environmental Assessment of the Gering-Stegall 115-kV Transmission Line Consolidation Project, Scotts Bluff County, Nebraska

    SciTech Connect

    1995-05-01

    The Department of Energy (DOE), Western Area Power Administration (Western) proposes to consolidate segments of two transmission lines near the Gering Substation in Gering, Nebraska. The transmission lines are both located in Scotts Bluff County, Nebraska. The transmission lines are both located in Scotts Bluff County, Nebraska, within the city of Gering. Presently, there are three parallel 115-kilovolt (kV) transmission lines on separate rights-of-way (ROW) that terminate at the Gering Substation. The project would include dismantling the Archer-Gering wood-pole transmission line and rebuilding the remaining two lines on single-pole steel double circuit structures. The project would consolidate the Gering-Stegall North and Gering-Stegall South 115-kV transmission lines on to one ROW for a 1.33-mile segment between the Gering Substation and a point west of the Gering Landfill. All existing wood-pole H-frame structures would be removed, and the Gering-Stegall North and South ROWs abandoned. Western is responsible for the design, construction, operation, and maintenance of the line. Western prepared an environmental assessment (EA) that analyzed the potential environmental impacts of the proposed construction, operation, and maintenance of the 115-kV transmission line consolidation. Based on the analyses in the EA, the DOE finds that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act of 1969 (NEPA).

  1. Studies of the acoustic transmission characteristics of coaxial nozzles with inverted velocity profiles: Comprehensive data report. [nozzle transfer functions

    NASA Technical Reports Server (NTRS)

    Dean, P. D.; Salikuddin, M.; Ahuja, K. K.; Plumblee, H. E.; Mungur, P.

    1979-01-01

    The efficiency of internal noise radiation through a coannular exhaust nozzle with an inverted velocity profile was studied. A preliminary investigation was first undertaken (1) to define the test parameters which influence the internal noise radiation; (2) to develop a test methodology which could realistically be used to examine the effects of the test parameters; and (3) to validate this methodology. The result was the choice of an acoustic impulse as the internal noise source in the jet nozzles. Noise transmission characteristics of a coannular nozzle system were then investigated. In particular, the effects of fan convergence angle, core extension length to annulus height ratio and flow Mach numbers and temperatures were studied. Relevant spectral data only is presented in the form of normalized nozzle transfer function versus nondimensional frequency.

  2. Full frequency-dependent phase-domain modelling of transmission lines and corona phenomena

    NASA Astrophysics Data System (ADS)

    Castellanos, Fernando

    This thesis presents two main developments in the modelling of power transmission lines for the simulation of electric networks. The first one is wide bandwidth circuit corona model and the second a phase-domain multiphase full frequency-dependent line model. The latter can be easily used in connection with the former. Both models have been developed for implementation in time domain simulation computer programs, such as the ElectroMagnetic Transients Program (EMTP). Corona in overhead transmission lines is a highly nonlinear and non deterministic phenomenon. Circuit models have been developed in the past to represent its behaviour, but the response of these models is usually limited to a narrow band of frequencies. The corona model presented in this thesis overcomes this problem by: (1) matching closely the topology of the circuit to the topology of the physical system, and (2) duplicating the high-order dynamic response of the phenomenon with a high-order transient circuit response. The resulting model is valid for a wide range of frequencies and is able to represent waveshapes from switching to lightning surges. A unique set of model parameters can be obtained directly from test-cage measurements, and the same set can be used directly for an arbitrary overhead line configuration. The model uses only standard EMTP circuit elements and requires no iterations. Simulations of corona charge-voltage (q-v) curves and of travelling surges were performed and compared to existing field test measurements. The proposed new transmission line model (z-line) can be used for the representation of multicircuit transmission lines in time-domain transient solutions. The model includes a full representation of the frequency-dependent line parameters and is formulated directly in phase coordinates. The solution in phase coordinates, as opposed to modal coordinates, avoids the problems associated with the representation of the frequency-dependent transformation matrices that relate

  3. Comprehensive techniques to determine broadband physically-consistent material characteristics using transmission lines

    NASA Astrophysics Data System (ADS)

    Zhou, Zhen

    Dispersion, attenuation, and crosstalk are several major challenges that both a high-speed digital and a microwave serial link must overcome to achieve their desirable performance. These phenomena are directly related to the frequency dependency of the dielectric property of the material used in package and interconnect. The dielectric property of a material is commonly measured by its manufacturer in a particular direction at a few discrete frequencies using resonator and waveguide methodology. Since the dielectric property may vary during manufacturing processing, the measurements taken by the manufacturer might be not adequate. Moreover, the dielectric property of a material in a bandwidth that covers at least the second harmonics of the fundamental operational frequency is required to accurately predict the link performance. One of the efforts in this research is to investigate the methodology of realizing broadband characteristics of the dielectric property of a material in its "as packaged" configuration using various transmission line topologies, such as microstrip line and Co-Planar Waveguide (CPW). Transitions from CPW to other transmission line topologies are mandatory if CPW probes are used to achieve broadband and repeatable measurements. Since microstrip line is one of the transmission line topologies involved in this research, a research effort is dedicated to develop a broadband CPW-to-microstrip line transition. An effort is also expended to creating casual material models that can be used in electromagnetic simulators to appropriately model the link based on the polarization mechanism of the materials. In addition to focusing on the measurement method in frequency domain, Short Pulse Propagation (SPP), a time domain method, is investigated as well. A virtual test bench is created to investigate the correlation between impedance variations in stripline structures due to fabricated tolerance and the attenuation predicted by SPP.

  4. The transmission of acoustic energy by a finite cylindrical shell excited by external plane waves

    NASA Astrophysics Data System (ADS)

    Cacciolati, C.; Gotteland, M.; Barbe, M.

    A qualitative method is presented for sensitivity analyses of acoustic coupling between cylindrical shells such as found in aerospace structures. The shells are excited by an exterior plane wave. The analysis is carried out in terms of coupling among the exterior and structural natural modes and the structural and cavity natural modes. Strong coupling is shown to be limited to cases of coincidence of resonance frequencies and when numerous identical incident waves arrive from multiple directions. Coupling will in any case be confined to low frequencies. Limits are defined for the necessary number of frequencies which must be considered when predicting whether or not coupling will occur.

  5. Transmission lines implementation on HDI flex circuits for the CMS tracker upgrade

    NASA Astrophysics Data System (ADS)

    Blanchot, G.; De Canio, F.; Gadek, T.; Honma, A.; Kovacs, M.; Rose, P.; Traversi, G.

    2016-01-01

    The upgrade of the CMS tracker at the HL-LHC relies on hybrid modules built on high density interconnecting flexible circuits. They contain several flip chip readout ASICs having high speed digital ports required for configuration and data readout, implemented as customized Scalable Low-Voltage Signalling (SLVS) differential pairs. This paper presents the connectivity requirements on the CMS tracker hybrids; it compares several transmission line implementations in terms of board area, achievable impedances and expected crosstalk. The properties obtained by means of simulations are compared with measurements made on a dedicated test circuit. The different transmission line implementations are also tested using a custom 65nm SLVS driver and receiver prototype ASIC.

  6. Optical transmission measurements for in-line monitoring of turbid oil-water emulsions

    NASA Astrophysics Data System (ADS)

    Metz, Philipp; Dopf, Katja; Aichholz, Markus; Riedel, Boris; Lemmer, Uli; Freudig, Barbara; Zimmermann, Clifton; Gerken, Martina

    2014-05-01

    For absorbing media the concentration may be calculated directly from the optical transmission following the logarithmic dependence given in the Lambert-Beer law. Due to multiple scattering events in oil-water emulsions (e.g. milk, cream, etc.), these exhibit a nonlinear relationship between the attenuation and the oil concentration. We demonstrate that for increasing oil content in oil-water emulsions the attenuation first increases, then levels out, and finally even decreases for a fat content of 60%. Single-wavelength optical transmission measurements are found to be well suited for the in-line monitoring of oil-water emulsions of fat contents below 20%, e.g., for the in-line fat content monitoring of milk. Using experiments and ray-tracing simulations we evaluate system optimization.

  7. Hybrid particle traps and conditioning procedure for gas insulated transmission lines

    DOEpatents

    Dale, Steinar J.; Cookson, Alan H.

    1982-01-01

    A gas insulated transmission line includes an outer sheath, an inner condor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping ring is disposed within the outer sheath, and the trapping ring has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the trapping ring along an arc. A support sheet having an adhesive coating thereon is secured to the trapping ring and disposed on the outer sheath within the low field region formed between the trapping ring and the outer sheath. A conditioning method used to condition the transmission line prior to activation in service comprises applying an AC voltage to the inner conductor in a plurality of voltage-time steps, with the voltage-time steps increasing in voltage magnitude while decreasing in time duration.

  8. High strength polymer post insulators enable economical transmission lines with low environmental impact

    SciTech Connect

    Burnham, J.T.; Givens, P.S.; Grisham, T.M.

    1994-12-31

    In today`s operational environment, utility transmission engineers are being challenged with a new set of design parameters. In addition to the traditional objective of system reliability, new issues of paramount importance heave evolved. These include the reduction of construction costs, addressing transmission line aesthetics, and optimizing power delivery within restricted right of way. This document describes a design approach which enables the engineer to maximize these criteria without sacrificing system reliability. A laboratory test method for polymer post insulators is also presented which effectively simulates combined mechanical load conditions expected in application, thus allowing the utility engineer to optimize span lengths, conductor size, and insulator selection. Polymer history and benefits associated with compact line design are also reviewed.

  9. AC and lightning performance of fiberglass crossarms aged in 115 kV transmission line

    SciTech Connect

    Grzybowski, S. . Dept. of Electrical and Computer Engineering); Jenkins, E.B. . Generation and Transmission Group)

    1993-10-01

    This paper presents the results of an investigation of the electrical performance of 115 kV transmission line fiberglass cross-arm used by Mississippi Power and Light Company. A transmission line fiberglass crossarm removed from service and companion cross-arms outdoors but not in service were examined. The evaluation of electrical performance was based on flashover voltage value at AC voltage and standard lightning impulses as well as under dry and wet conditions. The tests were performed in the Mississippi State University High Voltage Laboratory. The obtained flashover voltages show no large differences in electrical strength of fiberglass crossarms removed from service and those stored outdoors. The Added CFO voltage by fiberglass crossarm to the porcelain suspension insulators is presented versus the length of the fiberglass crossarm for dry and wet conditions.

  10. Application guide for transmission line non-ceramic insulators. Final report

    SciTech Connect

    Phillips, A.; Childs, D.; Gela, G.

    1998-11-01

    Although there has been a dramatic increase in NCI use over the last decade, there is a wide variation in NCI design procedures, procurement specifications, installation and handling practices, live working techniques, and inspection and maintenance methods. Consequently, practicing utility engineers need a source of relevant information and recommendations on these subjects. EPRI has responded to this need by investing in a major multiyear research program on NCI. This report provides guidelines for electric utilities considering the use of non-ceramic insulators (NCI). It includes information on new installations, the replacement of conventional porcelain or glass (ceramic) insulators with NCI on existing transmission lines, and the assessment of NCI in service on transmission lines.

  11. Overlap amplitude and localization properties in aperiodic diluted and non-diluted direct electric transmission lines

    NASA Astrophysics Data System (ADS)

    Lazo, E.; Castro, C. E.; Cortés-Cortés, F.

    2016-09-01

    In this work we study the relationship existing between the localization properties of the diluted and non-diluted direct electrical transmission lines with the overlap amplitude Cijω = 2 | Iiω Ijω | , where Ijω is the amplitude of the electric current function at jth cell of the transmission line for the state with frequency ω. We distribute two values of inductances LA and LB, according to the generalized aperiodic Thue-Morse m-tupling sequence. We find that the behavior of Ci,jω is directly related to the localization properties of the aperiodic sequences measured by the ξ normalized participation number, the Rq Rényi entropies and the μq moments. In addition, we generalize the scaling relationship for the overlap amplitude Ci,jω, i.e., <(Ci,jω) 2 q > =(2/N) 2 q.

  12. Mid-infrared metasurface made of composite right/left-handed transmission-line

    NASA Astrophysics Data System (ADS)

    Luo, Yi; Ying, Xiangxiao; Pu, Yang; Jiang, Yadong; Xu, Jimmy; Liu, Zhijun

    2016-06-01

    We report on the realization of a mid-infrared metasurface based on the concept of composite right/left-handed transmission-line. The metasurface consists of a three-layer metal-insulator-metal structure patterned into transmission-lines by electron-beam lithography. Angle-variable reflection spectroscopy measurements reveal resonant absorption features corresponding to both right- and left-handed propagations in the leaky-wave guided mode region. Material loss is shown to dominate the quality factor of the left-handed modes, while the radiative loss dominates the right-handed ones. The experimental results are in good agreement with full-wave numerical simulations and are explained with an equivalent circuit model.

  13. Suppression of the skin effect in radio frequency transmission lines via gridded conductor fibers

    NASA Astrophysics Data System (ADS)

    Williamson, Ian A. D.; Nguyen, Thien-An N.; Wang, Zheng

    2016-02-01

    Microwave propagation in transmission lines is fundamentally limited in bandwidth and reach by the skin and proximity effects. The resultant current crowding imparts a square-root frequency dependence on attenuation, and ultimately limits the spatial resolution of distributed transmission-line sensors and the data rate of communication systems. In this letter, we numerically analyze the microwave attenuation and impedance in μm-scale gridded fiber structures with currents arranged in a checkered pattern. The checkered lattice of currents significantly mitigates both the skin and proximity effects, and exhibits an unprecedented bandwidth (in excess of 1 GHz) of frequency-flat attenuation in a relatively small physical footprint (˜0.01 mm2).

  14. Effect of asphaltene deposition on the internal corrosion in transmission lines

    SciTech Connect

    Morales, J.L.; Viloria, A.; Palacios T, C.A.

    1996-12-31

    Crude oil from Norte de Monagas field, in Venezuela, contains large amounts of asphaltenes, some of them are very unstable with tendency to precipitate. Because liquid is carried over from the separation process in the flow stations, asphaltenes are also present in the gas gathering and transmission lines, precipitating on inner wall of pipelines. The gas gathering and transmission lines contain gas with high partial pressures of CO{sub 2}, some H{sub 2}S and are water saturated; therefore inhibitors are used to control the internal corrosion. There is uncertainty on how inhibitors perform in the presence of asphaltene deposition. To protect the pipelines from external corrosion, cathodic protection is used. Since asphaltenes have polar properties, there exists an uncertainty on whether it enhances asphaltene precipitation and deposition. The purpose of this paper to describe the causes that enhance asphaltene deposition on gas and some of the preliminary result from an ongoing research project carried out by Intevep and Corpoven.

  15. Coupling mid-infrared light from a photonic crystal waveguide to metallic transmission lines

    SciTech Connect

    Blanco-Redondo, Andrea E-mail: r.hillenbrand@nanogune.eu; Garcia-Adeva, Angel; Zubia, Joseba

    2014-01-06

    We propose and theoretically study a hybrid structure consisting of a photonic crystal waveguide (PhC-wg) and a two-wire metallic transmission line (TL), engineered for efficient transfer of mid-infrared (mid-IR) light between them. An efficiency of 32% is obtained for the coupling from the transverse magnetic (TM) photonic mode to the symmetric mode of the TL, with a predicted intensity enhancement factor of 53 at the transmission line surface. The strong coupling is explained by the small phase velocity mismatch and sufficient spatial overlapping between the modes. This hybrid structure could find applications in highly integrated mid-IR photonic-plasmonic devices for biological and gas sensing, among others.

  16. Transmission competency of single-female Xiphinema index lines for Grapevine fanleaf virus.

    PubMed

    Demangeat, Gérard; Komar, Véronique; Van-Ghelder, Cyril; Voisin, Roger; Lemaire, Olivier; Esmenjaud, Daniel; Fuchs, Marc

    2010-04-01

    Grapevine fanleaf virus (GFLV) is vectored specifically from grapevine to grapevine by the ectoparasitic nematode Xiphinema index. Limited information is available on the vector competency of X. index populations from diverse geographical origins. We determined the transmissibility of two GFLV strains showing 4.6% amino acid divergence within their coat protein (e.g., strains F13 and GHu) by seven clonal lines of X. index developed from seven distinct populations from the Mediterranean basin (Cyprus, southern France, Israel, Italy, and Spain), northern France, and California. X. index lines derived from single adult females were produced on fig (Ficus carica) plants to obtain genetically homogenous aviruliferous clones. A comparative reproductive rate analysis on Vitis rupestris du Lot and V. vinifera cv. Cabernet Sauvignon showed significant differences among clones, with the single-female Cyprus line showing the highest rate (30-fold the initial population) and the Spain and California lines showing the lowest rate (10-fold increase), regardless of the grapevine genotype. However, there was no differential vector competency among the seven X. index lines for GFLV strains F13 and GHu. The implications of our findings for the dynamic of GFLV transmission in vineyards and screening of Vitis spp. for resistance to GFLV are discussed.

  17. On-chip sub-terahertz surface plasmon polariton transmission lines with mode converter in CMOS.

    PubMed

    Liang, Yuan; Yu, Hao; Wen, Jincai; Apriyana, Anak Agung Alit; Li, Nan; Luo, Yu; Sun, Lingling

    2016-01-01

    An on-chip low-loss and high conversion efficiency plasmonic waveguide converter is demonstrated at sub-THz in CMOS. By introducing a subwavelength periodic corrugated structure onto the transmission line (T-line) implemented by a top-layer metal, surface plasmon polaritons (SPP) are established to propagate signals with strongly localized surface-wave. To match both impedance and momentum of other on-chip components with TEM-wave propagation, a mode converter structure featured by a smooth bridge between the Ground coplanar waveguide (GCPW) with 50 Ω impedance and SPP T-line is proposed. To further reduce area, the converter is ultimately simplified to a gradual increment of groove with smooth gradient. The proposed SPP T-lines with the converter is designed and fabricated in the standard 65 nm CMOS process. Both near-field simulation and measurement results show excellent conversion efficiency from quasi-TEM to SPP modes in a broadband frequency range. The converter achieves wideband impedance matching (<-9 dB) with excellent transmission efficiency (averagely -1.9 dB) from 110 GHz-325 GHz. The demonstrated compact and wideband SPP T-lines with mode converter have shown great potentials to replace existing waveguides as future on-chip THz interconnects. To the best of the author's knowledge, this is the first time to demonstrate the (sub)-THz surface mode conversion on-chip in CMOS technology.

  18. On-chip sub-terahertz surface plasmon polariton transmission lines with mode converter in CMOS.

    PubMed

    Liang, Yuan; Yu, Hao; Wen, Jincai; Apriyana, Anak Agung Alit; Li, Nan; Luo, Yu; Sun, Lingling

    2016-01-01

    An on-chip low-loss and high conversion efficiency plasmonic waveguide converter is demonstrated at sub-THz in CMOS. By introducing a subwavelength periodic corrugated structure onto the transmission line (T-line) implemented by a top-layer metal, surface plasmon polaritons (SPP) are established to propagate signals with strongly localized surface-wave. To match both impedance and momentum of other on-chip components with TEM-wave propagation, a mode converter structure featured by a smooth bridge between the Ground coplanar waveguide (GCPW) with 50 Ω impedance and SPP T-line is proposed. To further reduce area, the converter is ultimately simplified to a gradual increment of groove with smooth gradient. The proposed SPP T-lines with the converter is designed and fabricated in the standard 65 nm CMOS process. Both near-field simulation and measurement results show excellent conversion efficiency from quasi-TEM to SPP modes in a broadband frequency range. The converter achieves wideband impedance matching (<-9 dB) with excellent transmission efficiency (averagely -1.9 dB) from 110 GHz-325 GHz. The demonstrated compact and wideband SPP T-lines with mode converter have shown great potentials to replace existing waveguides as future on-chip THz interconnects. To the best of the author's knowledge, this is the first time to demonstrate the (sub)-THz surface mode conversion on-chip in CMOS technology. PMID:27444782

  19. On-chip sub-terahertz surface plasmon polariton transmission lines with mode converter in CMOS

    NASA Astrophysics Data System (ADS)

    Liang, Yuan; Yu, Hao; Wen, Jincai; Apriyana, Anak Agung Alit; Li, Nan; Luo, Yu; Sun, Lingling

    2016-07-01

    An on-chip low-loss and high conversion efficiency plasmonic waveguide converter is demonstrated at sub-THz in CMOS. By introducing a subwavelength periodic corrugated structure onto the transmission line (T-line) implemented by a top-layer metal, surface plasmon polaritons (SPP) are established to propagate signals with strongly localized surface-wave. To match both impedance and momentum of other on-chip components with TEM-wave propagation, a mode converter structure featured by a smooth bridge between the Ground coplanar waveguide (GCPW) with 50 Ω impedance and SPP T-line is proposed. To further reduce area, the converter is ultimately simplified to a gradual increment of groove with smooth gradient. The proposed SPP T-lines with the converter is designed and fabricated in the standard 65 nm CMOS process. Both near-field simulation and measurement results show excellent conversion efficiency from quasi-TEM to SPP modes in a broadband frequency range. The converter achieves wideband impedance matching (<-9 dB) with excellent transmission efficiency (averagely -1.9 dB) from 110 GHz-325 GHz. The demonstrated compact and wideband SPP T-lines with mode converter have shown great potentials to replace existing waveguides as future on-chip THz interconnects. To the best of the author’s knowledge, this is the first time to demonstrate the (sub)-THz surface mode conversion on-chip in CMOS technology.

  20. Transmission line relay mis-operation detection based on time-synchronized field data

    SciTech Connect

    Esmaeilian, Ahad; Popovic, Tomo; Kezunovic, Mladen

    2015-05-04

    In this paper, a real-time tool to detect transmission line relay mis-operation is implemented. The tool uses time-synchronized measurements obtained from both ends of the line during disturbances. The proposed fault analysis tool comes into the picture only after the protective device has operated and tripped the line. The proposed methodology is able not only to detect, classify, and locate transmission line faults, but also to accurately confirm whether the line was tripped due to a mis-operation of protective relays. The analysis report includes either detailed description of the fault type and location or detection of relay mis-operation. As such, it can be a source of very useful information to support the system restoration. The focus of the paper is on the implementation requirements that allow practical application of the methodology, which is illustrated using the field data obtained the real power system. Testing and validation is done using the field data recorded by digital fault recorders and protective relays. The test data included several hundreds of event records corresponding to both relay mis-operations and actual faults. The discussion of results addresses various challenges encountered during the implementation and validation of the presented methodology.

  1. Transmission line relay mis-operation detection based on time-synchronized field data

    DOE PAGES

    Esmaeilian, Ahad; Popovic, Tomo; Kezunovic, Mladen

    2015-05-04

    In this paper, a real-time tool to detect transmission line relay mis-operation is implemented. The tool uses time-synchronized measurements obtained from both ends of the line during disturbances. The proposed fault analysis tool comes into the picture only after the protective device has operated and tripped the line. The proposed methodology is able not only to detect, classify, and locate transmission line faults, but also to accurately confirm whether the line was tripped due to a mis-operation of protective relays. The analysis report includes either detailed description of the fault type and location or detection of relay mis-operation. As such,more » it can be a source of very useful information to support the system restoration. The focus of the paper is on the implementation requirements that allow practical application of the methodology, which is illustrated using the field data obtained the real power system. Testing and validation is done using the field data recorded by digital fault recorders and protective relays. The test data included several hundreds of event records corresponding to both relay mis-operations and actual faults. The discussion of results addresses various challenges encountered during the implementation and validation of the presented methodology.« less

  2. Mutual design: Overhead transmission lines and railroad facilities: Susceptibility program: Final report

    SciTech Connect

    Frazier, M.J.; Little, D.R.

    1989-07-01

    The sharing of common corridors by electric power transmission lines and railroad facilities can result in the coupling of unwanted electromagnetic energy from the power lines into nearby railroad systems. The coupling can result in voltage being induced onto the railroad system conductors that may compromise the inherent safety and reliability of the railroad signalling system. This broad-scoped research program, which is co-sponsored by EPRI and the AAR, is addressing the problem from two directions. This two volume report describes a Phase 1 effort to develop the methods and techniques for quantifying the signal system response to interference. 54 figs., 7 tabs.

  3. Attenuation of epsilon(sub eff) of coplanar waveguide transmission lines on silicon substrates

    NASA Technical Reports Server (NTRS)

    Taub, Susan R.; Young, Paul G.

    1993-01-01

    Attenuation and epsilon(sub eff) of Coplanar Waveguide (CPW) transmission lines were measured on Silicon substrates with resistivities ranging from 400 to greater than 30,000 ohm-cm, that have a 1000 angstrom coating of SiO2. Both attenuation and epsilon(sub eff) are given over the frequency range 5 to 40 GHz for various strip and slot widths. These measured values are also compared to the theoretical values.

  4. Numerical modeling of geomagnetically induced currents in a Brazilian transmission line

    NASA Astrophysics Data System (ADS)

    da Silva Barbosa, Cleiton; Hartmann, Gelvam André; Pinheiro, Katia Jasbinschek

    2015-02-01

    Rapid changes in the external geomagnetic field induce electric currents in conducting materials at the Earth's surface. These geomagnetically induced currents (GIC) are mostly studied in transmission lines at high-latitude due to their frequent hazards. However, recent studies have shown that low- and middle-latitude regions may also be subject to problems due to GIC occurrences. In this work we apply a numerical model, using plane wave theory and a one-dimensional electrical resistivity model of the region, to calculate the geoelectric field and the GIC measured directly at the Itumbiara-São Simão (IS) transmission line (Southeast Brazil) during a magnetic storm occurred between 7-10th November 2004. We use two electrical resistivity models: (a) one-layer model, in which our results do not reproduce the measured GIC directly in the IS transmission line, and (b) four-layer model, which presents similar patterns of temporal variation and intensities of the measured electric fields and GIC. After validating the four-layer numerical model, we calculate the electric fields and GIC during the “Halloween storm” (29th October-1st November 2003). Our results of the Halloween storm show maximum GIC amplitudes of 25 A, which are higher than registered in other middle latitude countries, such as South Africa and Uruguay. These results indicate that the Brazilian power network might be subjected to the GIC hazards in the future due to strong magnetic storms. In addition, our numerical model might be used as a potential tool for different geological sets, electrical resistivity models, transmission lines with distinct characteristics and for a range of magnetic storms intensities.

  5. 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.

  6. 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.

  7. Particle trap with dielectric barrier for use in gas insulated transmission lines

    DOEpatents

    Dale, Steinar J.

    1982-01-01

    A gas-insulated transmission line includes an outer sheath, an inner conductor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping electrode is disposed within the outer sheath, and the electrode has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the apertured electrode.

  8. Particle trap with dielectric barrier for use in gas insulated transmission lines

    DOEpatents

    Dale, S.J.

    1982-06-15

    A gas-insulated transmission line includes an outer sheath, an inner conductor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping electrode is disposed within the outer sheath, and the electrode has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the apertured electrode. 7 figs.

  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-way. 29.21-8 Section 29.21-8 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) THE NATIONAL WILDLIFE REFUGE SYSTEM LAND USE MANAGEMENT Rights-of-Way General Regulations § 29.21-8 Electric...

  10. Parallel-plate transmission line type of EMP simulators: Systematic review and recommendations

    NASA Astrophysics Data System (ADS)

    Giri, D. V.; Liu, T. K.; Tesche, F. M.; King, R. W. P.

    1980-05-01

    This report presents various aspects of the two-parallel-plate transmission line type of EMP simulator. Much of the work is the result of research efforts conducted during the last two decades at the Air Force Weapons Laboratory, and in industries/universities as well. The principal features of individual simulator components are discussed. The report also emphasizes that it is imperative to hybridize our understanding of individual components so that we can draw meaningful conclusions of simulator performance as a whole.

  11. ATOMIC AND MOLECULAR PHYSICS: Microtubule as a Transmission Line for Ionic Currents

    NASA Astrophysics Data System (ADS)

    Ilić, I. D.; Satarić, V. M.; Ralević, N.

    2009-07-01

    We establish a new model for ionic waves along microtubules based on polyelectrolyte features of cylindrical biopolymers. The nonlinear transmission line described by a nonlinear differential equation is obtained with stable kink solution pertinent to the shape of the front of accompanying potential. The localized ionic wave could be used to explain the behavior of microtubules as biomolecular transistors capable of amplifying electrical information in neurons.

  12. Transverse stability of solitary waves propagating in coupled nonlinear dispersive transmission lines.

    PubMed

    Kengne, E; Bozic, V; Viana, M; Vaillancourt, R

    2008-08-01

    In the semidiscrete limit and in suitably scaled coordinates, the voltage of a system of coupled nonlinear dispersive transmission lines is described by a nonlinear Schrödinger equation. This equation is used to study the transverse stability of solitary waves of the system. Exact results for the growth rate and the corresponding perturbation function of linear transverse perturbations are obtained in terms of the network's and soliton's parameters.

  13. Ground Isolation Circuit for Isolating a Transmission Line from Ground Interference

    NASA Technical Reports Server (NTRS)

    Davidson, Craig A. (Inventor)

    1996-01-01

    This invention relates generally to a system for isolating ground interference from a transmission line, e.g., a ground isolation circuit for isolating a wideband transmission signal (such as a video signal) from ground by modulating the base signal on a carrier signal to permit the transmission signal to be isolated. In one embodiment, the circuit includes a pair of matched mixer circuits, each of which receives a carrier signal from the same oscillator circuit. The first mixer circuit also receives the baseband signal input, after appropriate conditioning, and modulates the baseband signal onto the carrier signal. In a preferred embodiment the carrier signal has a predetermined frequency which is at least two times the frequency of the baseband signal. The modulated signal (which can comprise an rf signal) is transmitted via an rf transmission line to the second mixer, which demodulates the rf signal to recover the baseband signal. Each port of the mixer connects to an isolation transformer to ensure isolation from ground interference. The circuit is considered to be of commercial value in that it can provide isolation between transmitting and receiving circuits, e.g., ground isolation for television circuits or high frequency transmitters, without the need for video transformers or optical isolators, thereby reducing the complexity, power consumption, and weight of the system.

  14. Transmission and reflection of acoustic and entropy waves through a stator-rotor stage

    NASA Astrophysics Data System (ADS)

    Bauerheim, Michael; Duran, Ignacio; Livebardon, Thomas; Wang, Gaofeng; Moreau, Stéphane; Poinsot, Thierry

    2016-07-01

    The propagation of acoustic, entropy and vorticity waves through turbine stages is of significant interest in the field of core noise. In particular, entropy spots have been shown to generate significant noise when accelerated through turbine stages: the so-called indirect combustion noise. Analytical models for the propagation of acoustic, vorticity and entropy waves through a stator vane, developed since the seventies, are generally based on restrictive assumptions such as low frequency waves. In order to analyze such assumptions, the theory of Cumpsty and Marble is extended to rotating rows and applied to a 2D stator-rotor turbine stage. The theoretical transfer functions are then compared with numerical predictions from forced compressible Large-Eddy Simulations of a 2D stator-rotor configuration, using a fluid-fluid coupling strategy with an overset-grid method. The comparisons between the analytical model and the simulations are in good agreement. To improve the analytical predictions, the attenuation due to the entropy spot deformation through the stator vane or the rotor blade is then included, modeled either analytically or extracted from the mean flow of the simulations. The complete analytical model reveals a good agreement with 2D simulations, which allows the prediction and minimization of both direct and indirect noise at the design-stage without computation.

  15. Acoustic pathways revealed: simulated sound transmission and reception in Cuvier's beaked whale (Ziphius cavirostris).

    PubMed

    Cranford, Ted W; Krysl, Petr; Hildebrand, John A

    2008-03-01

    The finite element modeling (FEM) space reported here contains the head of a simulated whale based on CT data sets as well as physical measurements of sound-propagation characteristics of actual tissue samples. Simulated sound sources placed inside and outside of an adult male Cuvier's beaked whale (Ziphius cavirostris) reveal likely sound propagation pathways into and out of the head. Two separate virtual sound sources that were located at the left and right phonic lips produced beams that converged just outside the head. This result supports the notion that dual sound sources can interfere constructively to form a biologically useful and, in fact, excellent sonar beam in front of the animal. The most intriguing FEM results concern pathways by which sounds reach the ears. The simulations reveal a previously undescribed 'gular pathway' for sound reception in Ziphius. Propagated sound pressure waves enter the head from below and between the lower jaws, pass through an opening created by the absence of the medial bony wall of the posterior mandibles, and continue toward the bony ear complexes through the internal mandibular fat bodies. This new pathway has implications for understanding the evolution of underwater hearing in odontocetes. Our model also provides evidence for receive beam directionality, off-axis acoustic shadowing and a plausible mechanism for the long-standing orthodox sound reception pathway in odontocetes. The techniques developed for this study can be used to study acoustic perturbation in a wide variety of marine organisms.

  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. Accurate characterization and modeling of transmission lines for GaAs MMIC's

    NASA Astrophysics Data System (ADS)

    Finlay, Hugh J.; Jansen, Rolf H.; Jenkins, John A.; Eddison, Ian G.

    1988-06-01

    The authors discuss computer-aided design (CAD) tools together with high-accuracy microwave measurements to realize improved design data for GaAs monolithic microwave integrated circuits (MMICs). In particular, a combined theoretical and experimental approach to the generation of an accurate design database for transmission lines on GaAs MMICs is presented. The theoretical approach is based on an improved transmission-line theory which is part of the spectral-domain hybrid-mode computer program MCLINE. The benefit of this approach in the design of multidielectric-media transmission lines is described. The program was designed to include loss mechanisms in all dielectric layers and to include conductor and surface roughness loss contributions. As an example, using GaAs ring resonator techniques covering 2 to 24 GHz, accuracies in effective dielectric constant and loss of 1 percent and 15 percent respectively, are presented. By combining theoretical and experimental techniques, a generalized MMIC microstrip design database is outlined.

  18. Extra-high voltage transmission lines: mechanisms of biological effects on honeybees. Final report

    SciTech Connect

    Greenberg, B.; Bindokas, V.

    1985-08-01

    The authors confirmed that bee exposure to E fields, including 100 kV/m, under the dry conditions cause no detectable effect on colony behavior. If, however, exposure occurs when moisture is present, or if bees are on a conductive surface, they become visibly disturbed, mortality is increased, abnormal propolization occurs, and colony development may be impaired. It seems plausible that bees on conductive surfaces within a hive under a 765-kV/m transmission line can perceive shocks from body currents induced by enhanced intra-hive E fields. Hives exposed under a 765-kV/m transmission line to an ambient E field of 7 kV/m have internal step-potential-induced currents and interchamber chort-circuit currents which range from one-half to several microamperes. Total hive currents can exceed 100 ..mu..A. Thus, induced hive currents exceed the empirical sting threshold by up to a factor of 100 and the E-field-induced body current by up to a factor of 1000. The degree of disturbance which could be produced by these intra-hive currents will eclipse that produced by perception of E-field-induced body currents. The authors therefore attribute the disturbance of colonies under a transmission line primarily to electric shock from induced hive currents. 10 refs., 51 figs., 18 tabs. (DT)

  19. Fiber Bragg grating sensor for fault detection in high voltage overhead transmission lines

    NASA Astrophysics Data System (ADS)

    Moghadas, Amin

    2011-12-01

    A fiber optic based sensor capable of fault detection in both radial and network overhead transmission power line systems is investigated. Bragg wavelength shift is used to measure the fault current and detect fault in power systems. Magnetic fields generated by currents in the overhead transmission lines cause a strain in magnetostrictive material which is then detected by fiber Bragg grating (FBG) sensors. The Fiber Bragg interrogator senses the reflected FBG signals, and the Bragg wavelength shift is calculated and the signals are processed. A broadband light source in the control room scans the shift in the reflected signals. Any surge in the magnetic field relates to an increased fault current at a certain location. Also, fault location can be precisely defined with an artificial neural network (ANN) algorithm. This algorithm can be easily coordinated with other protective devices. It is shown that the faults in the overhead transmission line cause a detectable wavelength shift on the reflected signal of FBG sensors and can be used to detect and classify different kind of faults. The proposed method has been extensively tested by simulation and results confirm that the proposed scheme is able to detect different kinds of fault in both radial and network system.

  20. [Study on effects of bioelectric parameters of rats in electromagnetic radiation of HV transmission line].

    PubMed

    Zhang, Anying; Pang, Xiaofeng; Yuan, Ping

    2007-02-01

    With the development of economy and coming of information era, the chance of exposure to electromagnetic fields with various frequencies has been increased for every human. The effects of electromagnetic radiattion on human being's health are versatile. To study the effects of bioelctronic parameters of rats in the electromagnetic radiations of HV transmission line, EEG, ECG and CMAP were measured in rats exposed to simulating high-voltage transmission line electromagnetic radiation for over one year. Brain tissues were studied by Fourier transform infrared spectroscopy. The results showed that no significant difference between exposed group and control group in EEG; however the FT-infrared spectra of brain tissues were different; the ECG of the exposed animals was considerably altered. Significant slowing of heart rate was observed in those rates exposed to EMFs; the latent period of CMAP in exposed group were not different compared with those of control group however there was a significant difference in wave amplitude of CMAP between the exposed group and control group. All results indicated that there must be some effects on bioelectric parameters of rats exposed to electromagnetic radiation of high-voltage transmission line for a long time.