A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.

PubMed

Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A

2005-11-01

While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.

Coupled 2-dimensional cascade theory for noise an d unsteady aerodynamics of blade row interaction in turbofans. Volume 2: Documentation for computer code CUP2D

NASA Technical Reports Server (NTRS)

Hanson, Donald B.

1994-01-01

A two dimensional linear aeroacoustic theory for rotor/stator interaction with unsteady coupling was derived and explored in Volume 1 of this report. Computer program CUP2D has been written in FORTRAN embodying the theoretical equations. This volume (Volume 2) describes the structure of the code, installation and running, preparation of the input file, and interpretation of the output. A sample case is provided with printouts of the input and output. The source code is included with comments linking it closely to the theoretical equations in Volume 1.

Modeling of the gain distribution for diode pumping of a solid-state laser rod with nonimaging optics.

PubMed

Koshel, R J; Walmsley, I A

1993-03-20

We investigate the absorption distribution in a cylindrical gain medium that is pumped by a source of distributed laser diodes by means of a pump cavity developed from the edge-ray principle of nonimaging optics. The performance of this pumping arrangement is studied by using a nonsequential, numerical, three-dimensional ray-tracing scheme. A figure of merit is defined for the pump cavities that takes into account the coupling efficiency and uniformity of the absorption distribution. It is found that the nonimaging pump cavity maintains a high coupling efficiency with extended two-dimensional diode arrays and obtains a fairly uniform absorption distribution. The nonimaging cavity is compared with two other designs: a close-coupled side-pumped cavity and an imaging design in the form of a elliptical cavity. The nonimaging cavity has a better figure of merit per diode than these two designs. It also permits the use of an extended, sparse, two-dimensional diode array, which reduces thermal loading of the source and eliminates all cavity optics other than the main reflector.

Intermingled Klebsiella pneumoniae Populations Between Retail Meats and Human Urinary Tract Infections.

PubMed

Davis, Gregg S; Waits, Kara; Nordstrom, Lora; Weaver, Brett; Aziz, Maliha; Gauld, Lori; Grande, Heidi; Bigler, Rick; Horwinski, Joseph; Porter, Stephen; Stegger, Marc; Johnson, James R; Liu, Cindy M; Price, Lance B

2015-09-15

Klebsiella pneumoniae is a common colonizer of the gastrointestinal tract of humans, companion animals, and livestock. To better understand potential contributions of foodborne K. pneumoniae to human clinical infections, we compared K. pneumoniae isolates from retail meat products and human clinical specimens to assess their similarity based on antibiotic resistance, genetic relatedness, and virulence. Klebsiella pneumoniae was isolated from retail meats from Flagstaff grocery stores in 2012 and from urine and blood specimens from Flagstaff Medical Center in 2011-2012. Isolates underwent antibiotic susceptibility testing and whole-genome sequencing. Genetic relatedness of the isolates was assessed using multilocus sequence typing and phylogenetic analyses. Extraintestinal virulence of several closely related meat-source and urine isolates was assessed using a murine sepsis model. Meat-source isolates were significantly more likely to be multidrug resistant and resistant to tetracycline and gentamicin than clinical isolates. Four sequence types occurred among both meat-source and clinical isolates. Phylogenetic analyses confirmed close relationships among meat-source and clinical isolates. Isolates from both sources showed similar virulence in the mouse sepsis model. Meat-source K. pneumoniae isolates were more likely than clinical isolates to be antibiotic resistant, which could reflect selective pressures from antibiotic use in food-animal production. The close genetic relatedness of meat-source and clinical isolates, coupled with similarities in virulence, suggest that the barriers to transmission between these 2 sources are low. Taken together, our results suggest that retail meat is a potential vehicle for transmitting virulent, antibiotic-resistant K. pneumoniae from food animals to humans. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

Observation of the seismic anisotropy effects on free oscillations below 4 mHz

NASA Astrophysics Data System (ADS)

Hu, X.; Liu, L.

2009-12-01

We present observations of significant fundamental spheroidal-toroidal mode coupling at frequencies below 4 mHz in the early part of vertical component records from seismic stations on near-equatorial source-receiver propagation paths and in Antarctica after the 26 December 2004 and 28 March 2005 great Sumatra earthquakes. When seismic surface waves propagate along the equator, the particle motion of Love waves runs parallels to the Earth’s rotation axis, and the particle motion of Rayleigh waves runs perpendicular to it, thus the Coriolis force has no vertical deflection effect on Love waves and no transverse deflection effect on the Rayleigh waves. Coriolis coupling can be naturally minimized at a station on a nearequatorial source-receiver propagation path. In Antarctica, especially near the South Pole, the vertical deflection of toroidial motion is very weak but there are lateral gradients in the anisotropic properties of upper mantle. Therefore, we can find a chance to directly observe seismic anisotropy coupling below 4 mHz without the disturbance of Coriolis coupling at Antarctic station, and at the seismic station locate close to the Earth’s equator when the epicenter also locates close to the equator. Our observations of strong anomalous toroidal-spheroidal coupling at these stations provide direct evidence to confirm the theory that the azimuthal anisotropy has pronounced effects on the quasi-toroidal mode excitations at the frequencies below 4 mHz, which can convince the skeptics that anisotropy really is visible in the low-frequency normal mode data. Strong anisotropic coupling is usually observed at stations having the geometric nodes for the spheroidal fundamentals, giving the association of quasi-toroidal excitation with the geometric effect. The presence of significant anisotropy coupling below 4 mHz depends not only on anisotropic depth, anisotropic identities and orientations but also on radiation nodes for Rayleigh waves and geometry nodes for spheroidal fundamentals. The quasi-toroidal modes below 4 mHz have significant sensitivity throughout most of the mantle, extending into the lower mantle, and therefore, it is likely that the resolution of locating the depth of origin of azimuthal anisotropy in the mantle will be improved by joint inversions that take advantage of the partly complementary depth resolution of anisotropy coupling measurements, quasi-Love surface-wave measurements, body wave splitting measurements and surface-wave dispersion measurements.

Validity and reliability of in-situ air conduction thresholds measured through hearing aids coupled to closed and open instant-fit tips.

PubMed

O'Brien, Anna; Keidser, Gitte; Yeend, Ingrid; Hartley, Lisa; Dillon, Harvey

2010-12-01

Audiometric measurements through a hearing aid ('in-situ') may facilitate provision of hearing services where these are limited. This study investigated the validity and reliability of in-situ air conduction hearing thresholds measured with closed and open domes relative to thresholds measured with insert earphones, and explored sources of variability in the measures. Twenty-four adults with sensorineural hearing impairment attended two sessions in which thresholds and real-ear-to-dial-difference (REDD) values were measured. Without correction, significantly higher low-frequency thresholds in dB HL were measured in-situ than with insert earphones. Differences were due predominantly to differences in ear canal SPL, as measured with the REDD, which were attributed to leaking low-frequency energy. Test-retest data yielded higher variability with the closed dome coupling due to inconsistent seals achieved with this tip. For all three conditions, inter-participant variability in the REDD values was greater than intra-participant variability. Overall, in-situ audiometry is as valid and reliable as conventional audiometry provided appropriate REDD corrections are made and ambient sound in the test environment is controlled.

Analytical solutions for sequentially coupled one-dimensional reactive transport problems Part I: Mathematical derivations

NASA Astrophysics Data System (ADS)

Srinivasan, V.; Clement, T. P.

2008-02-01

Multi-species reactive transport equations coupled through sorption and sequential first-order reactions are commonly used to model sites contaminated with radioactive wastes, chlorinated solvents and nitrogenous species. Although researchers have been attempting to solve various forms of these reactive transport equations for over 50 years, a general closed-form analytical solution to this problem is not available in the published literature. In Part I of this two-part article, we derive a closed-form analytical solution to this problem for spatially-varying initial conditions. The proposed solution procedure employs a combination of Laplace and linear transform methods to uncouple and solve the system of partial differential equations. Two distinct solutions are derived for Dirichlet and Cauchy boundary conditions each with Bateman-type source terms. We organize and present the final solutions in a common format that represents the solutions to both boundary conditions. In addition, we provide the mathematical concepts for deriving the solution within a generic framework that can be used for solving similar transport problems.

An Assessment of Some Design Constraints on Heat Production of a 3D Conceptual EGS Model Using an Open-Source Geothermal Reservoir Simulation Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yidong Xia; Mitch Plummer; Robert Podgorney

2016-02-01

Performance of heat production process over a 30-year period is assessed in a conceptual EGS model with a geothermal gradient of 65K per km depth in the reservoir. Water is circulated through a pair of parallel wells connected by a set of single large wing fractures. The results indicate that the desirable output electric power rate and lifespan could be obtained under suitable material properties and system parameters. A sensitivity analysis on some design constraints and operation parameters indicates that 1) the fracture horizontal spacing has profound effect on the long-term performance of heat production, 2) the downward deviation anglemore » for the parallel doublet wells may help overcome the difficulty of vertical drilling to reach a favorable production temperature, and 3) the thermal energy production rate and lifespan has close dependence on water mass flow rate. The results also indicate that the heat production can be improved when the horizontal fracture spacing, well deviation angle, and production flow rate are under reasonable conditions. To conduct the reservoir modeling and simulations, an open-source, finite element based, fully implicit, fully coupled hydrothermal code, namely FALCON, has been developed and used in this work. Compared with most other existing codes that are either closed-source or commercially available in this area, this new open-source code has demonstrated a code development strategy that aims to provide an unparalleled easiness for user-customization and multi-physics coupling. Test results have shown that the FALCON code is able to complete the long-term tests efficiently and accurately, thanks to the state-of-the-art nonlinear and linear solver algorithms implemented in the code.« less

Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source.

PubMed

Welton, R F; Dudnikov, V G; Han, B X; Murray, S N; Pennisi, T R; Pillar, C; Santana, M; Stockli, M P; Turvey, M W

2014-02-01

The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H(-) beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.

Coherent interaction of single molecules and plasmonic nanowires

NASA Astrophysics Data System (ADS)

Gerhardt, Ilja; Grotz, Bernhard; Siyushev, Petr; Wrachtrup, Jörg

2017-09-01

Quantum plasmonics opens the option to integrate complex quantum optical circuitry onto chip scale devices. In the past, often external light sources were used and nonclassical light was coupled in and out of plasmonic structures, such as hole arrays or waveguide structures. Another option to launch single plasmonic excitations is the coupling of single emitters in the direct proximity of, e.g., a silver or gold nanostructure. Here, we present our attempts to integrate the research of single emitters with wet-chemically grown silver nanowires. The emitters of choice are single organic dye molecules under cryogenic conditions, which are known to act as high-brightness and extremely narrow-band single photon sources. Another advantage is their high optical nonlinearity, such that they might mediate photon-photon interactions on the nanoscale. We report on the coupling of a single molecule fluorescence emission through the wire over the length of several wavelengths. The transmission of coherently emitted photons is proven by an extinction type experiment. As for influencing the spectral properties of a single emitter, we are able to show a remote change of the line-width of a single terrylene molecule, which is in close proximity to the nanowire.

Analysis of induced electrical currents from magnetic field coupling inside implantable neurostimulator leads.

PubMed

Pantchenko, Oxana S; Seidman, Seth J; Guag, Joshua W

2011-10-21

Over the last decade, the number of neurostimulator systems implanted in patients has been rapidly growing. Nearly 50, 000 neurostimulators are implanted worldwide annually. The most common type of implantable neurostimulators is indicated for pain relief. At the same time, commercial use of other electromagnetic technologies is expanding, making electromagnetic interference (EMI) of neurostimulator function an issue of concern. Typically reported sources of neurostimulator EMI include security systems, metal detectors and wireless equipment. When near such sources, patients with implanted neurostimulators have reported adverse events such as shock, pain, and increased stimulation. In recent in vitro studies, radio frequency identification (RFID) technology has been shown to inhibit the stimulation pulse of an implantable neurostimulator system during low frequency exposure at close distances. This could potentially be due to induced electrical currents inside the implantable neurostimulator leads that are caused by magnetic field coupling from the low frequency identification system. To systematically address the concerns posed by EMI, we developed a test platform to assess the interference from coupled magnetic fields on implantable neurostimulator systems. To measure interference, we recorded the output of one implantable neurostimulator, programmed for best therapy threshold settings, when in close proximity to an operating low frequency RFID emitter. The output contained electrical potentials from the neurostimulator system and those induced by EMI from the RFID emitter. We also recorded the output of the same neurostimulator system programmed for best therapy threshold settings without RFID interference. Using the Spatially Extended Nonlinear Node (SENN) model, we compared threshold factors of spinal cord fiber excitation for both recorded outputs. The electric current induced by low frequency RFID emitter was not significant to have a noticeable effect on electrical stimulation. We demonstrated a method for analyzing effects of coupled magnetic field interference on implantable neurostimulator system and its electrodes which could be used by device manufacturers during the design and testing phases of the development process.

Analysis of induced electrical currents from magnetic field coupling inside implantable neurostimulator leads

PubMed Central

2011-01-01

Background Over the last decade, the number of neurostimulator systems implanted in patients has been rapidly growing. Nearly 50, 000 neurostimulators are implanted worldwide annually. The most common type of implantable neurostimulators is indicated for pain relief. At the same time, commercial use of other electromagnetic technologies is expanding, making electromagnetic interference (EMI) of neurostimulator function an issue of concern. Typically reported sources of neurostimulator EMI include security systems, metal detectors and wireless equipment. When near such sources, patients with implanted neurostimulators have reported adverse events such as shock, pain, and increased stimulation. In recent in vitro studies, radio frequency identification (RFID) technology has been shown to inhibit the stimulation pulse of an implantable neurostimulator system during low frequency exposure at close distances. This could potentially be due to induced electrical currents inside the implantable neurostimulator leads that are caused by magnetic field coupling from the low frequency identification system. Methods To systematically address the concerns posed by EMI, we developed a test platform to assess the interference from coupled magnetic fields on implantable neurostimulator systems. To measure interference, we recorded the output of one implantable neurostimulator, programmed for best therapy threshold settings, when in close proximity to an operating low frequency RFID emitter. The output contained electrical potentials from the neurostimulator system and those induced by EMI from the RFID emitter. We also recorded the output of the same neurostimulator system programmed for best therapy threshold settings without RFID interference. Using the Spatially Extended Nonlinear Node (SENN) model, we compared threshold factors of spinal cord fiber excitation for both recorded outputs. Results The electric current induced by low frequency RFID emitter was not significant to have a noticeable effect on electrical stimulation. Conclusions We demonstrated a method for analyzing effects of coupled magnetic field interference on implantable neurostimulator system and its electrodes which could be used by device manufacturers during the design and testing phases of the development process. PMID:22014169

Self-consistent multidimensional electron kinetic model for inductively coupled plasma sources

NASA Astrophysics Data System (ADS)

Dai, Fa Foster

Inductively coupled plasma (ICP) sources have received increasing interest in microelectronics fabrication and lighting industry. In 2-D configuration space (r, z) and 2-D velocity domain (νθ,νz), a self- consistent electron kinetic analytic model is developed for various ICP sources. The electromagnetic (EM) model is established based on modal analysis, while the kinetic analysis gives the perturbed Maxwellian distribution of electrons by solving Boltzmann-Vlasov equation. The self- consistent algorithm combines the EM model and the kinetic analysis by updating their results consistently until the solution converges. The closed-form solutions in the analytical model provide rigorous and fast computing for the EM fields and the electron kinetic behavior. The kinetic analysis shows that the RF energy in an ICP source is extracted by a collisionless dissipation mechanism, if the electron thermovelocity is close to the RF phase velocities. A criterion for collisionless damping is thus given based on the analytic solutions. To achieve uniformly distributed plasma for plasma processing, we propose a novel discharge structure with both planar and vertical coil excitations. The theoretical results demonstrate improved uniformity for the excited azimuthal E-field in the chamber. Non-monotonic spatial decay in electric field and space current distributions was recently observed in weakly- collisional plasmas. The anomalous skin effect is found to be responsible for this phenomenon. The proposed model successfully models the non-monotonic spatial decay effect and achieves good agreements with the measurements for different applied RF powers. The proposed analytical model is compared with other theoretical models and different experimental measurements. The developed model is also applied to two kinds of ICP discharges used for electrodeless light sources. One structure uses a vertical internal coil antenna to excite plasmas and another has a metal shield to prevent the electromagnetic radiation. The theoretical results delivered by the proposed model agree quite well with the experimental measurements in many aspects. Therefore, the proposed self-consistent model provides an efficient and reliable means for designing ICP sources in various applications such as VLSI fabrication and electrodeless light sources.

High-power diode lasers for optical communications applications

NASA Technical Reports Server (NTRS)

Carlin, D. B.; Goldstein, B.; Channin, D. J.

1985-01-01

High-power, single-mode, double-heterojunction AlGaAs diode lasers are being developed to meet source requirements for both fiber optic local area network and free space communications systems. An individual device, based on the channeled-substrate-planar (CSP) structure, has yielded single spatial and longitudinal mode outputs of up to 90 mW CW, and has maintained a single spatial mode to 150 mW CW. Phase-locked arrays of closely spaced index-guided lasers have been designed and fabricated with the aim of multiplying the outputs of the individual devices to even higher power levels in a stable, single-lobe, anastigmatic beam. The optical modes of the lasers in such arrays can couple together in such a way that they appear to be emanating from a single source, and can therefore be efficiently coupled into optical communications systems. This paper will review the state of high-power laser technology and discuss the communication system implications of these devices.

Separation of Opiate Isomers Using Electrospray Ionization and Paper Spray Coupled to High-Field Asymmetric Waveform Ion Mobility Spectrometry

NASA Astrophysics Data System (ADS)

Manicke, Nicholas E.; Belford, Michael

2015-05-01

One limitation in the growing field of ambient or direct analysis methods is reduced selectivity caused by the elimination of chromatographic separations prior to mass spectrometric analysis. We explored the use of high-field asymmetric waveform ion mobility spectrometry (FAIMS), an ambient pressure ion mobility technique, to separate the closely related opiate isomers of morphine, hydromorphone, and norcodeine. These isomers cannot be distinguished by tandem mass spectrometry. Separation prior to MS analysis is, therefore, required to distinguish these compounds, which are important in clinical chemistry and toxicology. FAIMS was coupled to a triple quadrupole mass spectrometer, and ionization was performed using either a pneumatically assisted heated electrospray ionization source (H-ESI) or paper spray, a direct analysis method that has been applied to the direct analysis of dried blood spots and other complex samples. We found that FAIMS was capable of separating the three opiate structural isomers using both H-ESI and paper spray as the ionization source.

The Lightning Electromagnetic Pulse Coupling Effect Inside the Shielding Enclosure With Penetrating Wire

NASA Astrophysics Data System (ADS)

Jiao, Xue; Yang, Bo

2017-10-01

To study the lightning electromagnetic pulse (LEMP) coupling and protection problems of shielding enclosure with penetrating wire, we adopt the model with proper size which is close to the practical engineering and the two-step finite-difference time-domain (FDTD) method is used for calculation in this paper. It is shown that the coupling voltage on the circuit lead inside the enclosure increases about 34 dB, when add 1.0 m long penetrating wire at the aperture, comparing with the case without penetrating wire. Meanwhile, the waveform, has the same wave outline as the lightning current source, shows that the penetrating wire brings a large number of low frequency component into the enclosure. The coupling effect in the enclosure will reduce greatly when penetrating wire has electrical connection with the enclosure at the aperture and the coupling voltage increase only about 12 dB than the case without penetrating wire. Moreover, the results show that though the waveguide pipe can reduce the coupling effect brought by the penetrating wire, the exposing part of penetrating wire can increase the coupling when the penetrating wire outside the enclosure is longer than the waveguide pipe and the longer the exposing part is, the stronger the coupling is.

Photoionization of Li2

NASA Astrophysics Data System (ADS)

Li, Y.; Pindzola, M. S.; Ballance, C. P.; Colgan, J.

2014-05-01

Single and double photoionization cross sections for Li2 are calculated using a time-dependent close-coupling method. The correlation between the outer two electrons of Li2 is obtained by relaxation of the close-coupled equations in imaginary time. Propagation of the close-coupled equations in real time yields single and double photoionization cross sections for Li2. The two active electron cross sections are compared with one active electron distorted-wave and close-coupling results for both Li and Li2. This work was supported in part by grants from NSF and US DoE. Computational work was carried out at NERSC in Oakland, California, NICS in Knoxville, Tennessee, and OLCF in Oak Ridge, Tennessee.

A closed-form solution for steady-state coupled phloem/xylem flow using the Lambert-W function.

PubMed

Hall, A J; Minchin, P E H

2013-12-01

A closed-form solution for steady-state coupled phloem/xylem flow is presented. This incorporates the basic Münch flow model of phloem transport, the cohesion model of xylem flow, and local variation in the xylem water potential and lateral water flow along the transport pathway. Use of the Lambert-W function allows this solution to be obtained under much more general and realistic conditions than has previously been possible. Variation in phloem resistance (i.e. viscosity) with solute concentration, and deviations from the Van't Hoff expression for osmotic potential are included. It is shown that the model predictions match those of the equilibrium solution of a numerical time-dependent model based upon the same mechanistic assumptions. The effect of xylem flow upon phloem flow can readily be calculated, which has not been possible in any previous analytical model. It is also shown how this new analytical solution can handle multiple sources and sinks within a complex architecture, and can describe competition between sinks. The model provides new insights into Münch flow by explicitly including interactions with xylem flow and water potential in the closed-form solution, and is expected to be useful as a component part of larger numerical models of entire plants. © 2013 John Wiley & Sons Ltd.

Rotational excitation of symmetric top molecules by collisions with atoms: Close coupling, coupled states, and effective potential calculations for NH3-He

NASA Technical Reports Server (NTRS)

Green, S.

1976-01-01

The formalism for describing rotational excitation in collisions between symmetric top rigid rotors and spherical atoms is presented both within the accurate quantum close coupling framework and also the coupled states approximation of McGuire and Kouri and the effective potential approximation of Rabitz. Calculations are reported for thermal energy NH3-He collisions, treating NH3 as a rigid rotor and employing a uniform electron gas (Gordon-Kim) approximation for the intermolecular potential. Coupled states are found to be in nearly quantitative agreement with close coupling results while the effective potential method is found to be at least qualitatively correct. Modifications necessary to treat the inversion motion in NH3 are discussed.

Free electron laser using Rf coupled accelerating and decelerating structures

DOEpatents

Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

1984-01-01

A free electron laser and free electron laser amplifier using beam transport devices for guiding an electron beam to a wiggler of a free electron laser and returning the electron beam to decelerating cavities disposed adjacent to the accelerating cavities of the free electron laser. Rf energy is generated from the energy depleted electron beam after it emerges from the wiggler by means of the decelerating cavities which are closely coupled to the accelerating cavities, or by means of a second bore within a single set of cavities. Rf energy generated from the decelerated electron beam is used to supplement energy provided by an external source, such as a klystron, to thereby enhance overall efficiency of the system.

Eshelby problem of polygonal inclusions in anisotropic piezoelectric full- and half-planes

NASA Astrophysics Data System (ADS)

Pan, E.

2004-03-01

This paper presents an exact closed-form solution for the Eshelby problem of polygonal inclusion in anisotropic piezoelectric full- and half-planes. Based on the equivalent body-force concept of eigenstrain, the induced elastic and piezoelectric fields are first expressed in terms of line integral on the boundary of the inclusion with the integrand being the Green's function. Using the recently derived exact closed-form line-source Green's function, the line integral is then carried out analytically, with the final expression involving only elementary functions. The exact closed-form solution is applied to a square-shaped quantum wire within semiconductor GaAs full- and half-planes, with results clearly showing the importance of material orientation and piezoelectric coupling. While the elastic and piezoelectric fields within the square-shaped quantum wire could serve as benchmarks to other numerical methods, the exact closed-form solution should be useful to the analysis of nanoscale quantum-wire structures where large strain and electric fields could be induced by the misfit strain.

Self-contained cryogenic gas sampling apparatus and method

DOEpatents

McManus, G.J.; Motes, B.G.; Bird, S.K.; Kotter, D.K.

1996-03-26

Apparatus for obtaining a whole gas sample, is composed of: a sample vessel having an inlet for receiving a gas sample; a controllable valve mounted for controllably opening and closing the inlet; a valve control coupled to the valve for opening and closing the valve at selected times; a portable power source connected for supplying operating power to the valve control; and a cryogenic coolant in thermal communication with the vessel for cooling the interior of the vessel to cryogenic temperatures. A method is described for obtaining an air sample using the apparatus described above, by: placing the apparatus at a location at which the sample is to be obtained; operating the valve control to open the valve at a selected time and close the valve at a selected subsequent time; and between the selected times maintaining the vessel at a cryogenic temperature by heat exchange with the coolant. 3 figs.

Self-contained cryogenic gas sampling apparatus and method

DOEpatents

McManus, Gary J.; Motes, Billy G.; Bird, Susan K.; Kotter, Dale K.

1996-01-01

Apparatus for obtaining a whole gas sample, composed of: a sample vessel having an inlet for receiving a gas sample; a controllable valve mounted for controllably opening and closing the inlet; a valve control coupled to the valve for opening and closing the valve at selected times; a portable power source connected for supplying operating power to the valve control; and a cryogenic coolant in thermal communication with the vessel for cooling the interior of the vessel to cryogenic temperatures. A method of obtaining an air sample using the apparatus described above, by: placing the apparatus at a location at which the sample is to be obtained; operating the valve control to open the valve at a selected time and close the valve at a selected subsequent time; and between the selected times maintaining the vessel at a cryogenic temperature by heat exchange with the coolant.

Electrical crosstalk-coupling measurement and analysis for digital closed loop fibre optic gyro

NASA Astrophysics Data System (ADS)

Jin, Jing; Tian, Hai-Ting; Pan, Xiong; Song, Ning-Fang

2010-03-01

The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed-loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing approach. It is found the variation of ramp amplitude will lead to the alternation of gyro bias. The amplitude and the phase parameters of the electrical crosstalk signal are measured by lock-in amplifier, and the variation of gyro bias is confirmed to be caused by the alternation of phase according to the amplitude of the ramp. A digital closed-loop fibre optic gyro electrical crosstalk-coupling model is built by approximating the electrical cross-coupling paths as a proportion and integration segment. The results of simulation and experiment show that the modulation signal electrical crosstalk-coupling can cause the dead zone of the gyro when a small angular velocity is inputted, and it could also lead to a periodic vibration of the bias error of the gyro when a large angular velocity is inputted.

Status of Charge Exchange Cross Section Measurements for Highly Charged Ions on Atomic Hydrogen

NASA Astrophysics Data System (ADS)

Draganic, I. N.; Havener, C. C.; Schultz, D. R.; Seely, D. G.; Schultz, P. C.

2011-05-01

Total cross sections of charge exchange (CX) for C5+, N6+, and O7+ ions on ground state atomic hydrogen are measured in an extended collision energy range of 1 - 20,000 eV/u. Absolute CX measurements are performed using an improved merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source mounted on a high voltage platform. In order to improve the problematic H+ signal collection for these exoergic CX collisions at low relative energies, a new double focusing electrostatic analyzer was installed. Experimental CX data are in good agreement with all previous H-oven relative measurements at higher collision energies. We compare our results with the most recent molecular orbital close-coupling (MOCC) and atomic orbital close-coupling (AOCC) theoretical calculations. Work supported by the NASA Solar & Heliospheric Physics Program NNH07ZDA001N, the Office of Fusion Energy Sciences and the Division of Chemical Sciences, Geosciences, and Biosciences, and the Office of Basic Energy Sciences of the U.S. DoE.

A One Dimensional, Time Dependent Inlet/Engine Numerical Simulation for Aircraft Propulsion Systems

NASA Technical Reports Server (NTRS)

Garrard, Doug; Davis, Milt, Jr.; Cole, Gary

1999-01-01

The NASA Lewis Research Center (LeRC) and the Arnold Engineering Development Center (AEDC) have developed a closely coupled computer simulation system that provides a one dimensional, high frequency inlet/engine numerical simulation for aircraft propulsion systems. The simulation system, operating under the LeRC-developed Application Portable Parallel Library (APPL), closely coupled a supersonic inlet with a gas turbine engine. The supersonic inlet was modeled using the Large Perturbation Inlet (LAPIN) computer code, and the gas turbine engine was modeled using the Aerodynamic Turbine Engine Code (ATEC). Both LAPIN and ATEC provide a one dimensional, compressible, time dependent flow solution by solving the one dimensional Euler equations for the conservation of mass, momentum, and energy. Source terms are used to model features such as bleed flows, turbomachinery component characteristics, and inlet subsonic spillage while unstarted. High frequency events, such as compressor surge and inlet unstart, can be simulated with a high degree of fidelity. The simulation system was exercised using a supersonic inlet with sixty percent of the supersonic area contraction occurring internally, and a GE J85-13 turbojet engine.

Detection of X-ray emission from the young low-mass star Rossiter 137B

NASA Technical Reports Server (NTRS)

Vilhu, O.; Linsky, J. L.

1987-01-01

Rst 137B, a close M-dwarf companion to the active K-star HD 36705, has been detected in a High Resolution Image in the Einstein Observatory Archive. The X-ray surface fluxes (0.2-4 keV) from both stars are close to the empirical saturation level, F(x)/F(bol) of about 0.001, defined by rapid rotators and very young stars. This supports the earlier results of the youthfulness of the system. This young couple is an excellent subject for studies of dependence of early evolution on stellar mass. Rst 137B is one of the latest spectral types and thus lowest-mass premain-sequence stars yet detected as an X-ray source.

High-sensitivity, high-speed continuous imaging system

DOEpatents

Watson, Scott A; Bender, III, Howard A

2014-11-18

A continuous imaging system for recording low levels of light typically extending over small distances with high-frame rates and with a large number of frames is described. Photodiode pixels disposed in an array having a chosen geometry, each pixel having a dedicated amplifier, analog-to-digital convertor, and memory, provide parallel operation of the system. When combined with a plurality of scintillators responsive to a selected source of radiation, in a scintillator array, the light from each scintillator being directed to a single corresponding photodiode in close proximity or lens-coupled thereto, embodiments of the present imaging system may provide images of x-ray, gamma ray, proton, and neutron sources with high efficiency.

Picosecond pulse generation in a hybrid Q-switched laser source by using a microelectromechanical mirror.

PubMed

Couderc, Vincent; Crunteanu, Aurelian; Fabert, Marc; Doutre, Florent; El Bassri, Farid; Pagnoux, Dominique; Jalocha, Alain

2012-02-27

We present a novel Q-switched laser source using a micro-optical-electromechanical mirror (MOEM) designed for short pulse emission. It is based on a hybrid configuration including a passively Q-switched microchip laser coupled to a fiber cavity closed by a cantilever type MOEM acting as an active modulator. This specially designed mirror with a single reflecting gold membrane is switched by low bias voltage ~50 V (peak to peak). This device emits pulses at tunable repetition rates up to 1.6 kHz, with ~564 ps duration and 3.4 kW peak power, which constitutes the shortest pulse duration ever reported with MOEMs based pulsed lasers.

Continental-scale river flow in climate models

NASA Technical Reports Server (NTRS)

Miller, James R.; Russell, Gary L.; Caliri, Guilherme

1994-01-01

The hydrologic cycle is a major part of the global climate system. There is an atmospheric flux of water from the ocean surface to the continents. The cycle is closed by return flow in rivers. In this paper a river routing model is developed to use with grid box climate models for the whole earth. The routing model needs an algorithm for the river mass flow and a river direction file, which has been compiled for 4 deg x 5 deg and 2 deg x 2.5 deg resolutions. River basins are defined by the direction files. The river flow leaving each grid box depends on river and lake mass, downstream distance, and an effective flow speed that depends on topography. As input the routing model uses monthly land source runoff from a 5-yr simulation of the NASA/GISS atmospheric climate model (Hansen et al.). The land source runoff from the 4 deg x 5 deg resolution model is quartered onto a 2 deg x 2.5 deg grid, and the effect of grid resolution is examined. Monthly flow at the mouth of the world's major rivers is compared with observations, and a global error function for river flow is used to evaluate the routing model and its sensitivity to physical parameters. Three basinwide parameters are introduced: the river length weighted by source runoff, the turnover rate, and the basinwide speed. Although the values of these parameters depend on the resolution at which the rivers are defined, the values should converge as the grid resolution becomes finer. When the routing scheme described here is coupled with a climate model's source runoff, it provides the basis for closing the hydrologic cycle in coupled atmosphere-ocean models by realistically allowing water to return to the ocean at the correct location and with the proper magnitude and timing.

Investigation to advance prediction techniques of the low-speed aerodynamics of V/STOL aircraft

NASA Technical Reports Server (NTRS)

Maskew, B.; Strash, D.; Nathman, J.; Dvorak, F. A.

1985-01-01

A computer program, VSAERO, has been applied to a number of V/STOL configurations with a view to advancing prediction techniques for the low-speed aerodynamic characteristics. The program couples a low-order panel method with surface streamline calculation and integral boundary layer procedures. The panel method--which uses piecewise constant source and doublet panels-includes an iterative procedure for wake shape and models boundary layer displacement effect using the source transpiration technique. Certain improvements to a basic vortex tube jet model were installed in the code prior to evaluation. Very promising results were obtained for surface pressures near a jet issuing at 90 deg from a flat plate. A solid core model was used in the initial part of the jet with a simple entrainment model. Preliminary representation of the downstream separation zone significantly improve the correlation. The program accurately predicted the pressure distribution inside the inlet on the Grumman 698-411 design at a range of flight conditions. Furthermore, coupled viscous/potential flow calculations gave very close correlation with experimentally determined operational boundaries dictated by the onset of separation inside the inlet. Experimentally observed degradation of these operational boundaries between nacelle-alone tests and tests on the full configuration were also indicated by the calculation. Application of the program to the General Dynamics STOL fighter design were equally encouraging. Very close agreement was observed between experiment and calculation for the effects of power on pressure distribution, lift and lift curve slope.

Recommended OSC design and analysis of AMTEC power system for outer-planet missions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schock, A.; Noravian, H.; Or, C.

1999-01-01

The paper describes OSC designs and analyses of AMTEC cells and radioisotope power systems for possible application to NASA{close_quote}s Europa Orbiter and Pluto Kuiper Express missions, and compares their predicted performance with JPL{close_quote}s preliminary mission goals. The latest cell and generator designs presented here were the culmination of studies covering a wide variety of generator configurations and operating parameters. The many steps and rationale leading to OSC{close_quote}s design evolution and materials selection were discussed in earlier publications and will not be repeated here except for a description of OSC{close_quote}s latest design, including a recent heat source support scheme and cellmore » configuration that have not been described in previous publications. As shown, that heat source support scheme eliminates all contact between the heat source and the AMTEC (Alkali Metal Thermal-to-Electrical Conversion) cells, which simplifies the generator{close_quote}s structural design as well as its fabrication and assembly procedure. An additional purpose of the paper is to describe a revised cell design and fabrication procedure which represent a major departure from previous OSC designs. Previous cells had a uniform diameter, but in the revised design the cell wall beyond the BASE tubes has a greatly reduced diameter. The paper presents analytical performance predictions which show that the revised ({open_quotes}chimney{close_quotes}) cell design yields substantially higher efficiencies than the previous (cylindrical) design. This makes it possible to meet and substantially exceed the JPL-stipulated EOM power goal with four instead of six General Purpose Heat Source (GPHS) modules, resulting in a one-third reduction in the heat source mass, cost, and fuel requirements. OSC{close_quote}s performance predictions were based on its techniques for the coupled thermal, electrical, and fluid flow analyses of AMTEC generators. Those analytical techniques have been partially validated by tests of prototypic test assemblies designed by OSC, built by AMPS, and tested by AFRL. The analytical results indicate that the OSC power system design, operating within the stipulated evaporator and clad temperature limits and well within its mass goals, can yield EOM power outputs and system efficiencies that substantially exceed the JPL-specified goals for the Europa and Pluto missions. However, those results only account for radioisotope decay. Other degradation mechanisms are still under study, and their short-and long-term effects must be quantified and understood before final conclusions about the adequacy and competitiveness of the AMTEC system can be drawn. {copyright} {ital 1999 American Institute of Physics.}« less

Scalable quantum information processing with photons and atoms

NASA Astrophysics Data System (ADS)

Pan, Jian-Wei

Over the past three decades, the promises of super-fast quantum computing and secure quantum cryptography have spurred a world-wide interest in quantum information, generating fascinating quantum technologies for coherent manipulation of individual quantum systems. However, the distance of fiber-based quantum communications is limited due to intrinsic fiber loss and decreasing of entanglement quality. Moreover, probabilistic single-photon source and entanglement source demand exponentially increased overheads for scalable quantum information processing. To overcome these problems, we are taking two paths in parallel: quantum repeaters and through satellite. We used the decoy-state QKD protocol to close the loophole of imperfect photon source, and used the measurement-device-independent QKD protocol to close the loophole of imperfect photon detectors--two main loopholes in quantum cryptograph. Based on these techniques, we are now building world's biggest quantum secure communication backbone, from Beijing to Shanghai, with a distance exceeding 2000 km. Meanwhile, we are developing practically useful quantum repeaters that combine entanglement swapping, entanglement purification, and quantum memory for the ultra-long distance quantum communication. The second line is satellite-based global quantum communication, taking advantage of the negligible photon loss and decoherence in the atmosphere. We realized teleportation and entanglement distribution over 100 km, and later on a rapidly moving platform. We are also making efforts toward the generation of multiphoton entanglement and its use in teleportation of multiple properties of a single quantum particle, topological error correction, quantum algorithms for solving systems of linear equations and machine learning. Finally, I will talk about our recent experiments on quantum simulations on ultracold atoms. On the one hand, by applying an optical Raman lattice technique, we realized a two-dimensional spin-obit (SO) coupling and topological bands with ultracold bosonic atoms. A controllable crossover between 2D and 1D SO couplings is studied, and the SO effects and nontrivial band topology are observe. On the other hand, utilizing a two-dimensional spin-dependent optical superlattice and a single layer of atom cloud, we directly observed the four-body ring-exchange coupling and the Anyonic fractional statistics.

Local residue coupling strategies by neural network for InSAR phase unwrapping

NASA Astrophysics Data System (ADS)

Refice, Alberto; Satalino, Giuseppe; Chiaradia, Maria T.

1997-12-01

Phase unwrapping is one of the toughest problems in interferometric SAR processing. The main difficulties arise from the presence of point-like error sources, called residues, which occur mainly in close couples due to phase noise. We present an assessment of a local approach to the resolution of these problems by means of a neural network. Using a multi-layer perceptron, trained with the back- propagation scheme on a series of simulated phase images, fashion the best pairing strategies for close residue couples. Results show that god efficiencies and accuracies can have been obtained, provided a sufficient number of training examples are supplied. Results show that good efficiencies and accuracies can be obtained, provided a sufficient number of training examples are supplied. The technique is tested also on real SAR ERS-1/2 tandem interferometric images of the Matera test site, showing a good reduction of the residue density. The better results obtained by use of the neural network as far as local criteria are adopted appear justified given the probabilistic nature of the noise process on SAR interferometric phase fields and allows to outline a specifically tailored implementation of the neural network approach as a very fast pre-processing step intended to decrease the residue density and give sufficiently clean images to be processed further by more conventional techniques.

Function projective synchronization in chaotic and hyperchaotic systems through open-plus-closed-loop coupling.

PubMed

Sudheer, K Sebastian; Sabir, M

2010-03-01

Recently introduced function projective synchronization in which chaotic systems synchronize up to a scaling function has important applications in secure communications. We design coupling function for unidirectional coupling in identical and mismatched oscillators to realize function projective synchronization through open-plus-closed-loop coupling method. Numerical simulations on Lorenz system, Rossler system, hyperchaotic Lorenz, and hyperchaotic Chen system are presented to verify the effectiveness of the proposed scheme.

Preliminary evidence that sub-chronic citalopram triggers the re-evaluation of value in intimate partnerships.

PubMed

Bilderbeck, Amy C; Wakeley, Judi; Godlewska, Beata R; McGlone, Francis; Harris, Tirril; Cowen, Phillip J; Rogers, Robert D

2014-09-01

Depression frequently involves disrupted inter-personal relationships, while treatment with serotonergic anti-depressants can interfere with libido and sexual function. However, little is known about how serotonin activity influences appraisals of intimate partnerships. Learning more could help to specify how serotonergic mechanisms mediate social isolation in psychiatric illness. Forty-four healthy heterosexual adults, currently in romantic relationships, received 8 days treatment with the selective serotonin re-uptake inhibitor citalopram (N = 21; 10 male) or placebo (N = 23; 12 male). Participants viewed photographs of unknown, heterosexual couples and made a series of judgements about their relationships. Participants also indicated the importance of relationship features in their own close partnerships, and close partnerships generally. Citalopram reduced the rated quality of couples' physical relationships and the importance attributed to physical and intimate aspects of participants' own relationships. In contrast, citalopram also enhanced the evaluated worth of mutual trust in relationships. Amongst males, citalopram was associated with judgements of reduced turbulence and bickering in others' relationships, and increased male dominance. These data constitute preliminary evidence that enhancing serotonin activity modulates cognitions about sexual activity as part of a re-appraisal of sources of value within close intimate relationships, enhancing the judged importance of longer-term benefits of trust and shared experiences. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Corneal coupling of astigmatism applied to incisional and ablative surgery.

PubMed

Alpins, Noel; Ong, James K Y; Stamatelatos, George

2014-11-01

To redefine measures of corneal coupling for use with incisional and ablation procedures for astigmatism. Private clinics, Melbourne, Victoria, Australia. Retrospective nonrandomized study. The measures known as the coupling ratio (CR) and coupling constant (CC) were redefined to ensure validity in most cases of incisional procedures and laser vision correction procedures. In addition, a new measure--the coupling adjustment (CAdj)--was developed to quantify the amount of spherical adjustment that must be applied to compensate for coupling that occurs as a result of astigmatism treatment. These quantitative measures of coupling were applied to retrospective data to show their applicability. Pure myopic, compound myopic, and compound hyperopic astigmatism excimer laser treatments showed a CR close to zero, a CC close to 0.5, and a CAdj close to zero. Incision LRIs showed a CR close to 1.0 and a CC close to zero. In all cases, the coupling measures were consistent for treatments with a larger astigmatic component (>1.0 diopter) but variable when the astigmatic component of the treatment was smaller. The revised definitions of CR and CC can be used with incisional and ablative surgery. Incorporating the CAdj into the planning of spherocylindrical treatments allows one to factor in the effect of the astigmatic treatment on the spherical component and thus to more accurately target the desired spherical equivalent. Dr. Alpins and Mr. Stamatelatos have a financial interest in the Assort software program. Dr. Ong is an employee of Assort. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Closed Brayton Cycle power system with a high temperature pellet bed reactor heat source for NEP applications

NASA Technical Reports Server (NTRS)

Juhasz, Albert J.; El-Genk, Mohamed S.; Harper, William B., Jr.

1992-01-01

Capitalizing on past and future development of high temperature gas reactor (HTGR) technology, a low mass 15 MWe closed gas turbine cycle power system using a pellet bed reactor heating helium working fluid is proposed for Nuclear Electric Propulsion (NEP) applications. Although the design of this directly coupled system architecture, comprising the reactor/power system/space radiator subsystems, is presented in conceptual form, sufficient detail is included to permit an assessment of overall system performance and mass. Furthermore, an attempt is made to show how tailoring of the main subsystem design characteristics can be utilized to achieve synergistic system level advantages that can lead to improved reliability and enhanced system life while reducing the number of parasitic load driven peripheral subsystems.

Applications of plasma core reactors to terrestrial energy systems

NASA Technical Reports Server (NTRS)

Latham, T. S.; Biancardi, F. R.; Rodgers, R. J.

1974-01-01

Plasma core reactors offer several new options for future energy needs in addition to space power and propulsion applications. Power extraction from plasma core reactors with gaseous nuclear fuel allows operation at temperatures higher than conventional reactors. Highly efficient thermodynamic cycles and applications employing direct coupling of radiant energy are possible. Conceptual configurations of plasma core reactors for terrestrial applications are described. Closed-cycle gas turbines, MHD systems, photo- and thermo-chemical hydrogen production processes, and laser systems using plasma core reactors as prime energy sources are considered. Cycle efficiencies in the range of 50 to 65 percent are calculated for closed-cycle gas turbine and MHD electrical generators. Reactor advantages include continuous fuel reprocessing which limits inventory of radioactive by-products and thorium-U-233 breeder configurations with about 5-year doubling times.-

Association between Body Mass Index and Depressive Symptoms of African American Married Couples: Mediating and Moderating Roles of Couples' Behavioral Closeness

ERIC Educational Resources Information Center

Wickrama, Thulitha; Bryant, Chalandra M.

2012-01-01

This study examined (a) associations between body mass index (BMI) and depressive symptoms in African American husbands and wives, (b) transactional associations between husbands and wives in this relationship, and (c) mediating and moderating role of couples' behavioral closeness in this association. Data came from a sample of 450 African…

The performance of the upgraded Los Alamos Neutron Source

NASA Astrophysics Data System (ADS)

Ito, Takeyasu; LANL UCN Source Collaboration

2017-09-01

Los Alamos National Laboratory has been operating an ultracold (UCN) source based on a solid deuterium (SD2) UCN converter driven by spallation neutrons for over 10 years. It has recently been successfully upgraded, by replacing the cryostat that contains the cold neutron moderator, SD2 volume, and vertical UCN guide. The horizontal UCN guide that transports UCN out of the radiation shield was also replaced. The new design reflects lessons learned from the 10+ year long operation of the previous version of the UCN source and is optimized to maximize the cold neutron flux at the SD2 volume, featuring a close coupled cold neutron moderator, and maximize the transport of the UCN to experiments. During the commissioning of the upgraded UCN source, data were collected to measure its performance, including cold neutron spectra as a function of the cold moderator temperature, and the UCN density in a vessel outside the source. In this talk, after a brief overview of the design of the upgraded source, the results of the performance tests and comparison to prediction will be presented. This work was funded by LANL LDRD.

Charge Exchange X-Ray Emission due to Highly Charged Ion Collisions with H, He, and H2: Line Ratios for Heliospheric and Interstellar Applications

NASA Astrophysics Data System (ADS)

Cumbee, R. S.; Mullen, P. D.; Lyons, D.; Shelton, R. L.; Fogle, M.; Schultz, D. R.; Stancil, P. C.

2018-01-01

The fundamental collisional process of charge exchange (CX) has been established as a primary source of X-ray emission from the heliosphere, planetary exospheres, and supernova remnants. In this process, X-ray emission results from the capture of an electron by a highly charged ion from a neutral atom or molecule, to form a highly excited, high-charge state ion. As the captured electron cascades down to the lowest energy level, photons are emitted, including X-rays. To provide reliable CX-induced X-ray spectral models to realistically simulate these environments, line ratios and spectra are computed using theoretical CX cross sections obtained with the multi-channel Landau-Zener, atomic-orbital close-coupling, molecular-orbital close-coupling, and classical trajectory Monte Carlo methods for various collisional velocities relevant to astrophysics. X-ray spectra were computed for collisions of bare and H-like C to Al ions with H, He, and H2 with results compared to available experimental data. Using these line ratios, XSPEC models of CX emission in the northeast rim of the Cygnus Loop supernova remnant and the heliosphere are shown as examples with ion velocity dependence.

Experiments with Lasers and Frequency Doublers

NASA Technical Reports Server (NTRS)

Bachor, H.-A.; Taubman, M.; White, A. G.; Ralph, T.; McClelland, D. E.

1996-01-01

Solid state laser sources, such as diode-pumped Nd:YAG lasers, have given us CW laser light of high power with unprecedented stability and low noise performance. In these lasers most of the technical sources of noise can be eliminated allowing them to be operated close to the theoretical noise limit set by the quantum properties of light. The next step of reducing the noise below the standard limit is known as squeezing. We present experimental progress in generating reliably squeezed light using the process of frequency doubling. We emphasize the long term stability that makes this a truly practical source of squeezed light. Our experimental results match noise spectra calculated with our recently developed models of coupled systems which include the noise generated inside the laser and its interaction with the frequency doubler. We conclude with some observations on evaluating quadrature squeezed states of light.

A coupled-cluster study of photodetachment cross sections of closed-shell anions

NASA Astrophysics Data System (ADS)

Cukras, Janusz; Decleva, Piero; Coriani, Sonia

2014-11-01

We investigate the performance of Stieltjes Imaging applied to Lanczos pseudo-spectra generated at the coupled cluster singles and doubles, coupled cluster singles and approximate iterative doubles and coupled cluster singles levels of theory in modeling the photodetachment cross sections of the closed shell anions H-, Li-, Na-, F-, Cl-, and OH-. The accurate description of double excitations is found to play a much more important role than in the case of photoionization of neutral species.

A coupled-cluster study of photodetachment cross sections of closed-shell anions.

PubMed

Cukras, Janusz; Decleva, Piero; Coriani, Sonia

2014-11-07

We investigate the performance of Stieltjes Imaging applied to Lanczos pseudo-spectra generated at the coupled cluster singles and doubles, coupled cluster singles and approximate iterative doubles and coupled cluster singles levels of theory in modeling the photodetachment cross sections of the closed shell anions H(-), Li(-), Na(-), F(-), Cl(-), and OH(-). The accurate description of double excitations is found to play a much more important role than in the case of photoionization of neutral species.

Multi-Source Generation Mechanisms for Low Frequency Noise Induced by Flood Discharge and Energy Dissipation from a High Dam with a Ski-Jump Type Spillway

PubMed Central

Lian, Jijian; Zhang, Wenjiao; Ma, Bin; Liu, Dongming

2017-01-01

As excess water is discharged from a high dam, low frequency noise (air pulsation lower than 10 Hz, LFN) is generated and propagated in the surrounding areas, causing environmental hazards such as the vibration of windows and doors and the discomfort of local residents. To study the generation mechanisms and key influencing factors of LFN induced by flood discharge and energy dissipation from a high dam with a ski-jump type spillway, detailed prototype observations and analyses of LFN are carried out. The discharge flow field is simulated and analyzed using a gas-liquid turbulent flow model. The acoustic response characteristics of the air cavity, which is formed between the discharge nappe and dam body, are analyzed using an acoustic numerical model. The multi-sources generation mechanisms are first proposed basing on the prototype observation results, vortex sound model, turbulent flow model and acoustic numerical model. Two kinds of sources of LFN are studied. One comes from the energy dissipation of submerged jets in the plunge pool, the other comes from nappe-cavity coupled vibration. The results of the analyses reveal that the submerged jets in the plunge pool only contribute to an on-site LFN energy of 0–1.0 Hz, and the strong shear layers around the high-velocity submerged jets and wall jet development areas are the main acoustic source regions of LFN in the plunge pool. In addition, the nappe-cavity coupled vibration, which is induced when the discharge nappe vibrates with close frequency to the model frequency of the cavity, can induce on-site LFN energy with wider frequency spectrum energy within 0–4.0 Hz. By contrast, the contribution degrees to LFN energy from two acoustic sources are almost same, while the contribution degree from nappe-cavity coupled vibration is slightly higher. PMID:29189750

Ultra-wideband horn antenna with abrupt radiator

DOEpatents

McEwan, Thomas E.

1998-01-01

An ultra-wideband horn antenna transmits and receives impulse waveforms for short-range radars and impulse time-of flight systems. The antenna reduces or eliminates various sources of close-in radar clutter, including pulse dispersion and ringing, sidelobe clutter, and feedline coupling into the antenna. Dispersion is minimized with an abrupt launch point radiator element; sidelobe and feedline coupling are minimized by recessing the radiator into a metallic horn. Low frequency cut-off associated with a horn is extended by configuring the radiator drive impedance to approach a short circuit at low frequencies. A tapered feed plate connects at one end to a feedline, and at the other end to a launcher plate which is mounted to an inside wall of the horn. The launcher plate and feed plate join at an abrupt edge which forms the single launch point of the antenna.

Challenges and constraints of dynamically emerged source and sink in atomtronic circuits: From closed-system to open-system approaches

PubMed Central

Lai, Chen-Yen; Chien, Chih-Chun

2016-01-01

While batteries offer electronic source and sink for electronic devices, atomic analogues of source and sink and their theoretical descriptions have been a challenge in cold-atom systems. Here we consider dynamically emerged local potentials as controllable source and sink for bosonic atoms. Although a sink potential can collect bosons in equilibrium and indicate its usefulness in the adiabatic limit, sudden switching of the potential exhibits low effectiveness in pushing bosons into it. This is due to conservation of energy and particle in isolated systems such as cold atoms. By varying the potential depth and interaction strength, the systems can further exhibit averse response, where a deeper emerged potential attracts less bosonic atoms into it. To explore possibilities for improving the effectiveness, we investigate what types of system-environment coupling can help bring bosons into a dynamically emerged sink, and a Lindblad operator corresponding to local cooling is found to serve the purpose. PMID:27849034

Bi-Tapered Fiber Sensor Using a Supercontinuum Light Source for a Broad Spectral Range

NASA Astrophysics Data System (ADS)

Garcia Mina, Diego Felipe

We describe the fabrication bi-tapered optical fiber sensors designed for shorter wavelength operation and we study their optical properties. The new sensing system designed and built for the project is a specialty optical fiber that is single-mode in the visible/near infrared wavelength region of interest. In fabricating the tapered fiber we control the taper parameters, such as the down-taper and up-taper rate, shape and length, and the fiber waist diameter and length. The sensing is mode is via the electromagnetic field, which is evanescent outside the optical fiber and is confined close to the fiber's surface (within a couple hundred nanometers). The fiber sensor system has multiple advantages as a compact, simple device with an ability to detected tiny changes in the refractive index. We developed a supercontinuum light source to provide a wide spectral wavelength range from visible to near IR. The source design was based on coupling light from a femtosecond laser in a photonic crystal fiber designed for high nonlinearity. The output light was efficiently coupled into the bi-tapered fiber sensor and good signal to noise was achieved across the wavelength region. The bi-tapered fiber starts and ends with a single mode fiber in the waist region there are many modes with different propagation constants that couple to the environment outside the fiber. The signals have a strong periodic component as the wavelength is scanned; we exploit the periodicity in the signal using a discrete Fourier transform analysis to correlate signal phase changes with the refractive index changes in the local environment. For small index changes we also measure a strong correlation with the dominant Fourier amplitude component. Our experiments show that our phase-based signal processing technique works well at shorter wavelengths and we extract a new feature, the Fourier amplitude, to measure the refractive index difference. We conducted experiments using aqueous medium with controlled refractive index, such as water-glycerol mixtures. We find sensitivity to changes in the refractive index close to 0.00002 in so-called Refractive Index Units (RIUs). That is smaller than reported in recent literature, but by no means a limiting value. The technique is not limited to aqueous solutions surrounding the fiber, but it can also be adapted to study volatile organic compounds. Future improvements in the fiber sensing system are discussed, including adding thin films to the surface for label-free detection and to draw the electromagnetic field to the fiber's surface.

The close relationships of Lesbians and gay men.

PubMed

Peplau, Letitia Anne; Fingerhut, Adam W

2007-01-01

This article reviews empirical studies of same-sex couples in the United States, highlighting consistent findings, drawing comparisons to heterosexual couples, and noting gaps in available research. U.S. Census data indicate that there were more than 600,000 same-sex couples living together in 2000. Research about relationship formation, the division of household labor, power, satisfaction, sexuality, conflict, commitment, and relationship stability is presented. Next, we highlight three recent research topics: the legalization of same-sex relationships through civil unions and same-sex marriage, the experiences of same-sex couples raising children, and the impact of societal prejudice and discrimination on same-sex partners. We conclude with comments about the contributions of empirical research to debunking negative stereotypes of same-sex couples, testing the generalizability of theories about close relationships, informing our understanding of gender and close relationships, and providing a scientific basis for public policy.

Accurate collision-induced line-coupling parameters for the fundamental band of CO in He - Close coupling and coupled states scattering calculations

NASA Technical Reports Server (NTRS)

Green, Sheldon; Boissoles, J.; Boulet, C.

1988-01-01

The first accurate theoretical values for off-diagonal (i.e., line-coupling) pressure-broadening cross sections are presented. Calculations were done for CO perturbed by He at thermal collision energies using an accurate ab initio potential energy surface. Converged close coupling, i.e., numerically exact values, were obtained for coupling to the R(0) and R(2) lines. These were used to test the coupled states (CS) and infinite order sudden (IOS) approximate scattering methods. CS was found to be of quantitative accuracy (a few percent) and has been used to obtain coupling values for lines to R(10). IOS values are less accurate, but, owing to their simplicity, may nonetheless prove useful as has been recently demonstrated.

Charge movement in gating-locked HCN channels reveals weak coupling of voltage sensors and gate.

PubMed

Ryu, Sujung; Yellen, Gary

2012-11-01

HCN (hyperpolarization-activated cyclic nucleotide gated) pacemaker channels have an architecture similar to that of voltage-gated K(+) channels, but they open with the opposite voltage dependence. HCN channels use essentially the same positively charged voltage sensors and intracellular activation gates as K(+) channels, but apparently these two components are coupled differently. In this study, we examine the energetics of coupling between the voltage sensor and the pore by using cysteine mutant channels for which low concentrations of Cd(2+) ions freeze the open-closed gating machinery but still allow the sensors to move. We were able to lock mutant channels either into open or into closed states by the application of Cd(2+) and measure the effect on voltage sensor movement. Cd(2+) did not immobilize the gating charge, as expected for strict coupling, but rather it produced shifts in the voltage dependence of voltage sensor charge movement, consistent with its effect of confining transitions to either closed or open states. From the magnitude of the Cd(2+)-induced shifts, we estimate that each voltage sensor produces a roughly three- to sevenfold effect on the open-closed equilibrium, corresponding to a coupling energy of ∼1.3-2 kT per sensor. Such coupling is not only opposite in sign to the coupling in K(+) channels, but also much weaker.

Origins of coevolution between residues distant in protein 3D structures

PubMed Central

Ovchinnikov, Sergey; Kamisetty, Hetunandan; Baker, David

2017-01-01

Residue pairs that directly coevolve in protein families are generally close in protein 3D structures. Here we study the exceptions to this general trend—directly coevolving residue pairs that are distant in protein structures—to determine the origins of evolutionary pressure on spatially distant residues and to understand the sources of error in contact-based structure prediction. Over a set of 4,000 protein families, we find that 25% of directly coevolving residue pairs are separated by more than 5 Å in protein structures and 3% by more than 15 Å. The majority (91%) of directly coevolving residue pairs in the 5–15 Å range are found to be in contact in at least one homologous structure—these exceptions arise from structural variation in the family in the region containing the residues. Thirty-five percent of the exceptions greater than 15 Å are at homo-oligomeric interfaces, 19% arise from family structural variation, and 27% are in repeat proteins likely reflecting alignment errors. Of the remaining long-range exceptions (<1% of the total number of coupled pairs), many can be attributed to close interactions in an oligomeric state. Overall, the results suggest that directly coevolving residue pairs not in repeat proteins are spatially proximal in at least one biologically relevant protein conformation within the family; we find little evidence for direct coupling between residues at spatially separated allosteric and functional sites or for increased direct coupling between residue pairs on putative allosteric pathways connecting them. PMID:28784799

Prediction of high-frequency vibration transmission across coupled, periodic ribbed plates by incorporating tunneling mechanisms.

PubMed

Yin, Jianfei; Hopkins, Carl

2013-04-01

Prediction of structure-borne sound transmission on built-up structures at audio frequencies is well-suited to Statistical Energy Analysis (SEA) although the inclusion of periodic ribbed plates presents challenges. This paper considers an approach using Advanced SEA (ASEA) that can incorporate tunneling mechanisms within a statistical approach. The coupled plates used for the investigation form an L-junction comprising a periodic ribbed plate with symmetric ribs and an isotropic homogeneous plate. Experimental SEA (ESEA) is carried out with input data from Finite Element Methods (FEM). This indicates that indirect coupling is significant at high frequencies where bays on the periodic ribbed plate can be treated as individual subsystems. SEA using coupling loss factors from wave theory leads to significant underestimates in the energy of the bays when the isotropic homogeneous plate is excited. This is due to the absence of tunneling mechanisms in the SEA model. In contrast, ASEA shows close agreement with FEM and laboratory measurements. The errors incurred with SEA rapidly increase as the bays become more distant from the source subsystem. ASEA provides significantly more accurate predictions by accounting for the spatial filtering that leads to non-diffuse vibration fields on these more distant bays.

State-selective charge exchange in slow collisions of Si3+ ions with H atoms: A molecular state close coupling treatment*)

NASA Astrophysics Data System (ADS)

Joseph, Dwayne C.; Saha, Bidhan C.

2012-11-01

Charge transfer cross sections are calculated by employing both the quantal and semiclassical ɛ(R) molecular orbital close coupling (MOCC) approximations in the adiabatic representation and compared with other theoretical and experimental results

Couple Infertility: From the Perspective of the Close-Relationship Model.

ERIC Educational Resources Information Center

Higgins, Barbara S.

1990-01-01

Presents Close-Relationship Model as comprehensive framework in which to examine interrelated nature of causes and effects of infertility on marital relationship. Includes these factors: physical and psychological characteristics of both partners; joint, couple characteristics; physical and social environment; and relationship itself. Discusses…

Daily Couple Experiences and Parent Affect in Families of Children with versus without Autism

PubMed Central

Hartley, Sigan L.; DaWalt, Leann Smith; Schultz, Haley M.

2017-01-01

We examined daily couple experiences in 174 couples who had a child with autism spectrum disorder (ASD) relative to 179 couples who had a child without disabilities and their same-day association with parent affect. Parents completed a 14-day daily diary in which they reported time with partner, partner support, partner closeness, and positive and negative couple interactions and level of positive and negative affect. One-way multivariate analyses of covariance and dyadic multilevel models were conducted. Parents of children with ASD reported less time with partner, lower partner closeness, and fewer positive couple interactions than the comparison group. Daily couple experiences were more strongly associated with parent affect in the ASD than comparison group. Findings have implications for programs and supports. PMID:28275928

Daily Couple Experiences and Parent Affect in Families of Children with Versus Without Autism.

PubMed

Hartley, Sigan L; DaWalt, Leann Smith; Schultz, Haley M

2017-06-01

We examined daily couple experiences in 174 couples who had a child with autism spectrum disorder (ASD) relative to 179 couples who had a child without disabilities and their same-day association with parent affect. Parents completed a 14-day daily diary in which they reported time with partner, partner support, partner closeness, and positive and negative couple interactions and level of positive and negative affect. One-way multivariate analyses of covariance and dyadic multilevel models were conducted. Parents of children with ASD reported less time with partner, lower partner closeness, and fewer positive couple interactions than the comparison group. Daily couple experiences were more strongly associated with parent affect in the ASD than comparison group. Findings have implications for programs and supports.

A multi-port power electronics interface for battery powered electric vehicles: Application of inductively coupled wireless power transfer and hybrid energy storage system

NASA Astrophysics Data System (ADS)

McDonough, Matthew Kelly

Climate change, pollution, and geopolitical conflicts arising from the extreme wealth concentrations caused by fossil fuel deposits are just a few of the side-effects of the way that we fuel our society. A new method to power our civilization is becoming more and more necessary. Research for new, more sustainable fuel sources is already underway due to research in wind, solar, geothermal, and hydro power. However this focus is mainly on stationary applications. A large portion of fossil fuel usage comes from transportation. Unfortunately, the transition to cleaner transportation fuels is being stunted by the inability to store adequate amounts of energy in electro-chemical batteries. The idea of charging while driving has been proposed by many researchers, however several challenges still exist. In this work some of these challenges are addressed. Specifically, the ability to route power from multiple sources/loads is investigated. Special attention is paid to adjusting the time constant of particular converters, namely the battery and ultra-capacitor converters to reduce the high frequency and high magnitude current components applied to the battery terminals. This is done by developing a closed loop model of the entire multi-port converter, including the state of charge of the ultra-capacitors. The development of closed loop models and two experimental testbeds for use as stationary vehicle charging platforms with their unique set of sources/loads are presented along-side an on-board charger to demonstrate the similarities and differences between stationary charging and mobile charging. Experimental results from each are given showing that it is not only possible, but feasible to utilize Inductively Coupled Wireless Power Transfer (ICWPT) to charge a battery powered electric vehicle while driving and still protect the life-span of the batteries under the new, harsher conditions generated by the ICWPT system.

Analytical model for investigation of interior noise characteristics in aircraft with multiple propellers including synchrophasing

NASA Technical Reports Server (NTRS)

Fuller, C. R.

1986-01-01

A simplified analytical model of transmission of noise into the interior of propeller-driven aircraft has been developed. The analysis includes directivity and relative phase effects of the propeller noise sources, and leads to a closed form solution for the coupled motion between the interior and exterior fields via the shell (fuselage) vibrational response. Various situations commonly encountered in considering sound transmission into aircraft fuselages are investigated analytically and the results obtained are compared to measurements in real aircraft. In general the model has proved successful in identifying basic mechanisms behind noise transmission phenomena.

Adaptive electric potential sensors for smart signal acquisition and processing

NASA Astrophysics Data System (ADS)

Prance, R. J.; Beardsmore-Rust, S.; Prance, H.; Harland, C. J.; Stiffell, P. B.

2007-07-01

Current applications of the Electric Potential Sensor operate in a strongly (capacitively) coupled limit, with the sensor physically close to or touching the source. This mode of operation screens the sensor effectively from the majority of external noise. To date however the full capability of these sensors operating in a remote mode has not been realised outside of a screened environment (Faraday cage). This paper describes the results of preliminary work in tailoring the response of the sensors to particular signals and so reject background noise, thereby enhancing both the dynamic range and signal to noise ratio significantly.

An improved coupled-states approximation including the nearest neighbor Coriolis couplings for diatom-diatom inelastic collision

NASA Astrophysics Data System (ADS)

Yang, Dongzheng; Hu, Xixi; Zhang, Dong H.; Xie, Daiqian

2018-02-01

Solving the time-independent close coupling equations of a diatom-diatom inelastic collision system by using the rigorous close-coupling approach is numerically difficult because of its expensive matrix manipulation. The coupled-states approximation decouples the centrifugal matrix by neglecting the important Coriolis couplings completely. In this work, a new approximation method based on the coupled-states approximation is presented and applied to time-independent quantum dynamic calculations. This approach only considers the most important Coriolis coupling with the nearest neighbors and ignores weaker Coriolis couplings with farther K channels. As a result, it reduces the computational costs without a significant loss of accuracy. Numerical tests for para-H2+ortho-H2 and para-H2+HD inelastic collision were carried out and the results showed that the improved method dramatically reduces the errors due to the neglect of the Coriolis couplings in the coupled-states approximation. This strategy should be useful in quantum dynamics of other systems.

DC source assemblies

DOEpatents

Campbell, Jeremy B; Newson, Steve

2013-02-26

Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

Comparison of Distributed Acoustic Sensing (DAS) from Fiber-Optic Cable to Three Component Geophones in an Underground Mine

NASA Astrophysics Data System (ADS)

Speece, M. A.; Nesladek, N. J.; Kammerer, C.; Maclaughlin, M.; Wang, H. F.; Lord, N. E.

2017-12-01

We conducted experiments in the Underground Education Mining Center on the Montana Tech campus, Butte, Montana, to make a direct comparison between Digital Acoustic Sensing (DAS) and three-component geophones in a mining setting. The sources used for this project where a vertical sledgehammer, oriented shear sledgehammer, and blasting caps set off in both unstemmed and stemmed drillholes. Three-component Geospace 20DM geophones were compared with three different types of fiber-optic cable: (1) Brugg strain, (2) Brugg temperature, and (3) Optical Cable Corporation strain. We attached geophones to the underground mine walls and on the ground surface above the mine. We attached fiber-optic cables to the mine walls and placed fiber-optic cable in boreholes drilled through an underground pillar. In addition, we placed fiber-optic cables in a shallow trench at the surface of the mine. We converted the DAS recordings from strain rate to strain prior to comparison with the geophone data. The setup of the DAS system for this project led to a previously unknown triggering problem that compromised the early samples of the DAS traces often including the first-break times on the DAS records. Geophones clearly recorded the explosives; however, the large amount of energy and its close distance from the fiber-optic cables seemed to compromise the entire fiber loop. The underground hammer sources produced a rough match between the DAS records and the geophone records. However, the sources on the surface of the mine, specifically the sources oriented inline with the fiber-optic cables, produced a close match between the fiber-optic traces and the geophone traces. All three types of fiber-optic cable that were in the mine produced similar results, and one type did not clearly outperform the others. Instead, the coupling of the cable to rock appears to be the most important factor determining DAS data quality. Moreover, we observed the importance of coupling in the boreholes, where fiber-optic cables that were pressed against the rock face with a spacer outperformed fiber-optic cables that were fully embedded within the grout filling the inside of the borehole.

Stabilized diode seed laser for flight and space-based remote lidar sensing applications

NASA Astrophysics Data System (ADS)

McNeil, Shirley; Pandit, Pushkar; Battle, Philip; Rudd, Joe; Hovis, Floyd

2017-08-01

AdvR, through support of the NASA SBIR program, has developed fiber-based components and sub-systems that are routinely used on NASA's airborne missions, and is now developing an environmentally hardened, diode-based, locked wavelength, seed laser for future space-based high spectral resolution lidar applications. The seed laser source utilizes a fiber-coupled diode laser, a fiber-coupled, calibrated iodine reference module to provide an absolute wavelength reference, and an integrated, dual-element, nonlinear optical waveguide component for second harmonic generation, spectral formatting and wavelength locking. The diode laser operates over a range close to 1064.5 nm, provides for stabilization of the seed to the desired iodine transition and allows for a highly-efficient, fully-integrated seed source that is well-suited for use in airborne and space-based environments. A summary of component level environmental testing and spectral purity measurements with a seeded Nd:YAG laser will be presented. A direct-diode, wavelength-locked seed laser will reduce the overall size weight and power (SWaP) requirements of the laser transmitter, thus directly addressing the need for developing compact, efficient, lidar component technologies for use in airborne and space-based environments.

Ultra-wideband horn antenna with abrupt radiator

DOEpatents

McEwan, T.E.

1998-05-19

An ultra-wideband horn antenna transmits and receives impulse waveforms for short-range radars and impulse time-of flight systems. The antenna reduces or eliminates various sources of close-in radar clutter, including pulse dispersion and ringing, sidelobe clutter, and feedline coupling into the antenna. Dispersion is minimized with an abrupt launch point radiator element; sidelobe and feedline coupling are minimized by recessing the radiator into a metallic horn. Low frequency cut-off associated with a horn is extended by configuring the radiator drive impedance to approach a short circuit at low frequencies. A tapered feed plate connects at one end to a feedline, and at the other end to a launcher plate which is mounted to an inside wall of the horn. The launcher plate and feed plate join at an abrupt edge which forms the single launch point of the antenna. 8 figs.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

2013-01-22

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N; Appel, Titus James; Wrye, IV, Walter C

2014-06-24

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Validation of an analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals in soil

PubMed Central

2013-01-01

Background The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. Results The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94–106% in atomic absorption and 97–103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6–5.2% in atomic absorption, similar with that of 1.9–6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference between the two spectrometric methods for 95% confidence interval. Conclusions High-resolution continuum source flame atomic absorption spectrometry can be successfully used for the rapid, multielemental determination of hazardous/priority hazardous metals in soil with similar analytical performances to those in inductively coupled plasma optical emission spectrometry. PMID:23452327

Validation of an analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals in soil.

PubMed

Frentiu, Tiberiu; Ponta, Michaela; Hategan, Raluca

2013-03-01

The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94-106% in atomic absorption and 97-103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6-5.2% in atomic absorption, similar with that of 1.9-6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference between the two spectrometric methods for 95% confidence interval. High-resolution continuum source flame atomic absorption spectrometry can be successfully used for the rapid, multielemental determination of hazardous/priority hazardous metals in soil with similar analytical performances to those in inductively coupled plasma optical emission spectrometry.

Modeling Coupled Movement of Water, Vapor, and Energy in Soils and at the Soil-Atmosphere Interface Using HYDRUS

NASA Astrophysics Data System (ADS)

Simunek, Jiri; Brunetti, Giuseppe; Saito, Hirotaka; Bristow, Keith

2017-04-01

Mass and energy fluxes in the subsurface are closely coupled and cannot be evaluated without considering their mutual interactions. However, only a few numerical models consider coupled water, vapor and energy transport in both the subsurface and at the soil-atmosphere interface. While hydrological and thermal processes in the subsurface are commonly implemented in existing models, which often consider both isothermally and thermally induced water and vapor flow, the interactions at the soil-atmosphere interface are often simplified, and the effects of slope inclination, slope azimuth, variable surface albedo and plant shading on incoming radiation and spatially variable surface mass and energy balance, and consequently on soil moisture and temperature distributions, are rarely considered. In this presentation we discuss these missing elements and our attempts to implement them into the HYDRUS model. We demonstrate implications of some of these interactions and their impact on the spatial distributions of soil temperature and water content, and their effect on soil evaporation. Additionally, we will demonstrate the use of the HYDRUS model to simulate processes relevant to the ground source heat pump systems.

Feed network and electromagnetic radiation source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ardavan, Arzhang; Singleton, John; Linehan, Kevin E.

An antenna may include a volume polarization current radiator and a feed network. The volume polarization current radiator, includes a dielectric solid (such as a dielectric strip), and a plurality of closely-spaced excitation elements (24), each excitation element (24) being configured to induce a volume polarization current distribution in the dielectric solid proximate to the excitation element when a voltage is applied to the excitation element. The feed network is coupled to the volume polarization current radiator. The feed network also includes a plurality of passive power divider elements (32) and a plurality of passive delay elements (d1-d6) coupling themore » first port (30) and the plurality of second ports (108, 109, 164), the plurality of power divider elements (32) and the plurality of phase delay elements (d1-d6) being configured such that a radio-frequency signal that is applied to the first port (30) experiences a progressive change of phase as it is coupled to the plurality of second ports (108, 109, 164) so as to cause the volume polarization current distribution to propagate along the dielectric solid.« less

Dry coupling for whole-body small-animal photoacoustic computed tomography

NASA Astrophysics Data System (ADS)

Yeh, Chenghung; Li, Lei; Zhu, Liren; Xia, Jun; Li, Chiye; Chen, Wanyi; Garcia-Uribe, Alejandro; Maslov, Konstantin I.; Wang, Lihong V.

2017-04-01

We have enhanced photoacoustic computed tomography with dry acoustic coupling that eliminates water immersion anxiety and wrinkling of the animal and facilitates incorporating complementary modalities and procedures. The dry acoustic coupler is made of a tubular elastic membrane enclosed by a closed transparent water tank. The tubular membrane ensures water-free contact with the animal, and the closed water tank allows pressurization for animal stabilization. The dry coupler was tested using a whole-body small-animal ring-shaped photoacoustic computed tomography system. Dry coupling was found to provide image quality comparable to that of conventional water coupling.

Aerodynamic excitation and sound production of blown-closed free reeds without acoustic coupling: the example of the accordion reed.

PubMed

Ricot, Denis; Caussé, René; Misdariis, Nicolas

2005-04-01

The accordion reed is an example of a blown-closed free reed. Unlike most oscillating valves in wind musical instruments, self-sustained oscillations occur without acoustic coupling. Flow visualizations and measurements in water show that the flow can be supposed incompressible and potential. A model is developed and the solution is calculated in the time domain. The excitation force is found to be associated with the inertial load of the unsteady flow through the reed gaps. Inertial effect leads to velocity fluctuations in the reed opening and then to an unsteady Bernoulli force. A pressure component generated by the local reciprocal air movement around the reed is added to the modeled aerodynamic excitation pressure. Since the model is two-dimensional, only qualitative comparisons with air flow measurements are possible. The agreement between the simulated pressure waveforms and measured pressure in the very near-field of the reed is reasonable. In addition, an aeroacoustic model using the permeable Ffowcs Williams-Hawkings integral method is presented. The integral expressions of the far-field acoustic pressure are also computed in the time domain. In agreement with experimental data, the sound is found to be dominated by the dipolar source associated by the strong momentum fluctuations of the flow through the reed gaps.

Aerodynamic excitation and sound production of blown-closed free reeds without acoustic coupling: The example of the accordion reed

NASA Astrophysics Data System (ADS)

Ricot, Denis; Caussé, René; Misdariis, Nicolas

2005-04-01

The accordion reed is an example of a blown-closed free reed. Unlike most oscillating valves in wind musical instruments, self-sustained oscillations occur without acoustic coupling. Flow visualizations and measurements in water show that the flow can be supposed incompressible and potential. A model is developed and the solution is calculated in the time domain. The excitation force is found to be associated with the inertial load of the unsteady flow through the reed gaps. Inertial effect leads to velocity fluctuations in the reed opening and then to an unsteady Bernoulli force. A pressure component generated by the local reciprocal air movement around the reed is added to the modeled aerodynamic excitation pressure. Since the model is two-dimensional, only qualitative comparisons with air flow measurements are possible. The agreement between the simulated pressure waveforms and measured pressure in the very near-field of the reed is reasonable. In addition, an aeroacoustic model using the permeable Ffowcs Williams-Hawkings integral method is presented. The integral expressions of the far-field acoustic pressure are also computed in the time domain. In agreement with experimental data, the sound is found to be dominated by the dipolar source associated by the strong momentum fluctuations of the flow through the reed gaps. .

Quantum close coupling calculation of transport and relaxation properties for Hg-H2 system

NASA Astrophysics Data System (ADS)

Nemati-Kande, Ebrahim; Maghari, Ali

2016-11-01

Quantum mechanical close coupling calculation of the state-to-state transport and relaxation cross sections have been done for Hg-H2 molecular system using a high-level ab initio potential energy surface. Rotationally averaged cross sections were also calculated to obtain the energy dependent Senftleben-Beenakker cross sections at the energy range of 0.005-25,000 cm-1. Boltzmann averaging of the energy dependent Senftleben-Beenakker cross sections showed the temperature dependency over a wide temperature range of 50-2500 K. Interaction viscosity and diffusion coefficients were also calculated using close coupling cross sections and full classical Mason-Monchick approximation. The results were compared with each other and with the available experimental data. It was found that Mason-Monchick approximation for viscosity is more reliable than diffusion coefficient. Furthermore, from the comparison of the experimental diffusion coefficients with the result of the close coupling and Mason-Monchick approximation, it was found that the Hg-H2 potential energy surface used in this work can reliably predict diffusion coefficient data.

An Anatomy of a Seismic Sequence in a Deep Gold Mine

NASA Astrophysics Data System (ADS)

Gibowicz, S. J.

1997-12-01

An unusual swarm-like seismic sequence occurred in April 1993 at the Western Deep Levels gold mine, South Africa. Altogether 199 events with moment magnitude from -0.5 to 3.1 were recorded and located by the mine seismic network. The sequence lasted 12 days and was composed in fact of four main shock-aftershocks sequences, closely following each other in space and time. The events were confined to a volume of rock extending to 670 m in the N-S, 630 m in the E-W, and 390 m in the vertical directions. The first sequence lasted 179 hours and the second only 13 hours, being interrupted by the third sequence which lasted 31 hours, being in turn interrupted by the fourth sequence. The parameter p, describing the rate of occurrence of aftershocks, ranged from 0.7 to 1. The first sequence is characterized by the lowest value of the fractal correlation dimension D = 1.75 and the second by the highest value of D = 2.4, whereas the third and fourth sequences are characterized by the middle value of D = 1.9.¶The corner frequencies of P and S waves are in close proximity and range from 14 to 220 Hz. A display of source parameters as a function of time shows that the four main shocks are most distinctly marked by their source radius. For 46 events a moment tensor inversion was performed. In most cases the double-couple component is dominant, ranging from 60 to 90 percent of the solution. The double-couple solutions correspond to the same number of normal and reverse faults and oblique-slip focal mechanisms. An analysis of space distribution of P, T and B axes reveals that the distribution of B axes is the most regular.

Efficiency of a closed-coupled solar pasteurization system in treating roof harvested rainwater.

PubMed

Dobrowsky, P H; Carstens, M; De Villiers, J; Cloete, T E; Khan, W

2015-12-01

Many studies have concluded that roof harvested rainwater is susceptible to chemical and microbial contamination. The aim of the study was thus to conduct a preliminary investigation into the efficiency of a closed-coupled solar pasteurization system in reducing the microbiological load in harvested rainwater and to determine the change in chemical components after pasteurization. The temperature of the pasteurized tank water samples collected ranged from 55 to 57°C, 64 to 66°C, 72 to 74°C, 78 to 81°C and 90 to 91°C. Cations analyzed were within drinking water guidelines, with the exception of iron [195.59 μg/L (55°C)-170.1 μg/L (91°C)], aluminum [130.98 μg/L (78°C)], lead [12.81 μg/L (55°C)-13.2 μg/L (91°C)] and nickel [46.43 μg/L (55°C)-32.82 μg/L (78°C)], which were detected at levels above the respective guidelines in the pasteurized tank water samples. Indicator bacteria including, heterotrophic bacteria, Escherichia coli and total coliforms were reduced to below the detection limit at pasteurization temperatures of 72°C and above. However, with the use of molecular techniques Yersinia spp., Legionella spp. and Pseudomonas spp. were detected in tank water samples pasteurized at temperatures greater than 72°C. The viability of the bacteria detected in this study at the higher temperature ranges should thus be assessed before pasteurized harvested rainwater is used as a potable water source. In addition, it is recommended that the storage tank of the pasteurization system be constructed from an alternative material, other than stainless steel, in order for a closed-coupled pasteurization system to be implemented and produce large quantities of potable water from roof harvested rainwater. Copyright © 2015 Elsevier B.V. All rights reserved.

Improvements in closeness, communication, and psychological distress mediate effects of couple therapy for veterans.

PubMed

Doss, Brian D; Mitchell, Alexandra; Georgia, Emily J; Biesen, Judith N; Rowe, Lorelei Simpson

2015-04-01

Empirically based couple therapy results in significant improvements in relationship satisfaction for the average couple; however, further research is needed to identify mediators that lead to change and to ensure that improvements in mediators predict subsequent-not just concurrent-relationship satisfaction. In addition, given that much of the current literature on couple therapy examines outcomes in a research environment, it is important to examine mediators in a treatment-as-usual setting. To address these questions, 161 heterosexual couples (322 individuals) received treatment-as-usual couple therapy at one of two Veteran Administration Medical Centers (M = 5.0 and 13.0 sessions at the two sites) and were assessed before every session. The majority of couples were married (85%) and had been together for a median of 7.8 years (SD = 13). Participants were primarily White, non-Hispanic (69%), African American (21%), and White, Hispanic/Latino (8%). Individuals' own self-reported improvements in communication, emotional closeness, and psychological distress (but not frequency of behaviors targeted in treatment) mediated the effect of treatment on their subsequent relationship satisfaction. When all significant mediators were examined simultaneously, improvements in men's and women's emotional closeness and men's psychological distress independently mediated subsequent relationship satisfaction. In contrast, improvements in earlier relationship satisfaction mediated the effect of treatment only on subsequent psychological distress. This study identifies unique mediators of treatment effects and shows that gains in mechanisms predict subsequent relationship satisfaction. Future investigations should focus on the role of emotional closeness and psychological distress-constructs that have often been neglected-in couple therapy. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Electron- and positron-molecule scattering: development of the molecular convergent close-coupling method

NASA Astrophysics Data System (ADS)

Zammit, Mark C.; Fursa, Dmitry V.; Savage, Jeremy S.; Bray, Igor

2017-06-01

Starting from first principles, this tutorial describes the development of the adiabatic-nuclei convergent close-coupling (CCC) method and its application to electron and (single-centre) positron scattering from diatomic molecules. We give full details of the single-centre expansion CCC method, namely the formulation of the molecular target structure; solving the momentum-space coupled-channel Lippmann-Schwinger equation; deriving adiabatic-nuclei cross sections and calculating V-matrix elements. Selected results are presented for electron and positron scattering from molecular hydrogen H2 and electron scattering from the vibrationally excited molecular hydrogen ion {{{H}}}2+ and its isotopologues (D2 +, {{{T}}}2+, HD+, HT+ and TD+). Convergence in both the close-coupling (target state) and projectile partial-wave expansions of fixed-nuclei electron- and positron-molecule scattering calculations is demonstrated over a broad energy-range and discussed in detail. In general, the CCC results are in good agreement with experiments.

Impact of Scale-Dependent Coupled Processes on Solute Fate and Transport in the Critical Zone: Case Studies Involving Inorganic and Radioactive Contaminants

NASA Astrophysics Data System (ADS)

Jardine, P. M.; Gentry, R. W.

2011-12-01

Soil, the thin veneer of matter covering the Earths surface that supports a web of living diversity, is often abused through anthropogenic inputs of toxic waste. This subsurface regime, coupled with life sustaining surface water and groundwater is known as the "Critical Zone". The disposal of radioactive and toxic organic and inorganic waste generated by industry and various government agencies has historically involved shallow land burial or the use of surface impoundments in unsaturated soils and sediments. Presently, contaminated sites have been closing rapidly and many remediation strategies have chosen to leave contaminants in-place. As such, contaminants will continue to interact with the geosphere and investigations on long term changes and interactive processes is imperative to verify risks. In this presentation we provide a snap-shot of subsurface science research from the past 25 y that seeks to provide an improved understanding and predictive capability of multi-scale contaminant fate and transport processes in heterogeneous unsaturated and saturated environments. Investigations focus on coupled hydrological, geochemical, and microbial processes that control reactive contaminant transport and that involve multi-scale fundamental research ranging from the molecular scale (e.g. synchrotrons, electron sources, arrays) to in situ plume interrogation strategies at the macroscopic scale (e.g. geophysics, field biostimulation, coupled processes monitoring). We show how this fundamental research is used to provide multi-process, multi-scale predictive monitoring and modeling tools that can be used at contaminated sites to (1) inform and improve the technical basis for decision making, and (2) assess which sites are amenable to natural attenuation and which would benefit from source zone remedial intervention.

Combining Charge Couple Devices and Rate Sensors for the Feedforward Control System of a Charge Coupled Device Tracking Loop.

PubMed

Tang, Tao; Tian, Jing; Zhong, Daijun; Fu, Chengyu

2016-06-25

A rate feed forward control-based sensor fusion is proposed to improve the closed-loop performance for a charge couple device (CCD) tracking loop. The target trajectory is recovered by combining line of sight (LOS) errors from the CCD and the angular rate from a fiber-optic gyroscope (FOG). A Kalman filter based on the Singer acceleration model utilizes the reconstructive target trajectory to estimate the target velocity. Different from classical feed forward control, additive feedback loops are inevitably added to the original control loops due to the fact some closed-loop information is used. The transfer function of the Kalman filter in the frequency domain is built for analyzing the closed loop stability. The bandwidth of the Kalman filter is the major factor affecting the control stability and close-loop performance. Both simulations and experiments are provided to demonstrate the benefits of the proposed algorithm.

BioXTAS RAW: improvements to a free open-source program for small-angle X-ray scattering data reduction and analysis.

PubMed

Hopkins, Jesse Bennett; Gillilan, Richard E; Skou, Soren

2017-10-01

BioXTAS RAW is a graphical-user-interface-based free open-source Python program for reduction and analysis of small-angle X-ray solution scattering (SAXS) data. The software is designed for biological SAXS data and enables creation and plotting of one-dimensional scattering profiles from two-dimensional detector images, standard data operations such as averaging and subtraction and analysis of radius of gyration and molecular weight, and advanced analysis such as calculation of inverse Fourier transforms and envelopes. It also allows easy processing of inline size-exclusion chromatography coupled SAXS data and data deconvolution using the evolving factor analysis method. It provides an alternative to closed-source programs such as Primus and ScÅtter for primary data analysis. Because it can calibrate, mask and integrate images it also provides an alternative to synchrotron beamline pipelines that scientists can install on their own computers and use both at home and at the beamline.

Co-Authorship and Bibliographic Coupling Network Effects on Citations

PubMed Central

Biscaro, Claudio; Giupponi, Carlo

2014-01-01

This paper analyzes the effects of the co-authorship and bibliographic coupling networks on the citations received by scientific articles. It expands prior research that limited its focus on the position of co-authors and incorporates the effects of the use of knowledge sources within articles: references. By creating a network on the basis of shared references, we propose a way to understand whether an article bridges among extant strands of literature and infer the size of its research community and its embeddedness. Thus, we map onto the article – our unit of analysis – the metrics of authors' position in the co-authorship network and of the use of knowledge on which the scientific article is grounded. Specifically, we adopt centrality measures – degree, betweenneess, and closeness centrality – in the co-authorship network and degree, betweenness centrality and clustering coefficient in the bibliographic coupling and show their influence on the citations received in first two years after the year of publication. Findings show that authors' degree positively impacts citations. Also closeness centrality has a positive effect manifested only when the giant component is relevant. Author's betweenness centrality has instead a negative effect that persists until the giant component - largest component of the network in which all nodes can be linked by a path - is relevant. Moreover, articles that draw on fragmented strands of literature tend to be cited more, whereas the size of the scientific research community and the embeddedness of the article in a cohesive cluster of literature have no effect. PMID:24911416

Addition and Removal Energies via the In-Medium Similarity Renormalization Group Method

NASA Astrophysics Data System (ADS)

Yuan, Fei

The in-medium similarity renormalization group (IM-SRG) is an ab initio many-body method suitable for systems with moderate numbers of particles due to its polynomial scaling in computational cost. The formalism is highly flexible and admits a variety of modifications that extend its utility beyond the original goal of computing ground state energies of closed-shell systems. In this work, we present an extension of IM-SRG through quasidegenerate perturbation theory (QDPT) to compute addition and removal energies (single particle energies) near the Fermi level at low computational cost. This expands the range of systems that can be studied from closed-shell ones to nearby systems that differ by one particle. The method is applied to circular quantum dot systems and nuclei, and compared against other methods including equations-of-motion (EOM) IM-SRG and EOM coupled-cluster (CC) theory. The results are in good agreement for most cases. As part of this work, we present an open-source implementation of our flexible and easy-to-use J-scheme framework as well as the HF, IM-SRG, and QDPT codes built upon this framework. We include an overview of the overall structure, the implementation details, and strategies for maintaining high code quality and efficiency. Lastly, we also present a graphical application for manipulation of angular momentum coupling coefficients through a diagrammatic notation for angular momenta (Jucys diagrams). The tool enables rapid derivations of equations involving angular momentum coupling--such as in J-scheme--and significantly reduces the risk of human errors.

Positive isolation disconnect

NASA Technical Reports Server (NTRS)

Friedell, M. V. (Inventor)

1978-01-01

A disconnect composed basically of two halves each consisting of a poppet valve operable to isolate fluid with essentially zero fluid loss is presented. The two halves are coupled together by a quickly releasable coupling which may be either a coupling ring tightened or loosened by a twisting motion, or a clamp operated by a pivoted to prevent disconnecting the two halves until both valves are in closed condition. The positive feature of the device is one requiring a valve closing step before a disconnect step, and takes structural form in an accentric lobe mounted on the valve operating stem. If some obstruction prevents the poppet from moving to its seat, the eccentric lobe cannot be rotated to the closed position, and the interlock prevents a disconnect.

Partial synchronization of relaxation oscillators with repulsive coupling in autocatalytic integrate-and-fire model and electrochemical experiments

NASA Astrophysics Data System (ADS)

Kori, Hiroshi; Kiss, István Z.; Jain, Swati; Hudson, John L.

2018-04-01

Experiments and supporting theoretical analysis are presented to describe the synchronization patterns that can be observed with a population of globally coupled electrochemical oscillators close to a homoclinic, saddle-loop bifurcation, where the coupling is repulsive in the electrode potential. While attractive coupling generates phase clusters and desynchronized states, repulsive coupling results in synchronized oscillations. The experiments are interpreted with a phenomenological model that captures the waveform of the oscillations (exponential increase) followed by a refractory period. The globally coupled autocatalytic integrate-and-fire model predicts the development of partially synchronized states that occur through attracting heteroclinic cycles between out-of-phase two-cluster states. Similar behavior can be expected in many other systems where the oscillations occur close to a saddle-loop bifurcation, e.g., with Morris-Lecar neurons.

Present status of numerical modeling of hydrogen negative ion source plasmas and its comparison with experiments: Japanese activities and their collaboration with experimental groups

NASA Astrophysics Data System (ADS)

Hatayama, A.; Nishioka, S.; Nishida, K.; Mattei, S.; Lettry, J.; Miyamoto, K.; Shibata, T.; Onai, M.; Abe, S.; Fujita, S.; Yamada, S.; Fukano, A.

2018-06-01

The present status of kinetic modeling of particle dynamics in hydrogen negative ion (H‑) source plasmas and their comparisons with experiments are reviewed and discussed with some new results. The main focus is placed on the following topics, which are important for the research and development of H‑ sources for intense and high-quality H‑ ion beams: (i) effects of non-equilibrium features of electron energy distribution function on volume and surface H‑ production, (ii) the origin of the spatial non-uniformity in giant multi-cusp arc-discharge H‑ sources, (iii) capacitive to inductive (E to H) mode transition in radio frequency-inductively coupled plasma H‑ sources and (iv) extraction physics of H‑ ions and beam optics, especially the present understanding of the meniscus formation in strongly electronegative plasmas (so-called ion–ion plasmas) and its effect on beam optics. For these topics, mainly Japanese modeling activities, and their domestic and international collaborations with experimental studies, are introduced with some examples showing how models have been improved and to what extent the modeling studies can presently contribute to improving the source performance. Close collaboration between experimental and modeling activities is indispensable for the validation/improvement of the modeling and its contribution to the source design/development.

Superconducting coil system and methods of assembling the same

DOEpatents

Rajput-Ghoshal, Renuka; Rochford, James H.; Ghoshal, Probir K.

2016-01-19

A superconducting magnet apparatus is provided. The superconducting magnet apparatus includes a power source configured to generate a current; a first switch coupled in parallel to the power source; a second switch coupled in series to the power source; a coil coupled in parallel to the first switch and the second switch; and a passive quench protection device coupled to the coil and configured to by-pass the current around the coil and to decouple the coil from the power source when the coil experiences a quench.

Ground Source Geothermal District Heating and Cooling System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowe, James William

2016-10-21

Ball State University converted its campus from a coal-fired steam boiler district heating system to a ground source heat pump geothermal district system that produces simultaneously hot water for heating and chilled water for cooling. This system will include the installation of 3,600 four hundred feet deep vertical closed loop boreholes making it the largest ground source geothermal district system in the country. The boreholes will act as heat exchangers and transfer heat by virtue of the earth’s ability to maintain an average temperature of 55 degree Fahrenheit. With growing international concern for global warming and the need to reducemore » worldwide carbon dioxide loading of the atmosphere geothermal is poised to provide the means to help reduce carbon dioxide emissions. The shift from burning coal to utilizing ground source geothermal will increase electrical consumption but an overall decrease in energy use and reduction in carbon dioxide output will be achieved. This achievement is a result of coupling the ground source geothermal boreholes with large heat pump chiller technology. The system provides the thermodynamic means to move large amounts of energy with limited energy input. Ball State University: http://cms.bsu.edu/About/Geothermal.aspx« less

Kilowatt Reactor Using Stirling TechnologY (KRUSTY) Demonstration. CEDT Phase 1 Preliminary Design Documentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchez, Rene Gerardo; Hutchinson, Jesson D.; Mcclure, Patrick Ray

2015-08-20

The intent of the integral experiment request IER 299 (called KiloPower by NASA) is to assemble and evaluate the operational performance of a compact reactor configuration that closely resembles the flight unit to be used by NASA to execute a deep space exploration mission. The reactor design will include heat pipes coupled to Stirling engines to demonstrate how one can generate electricity when extracting energy from a “nuclear generated” heat source. This series of experiments is a larger scale follow up to the DUFF series of experiments1,2 that were performed using the Flat-Top assembly.

Simulation of cortico-basal ganglia oscillations and their suppression by closed loop deep brain stimulation.

PubMed

Grant, Peadar F; Lowery, Madeleine M

2013-07-01

A new model of deep brain stimulation (DBS) is presented that integrates volume conduction effects with a neural model of pathological beta-band oscillations in the cortico-basal ganglia network. The model is used to test the clinical hypothesis that closed-loop control of the amplitude of DBS may be possible, based on the average rectified value of beta-band oscillations in the local field potential. Simulation of closed-loop high-frequency DBS was shown to yield energy savings, with the magnitude of the energy saved dependent on the strength of coupling between the subthalamic nucleus and the remainder of the cortico-basal ganglia network. When closed-loop DBS was applied to a strongly coupled cortico-basal ganglia network, the stimulation energy delivered over a 480 s period was reduced by up to 42%. Greater energy reductions were observed for weakly coupled networks, as the stimulation amplitude reduced to zero once the initial desynchronization had occurred. The results provide support for the application of closed-loop high-frequency DBS based on electrophysiological biomarkers.

Efficient fiber-coupled single-photon source based on quantum dots in a photonic-crystal waveguide

PubMed Central

DAVEAU, RAPHAËL S.; BALRAM, KRISHNA C.; PREGNOLATO, TOMMASO; LIU, JIN; LEE, EUN H.; SONG, JIN D.; VERMA, VARUN; MIRIN, RICHARD; NAM, SAE WOO; MIDOLO, LEONARDO; STOBBE, SØREN; SRINIVASAN, KARTIK; LODAHL, PETER

2017-01-01

Many photonic quantum information processing applications would benefit from a high brightness, fiber-coupled source of triggered single photons. Here, we present a fiber-coupled photonic-crystal waveguide single-photon source relying on evanescent coupling of the light field from a tapered out-coupler to an optical fiber. A two-step approach is taken where the performance of the tapered out-coupler is recorded first on an independent device containing an on-chip reflector. Reflection measurements establish that the chip-to-fiber coupling efficiency exceeds 80 %. The detailed characterization of a high-efficiency photonic-crystal waveguide extended with a tapered out-coupling section is then performed. The corresponding overall single-photon source efficiency is 10.9 % ± 2.3 %, which quantifies the success probability to prepare an exciton in the quantum dot, couple it out as a photon in the waveguide, and subsequently transfer it to the fiber. The applied out-coupling method is robust, stable over time, and broadband over several tens of nanometers, which makes it a highly promising pathway to increase the efficiency and reliability of planar chip-based single-photon sources. PMID:28584859

Flow visualization study of close-coupled canard wing and strake wing configuration

NASA Technical Reports Server (NTRS)

Miner, D. D.; Gloss, B. B.

1975-01-01

The Langley 1/8-scale V/STOL model tunnel was used to qualitatively determine the flow fields associated with semi-span close coupled canard wing and strake wing models. Small helium filled bubbles were injected upstream of the models to make the flow visible. Photographs were taken over the angle-of-attack ranges of -10 deg to 40 deg.

Positron-rubidium scattering

NASA Technical Reports Server (NTRS)

Mceachran, R. P.; Horbatsch, M.; Stauffer, A. D.

1990-01-01

A 5-state close-coupling calculation (5s-5p-4d-6s-6p) was carried out for positron-Rb scattering in the energy range 3.7 to 28.0 eV. In contrast to the results of similar close-coupling calculations for positron-Na and positron-K scattering the (effective) total integrated cross section has an energy dependence which is contrary to recent experimental measurements.

How coupling affects closely packed rectenna arrays used for wireless power transmission

NASA Astrophysics Data System (ADS)

Walls, Deidra; Choi, Sang H.; Yoon, Hargsoon; Geddis, Demetris; Song, Kyo D.

2017-04-01

The development of power transmission by microwave beam power harvesting attracts manufactures for use of wireless power transmission. Optimizing maximum conversion efficiency is affected by many design parameters, and has been mainly focused previously. Combining several rectennas in one array potentially aides in the amount of microwave energy that can be harvested for energy conversion. Closely packed rectenna arrays is the result of the demand to minimize size and weight for flexibility. This paper specifically focuses on the coupling effects on power; mutual coupling, comparing sparameters and gain total while varying effective parameters. This paper investigates how coupling between each dipole positively and negatively affects the microwave energy, harvesting, and the design limitations.

Single and Double Photoionization of Mg

NASA Astrophysics Data System (ADS)

Abdel-Naby, Shahin; Pindzola, M. S.; Colgan, J.

2014-05-01

Single and double photoionization cross sections for Mg are calculated using a time-dependent close-coupling method. The correlation between the two 3 s subshell electrons of Mg is obtained by relaxation of the close-coupled equations in imaginary time. An implicit method is used to propagate the close-coupled equations in real time to obtain single and double ionization cross sections for Mg. Energy and angle triple differential cross sections for double photoionization at equal energy sharing of E1 =E2 = 16 . 4 eV are compared with Elettra experiments and previous theoretical calculations. This work was supported in part by grants from NSF and US DoE. Computational work was carried out at NERSC in Oakland, California, NICS in Knoxville, Tennessee, and OLCF in Oak Ridge, Tennessee.

Photoionization of Ne8+

NASA Astrophysics Data System (ADS)

Pindzola, M. S.; Abdel-Naby, Sh. A.; Robicheaux, F.; Colgan, J.

2014-05-01

Single and double photoionization cross sections for Ne8+ are calculated using a non-perturbative fully relativistic time-dependent close-coupling method. A Bessel function expansion is used to include both dipole and quadrupole effects in the radiation field interaction and the repulsive interaction between electrons includes both the Coulomb and Gaunt interactions. The fully correlated ground state of Ne8+ is obtained by solving a time-independent inhomogeneous set of close-coupled equations. Propagation of the time-dependent close-coupled equations yields single and double photoionization cross sections for Ne8+ at energies easily accessible at advanced free electron laser facilities. This work was supported in part by grants from NSF and US DoE. Computational work was carried out at NERSC in Oakland, California, NICS in Knoxville, Tennessee, and OLCF in Oak Ridge, Tennessee.

Neutron-Impact Ionization of H and He

NASA Astrophysics Data System (ADS)

Lee, T.-G.; Ciappina, M. F.; Robicheaux, F.; Pindzola, M. S.

2014-05-01

Perturbative distorted-wave and non-perturbative close-coupling methods are used to study neutron-impact ionization of H and He. For single ionization of H, we find excellent agreement between the distorted-wave and close-coupling results at all incident energies. For double ionization of He, we find poor agreement between the distorted-wave and close-coupling results, except at the highest incident energies. We present the ratio of double to single ionization for He as a guide to experimental checks of theory at low energies and experimental confirmation of the rapid rise of the ratio at high energies. This work was supported in part by grants from NSF and US DoE. Computational work was carried out at NERSC in Oakland, California, NICS in Knoxville, Tennessee, and OLCF in Oak Ridge, Tennessee.

Vortex circulation and polarity patterns in closely packed cap arrays

DOE PAGES

Streubel, Robert; Kronast, Florian; Reiche, Christopher F.; ...

2016-01-25

For this work, we studied curvature-driven modifications to the magnetostatic coupling of vortex circulation and polarity in soft-magnetic closely packed cap arrays. A phase diagram for the magnetic remanent/transition states at room temperature as a function of diameter and thickness was assembled. For specimens with vortex remanent state (40 nm-thick Permalloy on 330 nm spherical nanoparticles), both vortex circulation and polarity were visualized. Intercap coupling upon vortex nucleation leads to the formation of vortex circulation patterns in closely packed arrays. The remanent circulation pattern can be tailored choosing the direction of the applied magnetic field with respect to the symmetrymore » axis of the hexagonal array. An even and random distribution of vortex polarity indicates the absence of any circulation-polarity coupling.« less

Optical Design And Performance Of A Dual-Grating, Direct-Reading Spectrograph For Spectrochemical Analyses

NASA Astrophysics Data System (ADS)

Steinhaus, David W.; Kline, John V.; Bieniewski, Thomas M.; Dow, Grove S.; Apel, Charles T.

1980-11-01

An all-mirror optical system is used to direct the light from a variety of spectroscopic sources to two 2-m spectrographs that are placed on either side of a sturdy vertical mounting plate. The gratings were chosen so that the first spectrograph covers the ultraviolet spectral region, and the second spectrograph covers the ultraviolet, visible, and near-infrared regions. With the over 2.5 m of focal curves, each ultraviolet line is available at more than one place. Thus, problems with close lines can be overcome. The signals from a possible maximum of 256 photoelectric detectors go to a small computer for reading and calculation of the element abundances. To our knowledge, no other direct-reading spectrograph has more than about 100 fixed detectors. With an inductively-coupled-plasma source, our calibration curves, and detection limits, are similar to those of other workers using a direct-reading spectrograph.

Ultralow-threshold cascaded Brillouin microlaser for tunable microwave generation.

PubMed

Guo, Changlei; Che, Kaijun; Cai, Zhiping; Liu, Shuai; Gu, Guoqiang; Chu, Chengxu; Zhang, Pan; Fu, Hongyan; Luo, Zhengqian; Xu, Huiying

2015-11-01

We experimentally demonstrate an ultralow-threshold cascaded Brillouin microlaser for tunable microwave generation in a high-Q silica microsphere resonator. The threshold of the Brillouin microlaser is as low as 8 μW, which is close to the theoretical prediction. Moreover, the fifth-order Stokes line with a frequency shift up to 55 GHz is achieved with a coupled pump power of less than 0.6 mW. Benefiting from resonant wavelength shifts driven by thermal dynamics in the microsphere, we further realized tunable microwave signals with tuning ranges of 40 MHz at an 11 GHz band and 20 MHz at a 22 GHz band. To the best of our knowledge, it was the first attempt for tunable microwave source based on the whispering-gallery-mode Brillouin microlaser. Such a tunable microwave source from a cascaded Brillouin microlaser could find significant applications in aerospace, communication engineering, and metrology.

Detection and modeling of the acoustic perturbation produced by the launch of the Space Shuttle using the Global Positioning System

NASA Astrophysics Data System (ADS)

Bowling, T. J.; Calais, E.; Dautermann, T.

2010-12-01

Rocket launches are known to produce infrasonic pressure waves that propagate into the ionosphere where coupling between electrons and neutral particles induces fluctuations in ionospheric electron density observable in GPS measurements. We have detected ionospheric perturbations following the launch of space shuttle Atlantis on 11 May 2009 using an array of continually operating GPS stations across the Southeastern coast of the United States and in the Caribbean. Detections are prominent to the south of the westward shuttle trajectory in the area of maximum coupling between the acoustic wave and Earth’s magnetic field, move at speeds consistent with the speed of sound, and show coherency between stations covering a large geographic range. We model the perturbation as an explosive source located at the point of closest approach between the shuttle path and each sub-ionospheric point. The neutral pressure wave is propagated using ray tracing, resultant changes in electron density are calculated at points of intersection between rays and satellite-to-reciever line-of-sight, and synthetic integrated electron content values are derived. Arrival times of the observed and synthesized waveforms match closely, with discrepancies related to errors in the apriori sound speed model used for ray tracing. Current work includes the estimation of source location and energy.

Spinning particles, axion radiation, and the classical double copy

NASA Astrophysics Data System (ADS)

Goldberger, Walter D.; Li, Jingping; Prabhu, Siddharth G.

2018-05-01

We extend the perturbative double copy between radiating classical sources in gauge theory and gravity to the case of spinning particles. We construct, to linear order in spins, perturbative radiating solutions to the classical Yang-Mills equations sourced by a set of interacting color charges with chromomagnetic dipole spin couplings. Using a color-to-kinematics replacement rule proposed earlier by one of the authors, these solutions map onto radiation in a theory of interacting particles coupled to massless fields that include the graviton, a scalar (dilaton) ϕ and the Kalb-Ramond axion field Bμ ν. Consistency of the double copy imposes constraints on the parameters of the theory on both the gauge and gravity sides of the correspondence. In particular, the color charges carry a chromomagnetic interaction which, in d =4 , corresponds to a gyromagnetic ratio equal to Dirac's value g =2 . The color-to-kinematics map implies that on the gravity side, the bulk theory of the fields (ϕ ,gμ ν,Bμ ν) has interactions which match those of d -dimensional "string gravity," as is the case both in the BCJ double copy of pure gauge theory scattering amplitudes and the KLT relations between the tree-level S -matrix elements of open and closed string theory.

Voltage control in pulsed system by predict-ahead control

DOEpatents

Payne, Anthony N.; Watson, James A.; Sampayan, Stephen E.

1994-01-01

A method and apparatus for predict-ahead pulse-to-pulse voltage control in a pulsed power supply system is disclosed. A DC power supply network is coupled to a resonant charging network via a first switch. The resonant charging network is coupled at a node to a storage capacitor. An output load is coupled to the storage capacitor via a second switch. A de-Q-ing network is coupled to the resonant charging network via a third switch. The trigger for the third switch is a derived function of the initial voltage of the power supply network, the initial voltage of the storage capacitor, and the present voltage of the storage capacitor. A first trigger closes the first switch and charges the capacitor. The third trigger is asserted according to the derived function to close the third switch. When the third switch is closed, the first switch opens and voltage on the node is regulated. The second trigger may be thereafter asserted to discharge the capacitor into the output load.

Voltage control in pulsed system by predict-ahead control

DOEpatents

Payne, A.N.; Watson, J.A.; Sampayan, S.E.

1994-09-13

A method and apparatus for predict-ahead pulse-to-pulse voltage control in a pulsed power supply system is disclosed. A DC power supply network is coupled to a resonant charging network via a first switch. The resonant charging network is coupled at a node to a storage capacitor. An output load is coupled to the storage capacitor via a second switch. A de-Q-ing network is coupled to the resonant charging network via a third switch. The trigger for the third switch is a derived function of the initial voltage of the power supply network, the initial voltage of the storage capacitor, and the present voltage of the storage capacitor. A first trigger closes the first switch and charges the capacitor. The third trigger is asserted according to the derived function to close the third switch. When the third switch is closed, the first switch opens and voltage on the node is regulated. The second trigger may be thereafter asserted to discharge the capacitor into the output load. 4 figs.

Electron– and positron–molecule scattering: development of the molecular convergent close-coupling method

DOE PAGES

Zammit, Mark C.; Fursa, Dmitry V.; Savage, Jeremy S.; ...

2017-05-22

Starting from first principles, this tutorial describes the development of the adiabatic-nuclei convergent close-coupling (CCC) method and its application to electron and (single-centre) positron scattering from diatomic molecules. In this paper, we give full details of the single-centre expansion CCC method, namely the formulation of the molecular target structure; solving the momentum-space coupled-channel Lippmann-Schwinger equation; deriving adiabatic-nuclei cross sections and calculatingmore » $V$-matrix elements. Selected results are presented for electron and positron scattering from molecular hydrogen H$$_2$$ and electron scattering from the vibrationally excited molecular hydrogen ion H$$_2^+$$ and its isotopologues (D$$_2^+$$, T$$_2^+$$, HD$^+$, HT$^+$ and TD$^+$). Finally, convergence in both the close-coupling (target state) and projectile partial-wave expansions of fixed-nuclei electron- and positron-molecule scattering calculations is demonstrated over a broad energy-range and discussed in detail. In general the CCC results are in good agreement with experiments.« less

Perturbation solutions of combustion instability problems

NASA Technical Reports Server (NTRS)

Googerdy, A.; Peddieson, J., Jr.; Ventrice, M.

1979-01-01

A method involving approximate modal analysis using the Galerkin method followed by an approximate solution of the resulting modal-amplitude equations by the two-variable perturbation method (method of multiple scales) is applied to two problems of pressure-sensitive nonlinear combustion instability in liquid-fuel rocket motors. One problem exhibits self-coupled instability while the other exhibits mode-coupled instability. In both cases it is possible to carry out the entire linear stability analysis and significant portions of the nonlinear stability analysis in closed form. In the problem of self-coupled instability the nonlinear stability boundary and approximate forms of the limit-cycle amplitudes and growth and decay rates are determined in closed form while the exact limit-cycle amplitudes and growth and decay rates are found numerically. In the problem of mode-coupled instability the limit-cycle amplitudes are found in closed form while the growth and decay rates are found numerically. The behavior of the solutions found by the perturbation method are in agreement with solutions obtained using complex numerical methods.

The source-filter theory of whistle-like calls in marmosets: Acoustic analysis and simulation of helium-modulated voices.

PubMed

Koda, Hiroki; Tokuda, Isao T; Wakita, Masumi; Ito, Tsuyoshi; Nishimura, Takeshi

2015-06-01

Whistle-like high-pitched "phee" calls are often used as long-distance vocal advertisements by small-bodied marmosets and tamarins in the dense forests of South America. While the source-filter theory proposes that vibration of the vocal fold is modified independently from the resonance of the supralaryngeal vocal tract (SVT) in human speech, a source-filter coupling that constrains the vibration frequency to SVT resonance effectively produces loud tonal sounds in some musical instruments. Here, a combined approach of acoustic analyses and simulation with helium-modulated voices was used to show that phee calls are produced principally with the same mechanism as in human speech. The animal keeps the fundamental frequency (f0) close to the first formant (F1) of the SVT, to amplify f0. Although f0 and F1 are primarily independent, the degree of their tuning can be strengthened further by a flexible source-filter interaction, the variable strength of which depends upon the cross-sectional area of the laryngeal cavity. The results highlight the evolutionary antiquity and universality of the source-filter model in primates, but the study can also explore the diversification of vocal physiology, including source-filter interaction and its anatomical basis in non-human primates.

RHCV Telescope System Operations Manual

DTIC Science & Technology

2018-01-05

hardware and software components. Several of the components are closely coupled and rely on one-another, while others are largely independent. This...of hardware and software components. Several of the components are closely coupled and rely on one-another, while others are largely independent. This...attendant training The use cases are briefly described in separate sections, and step-by-step instructions are presented. Each section begins on a new

Unsteady Aerodynamic Interaction in a Closely Coupled Turbine Consistent with Contra-Rotation

DTIC Science & Technology

2014-08-01

data on the blade required three instrumentation patches due to slip ring channel limitations. TRF blowdowns designated as experiments 280100...measurements from sensors on the rotating hardware due to slip ring limitations. The experimental data was compared to time-accurate simulations modeling...AFRL-RQ-WP-TR-2014-0195 UNSTEADY AERODYNAMIC INTERACTION IN A CLOSELY COUPLED TURBINE CONSISTENT WITH CONTRA-ROTATION Michael Kenneth

Sources of plutonium to the tropical Northwest Pacific Ocean (1943-1999) identified using a natural coral archive

NASA Astrophysics Data System (ADS)

Lindahl, Patric; Asami, Ryuji; Iryu, Yasufumi; Worsfold, Paul; Keith-Roach, Miranda; Choi, Min-Seok

2011-03-01

The Pu isotopes, 239Pu and 240Pu, were determined in annually-banded skeletons of an accurately dated (1943-1999) modern coral ( Porites lobata) from Guam Island to identify historical Pu sources to the tropical Northwest Pacific Ocean. Activity concentrations of 239+240Pu and 240Pu/ 239Pu atom ratios were determined in the dated coral bands using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Close-in fallout from the former US Pacific Proving Grounds (PPG) in the Marshall Islands and global fallout were identified as the two main sources. The Guam site was dominated by PPG close-in fallout in the 1950s, with an average 240Pu/ 239Pu atom ratio of 0.315 ± 0.005. In addition, a higher 240Pu/ 239Pu atom ratio (0.456 ± 0.020) was observed that could be attributed to fallout from the "Ivy Mike" thermonuclear detonation in 1952. The atom ratio decreased in the 1960s and 1970s due to increase in the global fallout with a low 240Pu/ 239Pu atom ratio (˜0.18). Recent coral bands (1981-1999) are dominated by the transport of remobilised Pu, with high 240Pu/ 239Pu atom ratios, from the Marshall Islands to Guam Island along the North Equatorial Current (NEC). This remobilised Pu was estimated to comprise 69% of the total Pu in the recent coral bands, although its contribution was variable over time.

A Summary of Closed Brayton Cycle Development Activities at NASA

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2009-01-01

NASA has been involved in the development of Closed Brayton Cycle (CBC) power conversion technology since the 1960's. CBC systems can be coupled to reactor, isotope, or solar heat sources and offer the potential for high efficiency, long life, and scalability to high power. In the 1960's and 1970's, NASA and industry developed the 10 kW Brayton Rotating Unit (BRU) and the 2 kW mini-BRU demonstrating technical feasibility and performance, In the 1980's, a 25 kW CBC Solar Dynamic (SD) power system option was developed for Space Station Freedom and the technology was demonstrated in the 1990's as part of the 2 kW SO Ground Test Demonstration (GTD). Since the early 2000's, NASA has been pursuing CBC technology for space reactor applications. Before it was cancelled, the Jupiter Icy Moons Orbiter (HMO) mission was considering a 100 kWclass CBC system coupled to a gas-cooled fission reactor. Currently, CBC technology is being explored for Fission Surface Power (FSP) systems to provide base power on the moon and Mars. These recent activities have resulted in several CBC-related technology development projects including a 50 kW Alternator Test Unit, a 20 kW Dual Brayton Test Loop, a 2 kW Direct Drive Gas Brayton Test Loop, and a 12 kW FSP Power Conversion Unit design.

Laser Microdissection and Atmospheric Pressure Chemical Ionization Mass Spectrometry Coupled for Multimodal Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lorenz, Matthias; Ovchinnikova, Olga S; Kertesz, Vilmos

2013-01-01

This paper describes the coupling of ambient laser ablation surface sampling, accomplished using a laser capture microdissection system, with atmospheric pressure chemical ionization mass spectrometry for high spatial resolution multimodal imaging. A commercial laser capture microdissection system was placed in close proximity to a modified ion source of a mass spectrometer designed to allow for sampling of laser ablated material via a transfer tube directly into the ionization region. Rhodamine 6G dye of red sharpie ink in a laser etched pattern as well as cholesterol and phosphatidylcholine in a cerebellum mouse brain thin tissue section were identified and imaged frommore » full scan mass spectra. A minimal spot diameter of 8 m was achieved using the 10X microscope cutting objective with a lateral oversampling pixel resolution of about 3.7 m. Distinguishing between features approximately 13 m apart in a cerebellum mouse brain thin tissue section was demonstrated in a multimodal fashion including co-registered optical and mass spectral chemical images.« less

The evolving Planck mass in classically scale-invariant theories

NASA Astrophysics Data System (ADS)

Kannike, K.; Raidal, M.; Spethmann, C.; Veermäe, H.

2017-04-01

We consider classically scale-invariant theories with non-minimally coupled scalar fields, where the Planck mass and the hierarchy of physical scales are dynamically generated. The classical theories possess a fixed point, where scale invariance is spontaneously broken. In these theories, however, the Planck mass becomes unstable in the presence of explicit sources of scale invariance breaking, such as non-relativistic matter and cosmological constant terms. We quantify the constraints on such classical models from Big Bang Nucleosynthesis that lead to an upper bound on the non-minimal coupling and require trans-Planckian field values. We show that quantum corrections to the scalar potential can stabilise the fixed point close to the minimum of the Coleman-Weinberg potential. The time-averaged motion of the evolving fixed point is strongly suppressed, thus the limits on the evolving gravitational constant from Big Bang Nucleosynthesis and other measurements do not presently constrain this class of theories. Field oscillations around the fixed point, if not damped, contribute to the dark matter density of the Universe.

Coupling of oceanic carbon and nitrogen facilitates spatially resolved quantitative reconstruction of nitrate inventories.

PubMed

Glock, Nicolaas; Erdem, Zeynep; Wallmann, Klaus; Somes, Christopher J; Liebetrau, Volker; Schönfeld, Joachim; Gorb, Stanislav; Eisenhauer, Anton

2018-03-23

Anthropogenic impacts are perturbing the global nitrogen cycle via warming effects and pollutant sources such as chemical fertilizers and burning of fossil fuels. Understanding controls on past nitrogen inventories might improve predictions for future global biogeochemical cycling. Here we show the quantitative reconstruction of deglacial bottom water nitrate concentrations from intermediate depths of the Peruvian upwelling region, using foraminiferal pore density. Deglacial nitrate concentrations correlate strongly with downcore δ 13 C, consistent with modern water column observations in the intermediate Pacific, facilitating the use of δ 13 C records as a paleo-nitrate-proxy at intermediate depths and suggesting that the carbon and nitrogen cycles were closely coupled throughout the last deglaciation in the Peruvian upwelling region. Combining the pore density and intermediate Pacific δ 13 C records shows an elevated nitrate inventory of >10% during the Last Glacial Maximum relative to the Holocene, consistent with a δ 13 C-based and δ 15 N-based 3D ocean biogeochemical model and previous box modeling studies.

Determination of fucoxanthin isomers in microalgae (Isochrysis sp.) by high-performance liquid chromatography coupled with diode-array detector multistage mass spectrometry coupled with positive electrospray ionization.

PubMed

Crupi, Pasquale; Toci, Aline Theodore; Mangini, Silvio; Wrubl, Federico; Rodolfi, Liliana; Tredici, Mario R; Coletta, Antonio; Antonacci, Donato

2013-05-15

Due to their health benefits, there is growing interest in the production and use of carotenoids from natural sources, e.g. microalgae. To date, only Haematococcus pluvialis and Dunaliella, that accumulate, respectively, astaxanthin and β-carotene in large quantities, are grown commercially. However, interest is also being focused on other xanthophylls, such as (all-E)-fucoxanthin characterized by anti-obesity and anti-carcinogenic effects. In this regard, rigorous chemical and analytical techniques following preparative isolation of components are needed to unequivocally identify individual carotenoids in microalgae. The carotenoid profile of Isochrysis sp. biomass, produced in closed photobioreactors, was determined by reversed-phase C30 (RP-30) high-performance liquid chromatography coupled with diode-array detector mass spectrometry using positive electrospray ionization (HPLC/DAD-MS/ESI(+) ) analysis. Additionally, multistage mass spectrometry (MS(n) ) analyses, together with fine structures of the UV-vis spectra, were used to differentiate structural and geometrical isomers. This technique allowed the simultaneous determination of geometrical, isomers of fucoxanthin (all-E-fucoxanthin, 13Z-, 13'Z- and 9'Z-fucoxanthin), diatoxanthin and 5,8-epoxydiadinoxanthin diasteroisomers (R/S). The analyzed extracts contained fucoxanthin isomers as the major carotenoids and, in particular, (all-E)-fucoxanthin was the main geometrical isomer (~85%) found at a concentration of 17 mg/g of the lyophilized biomass. Considering the high content of fucoxanthin in Isochrysis sp. biomass, the microalga could be proposed as a source of this compound for nutraceutical and pharmaceutical applications. Copyright © 2013 John Wiley & Sons, Ltd.

[Exchange Fluxes and Coupling Relationship of Dissolved Inorganic Carbon and Dissolved Organic Carbon Across the Water-Sediment Interface in Lakes].

PubMed

Wang, Wei-ying; Lü, Chang-wei; He, Jiang; Zuo, Le; Yan, Dao-hao

2015-10-01

In this work, the exchange fluxes and coupling relationship of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) were investigated across the water-sediment interface in Lake Wuliangsuhai and Daihai by employing columnar simulation method. The results showed that the sediments in non-Phragmitescommunis area from Lake Wuliangsuhai functioned as the sources of DIC and DOC for overlying water, whereas the sediments from Lake Daihai as the sinks during the period of summer (90 days). In the experimental period, the average exchange rates of DIC and DOC were 71.07 mmol x (m2 x d)(-1) and 185.09 mmol x (m2 x d)(-1) in non-Phragmitescommunis area from Lake Wuliangsuhai, respectively; while in Lake Daihai, they were 155.75 mmol x (m2 x d)(-1) and -1478.08 mmol x (m2 x d)(-1) in shoal water zone, and -486.53 mmol x (m2 x d)(-1) and -1274.02 mmol x (m2 x d)(-1) in deep water zone, respectively. The coupling effects between DIC and DOC were governed by hydrobios, microbial uptake, abiotic and microbiological degradation in Lake Wuliangsuhai and in shoal water zone of Lake Daihai; while they were closely related to the coprecipitation process of CaCO3 and the fraction distribution of inorganic carbon in sediments in deep water zone of Lake Daihai. In summary, the sink or source functions of sediments could be considered as the results of synthetic action of lake types, offshore distance, geohydrochemistry and the fraction distribution of inorganic carbon.

Demonstration of close-coupled barriers for subsurface containment of buried waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dwyer, B.P.

1996-05-01

A close-coupled barrier is produced by first installing a conventional cement grout curtain followed by a thin inner lining of a polymer grout. The resultant barrier is a cement polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. Close-coupled barrier technology is applicable for final, interim, or emergency containment of subsurface waste forms. Consequently, when considering the diversity of technology application, the construction emplacement and material technology maturity, general site operational requirements, and regulatory compliance incentives, the close-coupled barrier system provides an alternative for any hazardous or mixed wastemore » remediation plan. This paper discusses the installation of a close-coupled barrier and the subsequent integrity verification. The demonstration was installed at a benign site at the Hanford Geotechnical Test Facility, 400 Area, Hanford, Washington. The composite barrier was emplaced beneath a 7,500 liter tank. The tank was chosen to simulate a typical DOE Complex waste form. The stresses induced on the waste form were evaluated during barrier construction. The barrier was constructed using conventional jet grouting techniques. Drilling was completed at a 45{degree} angle to the ground, forming a conical shaped barrier with the waste form inside the cone. Two overlapping rows of cylindrical cement columns were grouted in a honeycomb fashion to form the secondary backdrop barrier layer. The primary barrier, a high molecular weight polymer manufactured by 3M Company, was then installed providing a relatively thin inner liner for the secondary barrier. The primary barrier was emplaced by panel jet grouting with a dual wall drill stem, two phase jet grouting system.« less

Evanescent wave coupling in terahertz waveguide arrays.

PubMed

Reichel, K S; Sakoda, N; Mendis, R; Mittleman, D M

2013-07-15

We study energy transfer among an array of identical finite-width parallel-plate waveguides in close proximity, via evanescent wave coupling of broadband terahertz waves. We observe stronger coupling with larger plate separations and longer propagation paths. This work establishes a platform to investigate new opportunities for THz components and devices based on evanescent wave coupling.

Propulsion system for a motor vehicle using a bidirectional energy converter

DOEpatents

Tamor, Michael Alan; Gale, Allan Roy

1999-01-01

A motor vehicle propulsion system includes an electrical energy source and a traction motor coupled to receive electrical energy from the electrical energy source. The system also has a first bus provided electrical energy by the electrical energy source and a second bus of relatively lower voltage than the first bus. In addition, the system includes an electrically-driven source of reaction gas for the electrical energy source, the source of reaction gas coupled to receive electrical energy from the first bus. Also, the system has an electrical storage device coupled to the second bus for storing electrical energy at the lower voltage. The system also includes a bidirectional energy converter coupled to convert electrical energy from the first bus to the second bus and from the second bus to the first bus.

Internal nitrogen removal from sediments by the hybrid system of microbial fuel cells and submerged aquatic plants

PubMed Central

Xu, Peng; Xiao, En-Rong; Xu, Dan; Zhou, Yin; He, Feng; Liu, Bi-Yun; Zeng, Lei; Wu, Zhen-Bin

2017-01-01

Sediment internal nitrogen release is a significant pollution source in the overlying water of aquatic ecosystems. This study aims to remove internal nitrogen in sediment-water microcosms by coupling sediment microbial fuel cells (SMFCs) with submerged aquatic plants. Twelve tanks including four treatments in triplicates were designed: open-circuit (SMFC-o), closed-circuit (SMFC-c), aquatic plants with open-circuit (P-SMFC-o) and aquatic plants with closed-circuit (P-SMFC-c). The changes in the bio-electrochemical characteristics of the nitrogen levels in overlying water, pore water, sediments, and aquatic plants were documented to explain the migration and transformation pathways of internal nitrogen. The results showed that both electrogenesis and aquatic plants could facilitate the mineralization of organic nitrogen in sediments. In SMFC, electrogenesis promoted the release of ammonium from the pore water, followed by the accumulation of ammonium and nitrate in the overlying water. The increased redox potential of sediments due to electrogenesis also contributed to higher levels of nitrate in overlying water when nitrification in pore water was facilitated and denitrification at the sediment-water interface was inhibited. When the aquatic plants were introduced into the closed-circuit SMFC, the internal ammonium assimilation by aquatic plants was advanced by electrogenesis; nitrification in pore water and denitrification in sediments were also promoted. These processes might result in the maximum decrease of internal nitrogen with low nitrogen levels in the overlying water despite the lower power production. The P-SMFC-c reduced 8.1%, 16.2%, 24.7%, and 25.3% of internal total nitrogen compared to SMFC-o on the 55th, 82th, 136th, and 190th days, respectively. The smaller number of Nitrospira and the larger number of Bacillus and Pseudomonas on the anodes via high throughput sequencing may account for strong mineralization and denitrification in the sediments under closed-circuit. The coupled P-SMFC system has shown good potential for the efficient removal of internal nitrogen. PMID:28241072

Internal nitrogen removal from sediments by the hybrid system of microbial fuel cells and submerged aquatic plants.

PubMed

Xu, Peng; Xiao, En-Rong; Xu, Dan; Zhou, Yin; He, Feng; Liu, Bi-Yun; Zeng, Lei; Wu, Zhen-Bin

2017-01-01

Sediment internal nitrogen release is a significant pollution source in the overlying water of aquatic ecosystems. This study aims to remove internal nitrogen in sediment-water microcosms by coupling sediment microbial fuel cells (SMFCs) with submerged aquatic plants. Twelve tanks including four treatments in triplicates were designed: open-circuit (SMFC-o), closed-circuit (SMFC-c), aquatic plants with open-circuit (P-SMFC-o) and aquatic plants with closed-circuit (P-SMFC-c). The changes in the bio-electrochemical characteristics of the nitrogen levels in overlying water, pore water, sediments, and aquatic plants were documented to explain the migration and transformation pathways of internal nitrogen. The results showed that both electrogenesis and aquatic plants could facilitate the mineralization of organic nitrogen in sediments. In SMFC, electrogenesis promoted the release of ammonium from the pore water, followed by the accumulation of ammonium and nitrate in the overlying water. The increased redox potential of sediments due to electrogenesis also contributed to higher levels of nitrate in overlying water when nitrification in pore water was facilitated and denitrification at the sediment-water interface was inhibited. When the aquatic plants were introduced into the closed-circuit SMFC, the internal ammonium assimilation by aquatic plants was advanced by electrogenesis; nitrification in pore water and denitrification in sediments were also promoted. These processes might result in the maximum decrease of internal nitrogen with low nitrogen levels in the overlying water despite the lower power production. The P-SMFC-c reduced 8.1%, 16.2%, 24.7%, and 25.3% of internal total nitrogen compared to SMFC-o on the 55th, 82th, 136th, and 190th days, respectively. The smaller number of Nitrospira and the larger number of Bacillus and Pseudomonas on the anodes via high throughput sequencing may account for strong mineralization and denitrification in the sediments under closed-circuit. The coupled P-SMFC system has shown good potential for the efficient removal of internal nitrogen.

The synrift evolution of the early Domeyko Basin (Domeyko Range, northern Chile): Coupling detrital 40Ar-39Ar white mica and U-Pb zircon analysis into a tectonostratigraphic framework

NASA Astrophysics Data System (ADS)

Espinoza, M. E.; Oliveros, V.; Solari, L.

2017-12-01

Compressional tectonics that shaped the western flank of the Andes seems to have been strongly influenced by the heritage of extensional basins developed during the break-up of Gondwana. However, major questions remain about the exact timing, architecture and driving mechanism of these basins (subduction-related rift versus continental rift). In this work, we coupled U-Pb detrital zircon (DZ) and 39Ar-40Ar in detrital muscovites (DM) into a tectonostratigraphic framework in order to unravel the synrift evolution of the Domeyko Basin (northern Chile, 24° - 26° S). U-Pb data indicate that the rifting in the Domeyko Basin occurred in two stages; a first from ca. 240-225 Ma which led to the formation of the Sierra Exploradora sub-basin (SESB) and a second from ca. 217-200 Ma, opening the Sierra de Varas sub-basin (SVSB) and reactivating the SESB. The competition between mechanical subsidence and the volcanic supply rates in these magma-rich depocenters, led to the dominance of the inter-eruption period in the SVSB and a predominance of the syn-eruptive period along the SESB. Geochronology of detrital minerals deposited during the second rift stage reveal significant differences between both sub-basins. At the SVSB, DZ ages show a main peak at ca. 285-295 Ma and much younger WDM ages, with a main peak close to ca. 200 Ma, slightly younger than the depositional age at ca. 213-210 Ma, likely due to partial resetting of the WDM ages by burial. A lack of muscovite-bearing plutonic sources of 230-200 Ma, leads us to interpret that WDM ages indicate a significant cooling of the Permian plutonic sources close to the basin aperture. On the contrary, along the SESB, WDM ages (260-265 Ma) are only slightly younger than DZ ages (280-270 Ma). The small difference between the WDM and the DZ ages, points to a rapid cooling of plutonic source rocks at ca. 260 Ma, coinciding with the age of the San Rafael orogenic phase in northern Chile. DZ data of the Domeyko Basin show a predominance of sediments from the Gondwanic basement with a scarcity of zircons >500 Ma, indicating erosion from the margins of fault-bounded closed basins. All samples fall in the convergent regime of tectonic discriminator plots for DZ data, suggesting a subduction-related origin for these basins, which contrasts with the classical view of these basins as having a continental rift origin.

Medium effect on the characteristics of the coupled seismic and electromagnetic signals.

PubMed

Huang, Qinghua; Ren, Hengxin; Zhang, Dan; Chen, Y John

2015-01-01

Recently developed numerical simulation technique can simulate the coupled seismic and electromagnetic signals for a double couple point source or a finite fault planar source. Besides the source effect, the simulation results showed that both medium structure and medium property could affect the coupled seismic and electromagnetic signals. The waveform of coupled signals for a layered structure is more complicated than that for a simple uniform structure. Different from the seismic signals, the electromagnetic signals are sensitive to the medium properties such as fluid salinity and fluid viscosity. Therefore, the co-seismic electromagnetic signals may be more informative than seismic signals.

Medium effect on the characteristics of the coupled seismic and electromagnetic signals

PubMed Central

HUANG, Qinghua; REN, Hengxin; ZHANG, Dan; CHEN, Y. John

2015-01-01

Recently developed numerical simulation technique can simulate the coupled seismic and electromagnetic signals for a double couple point source or a finite fault planar source. Besides the source effect, the simulation results showed that both medium structure and medium property could affect the coupled seismic and electromagnetic signals. The waveform of coupled signals for a layered structure is more complicated than that for a simple uniform structure. Different from the seismic signals, the electromagnetic signals are sensitive to the medium properties such as fluid salinity and fluid viscosity. Therefore, the co-seismic electromagnetic signals may be more informative than seismic signals. PMID:25743062

Effect of twist and camber on the low-speed aerodynamic characteristics of a powered close-coupled wing-canard configuration

NASA Technical Reports Server (NTRS)

Paulson, J. W., Jr.; Thomas, J. L.

1978-01-01

A series of wind-tunnel tests were conducted in a V/STOL tunnel to determine the low-speed longitudinal aerodynamic characteristics of a powered close-coupled wing/canard fighter configuration. The data was obtained for a high angle-of-attack maneuvering configuration and a takeoff and landing configuration. The data presented in tabulated form are intended for reference purposes.

Modeling and analysis of secondary sources coupling for active sound field reduction in confined spaces

NASA Astrophysics Data System (ADS)

Montazeri, Allahyar; Taylor, C. James

2017-10-01

This article addresses the coupling of acoustic secondary sources in a confined space in a sound field reduction framework. By considering the coupling of sources in a rectangular enclosure, the set of coupled equations governing its acoustical behavior are solved. The model obtained in this way is used to analyze the behavior of multi-input multi-output (MIMO) active sound field control (ASC) systems, where the coupling of sources cannot be neglected. In particular, the article develops the analytical results to analyze the effect of coupling of an array of secondary sources on the sound pressure levels inside an enclosure, when an array of microphones is used to capture the acoustic characteristics of the enclosure. The results are supported by extensive numerical simulations showing how coupling of loudspeakers through acoustic modes of the enclosure will change the strength and hence the driving voltage signal applied to the secondary loudspeakers. The practical significance of this model is to provide a better insight on the performance of the sound reproduction/reduction systems in confined spaces when an array of loudspeakers and microphones are placed in a fraction of wavelength of the excitation signal to reduce/reproduce the sound field. This is of particular importance because the interaction of different sources affects their radiation impedance depending on the electromechanical properties of the loudspeakers.

Visualizing the kinetic power stroke that drives proton-coupled Zn(II) transport

PubMed Central

Gupta, Sayan; Chai, Jin; Cheng, Jie; D'Mello, Rhijuta; Chance, Mark R.; Fu, Dax

2014-01-01

The proton gradient is a principal energy source for respiration-dependent active transport, but the structural mechanisms of proton-coupled transport processes are poorly understood. YiiP is a proton-coupled zinc transporter found in the cytoplasmic membrane of E. coli, and the transport-site of YiiP receives protons from water molecules that gain access to its hydrophobic environment and transduces the energy of an inward proton gradient to drive Zn(II) efflux1,2. This membrane protein is a well characterized member3-7 of the protein family of cation diffusion facilitators (CDFs) that occurs at all phylogenetic levels8-10. X-ray mediated hydroxyl radical labeling of YiiP and mass spectrometric analysis showed that Zn(II) binding triggered a highly localized, all-or-none change of water accessibility to the transport-site and an adjacent hydrophobic gate. Millisecond time-resolved dynamics revealed a concerted and reciprocal pattern of accessibility changes along a transmembrane helix, suggesting a rigid-body helical reorientation linked to Zn(II) binding that triggers the closing of the hydrophobic gate. The gated water access to the transport-site enables a stationary proton gradient to facilitate the conversion of zinc binding energy to the kinetic power stroke of a vectorial zinc transport. The kinetic details provide energetic insights into a proton-coupled active transport reaction. PMID:25043033

Single-pulse x-ray diffraction using polycapillary optics for in situ dynamic diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maddox, B. R., E-mail: maddox3@llnl.gov; Akin, M. C., E-mail: akin1@llnl.gov; Teruya, A.

2016-08-15

Diagnostic use of single-pulse x-ray diffraction (XRD) at pulsed power facilities can be challenging due to factors such as the high flux and brightness requirements for diffraction and the geometric constraints of experimental platforms. By necessity, the x-ray source is usually positioned very close, within a few inches of the sample. On dynamic compression platforms, this puts the x-ray source in the debris field. We coupled x-ray polycapillary optics to a single-shot needle-and-washer x-ray diode source using a laser-based alignment scheme to obtain high-quality x-ray diffraction using a single 16 ns x-ray pulse with the source >1 m from themore » sample. The system was tested on a Mo sample in reflection geometry using 17 keV x-rays from a Mo anode. We also identified an anode conditioning effect that increased the x-ray intensity by 180%. Quantitative measurements of the x-ray focal spot produced by the polycapillary yielded a total x-ray flux on the sample of 3.3 ± 0.5 × 10{sup 7} molybdenum Kα photons.« less

ONLINE MINIMIZATION OF VERTICAL BEAM SIZES AT APS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yipeng

In this paper, online minimization of vertical beam sizes along the APS (Advanced Photon Source) storage ring is presented. A genetic algorithm (GA) was developed and employed for the online optimization in the APS storage ring. A total of 59 families of skew quadrupole magnets were employed as knobs to adjust the coupling and the vertical dispersion in the APS storage ring. Starting from initially zero current skew quadrupoles, small vertical beam sizes along the APS storage ring were achieved in a short optimization time of one hour. The optimization results from this method are briefly compared with the onemore » from LOCO (Linear Optics from Closed Orbits) response matrix correction.« less

High-power 1.25 µm InAs QD VECSEL based on resonant periodic gain structure

NASA Astrophysics Data System (ADS)

Albrecht, Alexander R.; Rotter, Thomas J.; Hains, Christopher P.; Stintz, Andreas; Xin, Guofeng; Wang, Tsuei-Lian; Kaneda, Yushi; Moloney, Jerome V.; Malloy, Kevin J.; Balakrishnan, Ganesh

2011-03-01

We compare an InAs quantum dot (QD) vertical external-cavity surface-emitting laser (VECSEL) design consisting of 4 groups of 3 closely spaced QD layers with a resonant periodic gain (RPG) structure, where each of the 12 QD layers is placed at a separate field antinode. This increased the spacing between the QDs, reducing strain and greatly improving device performance. For thermal management, the GaAs substrate was thinned and indium bonded to CVD diamond. A fiber-coupled 808 nm diode laser was used as pump source, a 1% transmission output coupler completed the cavity. CW output powers over 4.5 W at 1250 nm were achieved.

Atomic force microscopy of atomic-scale ledges and etch pits formed during dissolution of quartz

NASA Technical Reports Server (NTRS)

Gratz, A. J.; Manne, S.; Hansma, P. K.

1991-01-01

The processes involved in the dissolution and growth of crystals are closely related. Atomic force microscopy (AFM) of faceted pits (called negative crystals) formed during quartz dissolution reveals subtle details of these underlying physical mechanisms for silicates. In imaging these surfaces, the AFM detected ledges less than 1 nm high that were spaced 10 to 90 nm apart. A dislocation pit, invisible to optical and scanning electron microscopy measurements and serving as a ledge source, was also imaged. These observations confirm the applicability of ledge-motion models to dissolution and growth of silicates; coupled with measurements of dissolution rate on facets, these methods provide a powerful tool for probing mineral surface kinetics.

Carbon dioxide (CO2) sequestration in deep saline aquifers and formations: Chapter 3

USGS Publications Warehouse

Rosenbauer, Robert J.; Thomas, Burt

2010-01-01

Carbon dioxide (CO2) capture and sequestration in geologic media is one among many emerging strategies to reduce atmospheric emissions of anthropogenic CO2. This chapter looks at the potential of deep saline aquifers – based on their capacity and close proximity to large point sources of CO2 – as repositories for the geologic sequestration of CO2. The petrochemical characteristics which impact on the suitability of saline aquifers for CO2 sequestration and the role of coupled geochemical transport models and numerical tools in evaluating site feasibility are also examined. The full-scale commercial CO2 sequestration project at Sleipner is described together with ongoing pilot and demonstration projects.

Propeller modelling effects on interior noise in cylindrical cavities with application to active control

NASA Technical Reports Server (NTRS)

Silcox, R. J.; Lester, H. C.

1989-01-01

The coupling of a vibrating finite elastic cylinder and its interior cavity, closed with rigid end caps, is examined. Results are presented for several types of excitation including a point force, a single external acoustic monopole, and an array of external monopoles. Modal spectra are examined for a frequency range typical of the harmonic noise produced by advanced turbo-props. The effect of frequency and source distribution on modal content is presented. Significant interface modal filtering, which would have a beneficial impact on an active system for reducing interior noise, was found to occur for all cases. Some preliminary experimental data for a stiffened, composite cylinder are presented and discussed.

The Unidimensional Relationship Closeness Scale (URCS): Reliability and Validity Evidence for a New Measure of Relationship Closeness

ERIC Educational Resources Information Center

Dibble, Jayson L.; Levine, Timothy R.; Park, Hee Sun

2012-01-01

A fundamental dimension along which all social and personal relationships vary is closeness. The Unidimensional Relationship Closeness Scale (URCS) is a 12-item self-report scale measuring the closeness of social and personal relationships. The reliability and validity of the URCS were assessed with college dating couples (N = 192), female friends…

The infrared counterpart of the eclipsing X-ray binary HO253 + 193

NASA Technical Reports Server (NTRS)

Zuckerman, B.; Becklin, E. E.; Mclean, I. S.; Patterson, Joseph

1992-01-01

We report the identification of the infrared counterpart of the pulsating X-ray source HO253 + 193. It is a highly reddened star varying in K light with a period near 3 hr, but an apparent even-odd effect in the light curve implies that the true period is 6.06 hr. Together with the recent report of X-ray eclipses at the latter period, this establishes the close binary nature of the source. Infrared minimum occurs at X-ray minimum, certifying that the infrared variability arises from the tidal distortion of the lobe-filling secondary. The absence of a point source at radio wavelengths, plus the distance derived from the infrared data, suggests that the binary system is accidentally located behind the dense core of the molecular cloud Lynds 1457. The eclipses and pulsations in the X-ray light curve, coupled with the hard X-ray spectrum and low luminosity, demonstrate that HO253 + 193 contains an accreting magnetic white dwarf, and hence belongs to the 'DQ Herculis' class of cataclysmic variables.

System identification of closed-loop cardiovascular control mechanisms: diabetic autonomic neuropathy

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Mathias, J. M.; Mullen, T. J.; Cohen, R. J.; Freeman, R.

1999-01-01

We applied cardiovascular system identification (CSI) to characterize closed-loop cardiovascular regulation in patients with diabetic autonomic neuropathy (DAN). The CSI method quantitatively analyzes beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize four physiological coupling mechanisms, two of which are autonomically mediated (the heart rate baroreflex and the coupling of respiration, measured in terms of ILV, to heart rate) and two of which are mechanically mediated (the coupling of ventricular contraction to the generation of the ABP wavelet and the coupling of respiration to ABP). We studied 37 control and 60 diabetic subjects who were classified as having minimal, moderate, or severe DAN on the basis of standard autonomic tests. The autonomically mediated couplings progressively decreased with increasing severity of DAN, whereas the mechanically mediated couplings were essentially unchanged. CSI identified differences between the minimal DAN and control groups, which were indistinguishable based on the standard autonomic tests. CSI may provide a powerful tool for assessing DAN.

The dependency paradox in close relationships: accepting dependence promotes independence.

PubMed

Feeney, Brooke C

2007-02-01

Using multiple methods, this investigation tested the hypothesis that a close relationship partner's acceptance of dependence when needed (e.g., sensitive responsiveness to distress cues) is associated with less dependence, more autonomous functioning, and more self-sufficiency (as opposed to more dependence) on the part of the supported individual. In two studies, measures of acceptance of dependency needs and independent functioning were obtained through couple member reports, by observing couple members' behaviors during laboratory interactions, by observing responses to experimentally manipulated partner assistance provided during an individual laboratory task, and by following couples over a period of 6 months to examine independent goal striving as a function of prior assessments of dependency acceptance. Results provided converging evidence in support of the proposed hypothesis. Implications of the importance of close relationships for optimal individual functioning are discussed. ((c) 2007 APA, all rights reserved).

A Close-Coupled, Heavy Ion ICF Target

NASA Astrophysics Data System (ADS)

Callahan-Miller, Debra A.; Tabak, Max

1998-11-01

A ``close-coupled'' version of the distributed radiator, heavy ion ICF target has produced gain > 130 from 3.1 MJ of ion beam energy. To achieve these results, we reduced the hohlraum dimensions by 27% from our previous designs(M. Tabak, D. Callahan-Miller, D. D.-M. Ho, G. B. Zimmerman, Nuc. Fusion, 38, 509 (1998)) (M. Tabak, D. A. Callahan-Miller, Phys. Plasmas, 5, 1895 (1998).) while driving the same capsule. This reduced the beam energy required from 5.9-6.5 MJ to 3.1 MJ. The smaller hohlraum resulted in a smaller beam spot; elliptically shaped beams with effective radius 1.7 mm were used in this design. In addition to describing this target, we will discuss the effect of the close-coupled hohlraum on the Rayleigh-Taylor instability and scaling this design down to 1.5-2 MJ for an ETF (Engineering Test Facility).

Body frame close coupling wave packet approach to gas phase atom-rigid rotor inelastic collisions

NASA Technical Reports Server (NTRS)

Sun, Y.; Judson, R. S.; Kouri, D. J.

1989-01-01

The close coupling wave packet (CCWP) method is formulated in a body-fixed representation for atom-rigid rotor inelastic scattering. For J greater than j-max (where J is the total angular momentum and j is the rotational quantum number), the computational cost of propagating the coupled channel wave packets in the body frame is shown to scale approximately as N exp 3/2, where N is the total number of channels. For large numbers of channels, this will be much more efficient than the space frame CCWP method previously developed which scales approximately as N-squared under the same conditions.

Printed freeform lens arrays on multi-core fibers for highly efficient coupling in astrophotonic systems.

PubMed

Dietrich, Philipp-Immanuel; Harris, Robert J; Blaicher, Matthias; Corrigan, Mark K; Morris, Tim M; Freude, Wolfgang; Quirrenbach, Andreas; Koos, Christian

2017-07-24

Coupling of light into multi-core fibers (MCF) for spatially resolved spectroscopy is of great importance to astronomical instrumentation. To achieve high coupling efficiencies along with fill-fractions close to unity, micro-optical elements are required to concentrate the incoming light to the individual cores of the MCF. In this paper we demonstrate facet-attached lens arrays (LA) fabricated by two-photon polymerization. The LA provide close to 100% fill-fraction along with efficiencies of up to 73% (down to 1.4 dB loss) for coupling of light from free space into an MCF core. We show the viability of the concept for astrophotonic applications by integrating an MCF-LA assembly in an adaptive-optics test bed and by assessing its performance as a tip/tilt sensor.

Systems and methods for an integrated electrical sub-system powered by wind energy

DOEpatents

Liu, Yan [Ballston Lake, NY; Garces, Luis Jose [Niskayuna, NY

2008-06-24

Various embodiments relate to systems and methods related to an integrated electrically-powered sub-system and wind power system including a wind power source, an electrically-powered sub-system coupled to and at least partially powered by the wind power source, the electrically-powered sub-system being coupled to the wind power source through power converters, and a supervisory controller coupled to the wind power source and the electrically-powered sub-system to monitor and manage the integrated electrically-powered sub-system and wind power system.

Daily Couple Experiences and Parent Affect in Families of Children with versus without Autism

ERIC Educational Resources Information Center

Hartley, Sigan L.; DaWalt, Leann Smith; Schultz, Haley M.

2017-01-01

We examined daily couple experiences in 174 couples who had a child with autism spectrum disorder (ASD) relative to 179 couples who had a child without disabilities and their same-day association with parent affect. Parents completed a 14-day daily diary in which they reported time with partner, partner support, partner closeness, and positive and…

Synchronization between two coupled direct current glow discharge plasma sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaubey, Neeraj; Mukherjee, S.; Sen, A.

2015-02-15

Experimental results on the nonlinear dynamics of two coupled glow discharge plasma sources are presented. A variety of nonlinear phenomena including frequency synchronization and frequency pulling are observed as the coupling strength is varied. Numerical solutions of a model representation of the experiment consisting of two coupled asymmetric Van der Pol type equations are found to be in good agreement with the observed results.

Doubly fed induction machine

DOEpatents

Skeist, S. Merrill; Baker, Richard H.

2005-10-11

An electro-mechanical energy conversion system coupled between an energy source and an energy load including an energy converter device having a doubly fed induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer coupled to the energy converter device to control the flow of power or energy through the doubly fed induction machine.

Effect of damage on elastically tailored composite laminates

NASA Technical Reports Server (NTRS)

Armanios, Erian; Badir, Ashraf; Berdichevsky, Victor

1991-01-01

A variationally consistent theory is derived in order to predict the response of anisotropic thin-walled closed sections subjected to axial load, torsion and bending. The theory is valid for arbitrary cross-sections made of laminated composite materials with variable thickness and stiffness. Closed form expressions for the stiffness coefficients are provided as integrals in terms of lay-ups parameters and cross-sectional geometry. A comparison of stiffness coefficients and response with finite element predictions and a closed form solution is performed. The theory is applied to the investigation of the effect of damage on the extension-twist coupling in a thin-walled closed section beam. The damage is simulated as a progressive ply-by-ply failure. Results show that damage can have a significant effect on the extension-twist coupling.

Exobiochemistry

NASA Technical Reports Server (NTRS)

Jones, Harry

2001-01-01

Exobiochemistry is the putative biochemistry of extraterrestrial life. It suggests the possible energy and material bases of extraterrestrial life and could help detect it. The diverse biochemistry of Earth indicates that a wide range of exobiochemistry is possible on other planets. An exobiochemistry will probably use the same energy sources as Earths ecology, light, biological organic material, and more rarely abiotic chemicals. Extraterrestrial life will be based on familiar chemical principles and probably capture, store, and release energy using oxidation-reduction reactions. Extraterrestrial life will give chemical indications of its existence. Key elements will be concentrated, stored, and recycled, altering their availability and isotopic composition. Any significant departure from chemical equilibrium would be good evidence for exobiochemistry, but an integrated system of departures from the expected equilibrium would be better. Exobiochemistry can be expected to include closed biogeochemical cycles of the major life supporting elements and may well show the complex dynamic close-coupled interactions that characterize the terrestrial biosphere. Terrestrial biochemistry provides a basis for generalization and extrapolation but it does not set bounds on exobiochemistry. In exobiochemistry we can expect: 1. closed chemical cycles that recycle materials, nutrients, and catalysts, 2. organisms with complementary metabolisms that cooperate to close the chemical cycles, 3. a high probability of a carbon and water chemistry, but some possibility of a non-carbon or non-water chemistry in extreme environments, and, 4. life similar to bacteria more prevalent than higher plants and animals.

Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air

NASA Astrophysics Data System (ADS)

Lui, K. H.; Ho, Steven Sai Hang; Louie, Peter K. K.; Chan, C. S.; Lee, S. C.; Hu, Di; Chan, P. W.; Lee, Jeffrey Chi Wai; Ho, K. F.

2017-03-01

Gas-phase formaldehyde (HCHO) is an intermediate and a sensitive indicator for volatile organic compounds (VOCs) oxidation, which drives tropospheric ozone production. Effective photochemical pollution control strategies demand a thorough understanding of photochemical oxidation precursors, making differentiation between sources of primary and secondary generated HCHO inevitable. Spatial and seasonal variations of airborne carbonyls based on two years of measurements (2012-2013), coupled with a correlation-based HCHO source apportionment analysis, were determined for three sampling locations in Hong Kong (denoted HT, TC, and YL). Formaldehyde and acetaldehyde were the two most abundant compounds of the total quantified carbonyls. Pearson's correlation analysis (r > 0.7) implies that formaldehyde and acetaldehyde possibly share similar sources. The total carbonyl concentration trends (HT < TC < YL) reflect location characteristics (urban > rural). A regression analysis further quantifies the relative primary HCHO source contributions at HT (∼13%), TC (∼21%), and YL (∼40%), showing more direct vehicular emissions in urban than rural areas. Relative secondary source contributions at YL (∼36%) and TC (∼31%) resemble each other, implying similar urban source contributions. Relative background source contributions at TC could be due to a closed structure microenvironment that favors the trapping of HCHO. Comparable seasonal differences are observed at all stations. The results of this study will aid in the development of a new regional ozone (O3) control policy, as ambient HCHO can enhance O3 production and also be produced from atmospheric VOCs oxidation (secondary HCHO).

Bright radio emission from an ultraluminous stellar-mass microquasar in M 31.

PubMed

Middleton, Matthew J; Miller-Jones, James C A; Markoff, Sera; Fender, Rob; Henze, Martin; Hurley-Walker, Natasha; Scaife, Anna M M; Roberts, Timothy P; Walton, Dominic; Carpenter, John; Macquart, Jean-Pierre; Bower, Geoffrey C; Gurwell, Mark; Pietsch, Wolfgang; Haberl, Frank; Harris, Jonathan; Daniel, Michael; Miah, Junayd; Done, Chris; Morgan, John S; Dickinson, Hugh; Charles, Phil; Burwitz, Vadim; Della Valle, Massimo; Freyberg, Michael; Greiner, Jochen; Hernanz, Margarita; Hartmann, Dieter H; Hatzidimitriou, Despina; Riffeser, Arno; Sala, Gloria; Seitz, Stella; Reig, Pablo; Rau, Arne; Orio, Marina; Titterington, David; Grainge, Keith

2013-01-10

A subset of ultraluminous X-ray sources (those with luminosities of less than 10(40) erg s(-1); ref. 1) are thought to be powered by the accretion of gas onto black holes with masses of ∼5-20M cicled dot, probably by means of an accretion disk. The X-ray and radio emission are coupled in such Galactic sources; the radio emission originates in a relativistic jet thought to be launched from the innermost regions near the black hole, with the most powerful emission occurring when the rate of infalling matter approaches a theoretical maximum (the Eddington limit). Only four such maximal sources are known in the Milky Way, and the absorption of soft X-rays in the interstellar medium hinders the determination of the causal sequence of events that leads to the ejection of the jet. Here we report radio and X-ray observations of a bright new X-ray source in the nearby galaxy M 31, whose peak luminosity exceeded 10(39) erg s(-1). The radio luminosity is extremely high and shows variability on a timescale of tens of minutes, arguing that the source is highly compact and powered by accretion close to the Eddington limit onto a black hole of stellar mass. Continued radio and X-ray monitoring of such sources should reveal the causal relationship between the accretion flow and the powerful jet emission.

Millimeter Wave Sensor For On-Line Inspection Of Thin Sheet Dielectrics

DOEpatents

Bakhtiari, Sasan; Gopalsami, Nachappa; Raptis, Apostolos C.

1999-03-23

A millimeter wave sensor is provided for non-destructive inspection of thin sheet dielectric materials. The millimeter wave sensor includes a Gunn diode oscillator (GDO) source generating a mill meter wave electromagnetic energy signal having a single frequency. A heater is coupled to the GDO source for stabilizing the single frequency. A small size antenna is coupled to the GDO source for transmitting the millimeter wave electromagnetic energy signal to a sample material and for receiving a reflected millimeter wave electromagnetic energy signal from the sample material. Ferrite circulator isolators coupled between the GDO source and the antenna separate the millimeter wave electromagnetic energy signal into transmitted and received electromagnetic energy signal components and a detector detects change in both amplitude and phase of the transmitted and received electromagnetic energy signal components. A millimeter wave sensor is provided for non-destructive inspection of thin sheet dielectric materials. The millimeter wave sensor includes a Gunn diode oscillator (GDO) source generating a mill meter wave electromagnetic energy signal having a single frequency. A heater is coupled to the GDO source for stabilizing the single frequency. A small size antenna is coupled to the GDO source for transmitting the millimeter wave electromagnetic energy signal to a sample material and for receiving a reflected millimeter wave electromagnetic energy signal from the sample material. Ferrite circulator isolators coupled between the GDO source and the antenna separate the millimeter wave electromagnetic energy signal into transmitted and received electromagnetic energy signal components and a detector detects change in both amplitude and phase of the transmitted and received electromagnetic energy signal components.

Electron mass stopping power in H2

NASA Astrophysics Data System (ADS)

Fursa, Dmitry V.; Zammit, Mark C.; Threlfall, Robert L.; Savage, Jeremy S.; Bray, Igor

2017-08-01

Calculations of electron mass stopping power (SP) of electrons in H2 have been performed using the convergent close-coupling method for incident electron energies up to 2000 eV. Convergence of the calculated SP has been established by increasing the size of the close-coupling expansion from 9 to 491 states. Good agreement was found with the SP measurements of Munoz et al. [Chem. Phys. Lett. 433, 253 (2007), 10.1016/j.cplett.2006.10.114].

Dual-Spool Turbine Facility Design Overview

NASA Technical Reports Server (NTRS)

Giel, Paul; Pachlhofer, Pete

2003-01-01

The next generation of aircraft engines, both commercial and military, will attempt to capitalize on the benefits of close-coupled, vaneless, counter-rotating turbine systems. Experience has shown that significant risks and challenges are present with close-coupled systems in terms of efficiency and durability. The UEET program needs to demonstrate aerodynamic loading and efficiency goals for close-coupled, reduced-stage HP/LP turbine systems as a Level 1 Milestone for FY05. No research facility exists in the U.S. to provide risk reduction for successful development of close-coupled, high and low pressure turbine systems for the next generations of engines. To meet these objectives, the design, construction, and integrated systems testing of a Dual-Spool Turbine Facility (DSTF) facility has been initiated at the NASA Glenn Research Center. The facility will be a warm (-IOOO'F), continuous flow facility for overall aerodynamic performance and detailed flow field measurement acquisition. The facility will have state-of-the-art instrumentation to capture flow physics details. Accurate and reliable speed control will be achieved by utilizing the existing Variable Frequency Drive System. Utilization of this and other existing GRC centralized utilities will reduce the overall construction costs. The design allows for future installation of a turbine inlet combustor profile simulator. This presentation details the objectives of the facility and the concepts used in specifying its capabilities. Some preliminary design results will be presented along with a discussion of plans and schedules.

Bendable Focusing X-Ray Optics for the ALS and the LCLS/FEL: Design, Metrology, and Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yashchuk, V. V.; Yuan, S.; Baker, S.

2010-06-02

We review the recent development of bendable x-ray optics used for focusing of beams of soft and hard x-rays at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory and at the Linac Coherent Light Source (LCLS) x-ray free electron laser (FEL) at the Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory. For simultaneous focusing in the tangential and sagittal directions, two elliptically cylindrical reflecting elements, a Kirkpatrick-Baez (KB) pair, are used. Because fabrication of elliptical surfaces is complicated, the cost of directly fabricated tangential elliptical cylinders is often prohibitive. Moreover, such optics cannot be easily readjusted for usemore » in multiple, different experimental arrangements, e.g. at different focal distances. This is in contrast to flat optics that are simpler to manufacture and easier to measure by conventional interferometry. The tangential figure of a flat substrate is changed by placing torques (couples) at each end. Depending on the applied couples, one can tune the shape close to a desired tangential cylinder, ellipse or parabola. We review the nature of the bending, requirements and approaches to the mechanical design, describe original optical and at-wavelength techniques for optimal tuning of bendable optics and alignment on the beamline, and provide beamline performance of the bendable optics used for sub-micro and nano focusing of soft x-rays.« less

A continuous time random walk (CTRW) integro-differential equation with chemical interaction

NASA Astrophysics Data System (ADS)

Ben-Zvi, Rami; Nissan, Alon; Scher, Harvey; Berkowitz, Brian

2018-01-01

A nonlocal-in-time integro-differential equation is introduced that accounts for close coupling between transport and chemical reaction terms. The structure of the equation contains these terms in a single convolution with a memory function M ( t), which includes the source of non-Fickian (anomalous) behavior, within the framework of a continuous time random walk (CTRW). The interaction is non-linear and second-order, relevant for a bimolecular reaction A + B → C. The interaction term ΓP A ( s, t) P B ( s, t) is symmetric in the concentrations of A and B (i.e. P A and P B ); thus the source terms in the equations for A, B and C are similar, but with a change in sign for that of C. Here, the chemical rate coefficient, Γ, is constant. The fully coupled equations are solved numerically using a finite element method (FEM) with a judicious representation of M ( t) that eschews the need for the entire time history, instead using only values at the former time step. To begin to validate the equations, the FEM solution is compared, in lieu of experimental data, to a particle tracking method (CTRW-PT); the results from the two approaches, particularly for the C profiles, are in agreement. The FEM solution, for a range of initial and boundary conditions, can provide a good model for reactive transport in disordered media.

Regional measurements of infrasound signals from ARIANE-5 engine tests in Southern Germany

NASA Astrophysics Data System (ADS)

Koch, K.

2012-04-01

A well-controlled source of repetitive infrasound emissions was previously identified and has been related to development and acceptance tests of the European Space Agencies ARIANE-5 main engine. The propulsion testing facility of the German Aerospace Agency (DLR) near Heilbronn, Southern Germany, is a distance of about 320 km away from the International Monitoring System (IMS) station IS26 in east-southeasterly direction. In the past, signals associated with these propulsion tests could normally be detected at IS26 during winter months, but not during summer months, reflecting the changes in atmospheric conditions between winter and summer. Over the last year, DLR has prepared to conduct a series of seven propulsion tests which started in November 2011; with interim times between tests of 3-4 weeks it will last until late March or early April 2012. With mobile infrasound recording equipment available at BGR we planned to record the infrasonic wavefield along the path to IS26 at regular distances starting as close as 20 km from the source. Our aim is to study sound propagation from direct paths mainly involving the tropospheric layer through the "zone of silence" to distances close to IS26, where paths through stratospheric layers are followed. Preliminary results show that during the relevant winter season direct path propagation can be observed to some 40 km from the propulsion test source, even at seismographic stations where the acoustic wave couples into the ground. The tests are also observed at IS26, and waveform duration and f-k-analysis confirm the signals to be associated with the GT-type propulsion tests.

Plume-related mantle source of super-large rare metal deposits from the Lovozero and Khibina massifs on the Kola Peninsula, Eastern part of Baltic Shield: Sr, Nd and Hf isotope systematics

NASA Astrophysics Data System (ADS)

Kogarko, L. N.; Lahaye, Y.; Brey, G. P.

2010-03-01

The two world’s largest complexes of highly alkaline nepheline syenites and related rare metal loparite and eudialyte deposits, the Khibina and Lovozero massifs, occur in the central part of the Kola Peninsula. We measured for the first time in situ the trace element concentrations and the Sr, Nd and Hf isotope ratios by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometer) in loparite, eudialyte an in some other pegmatitic minerals. The results are in aggreement with the whole rock Sr and Nd isotope which suggests the formation of these superlarge rare metal deposits in a magmatic closed system. The initial Hf, Sr, Nd isotope ratios are similar to the isotopic signatures of OIB indicating depleted mantle as a source. This leads to the suggestion that the origin of these gigantic alkaline intrusions is connected to a deep seated mantle source—possibly to a lower mantle plume. The required combination of a depleted mantle and high rare metal enrichment in the source can be explained by the input of incompatible elements by metasomatising melts/fluids into the zones of alkaline magma generation shortly before the partial melting event (to avoid ingrowth of radiogenic isotopes). The minerals belovite and pyrochlore from the pegmatites are abnormally high in 87Sr /86Sr ratios. This may be explained by closed system isotope evolution as a result of a significant increase in Rb/Sr during the evolution of the peralkaline magma.

Towards an integrated forecasting system for fisheries on habitat-bound stocks

NASA Astrophysics Data System (ADS)

Christensen, A.; Butenschön, M.; Gürkan, Z.; Allen, I. J.

2013-03-01

First results of a coupled modelling and forecasting system for fisheries on habitat-bound stocks are being presented. The system consists currently of three mathematically, fundamentally different model subsystems coupled offline: POLCOMS providing the physical environment implemented in the domain of the north-west European shelf, the SPAM model which describes sandeel stocks in the North Sea, and the third component, the SLAM model, which connects POLCOMS and SPAM by computing the physical-biological interaction. Our major experience by the coupling model subsystems is that well-defined and generic model interfaces are very important for a successful and extendable coupled model framework. The integrated approach, simulating ecosystem dynamics from physics to fish, allows for analysis of the pathways in the ecosystem to investigate the propagation of changes in the ocean climate and to quantify the impacts on the higher trophic level, in this case the sandeel population, demonstrated here on the basis of hindcast data. The coupled forecasting system is tested for some typical scientific questions appearing in spatial fish stock management and marine spatial planning, including determination of local and basin-scale maximum sustainable yield, stock connectivity and source/sink structure. Our presented simulations indicate that sandeel stocks are currently exploited close to the maximum sustainable yield, even though periodic overfishing seems to have occurred, but large uncertainty is associated with determining stock maximum sustainable yield due to stock inherent dynamics and climatic variability. Our statistical ensemble simulations indicates that the predictive horizon set by climate interannual variability is 2-6 yr, after which only an asymptotic probability distribution of stock properties, like biomass, are predictable.

Amplitude loss of sonic waveform due to source coupling to the medium

NASA Astrophysics Data System (ADS)

Lee, Myung W.; Waite, William F.

2007-03-01

In contrast to hydrate-free sediments, sonic waveforms acquired in gas hydrate-bearing sediments indicate strong amplitude attenuation associated with a sonic velocity increase. The amplitude attenuation increase has been used to quantify pore-space hydrate content by attributing observed attenuation to the hydrate-bearing sediment's intrinsic attenuation. A second attenuation mechanism must be considered, however. Theoretically, energy radiation from sources inside fluid-filled boreholes strongly depends on the elastic parameters of materials surrounding the borehole. It is therefore plausible to interpret amplitude loss in terms of source coupling to the surrounding medium as well as to intrinsic attenuation. Analyses of sonic waveforms from the Mallik 5L-38 well, Northwest Territories, Canada, indicate a significant component of sonic waveform amplitude loss is due to source coupling. Accordingly, all sonic waveform amplitude analyses should include the effect of source coupling to accurately characterize a formation's intrinsic attenuation.

Amplitude loss of sonic waveform due to source coupling to the medium

USGS Publications Warehouse

Lee, Myung W.; Waite, William F.

2007-01-01

In contrast to hydrate-free sediments, sonic waveforms acquired in gas hydrate-bearing sediments indicate strong amplitude attenuation associated with a sonic velocity increase. The amplitude attenuation increase has been used to quantify pore-space hydrate content by attributing observed attenuation to the hydrate-bearing sediment's intrinsic attenuation. A second attenuation mechanism must be considered, however. Theoretically, energy radiation from sources inside fluid-filled boreholes strongly depends on the elastic parameters of materials surrounding the borehole. It is therefore plausible to interpret amplitude loss in terms of source coupling to the surrounding medium as well as to intrinsic attenuation. Analyses of sonic waveforms from the Mallik 5L-38 well, Northwest Territories, Canada, indicate a significant component of sonic waveform amplitude loss is due to source coupling. Accordingly, all sonic waveform amplitude analyses should include the effect of source coupling to accurately characterize a formation's intrinsic attenuation.

An evaluation and comparison of intraventricular, intraparenchymal, and fluid-coupled techniques for intracranial pressure monitoring in patients with severe traumatic brain injury.

PubMed

Vender, John; Waller, Jennifer; Dhandapani, Krishnan; McDonnell, Dennis

2011-08-01

Intracranial pressure measurements have become one of the mainstays of traumatic brain injury management. Various technologies exist to monitor intracranial pressure from a variety of locations. Transducers are usually placed to assess pressure in the brain parenchyma and the intra-ventricular fluid, which are the two most widely accepted compartmental monitoring sites. The individual reliability and inter-reliability of these devices with and without cerebrospinal fluid diversion is not clear. The predictive capability of monitors in both of these sites to local, regional, and global changes also needs further clarification. The technique of monitoring intraventricular pressure with a fluid-coupled transducer system is also reviewed. There has been little investigation into the relationship among pressure measurements obtained from these two sources using these three techniques. Eleven consecutive patients with severe, closed traumatic brain injury not requiring intracranial mass lesion evacuation were admitted into this prospective study. Each patient underwent placement of a parenchymal and intraventricular pressure monitor. The ventricular catheter tubing was also connected to a sensor for fluid-coupled measurement. Pressure from all three sources was measured hourly with and without ventricular drainage. Statistically significant correlation within each monitoring site was seen. No monitoring location was more predictive of global pressure changes or more responsive to pressure changes related to patient stimulation. However, the intraventricular pressure measurements were not reliable in the presence of cerebrospinal fluid drainage whereas the parenchymal measurements remained unaffected. Intraparenchymal pressure monitoring provides equivalent, statistically similar pressure measurements when compared to intraventricular monitors in all care and clinical settings. This is particularly valuable when uninterrupted cerebrospinal fluid drainage is desirable.

Alternative RF coupling configurations for H{sup −} ion sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Briefi, S.; Fantz, U.; AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg

2015-04-08

RF heated sources for negative hydrogen ions both for fusion and accelerators require very high RF powers in order to achieve the required H{sup −} current what poses high demands on the RF generators and the RF circuit. Therefore it is highly desirable to improve the RF efficiency of the sources. This could be achieved by applying different RF coupling concepts than the currently used inductive coupling via a helical antenna, namely Helicon coupling or coupling via a planar ICP antenna enhanced with ferrites. In order to investigate the feasibility of these concepts, two small laboratory experiments have been setmore » up. The PlanICE experiment, where the enhanced inductive coupling is going to be investigated, is currently under assembly. At the CHARLIE experiment systematic measurements concerning Helicon coupling in hydrogen and deuterium are carried out. The investigations show that a prominent feature of Helicon discharges occurs: the so-called low-field peak. This is a local improvement of the coupling efficiency at a magnetic field strength of a few mT which results in an increased electron density and dissociation degree. The full Helicon mode has not been achieved yet due to the limited available RF power and magnetic field strength but it might be sufficient for the application of the coupling concept to ion sources to operate the discharge in the low-field-peak region.« less

Alternative RF coupling configurations for H- ion sources

NASA Astrophysics Data System (ADS)

Briefi, S.; Gutmann, P.; Fantz, U.

2015-04-01

RF heated sources for negative hydrogen ions both for fusion and accelerators require very high RF powers in order to achieve the required H- current what poses high demands on the RF generators and the RF circuit. Therefore it is highly desirable to improve the RF efficiency of the sources. This could be achieved by applying different RF coupling concepts than the currently used inductive coupling via a helical antenna, namely Helicon coupling or coupling via a planar ICP antenna enhanced with ferrites. In order to investigate the feasibility of these concepts, two small laboratory experiments have been set up. The PlanICE experiment, where the enhanced inductive coupling is going to be investigated, is currently under assembly. At the CHARLIE experiment systematic measurements concerning Helicon coupling in hydrogen and deuterium are carried out. The investigations show that a prominent feature of Helicon discharges occurs: the so-called low-field peak. This is a local improvement of the coupling efficiency at a magnetic field strength of a few mT which results in an increased electron density and dissociation degree. The full Helicon mode has not been achieved yet due to the limited available RF power and magnetic field strength but it might be sufficient for the application of the coupling concept to ion sources to operate the discharge in the low-field-peak region.

Diversity and Ubiquity of Bacteria Capable of Utilizing Humic Substances as Electron Donors for Anaerobic Respiration

PubMed Central

Coates, John D.; Cole, Kimberly A.; Chakraborty, Romy; O'Connor, Susan M.; Achenbach, Laurie A.

2002-01-01

Previous studies have demonstrated that reduced humic substances (HS) can be reoxidized by anaerobic bacteria such as Geobacter, Geothrix, and Wolinella species with a suitable electron acceptor; however, little is known of the importance of this metabolism in the environment. Recently we investigated this metabolism in a diversity of environments including marine and aquatic sediments, forest soils, and drainage ditch soils. Most-probable-number enumeration studies were performed using 2,6-anthrahydroquinone disulfonate (AHDS), an analog for reduced HS, as the electron donor with nitrate as the electron acceptor. Anaerobic organisms capable of utilizing reduced HS as an electron donor were found in all environments tested and ranged from a low of 2.31 × 101 in aquifer sediments to a high of 9.33 × 106 in lake sediments. As part of this study we isolated six novel organisms capable of anaerobic AHDS oxidation. All of the isolates coupled the oxidation of AHDS to the reduction of nitrate with acetate (0.1 mM) as the carbon source. In the absence of cells, no AHDS oxidation was apparent, and in the absence of AHDS, no cell density increase was observed. Generally, nitrate was reduced to N2. Analysis of the AHDS and its oxidized form, 2,6-anthraquinone disulfonate (AQDS), in the medium during growth revealed that the anthraquinone was not being biodegraded as a carbon source and was simply being oxidized as an energy source. Determination of the AHDS oxidized and nitrate reduced accounted for 109% of the theoretical electron transfer. In addition to AHDS, all of these isolates could also couple the oxidation of reduced humic substances to the reduction of nitrate. No HS oxidation occurred in the absence of cells and in the absence of a suitable electron acceptor, demonstrating that these organisms were capable of utilizing natural HS as an energy source and that AHDS serves as a suitable analog for studying this metabolism. Alternative electron donors included simple volatile fatty acids such as propionate, butyrate, and valerate as well as simple organic acids such as lactate and pyruvate. Analysis of the complete sequences of the 16S rRNA genes revealed that the isolates were not closely related to each other and were phylogenetically diverse, with members in the alpha, beta, gamma, and delta subdivisions of the Proteobacteria. Most of the isolates were closely related to known genera not previously recognized for their ability to couple growth to HS oxidation, while one of the isolates represented a new genus in the delta subclass of the Proteobacteria. The results presented here demonstrate that microbial oxidation of HS is a ubiquitous metabolism in the environment. This study represents the first description of HS-oxidizing isolates and demonstrates that microorganisms capable of HS oxidation are phylogenetically diverse. PMID:11976120

Diversity and ubiquity of bacteria capable of utilizing humic substances as electron donors for anaerobic respiration.

PubMed

Coates, John D; Cole, Kimberly A; Chakraborty, Romy; O'Connor, Susan M; Achenbach, Laurie A

2002-05-01

Previous studies have demonstrated that reduced humic substances (HS) can be reoxidized by anaerobic bacteria such as Geobacter, Geothrix, and Wolinella species with a suitable electron acceptor; however, little is known of the importance of this metabolism in the environment. Recently we investigated this metabolism in a diversity of environments including marine and aquatic sediments, forest soils, and drainage ditch soils. Most-probable-number enumeration studies were performed using 2,6-anthrahydroquinone disulfonate (AHDS), an analog for reduced HS, as the electron donor with nitrate as the electron acceptor. Anaerobic organisms capable of utilizing reduced HS as an electron donor were found in all environments tested and ranged from a low of 2.31 x 10(1) in aquifer sediments to a high of 9.33 x 10(6) in lake sediments. As part of this study we isolated six novel organisms capable of anaerobic AHDS oxidation. All of the isolates coupled the oxidation of AHDS to the reduction of nitrate with acetate (0.1 mM) as the carbon source. In the absence of cells, no AHDS oxidation was apparent, and in the absence of AHDS, no cell density increase was observed. Generally, nitrate was reduced to N(2). Analysis of the AHDS and its oxidized form, 2,6-anthraquinone disulfonate (AQDS), in the medium during growth revealed that the anthraquinone was not being biodegraded as a carbon source and was simply being oxidized as an energy source. Determination of the AHDS oxidized and nitrate reduced accounted for 109% of the theoretical electron transfer. In addition to AHDS, all of these isolates could also couple the oxidation of reduced humic substances to the reduction of nitrate. No HS oxidation occurred in the absence of cells and in the absence of a suitable electron acceptor, demonstrating that these organisms were capable of utilizing natural HS as an energy source and that AHDS serves as a suitable analog for studying this metabolism. Alternative electron donors included simple volatile fatty acids such as propionate, butyrate, and valerate as well as simple organic acids such as lactate and pyruvate. Analysis of the complete sequences of the 16S rRNA genes revealed that the isolates were not closely related to each other and were phylogenetically diverse, with members in the alpha, beta, gamma, and delta subdivisions of the PROTEOBACTERIA: Most of the isolates were closely related to known genera not previously recognized for their ability to couple growth to HS oxidation, while one of the isolates represented a new genus in the delta subclass of the PROTEOBACTERIA: The results presented here demonstrate that microbial oxidation of HS is a ubiquitous metabolism in the environment. This study represents the first description of HS-oxidizing isolates and demonstrates that microorganisms capable of HS oxidation are phylogenetically diverse.

Charge Transfer in Collisions of S^4+ with H.

NASA Astrophysics Data System (ADS)

Stancil, P. C.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Zygelman, B.

2001-05-01

Charge transfer processes due to collisions of ground state S^4+ ions with atomic hydrogen were investigated for energies between 1 meV/u and 10 MeV/u using the quantum-mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC), and continuum distorted wave methods. The MOCC calculations utilized ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially-stripped S^3+ excited classical states. Hydrogen target isotope effects were explored and rate coefficients for temperatures between 100 and 10^6 K will be presented

Charge Transfer in Collisions of S^4+ with He.

NASA Astrophysics Data System (ADS)

Wang, J. G.; Stancil, P. C.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Zygelman, B.

2001-05-01

Charge transfer processes due to collisions of ground state S^4+ ions with atomic helium were investigated for energies between 0.1 meV/u and 10 MeV/u. Total and state-selective cross sections and rate coefficients were obtained utilizing the quantum-mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC), and continuum distorted wave methods. The MOCC calculations utilized ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were also explored. Previous data are limited to an earlier Landau-Zener calculation of the total rate coefficient for which our results are two orders of magnitude larger. An observed multichannel interference effect in the MOCC results will also be discussed.

Strength of Drug–Polymer Interactions: Implications for Crystallization in Dispersions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mistry, Pinal; Suryanarayanan, Raj

We investigated the influence of the strength of drug–polymer interactions on the crystallization behavior of a model drug in amorphous solid dispersions (ASDs). Ketoconazole ASDs were prepared with each poly(acrylic acid), poly(2-hydroxyethyl methacrylate), and polyvinylpyrrolidone. Over a wide temperature range in the supercooled region, the α-relaxation time was obtained, which provided a measure of molecular mobility. Isothermal crystallization studies were performed in the same temperature interval using either a synchrotron (for low levels of crystallinity) or a laboratory X-ray (for crystallization kinetics) source. The stronger the drug–polymer interaction, the longer was the delay in crystallization onset time, indicating an increasemore » in physical stability. Stronger drug–polymer interactions also translated to a decrease in the magnitude of the crystallization rate constant. In amorphous ketoconazole as well as in the dispersions, the coupling coefficient, a measure of the extent of coupling between relaxation and crystallization times was ~0.5. This value was unaffected by the strength of drug–polymer interactions. On the basis of these results, the crystallization times in ASDs were predicted at temperatures very close to Tg, using the coupling coefficient experimentally determined for amorphous ketoconazole. The predicted and experimental crystallization times were in good agreement, indicating the usefulness of the model.« less

CCC calculated differential cross sections of electron-H2 scattering

NASA Astrophysics Data System (ADS)

Fursa, Dmitry; Zammit, Mark; Savage, Jeremy; Bray, Igor

2016-09-01

Recently we applied the molecular convergent close-coupling (CCC) method to electron scattering from molecular hydrogen H2. Convergence of the major differential cross sections has been explicitly demonstrated in the fixed-nuclei approximation. A large close-coupling expansion that coupled highly excited states and ionization channels proved to be important to obtain convergent results. Here we present benchmark elastic and electronic excitation differential cross sections for b3Σu+ , a3Σg+ , c3Πu , B1Σu+ , EF1Σg+ , C1Πu , and e3Σu+ states and compare with available experiment and previous calculations. Work supported by Los Alamos National Laboratory and Curtin University.

Dual Expander Cycle Rocket Engine with an Intermediate, Closed-cycle Heat Exchanger

NASA Technical Reports Server (NTRS)

Greene, William D. (Inventor)

2008-01-01

A dual expander cycle (DEC) rocket engine with an intermediate closed-cycle heat exchanger is provided. A conventional DEC rocket engine has a closed-cycle heat exchanger thermally coupled thereto. The heat exchanger utilizes heat extracted from the engine's fuel circuit to drive the engine's oxidizer turbomachinery.

New OBS network deployment offshore Ireland

NASA Astrophysics Data System (ADS)

Le Pape, Florian; Bean, Chris; Craig, David; Jousset, Philippe; Horan, Clare; Hogg, Colin; Donne, Sarah; McCann, Hannah; Möllhoff, Martin; Kirk, Henning; Ploetz, Aline

2016-04-01

With the presence of the stormy NE Atlantic, Ireland is ideally located to investigate further our understanding of ocean generated microseisms and use noise correlation methods to develop seismic imaging in marine environments as well as time-lapse monitoring. In order to study the microseismic activity offshore Ireland, 10 Broad Band Ocean Bottom Seismographs (OBSs) units including hydrophones have been deployed in January 2016 across the shelf offshore Donegal and out into the Rockall Trough. This survey represents the first Broadband passive study in this part of the NE Atlantic. The instruments will be recovered in August 2016 providing 8 months worth of data to study microseisms but also the offshore seismic activity in the area. One of the main goal of the survey is to investigate the spatial and temporal distributions of dominant microseism source regions, close to the microseism sources. Additionally we will study the coupling of seismic and acoustic signals at the sea bed and its evolution in both the deep water and continental shelf areas. Furthermore, the survey also aims to investigate further the relationship between sea state conditions (e.g. wave height, period), seafloor pressure variations and seismic data recorded on both land and seafloor. Finally, the deployed OBS network is also the first ever attempt to closely monitor local offshore earthquakes in Ireland. Ireland seismicity although relatively low can reduce slope stability and poses the possibility of triggering large offshore landslides and local tsunamis.

System identification of closed-loop cardiovascular control: effects of posture and autonomic blockade

NASA Technical Reports Server (NTRS)

Mullen, T. J.; Appel, M. L.; Mukkamala, R.; Mathias, J. M.; Cohen, R. J.

1997-01-01

We applied system identification to the analysis of fluctuations in heart rate (HR), arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize quantitatively the physiological mechanisms responsible for the couplings between these variables. We characterized two autonomically mediated coupling mechanisms [the heart rate baroreflex (HR baroreflex) and respiratory sinus arrhythmia (ILV-HR)] and two mechanically mediated coupling mechanisms [the blood pressure wavelet generated with each cardiac contraction (circulatory mechanics) and the direct mechanical effects of respiration on blood pressure (ILV-->ABP)]. We evaluated the method in humans studied in the supine and standing postures under control conditions and under conditions of beta-sympathetic and parasympathetic pharmacological blockades. Combined beta-sympathetic and parasympathetic blockade abolished the autonomically mediated couplings while preserving the mechanically mediated coupling. Selective autonomic blockade and postural changes also altered the couplings in a manner consistent with known physiological mechanisms. System identification is an "inverse-modeling" technique that provides a means for creating a closed-loop model of cardiovascular regulation for an individual subject without altering the underlying physiological control mechanisms.

Thermal Interface Evaluation of Heat Transfer from a Pumped Loop to Titanium-Water Thermosyphons

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Sanzi, James L.; Gibson, Marc A.; Sechkar, Edward A.

2009-01-01

Titanium-water thermosyphons are being considered for use in the heat rejection system for lunar outpost fission surface power. Key to their use is heat transfer between a closed loop heat source and the heat pipe evaporators. This work describes laboratory testing of several interfaces that were evaluated for their thermal performance characteristics, in the temperature range of 350 to 400 K, utilizing a water closed loop heat source and multiple thermosyphon evaporator geometries. A gas gap calorimeter was used to measure heat flow at steady state. Thermocouples in the closed loop heat source and on the evaporator were used to measure thermal conductance. The interfaces were in two generic categories, those immersed in the water closed loop heat source and those clamped to the water closed loop heat source with differing thermal conductive agents. In general, immersed evaporators showed better overall performance than their clamped counterparts. Selected clamped evaporator geometries offered promise.

Noise characteristics of nanoscaled redox-cycling sensors: investigations based on random walks.

PubMed

Kätelhön, Enno; Krause, Kay J; Singh, Pradyumna S; Lemay, Serge G; Wolfrum, Bernhard

2013-06-19

We investigate noise effects in nanoscaled electrochemical sensors using a three-dimensional simulation based on random walks. The presented approach allows the prediction of time-dependent signals and noise characteristics for redox cycling devices of arbitrary geometry. We demonstrate that the simulation results closely match experimental data as well as theoretical expectations with regard to measured currents and noise power spectra. We further analyze the impact of the sensor design on characteristics of the noise power spectrum. Specific transitions between independent noise sources in the frequency domain are indicative of the sensor-reservoir coupling and can be used to identify stationary design features or time-dependent blocking mechanisms. We disclose the source code of our simulation. Since our approach is highly flexible with regard to the implemented boundary conditions, it opens up the possibility for integrating a variety of surface-specific molecular reactions in arbitrary electrochemical systems. Thus, it may become a useful tool for the investigation of a wide range of noise effects in nanoelectrochemical sensors.

"What We Breathe Impacts Our Health: Improving Understanding of the Link between Air Pollution and Health".

PubMed

West, J Jason; Cohen, Aaron; Dentener, Frank; Brunekreef, Bert; Zhu, Tong; Armstrong, Ben; Bell, Michelle L; Brauer, Michael; Carmichael, Gregory; Costa, Dan L; Dockery, Douglas W; Kleeman, Michael; Krzyzanowski, Michal; Künzli, Nino; Liousse, Catherine; Lung, Shih-Chun Candice; Martin, Randall V; Pöschl, Ulrich; Pope, C Arden; Roberts, James M; Russell, Armistead G; Wiedinmyer, Christine

2016-05-17

Air pollution contributes to the premature deaths of millions of people each year around the world, and air quality problems are growing in many developing nations. While past policy efforts have succeeded in reducing particulate matter and trace gases in North America and Europe, adverse health effects are found at even these lower levels of air pollution. Future policy actions will benefit from improved understanding of the interactions and health effects of different chemical species and source categories. Achieving this new understanding requires air pollution scientists and engineers to work increasingly closely with health scientists. In particular, research is needed to better understand the chemical and physical properties of complex air pollutant mixtures, and to use new observations provided by satellites, advanced in situ measurement techniques, and distributed micro monitoring networks, coupled with models, to better characterize air pollution exposure for epidemiological and toxicological research, and to better quantify the effects of specific source sectors and mitigation strategies.

Low-energy electron-impact single ionization of helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colgan, J.; Pindzola, M. S.; Childers, G.

2006-04-15

A study is made of low-energy electron-impact single ionization of ground-state helium. The time-dependent close-coupling method is used to calculate total integral, single differential, double differential, and triple differential ionization cross sections for impact electron energies ranging from 32 to 45 eV. For all quantities, the calculated cross sections are found to be in very good agreement with experiment, and for the triple differential cross sections, good agreement is also found with calculations made using the convergent close-coupling technique.

Closed inductively coupled plasma cell

DOEpatents

Manning, Thomas J.; Palmer, Byron A.; Hof, Douglas E.

1990-01-01

A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy.

Imperfect coupling between northern and southern ionospheres: asymmetry in TEC anomalies before earthquakes

NASA Astrophysics Data System (ADS)

Jhuang, Hau-Kun; Ho, Yi-Ying; Lee, Lou-Chuang

2016-04-01

The northern ionosphere is coupled to the conjugate southern ionosphere through the highly conducting geomagenetic field lines. The coupling is very strong or "perfect" if the geomagnetic field lines are equipotential (the parallel electric field E||=0) and hence the perpendicular electric field (E⊥) at the conjugate sites of both ionospheres are equal. The coupling is "imperfect" if some of the geomagnetic field lines are non-equipotential (E||≠0). The field-aligned electric field E|| can be associated with electron inertia, pressure gradient and collisions appearing in the form of double layer, kinetic Alfvén waves and finite field-aligned conductivity σ||. We use the Global Ionospheric Maps (GIM) data to examine the conjugate effect of total electron content (TEC) for six significant earthquakes. The anomalous (ΔTEC)source in the source ionosphere and (ΔTEC)conjugate in the conjugate ionosphere are obtained for 85 events before the six earthquakes. The ΔTEC ratio β = (ΔTEC)conjugate / (ΔTEC)source is calculated for each anomaly. For a "perfect" coupling, β=1. There are 85 anomalous events before the six significant earthquakes, with 62 events occurring in the daytime (07-18 LT) and 23 events in the nighttime (19-06 LT). The average value of daytime (07-18 LT) TEC variations in the source ionosphere is |ΔTEC|source =20.13 TECu, while the average value in the nighttime (19-06 LT) ionosphere is |ΔTEC|source=14.43 TECu. The value of ΔTEC ratio β ranges from 0.05 (very weak coupling) to 0.98 (nearly perfect coupling) with an average of 0.52. There are 14 strong coupling cases with β ≥0.8, which take place from 11 LT to 19 LT. The daytime (07-18 LT) β average value is 0.57 and the nighttime (19-06 LT) β average is 0.37. The south-north ionosphere coupling is stronger (weaker) in the daytime (nighttime).

Dyadic Qualitative Analysis of Condom Use Scripts Among Emerging Adult Gay Male Couples.

PubMed

Starks, Tyrel J; Pawson, Mark; Stephenson, Rob; Sullivan, Patrick; Parsons, Jeffrey T

2018-04-03

Sexual risk reduction among gay male couples has received increasing attention in light of evidence that primary partners account for many-and possibly most-new HIV infections. This study examined the content of condom use scripts in interviews conducted with both members of 17 HIV-negative gay male couples. In each couple, at least one partner was an emerging adult (aged 18 to 29). Three scripts were identified: romantic love, unanticipated condomless anal intercourse (CAI), and negotiated safety. Scripts varied in their emphasis on emotional factors versus HIV risk reduction, the salience of sexual agreements, and the presence of an explicit communication goal. Results indicated that condom use may vary for couples as a result of script content and from the fluid adoption of scripts across contexts. Results highlighted potential tensions between emotional closeness and HIV prevention. Condom use cessation and sexual agreements-a potential mechanism for HIV risk reduction-may also serve as expressions of intimacy. This implies interventions that facilitate direct communication about sexual and relational goals-as well as those that expand couples' repertoires for expressing emotional closeness-may enhance sexual health for gay couples, particularly during the period of emerging adulthood.

High-Power Single-Mode 2.65-micron InGaAsSb/AlInGaAsSb Diode Lasers

NASA Technical Reports Server (NTRS)

Frez, Clifford F.; Briggs, Ryan M.; Forouhar, Siamak; Borgentun, Carl E.; Gupta, James

2013-01-01

Central to the advancement of both satellite and in-situ science are improvements in continuous-wave and pulsed infrared laser systems coupled with integrated miniaturized optics and electronics, allowing for the use of powerful, single-mode light sources aboard both satellite and unmanned aerial vehicle platforms. There is a technological gap in supplying adequate laser sources to address the mid-infrared spectral window for spectroscopic characterization of important atmospheric gases. For high-power applications between 2 to 3 micron, commercial laser technologies are unsuitable because of limitations in output power. For instance, existing InP-based laser systems developed for fiber-based telecommunications cannot be extended to wavelengths longer than 2 micron. For emission wavelengths shorter than 3 micron, intersubband devices, such as infrared quantum cascade lasers, become inefficient due to band-offset limitations. To date, successfully demonstrated singlemode GaSb-based laser diodes emitting between 2 and 3 micron have employed lossy metal Bragg gratings for distributed- feedback coupling, which limits output power due to optical absorption. By optimizing both the quantum well design and the grating fabrication process, index-coupled distributed-feedback 2.65-micron lasers capable of emitting in excess of 25 mW at room temperature have been demonstrated. Specifically, lasers at 3,777/cm (2.65 micron) have been realized to interact with strong absorption lines of HDO and other isotopologues of H2O. With minor modifications of the optical cavity and quantum well designs, lasers can be fabricated at any wavelength within the 2-to-3-micron spectral window with similar performance. At the time of this reporting, lasers with this output power and wavelength accuracy are not commercially available. Monolithic ridge-waveguide GaSb lasers were fabricated that utilize secondorder lateral Bragg gratings to generate single-mode emission from InGaAsSb/ AlInGaAsSb multi-quantum well structures. The device fabrication utilizes etched index-coupled gratings in the top AlGaAsSb cladding of the laser chip along the ridge waveguide, whereas commercial lasers that emit close to this wavelength include loss-coupled metal gratings that limit the output power of the laser. Semiconductor-laser-based spectrometers can be used to replace gas sensors currently used in industry and government. With the availability of high-power laser sources at mid-infrared wavelengths, sensors can target strong fundamental gas absorption lines to maximize instrument sensitivity.

Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat.

PubMed

Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

2015-04-21

Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation.

Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat

PubMed Central

Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

2015-01-01

Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation. PMID:25897892

QCD triple Pomeron coupling from string amplitudes

NASA Astrophysics Data System (ADS)

Bialas, A.; Navelet, H.; Peschanski, R.

1998-06-01

Using the recent solution of the triple Pomeron coupling in the QCD dipole picture as a closed string amplitude with six legs, its analytical form in terms of hypergeometric functions and numerical value are derived.

Performance of end-face seals with diametral tilt and coning - Hydrodynamic effects

NASA Technical Reports Server (NTRS)

Sharoni, A.; Etsion, I.

1979-01-01

Hydrodynamic effects in end-face seals with diametral tilt and coning are analyzed. A closed-form solution for the axial separating force and the restoring and transverse moments is presented that covers the whole range from zero to full angular misalignment at various degrees of coning. Both low-pressure seals with cavitating flow and high-pressure seals with full fluid film are considered. The effect of coning is to reduce the axial force and the restoring and transverse moments compared to their magnitude in flat-face seals. Strong coupling between diametral tilt and transverse moment is demonstrated. This transverse moment which is entirely due to hydrodynamic effects can be the source of dynamic instability in the form of seal wobble.

Radiative decays of massive relic particles and the submillimeter background

NASA Technical Reports Server (NTRS)

Field, George B.; Walker, Terry P.

1989-01-01

The interaction of the decay photons of an unstable relic particle species with the microwave background radiation is considered. The radiative decays of these particles delay recombination and serve as an energy source for the resultant plasma. Nonrelativistic Compton scattering by these electrons couples the decay photons to the microwave background, producing submillimeter distortions. If the decay products close the universe, they must decay with a radiative branching ratio larger than 2.5 x 10 to the -5th in order to produce recently observed excess submillimeter background radiation. To be consistent with measurements of the UV background, their mass m is much greater than 114 keV and their decay redshift z is much greater than 5200.

Radiative transitions involving the (2p2)(3 Pe) metastable autodetaching of H(-)

NASA Technical Reports Server (NTRS)

Jacobs, V. L.; Bhatia, A. K.; Temkin, A.

1974-01-01

The absorption coefficient for the free-bound transition H (ls) + e(-)+ h omega yields H(-)(2 sq p,(3)P(e)) is calculated (together with the differential emission rate for the inverse process) using ls - 2s - 2p close coupling continuum wave functions and a Hylleraas bound state wave function. A maximum in the absorption and emission spectra is found to occur at a photon wavelength of 1219.5 A, which is 2 A closer to the Lyman alpha line than predicted by the calculations of Drake, and is in closer agreement with the stellar absorption feature identified by Heap and Stecher. The free-bound absorption process appears to be a significant source of continuous ultraviolet opacity.

Real-time pricing strategy of micro-grid energy centre considering price-based demand response

NASA Astrophysics Data System (ADS)

Xu, Zhiheng; Zhang, Yongjun; Wang, Gan

2017-07-01

With the development of energy conversion technology such as power to gas (P2G), fuel cell and so on, the coupling between energy sources becomes more and more closely. Centralized dispatch among electricity, natural gas and heat will become a trend. With the goal of maximizing the system revenue, this paper establishes the model of micro-grid energy centre based on energy hub. According to the proposed model, the real-time pricing strategy taking into account price-based demand response of load is developed. And the influence of real-time pricing strategy on the peak load shifting is discussed. In addition, the impact of wind power predicted inaccuracy on real-time pricing strategy is analysed.

Adaptive super twisting vibration control of a flexible spacecraft with state rate estimation

NASA Astrophysics Data System (ADS)

Malekzadeh, Maryam; Karimpour, Hossein

2018-05-01

The robust attitude and vibration control of a flexible spacecraft trying to perform accurate maneuvers in spite of various sources of uncertainty is addressed here. Difficulties for achieving precise and stable pointing arise from noisy onboard sensors, parameters indeterminacy, outer disturbances as well as un-modeled or hidden dynamics interactions. Based on high-order sliding-mode methods, the non-minimum phase nature of the problem is dealt with through output redefinition. An adaptive super-twisting algorithm (ASTA) is incorporated with its observer counterpart on the system under consideration to get reliable attitude and vibration control in the presence of sensor noise and momentum coupling. The closed-loop efficiency is verified through simulations under various indeterminate situations and got compared to other methods.

Satisfaction with sex life in sexually active heterosexual couples dealing with breast cancer: a nationwide longitudinal study.

PubMed

Rottmann, Nina; Gilså Hansen, Dorte; dePont Christensen, René; Hagedoorn, Mariët; Frisch, Morten; Nicolaisen, Anne; Kroman, Niels; Flyger, Henrik; Johansen, Christoffer

2017-02-01

A breast cancer (BC) diagnosis can profoundly affect the sex life of patient and partner within a couple. The purpose of the present study is to examine whether individual and partner sexual functioning, affectionate behavior, emotional closeness and depressive symptoms are associated with change over time in satisfaction with sex life of sexually active heterosexual couples dealing with BC and to explore whether the associations differ between patients and partners after adjustment for basic sociodemographic characteristics, comorbidity and BC treatment. Women with BC and their male partners participated in a longitudinal study (Time 1, ≤4 months after surgery; Time 2, 5 months later). Participants completed items from the PROMIS ® Sexual Function and Satisfaction measure (version 1.0), two items measuring affectionate behavior, a single item measuring emotional closeness and the Center for Epidemiologic Studies-Depression Scale. Registers provided sociodemographic and medical information. Multilevel models were used, which take the interdependency of couples' scores into account. A total of 287 sexually active couples were included in the analyses. Less vaginal discomfort and more vaginal lubrication were associated with increases in patients' satisfaction with sex life. Patients' and partners' satisfaction increased with higher ratings of their own orgasm ability and of partners' timing of ejaculation. Patients' reports of affectionate behavior were positively associated with their partners' satisfaction, and vice versa for partners. Patients' satisfaction increased the more emotional closeness their partner experienced. Partners' depressive symptoms were negatively associated with their satisfaction. Sociodemographic factors and BC treatment were not significantly associated with change in satisfaction. Satisfaction with sex life in sexually active couples dealing with BC needs to be seen as a couple issue. Health professionals should take the partner into account when addressing sexuality issues. Couples' functioning and relationship-related factors may be promising targets for couple interventions.

Coupling between the Voltage-sensing and Pore Domains in a Voltage-gated Potassium Channel

PubMed Central

Schow, Eric V.; Freites, J. Alfredo; Nizkorodov, Alex; White, Stephen H.; Tobias, Douglas J.

2012-01-01

Voltage-dependent potassium (Kv), sodium (Nav), and calcium channels open and close in response to changes in transmembrane (TM) potential, thus regulating cell excitability by controlling ion flow across the membrane. An outstanding question concerning voltage gating is how voltage-induced conformational changes of the channel voltage-sensing domains (VSDs) are coupled through the S4-S5 interfacial linking helices to the opening and closing of the pore domain (PD). To investigate the coupling between the VSDs and the PD, we generated a closed Kv channel configuration from Aeropyrum pernix (KvAP) using atomistic simulations with experiment-based restraints on the VSDs. Full closure of the channel required, in addition to the experimentally determined TM displacement, that the VSDs be displaced both inwardly and laterally around the PD. This twisting motion generates a tight hydrophobic interface between the S4-S5 linkers and the C-terminal ends of the pore domain S6 helices in agreement with available experimental evidence. PMID:22425907

Coupling between the voltage-sensing and pore domains in a voltage-gated potassium channel.

PubMed

Schow, Eric V; Freites, J Alfredo; Nizkorodov, Alex; White, Stephen H; Tobias, Douglas J

2012-07-01

Voltage-dependent potassium (Kv), sodium (Nav), and calcium channels open and close in response to changes in transmembrane (TM) potential, thus regulating cell excitability by controlling ion flow across the membrane. An outstanding question concerning voltage gating is how voltage-induced conformational changes of the channel voltage-sensing domains (VSDs) are coupled through the S4-S5 interfacial linking helices to the opening and closing of the pore domain (PD). To investigate the coupling between the VSDs and the PD, we generated a closed Kv channel configuration from Aeropyrum pernix (KvAP) using atomistic simulations with experiment-based restraints on the VSDs. Full closure of the channel required, in addition to the experimentally determined TM displacement, that the VSDs be displaced both inwardly and laterally around the PD. This twisting motion generates a tight hydrophobic interface between the S4-S5 linkers and the C-terminal ends of the pore domain S6 helices in agreement with available experimental evidence.

Experimental and theoretical studies of Sub-THz detection using strained-Si FETs

NASA Astrophysics Data System (ADS)

Delgado Notario, J. A.; Javadi, E.; Clericò, V.; Fobelets, K.; Otsuji, T.; Diez, E.; Velázquez-Pérez, J. E.; Meziani, Y. M.

2017-10-01

We report on experimental and theoretical studies of nanoscale gate-lengths strained Silicon MODFETs as room temperature non resonant detectors. Devices were excited at room temperature by an electronic source at 150 and 300 GHz to characterize their sub-THz response. The maximum of the photovoltaic response was obtained when the FET gate was biased at a value close to the threshold voltage. Simulations based on a bi-dimensional hydrodynamic model for the charge transport coupled to a Poisson equation solver were performed by using Synopsys TCAD. A charge boundary condition for the floating drain contact was implemented to obtain the photovoltaic response. Results from numerical simulations are in agreement with experimental ones. To understand the coupling between terahertz radiation and devices, the devices were rotated at different angles under excitation at both sub-terahertz frequencies and their response measured. Both NEP (Noise Equivalent Power) and Responsivity were calculated from measurements. To demonstrate their utility, devices were used as sensors in a terahertz imaging system for inspection of hidden objects at both frequencies.

MEG Connectivity and Power Detections with Minimum Norm Estimates Require Different Regularization Parameters.

PubMed

Hincapié, Ana-Sofía; Kujala, Jan; Mattout, Jérémie; Daligault, Sebastien; Delpuech, Claude; Mery, Domingo; Cosmelli, Diego; Jerbi, Karim

2016-01-01

Minimum Norm Estimation (MNE) is an inverse solution method widely used to reconstruct the source time series that underlie magnetoencephalography (MEG) data. MNE addresses the ill-posed nature of MEG source estimation through regularization (e.g., Tikhonov regularization). Selecting the best regularization parameter is a critical step. Generally, once set, it is common practice to keep the same coefficient throughout a study. However, it is yet to be known whether the optimal lambda for spectral power analysis of MEG source data coincides with the optimal regularization for source-level oscillatory coupling analysis. We addressed this question via extensive Monte-Carlo simulations of MEG data, where we generated 21,600 configurations of pairs of coupled sources with varying sizes, signal-to-noise ratio (SNR), and coupling strengths. Then, we searched for the Tikhonov regularization coefficients (lambda) that maximize detection performance for (a) power and (b) coherence. For coherence, the optimal lambda was two orders of magnitude smaller than the best lambda for power. Moreover, we found that the spatial extent of the interacting sources and SNR, but not the extent of coupling, were the main parameters affecting the best choice for lambda. Our findings suggest using less regularization when measuring oscillatory coupling compared to power estimation.

MEG Connectivity and Power Detections with Minimum Norm Estimates Require Different Regularization Parameters

PubMed Central

Hincapié, Ana-Sofía; Kujala, Jan; Mattout, Jérémie; Daligault, Sebastien; Delpuech, Claude; Mery, Domingo; Cosmelli, Diego; Jerbi, Karim

2016-01-01

Minimum Norm Estimation (MNE) is an inverse solution method widely used to reconstruct the source time series that underlie magnetoencephalography (MEG) data. MNE addresses the ill-posed nature of MEG source estimation through regularization (e.g., Tikhonov regularization). Selecting the best regularization parameter is a critical step. Generally, once set, it is common practice to keep the same coefficient throughout a study. However, it is yet to be known whether the optimal lambda for spectral power analysis of MEG source data coincides with the optimal regularization for source-level oscillatory coupling analysis. We addressed this question via extensive Monte-Carlo simulations of MEG data, where we generated 21,600 configurations of pairs of coupled sources with varying sizes, signal-to-noise ratio (SNR), and coupling strengths. Then, we searched for the Tikhonov regularization coefficients (lambda) that maximize detection performance for (a) power and (b) coherence. For coherence, the optimal lambda was two orders of magnitude smaller than the best lambda for power. Moreover, we found that the spatial extent of the interacting sources and SNR, but not the extent of coupling, were the main parameters affecting the best choice for lambda. Our findings suggest using less regularization when measuring oscillatory coupling compared to power estimation. PMID:27092179

Preliminary evidence that sub-chronic citalopram triggers the re-evaluation of value in intimate partnerships

PubMed Central

Bilderbeck, Amy C.; Wakeley, Judi; Godlewska, Beata R.; McGlone, Francis; Harris, Tirril; Cowen, Phillip J.

2014-01-01

Depression frequently involves disrupted inter-personal relationships, while treatment with serotonergic anti-depressants can interfere with libido and sexual function. However, little is known about how serotonin activity influences appraisals of intimate partnerships. Learning more could help to specify how serotonergic mechanisms mediate social isolation in psychiatric illness. Forty-four healthy heterosexual adults, currently in romantic relationships, received 8 days treatment with the selective serotonin re-uptake inhibitor citalopram (N = 21; 10 male) or placebo (N = 23; 12 male). Participants viewed photographs of unknown, heterosexual couples and made a series of judgements about their relationships. Participants also indicated the importance of relationship features in their own close partnerships, and close partnerships generally. Citalopram reduced the rated quality of couples’ physical relationships and the importance attributed to physical and intimate aspects of participants’ own relationships. In contrast, citalopram also enhanced the evaluated worth of mutual trust in relationships. Amongst males, citalopram was associated with judgements of reduced turbulence and bickering in others’ relationships, and increased male dominance. These data constitute preliminary evidence that enhancing serotonin activity modulates cognitions about sexual activity as part of a re-appraisal of sources of value within close intimate relationships, enhancing the judged importance of longer-term benefits of trust and shared experiences. PMID:23996287

High heralding-efficiency of near-IR fiber coupled photon pairs for quantum technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, P. Ben; Murphy, Ryan; Rosenberg, Danna

We report on the development and use of a high heralding-efficiency, single-mode-fiber coupled telecom-band source of entangled photons for quantum technology applications. The source development efforts consisted of theoretical and experimental efforts and we demonstrated a correlated-mode coupling efficiency of 97% 2%, the highest efficiency yet achieved for this type of system. We then incorporated these beneficial source development techniques in a Sagnac configured telecom-band entangled photon source that generates photon pairs entangled in both time/energy and polarization degrees of freedom. We made use of these highly desirable entangled states to investigate several promising quantum technologies.

Saclay Compact Accelerator-driven Neutron Sources (SCANS)

NASA Astrophysics Data System (ADS)

Marchix, A.; Letourneau, A.; Tran, HN; Chauvin, N.; Menelle, A.; Ott, F.; Schwindling, J.

2018-06-01

For next decade, the European neutron scattering community will face of important changes, as many facilities will close, strictly fission-based sources. This statement mainly concerns France with the planned closure of Orphee and ILL. At CEA-Saclay, the project SONATE has been launched in order to provide a high intensity neutron source in Saclay site, this project is based on Compact Accelerator-driven Neutron Sources technology coupled to high-intensity beams. The goal of SONATE is to develop a 50 kW target, aiming to produce at least a neutron yield of 1013 s-1 in pulse mode with a peak current of 100 mA. We have investigated in this document the best combinations of beam/target which would lead to this substantial neutron yields. Further investigations and tests have to be carry out, especially due to sparse data on thick target and such low-energy beams considered in this document. An intermediate step to the SONATE project is under test and development, called IPHI-NEUTRON, which would lead to provide a small-size neutron facility mainly devoted to neutron imagery for industry. This step is based on the existing 3 MeV proton beam, named IPHI. Best target candidates are Lithium and Beryllium, leading respectively to a neutron yield of about 2.1013 s-1 and 4.1012 s-1.

Hydrogeochemistry of the drinking water sources of Derebogazi Village (Kahramanmaras) and their effects on human health.

PubMed

Uras, Yusuf; Uysal, Yagmur; Arikan, Tugba Atilan; Kop, Alican; Caliskan, Mustafa

2015-06-01

The aim of this study was to investigate the sources of drinking water for Derebogazi Village, Kahramanmaras Province, Turkey, in terms of hydrogeochemistry, isotope geochemistry, and medical geology. Water samples were obtained from seven different water sources in the area, all of which are located within quartzite units of Paleozoic age, and isotopic analyses of (18)O and (2)H (deuterium) were conducted on the samples. Samples were collected from the region for 1 year. Water quality of the samples was assessed in terms of various water quality parameters, such as temperature, pH, conductivity, alkalinity, trace element concentrations, anion-cation measurements, and metal concentrations, using ion chromatography, inductively coupled plasma (ICP) mass spectrometry, ICP-optical emission spectrometry techniques. Regional health surveys had revealed that the heights of local people are significantly below the average for the country. In terms of medical geology, the sampled drinking water from the seven sources was deficient in calcium and magnesium ions, which promote bone development. Bone mineral density screening tests were conducted on ten females using dual energy X-ray absorptiometry to investigate possible developmental disorder(s) and potential for mineral loss in the region. Of these ten women, three had T-scores close to the osteoporosis range (T-score < -2.5).

Electromechanical coupling and temperature-dependent polarization reversal in piezoelectric ceramics.

PubMed

Weaver, Paul M; Cain, Markys G; Correia, Tatiana M; Stewart, Mark

2011-09-01

Electrostriction plays a central role in describing the electromechanical properties of ferroelectric materials, including widely used piezoelectric ceramics. The piezoelectric properties are closely related to the underlying electrostriction. Small-field piezoelectric properties can be described as electrostriction offset by the remanent polarization which characterizes the ferroelectric state. Indeed, even large-field piezoelectric effects are accurately accounted for by quadratic electrostriction. However, the electromechanical properties deviate from this simple electrostrictive description at electric fields near the coercive field. This is particularly important for actuator applications, for which very high electromechanical coupling can be obtained in this region. This paper presents the results of an experimental study of electromechanical coupling in piezoelectric ceramics at electric field strengths close to the coercive field, and the effects of temperature on electromechanical processes during polarization reversal. The roles of intrinsic ferroelectric strain coupling and extrinsic domain processes and their temperature dependence in determining the electromechanical response are discussed.

Improved RF Measurements of SRF Cavity Quality Factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holzbauer, J. P.; Contreras, C.; Pischalnikov, Y.

SRF cavity quality factors can be accurately measured using RF-power based techniques only when the cavity is very close to critically coupled. This limitation is from systematic errors driven by non-ideal RF components. When the cavity is not close to critically coupled, these systematic effects limit the accuracy of the measurements. The combination of the complex base-band envelopes of the cavity RF signals in combination with a trombone in the circuit allow the relative calibration of the RF signals to be extracted from the data and systematic effects to be characterized and suppressed. The improved calibration allows accurate measurements tomore » be made over a much wider range of couplings. Demonstration of these techniques during testing of a single-spoke resonator with a coupling factor of near 7 will be presented, along with recommendations for application of these techniques.« less

Electron capture in collisions of S4+ with atomic hydrogen

NASA Astrophysics Data System (ADS)

Stancil, P. C.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Zygelman, B.

2001-06-01

Charge transfer processes due to collisions of ground state S4+(3s2 1S) ions with atomic hydrogen are investigated for energies between 1 meV u-1 and 10 MeV u-1 using the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially stripped S3+ excited classical states. Hydrogen target isotope effects are explored and rate coefficients for temperatures between 100 and 106 K are also presented.

Spatial patterns of close relationships across the lifespan

NASA Astrophysics Data System (ADS)

Jo, Hang-Hyun; Saramäki, Jari; Dunbar, Robin I. M.; Kaski, Kimmo

2014-11-01

The dynamics of close relationships is important for understanding the migration patterns of individual life-courses. The bottom-up approach to this subject by social scientists has been limited by sample size, while the more recent top-down approach using large-scale datasets suffers from a lack of detail about the human individuals. We incorporate the geographic and demographic information of millions of mobile phone users with their communication patterns to study the dynamics of close relationships and its effect in their life-course migration. We demonstrate how the close age- and sex-biased dyadic relationships are correlated with the geographic proximity of the pair of individuals, e.g., young couples tend to live further from each other than old couples. In addition, we find that emotionally closer pairs are living geographically closer to each other. These findings imply that the life-course framework is crucial for understanding the complex dynamics of close relationships and their effect on the migration patterns of human individuals.

On-Chip Waveguide Coupling of a Layered Semiconductor Single-Photon Source.

PubMed

Tonndorf, Philipp; Del Pozo-Zamudio, Osvaldo; Gruhler, Nico; Kern, Johannes; Schmidt, Robert; Dmitriev, Alexander I; Bakhtinov, Anatoly P; Tartakovskii, Alexander I; Pernice, Wolfram; Michaelis de Vasconcellos, Steffen; Bratschitsch, Rudolf

2017-09-13

Fully integrated quantum technology based on photons is in the focus of current research, because of its immense potential concerning performance and scalability. Ideally, the single-photon sources, the processing units, and the photon detectors are all combined on a single chip. Impressive progress has been made for on-chip quantum circuits and on-chip single-photon detection. In contrast, nonclassical light is commonly coupled onto the photonic chip from the outside, because presently only few integrated single-photon sources exist. Here, we present waveguide-coupled single-photon emitters in the layered semiconductor gallium selenide as promising on-chip sources. GaSe crystals with a thickness below 100 nm are placed on Si 3 N 4 rib or slot waveguides, resulting in a modified mode structure efficient for light coupling. Using optical excitation from within the Si 3 N 4 waveguide, we find nonclassicality of generated photons routed on the photonic chip. Thus, our work provides an easy-to-implement and robust light source for integrated quantum technology.

MAGNETIC DENSITOMETER

DOEpatents

McCann, J.A.; Jones, R.H.

1961-08-15

A magnetic densitometer for locating defects and metallic inclusions in materials is described. The apparatus consists of two primary coils connected in series opposition and adapted te be placed in inductive relation to the material under test, a source of constant frequency alternating current coupled across the primary coil combination, a pick-up coil disposed in symmetrical inductive relationship with said primary coils, a phase-shifter coupled to the output of the energizing source. The output of the phase-shifter is coupled in series with the pick-up coil. An amplifier is provided selective to the third harmonic of the energizing source frequency. The series combination of the pick-up coil and the phase-shifter output are connected across the input of the amplifier, and an amplitude comparitor is coupled to the output of the amplifier and the energizing source for comparing the instantaneous amplitude of the amplifier output and the instantaneous output of the energizing source and producing an output proportional to the difference in amplitude. A recorder is coupled to the output of the amplitude comparison means to give an indication of the amplitude difference, thereby providing a permanent presentation of the character of the changes in characteristics exhibited by the material under test. (AEC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Streubel, Robert; Kronast, Florian; Reiche, Christopher F.

For this work, we studied curvature-driven modifications to the magnetostatic coupling of vortex circulation and polarity in soft-magnetic closely packed cap arrays. A phase diagram for the magnetic remanent/transition states at room temperature as a function of diameter and thickness was assembled. For specimens with vortex remanent state (40 nm-thick Permalloy on 330 nm spherical nanoparticles), both vortex circulation and polarity were visualized. Intercap coupling upon vortex nucleation leads to the formation of vortex circulation patterns in closely packed arrays. The remanent circulation pattern can be tailored choosing the direction of the applied magnetic field with respect to the symmetrymore » axis of the hexagonal array. An even and random distribution of vortex polarity indicates the absence of any circulation-polarity coupling.« less

Which nanowire couples better electrically to a metal contact: Armchair or zigzag nanotube?

NASA Technical Reports Server (NTRS)

Anantram, M. P.; Biegel, Bryan (Technical Monitor)

2001-01-01

The fundamental question of how chirality affects tile electronic coupling of a nanotube to metal contacts is important for tile application of nanotubes as nanowires. We show that metallic-zigzag nanotubes are superior to armchair nanotubes as nanowires, by modeling the metal-nanotube interface. More specifically, we show that as a function of coupling strength, the total electron transmission of armchair nanotubes increases and tends to be pinned close to unity for a metal with Fermi wave vector close to that of gold. In contrast, the transmission probability of zigzag nanotubes increases to the maximum possible value of two. The origin of these effects lies in the details of the wave function, which is explained.

Unidirectional reflectionless phenomenon in ultracompact non-Hermitian plasmonic waveguide system based on phase coupling

NASA Astrophysics Data System (ADS)

Zhang, Cong; Bai, Ruiping; Gu, Xintong; Jin, Yingjiu; Qiao Zhang, Ying; Jin, Xing Ri; Zhang, Shou; Lee, YoungPak

2017-12-01

Unidirectional reflectionless phenomenon is theoretically investigated based on phase coupling in an ultracompact non-Hermitian plasmonic waveguide system, which consists of two metal-insulator-metal (MIM) stub resonators side coupled to a MIM plasmonic waveguide. By appropriately tuning the phase difference between two stub resonators, the reflectivity for forward direction reaches to 0.91 and backward direction is close to 0 at the exception point (EP), while the backward absorption reaches to 0.98 and the forward absorption is close to 0.05. Hence, the unidirectional coherent perfect absorption (CPA) is realized at the vicinity of EP. This work will provide potential applications in the filter, sensor, plasmonic diode-like device, and so on.

Hybrid semiconductor fiber lasers for telecommunications

NASA Astrophysics Data System (ADS)

Khalili, Alireza

2006-12-01

Highly stable edge emitting semiconductor lasers are of utmost importance in most telecommunications applications where high-speed data transmission sets strict limits on the purity of the laser signal. Unfortunately, most edge emitting semiconductor lasers, unlike gaseous or solid-state laser sources, operate with many closely spaced axial modes, which accounts for the observed instability and large spikes in the output spectrum of such lasers. Consequently, in most telecom applications distributed feedback (DFB) or distributed Bragg reflector (DBR) techniques are used to ensure stability and single-frequency operation, further adding to the cost and complexity of such lasers. Additionally, coupling of the highly elliptical output beam of these lasers to singlemode fibers complicates the packaging procedure and sub-micron alignment of various optical components is often necessary. Utilizing the evanescent coupling between a semiconductor antiresonant reflecting optical waveguide (ARROW) and a side polished fiber, this thesis presents an alternative side-coupled laser module that eliminates the need for the cumbersome multi-component alignment processes of conventional laser packages, and creates an inherent mode selection mechanism that guarantees singlemode radiation into the fiber without any gratings. We have been able to demonstrate the first side-coupled fiber semiconductor laser in this technology, coupling more than 3mW of power at 850nm directly into a 5/125mum singlemode fiber. This mixed-cavity architecture yields a high thermal stability (˜0.06nm/°C), and negligible spectral spikes are observed. Theoretical background and simulation results, as well as several supplementary materials are also presented to further rationalize the experimental data. A side-coupled light-emitter and pre-amplifier are also proposed and discussed. We also study different architectures for attaining higher efficiency, higher output power, and wavelength tunability in such lasers. Finally, we discuss possible venues for integration of these side-coupled devices in a telecommunication system. Approved for publication.

Investigation of a long time series of CO2 from a tall tower using WRF-SPA

NASA Astrophysics Data System (ADS)

Smallman, Luke; Williams, Mathew; Moncrieff, John B.

2013-04-01

Atmospheric observations from tall towers are an important source of information about CO2 exchange at the regional scale. Here, we have used a forward running model, WRF-SPA, to generate a time series of CO2 at a tall tower for comparison with observations from Scotland over multiple years (2006-2008). We use this comparison to infer strength and distribution of sources and sinks of carbon and ecosystem process information at the seasonal scale. The specific aim of this research is to combine a high resolution (6 km) forward running meteorological model (WRF) with a modified version of a mechanistic ecosystem model (SPA). SPA provides surface fluxes calculated from coupled energy, hydrological and carbon cycles. This closely coupled representation of the biosphere provides realistic surface exchanges to drive mixing within the planetary boundary layer. The combined model is used to investigate the sources and sinks of CO2 and to explore which land surfaces contribute to a time series of hourly observations of atmospheric CO2 at a tall tower, Angus, Scotland. In addition to comparing the modelled CO2 time series to observations, modelled ecosystem specific (i.e. forest, cropland, grassland) CO2 tracers (e.g., assimilation and respiration) have been compared to the modelled land surface assimilation to investigate how representative tall tower observations are of land surface processes. WRF-SPA modelled CO2 time series compares well to observations (R2 = 0.67, rmse = 3.4 ppm, bias = 0.58 ppm). Through comparison of model-observation residuals, we have found evidence that non-cropped components of agricultural land (e.g., hedgerows and forest patches) likely contribute a significant and observable impact on regional carbon balance.

Sensitivity enhancement of fluorescence detection in CE by coupling and conducting excitation light with tapered optical fiber.

PubMed

Yang, Xiupei; Huo, Feng; Yuan, Hongyan; Zhang, Bo; Xiao, Dan; Choi, Martin M F

2011-01-01

This paper reports the enhancement of sensitivity of detection for in-column fiber optic-induced fluorescence detection system in CE by tapered optical fiber (TOF). Two types of optical fiber, TOF and conventional cylindrical optical fiber (COF), were employed to construct the CE (TOF-CE and COF-CE) and were compared for sensitivity to riboflavin (RF). The fluorescence intensities from a RF sample with excitation light sources and fibers at various coupling angles were investigated. The fluorescence signal from TOF-CE was ca. ten times that of COF-CE. In addition, the detection performance of four excitation light source-fiber configurations including Laser-TOF, Laser-COF, LED-TOF, and LED-COF were compared. The LODs for RF were 0.21, 0.82, 0.80, and 7.5 nM, respectively, for the four excitation light source-fiber configurations. The results demonstrate that the sensitivity obtained by LED-TOF is close to that of Laser-COF. Both Laser-TOF and LED-TOF can greatly improve the sensitivity of detection in CE. TOF has the major attribute of collecting and focusing the excitation light intensity. Thus, the sensitivity obtained by LED-TOF without focusing lens is just same as that of LED-COF with a focusing lens. This demonstrates that the CE system can be further simplified by eliminating the focusing lens for excitation light. LED-TOF-CE and LED-COF-CE system were applied to the separation and determination of RF in real sample (green tea), respectively. The tapered fiber optic-induced fluorescence detection system in CE is an ideal tool for trace analysis. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Large dynamic range radiation detector and methods thereof

DOEpatents

Marrs, Roscoe E [Livermore, CA; Madden, Norman W [Sparks, NV

2012-02-14

According to one embodiment, a radiation detector comprises a scintillator and a photodiode optically coupled to the scintillator. The radiation detector also includes a bias voltage source electrically coupled to the photodiode, a first detector operatively electrically coupled to the photodiode for generating a signal indicative of a level of a charge at an output of the photodiode, and a second detector operatively electrically coupled to the bias voltage source for generating a signal indicative of an amount of current flowing through the photodiode.

Hybrid concatenated codes and iterative decoding

NASA Technical Reports Server (NTRS)

Divsalar, Dariush (Inventor); Pollara, Fabrizio (Inventor)

2000-01-01

Several improved turbo code apparatuses and methods. The invention encompasses several classes: (1) A data source is applied to two or more encoders with an interleaver between the source and each of the second and subsequent encoders. Each encoder outputs a code element which may be transmitted or stored. A parallel decoder provides the ability to decode the code elements to derive the original source information d without use of a received data signal corresponding to d. The output may be coupled to a multilevel trellis-coded modulator (TCM). (2) A data source d is applied to two or more encoders with an interleaver between the source and each of the second and subsequent encoders. Each of the encoders outputs a code element. In addition, the original data source d is output from the encoder. All of the output elements are coupled to a TCM. (3) At least two data sources are applied to two or more encoders with an interleaver between each source and each of the second and subsequent encoders. The output may be coupled to a TCM. (4) At least two data sources are applied to two or more encoders with at least two interleavers between each source and each of the second and subsequent encoders. (5) At least one data source is applied to one or more serially linked encoders through at least one interleaver. The output may be coupled to a TCM. The invention includes a novel way of terminating a turbo coder.

Load distribution on a closed-coupled wing canard at transonic speeds

NASA Technical Reports Server (NTRS)

Gloss, B. B.; Washburn, K. E.

1977-01-01

A wind tunnel test where load distributions were obtained at transonic speeds on both the canard and wing surfaces of a closely coupled wing canard configuration is reported. Detailed component and configuration arrangement studies to provide insight into the various aerodynamic interference effects for the leading edge vortex flow conditions encountered are included. Data indicate that increasing the Mach number from 0.70 to 0.95 caused the wing leading edge vortex to burst over the wing when the wing was in the presence of the high canard.

Convergent close-coupling approach to positron scattering on He+★

NASA Astrophysics Data System (ADS)

Rawlins, Charlie M.; Kadyrov, Alisher S.; Bray, Igor

2018-05-01

A close-coupling method is used to generate electron-loss and total scattering cross sections for the first three partial waves with both a single-centre and two-centre expansion of the scattering wave function for positron scattering on He +. The two expansions are consistent with each other above the ionisation threshold verifying newly-developed positronium-formation matrix elements. Below the positronium-formation threshold both the single- and two-centre results agree with the elastic-scattering cross sections generated from the phase shifts reported in previous calculations.

Closed inductively coupled plasma cell

DOEpatents

Manning, T.J.; Palmer, B.A.; Hof, D.E.

1990-11-06

A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies is disclosed. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy. 1 fig.

Multifunctional voltage source inverter for renewable energy integration and power quality conditioning.

PubMed

Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

2014-01-01

In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.

Multifunctional Voltage Source Inverter for Renewable Energy Integration and Power Quality Conditioning

PubMed Central

Dai, NingYi; Lam, Chi-Seng; Zhang, WenChen

2014-01-01

In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling VSI when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity. PMID:25177725

Relationship of Dyadic Closeness with Work-Related Stress: A Daily Diary Study

ERIC Educational Resources Information Center

Lavee, Yoav; Ben-Ari, Adital

2007-01-01

We examined the association between work-related stress of both spouses and daily fluctuations in their affective states and dyadic closeness. Daily diary data from 169 Israeli dual-earner couples were analyzed using multilevel modeling. The findings indicate that work stress has no direct effect on dyadic closeness but rather is mediated by the…

Generation and transfer of single photons on a photonic crystal chip.

PubMed

Englund, Dirk; Faraon, Andrei; Zhang, Bingyang; Yamamoto, Yoshihisa; Vucković, Jelena

2007-04-30

We present a basic building block of a quantum network consisting of a quantum dot coupled to a source cavity, which in turn is coupled to a target cavity via a waveguide. The single photon emission from the high-Q/V source cavity is characterized by twelve-fold spontaneous emission (SE) rate enhancement, SE coupling efficiency beta ~ 0.98 into the source cavity mode, and mean wavepacket indistinguishability of ~67%. Single photons are efficiently transferred into the target cavity via the waveguide, with a target/source field intensity ratio of 0.12 +/- 0.01. This system shows great promise as a building block of future on-chip quantum information processing systems.

Pre-marital genetic counselling to consanguineous couples: attitudes, beliefs and decisions among counselled, noncounselled and unrelated couples in Israel.

PubMed

Shiloh, S; Reznik, H; Bat-Miriam-Katznelson, M; Goldman, B

1995-11-01

Semi-structured interviews were conducted with 65 Israeli subjects who received genetic counselling while considering marriage to a close relative, 40 subjects married to a close relative who did not receive pre-marital genetic counselling, and 125 controls married to a nonrelative and never having considered marrying a relative. It was found that 72% of the consanguineous couples who received pre-marital genetic counselling proceeded with their plans and married their relative; 86% of them reported that the counselling influenced their final decision to some degree. Counsellees' appraisals of genetic counselling revealed unfulfilled expectations to obtain more definitive answers, and mixed reactions to the nondirective approach applied by the counsellors. Comparisons between consanguineous and control couples revealed different views about consanguinity in general, and genetic risks in particular. Consanguineous couples, unlike controls, perceived consanguinity as an ordinary form of marriage, and had more favorable attitudes towards it. Compared to the noncounselled consanguineous group, consanguineous couples who received pre-marital genetic counselling had fewer children, estimated their genetic risk as lower but its subjective significance as higher, and perceived genetic disorders as more severe. The implications of these results are discussed from both theoretical and practical standpoints.

Is there a Stobbs factor in atomic-resolution STEM-EELS mapping?

PubMed

Xin, Huolin L; Dwyer, Christian; Muller, David A

2014-04-01

Recent work has convincingly argued that the Stobbs factor-disagreement in contrast between simulated and experimental atomic-resolution images-in ADF-STEM imaging can be accounted for by including the incoherent source size in simulation. However, less progress has been made for atomic-resolution STEM-EELS mapping. Here we have performed carefully calibrated EELS mapping experiments of a [101] DyScO3 single-crystal specimen, allowing atomic-resolution EELS signals to be extracted on an absolute scale for a large range of thicknesses. By simultaneously recording the elastic signal, also on an absolute scale, and using it to characterize the source size, sample thickness and inelastic mean free path, we eliminate all free parameters in the simulation of the core-loss signals. Coupled with double channeling simulations that incorporate both core-loss inelastic scattering and dynamical elastic and thermal diffuse scattering, the present work enables a close scrutiny of the scattering physics in the inelastic channel. We found that by taking into account the effective source distribution determined from the ADF images, both the absolute signal and the contrast in atomic-resolution Dy-M5 maps can be closely reproduced by the double-channeling simulations. At lower energy losses, discrepancies are present in the Sc-L2,3 and Dy-N4,5 maps due to the energy-dependent spatial distribution of the background spectrum, core-hole effects, and omitted complexities in the final states. This work has demonstrated the possibility of using quantitative STEM-EELS for element-specific column-by-column atom counting at higher energy losses and for atomic-like final states, and has elucidated several possible improvements for future theoretical work. Copyright © 2014 Elsevier B.V. All rights reserved.

Self-Sustained Ultrafast Pulsation in Coupled VCSELs

NASA Technical Reports Server (NTRS)

Ning, Cun-Zheng

2001-01-01

High frequency, narrow-band self-pulsating operation is demonstrated in two coupled vertical-cavity surface-emitting lasers (VCSELs). The coupled VCSELs provide an ideal source for high-repetition rate (over 40 GHz), sinusoidal-like modulated laser source with Gaussian-like near- and far-field profiles. We also show that the frequency of the modulation can be tuned by the inter-VCSEL separation or by DC-bias level.

Fan Noise Prediction System Development: Source/Radiation Field Coupling and Workstation Conversion for the Acoustic Radiation Code

NASA Technical Reports Server (NTRS)

Meyer, H. D.

1993-01-01

The Acoustic Radiation Code (ARC) is a finite element program used on the IBM mainframe to predict far-field acoustic radiation from a turbofan engine inlet. In this report, requirements for developers of internal aerodynamic codes regarding use of their program output an input for the ARC are discussed. More specifically, the particular input needed from the Bolt, Beranek and Newman/Pratt and Whitney (turbofan source noise generation) Code (BBN/PWC) is described. In a separate analysis, a method of coupling the source and radiation models, that recognizes waves crossing the interface in both directions, has been derived. A preliminary version of the coupled code has been developed and used for initial evaluation of coupling issues. Results thus far have shown that reflection from the inlet is sufficient to indicate that full coupling of the source and radiation fields is needed for accurate noise predictions ' Also, for this contract, the ARC has been modified for use on the Sun and Silicon Graphics Iris UNIX workstations. Changes and additions involved in this effort are described in an appendix.

A Hammer-Impact, Aluminum, Shear-Wave Seismic Source

USGS Publications Warehouse

Haines, Seth

2007-01-01

Near-surface seismic surveys often employ hammer impacts to create seismic energy. Shear-wave surveys using horizontally polarized waves require horizontal hammer impacts against a rigid object (the source) that is coupled to the ground surface. I have designed, built, and tested a source made out of aluminum and equipped with spikes to improve coupling. The source is effective in a variety of settings, and it is relatively simple and inexpensive to build.

An emerging reactor technology for chemical synthesis: surface acoustic wave-assisted closed-vessel Suzuki coupling reactions.

PubMed

Kulkarni, Ketav; Friend, James; Yeo, Leslie; Perlmutter, Patrick

2014-07-01

In this paper we demonstrate the use of an energy-efficient surface acoustic wave (SAW) device for driving closed-vessel SAW-assisted (CVSAW), ligand-free Suzuki couplings in aqueous media. The reactions were carried out on a mmolar scale with low to ultra-low catalyst loadings. The reactions were driven by heating resulting from the penetration of acoustic energy derived from RF Raleigh waves generated by a piezoelectric chip via a renewable fluid coupling layer. The yields were uniformly high and the reactions could be executed without added ligand and in water. In terms of energy density this new technology was determined to be roughly as efficient as microwaves and superior to ultrasound. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Rotational quenching of H2CO by molecular hydrogen: cross-sections, rates and pressure broadening

NASA Astrophysics Data System (ADS)

Wiesenfeld, L.; Faure, A.

2013-07-01

We compute the rotational quenching rates of the first 81 rotational levels of ortho- and para-H2CO in collision with ortho- and para-H2, for a temperature range of 10-300 K. We make use of the quantum close-coupling and coupled-state scattering methods combined with the high accuracy potential energy surface of Troscompt et al. Rates are significantly different from the scaled rates of H2CO in collision with He; consequently, critical densities are notably lower. We compare a full close-coupling computation of pressure broadening cross-sections with experimental data and show that our results are compatible with the low-temperature measurements of Mengel & De Lucia, for a spin temperature of H2 around 50 K.

Is amplitude loss of sonic waveforms due to intrinsic attenuation or source coupling to the medium?

USGS Publications Warehouse

Lee, Myung W.

2006-01-01

Sonic waveforms acquired in gas-hydrate-bearing sediments indicate strong amplitude loss associated with an increase in sonic velocity. Because the gas hydrate increases sonic velocities, the amplitude loss has been interpreted as due to intrinsic attenuation caused by the gas hydrate in the pore space, which apparently contradicts conventional wave propagation theory. For a sonic source in a fluid-filled borehole, the signal amplitude transmitted into the formation depends on the physical properties of the formation, including any pore contents, in the immediate vicinity of the source. A signal in acoustically fast material, such as gas-hydrate-bearing sediments, has a smaller amplitude than a signal in acoustically slower material. Therefore, it is reasonable to interpret the amplitude loss in the gas-hydrate-bearing sediments in terms of source coupling to the surrounding medium as well as intrinsic attenuation. An analysis of sonic waveforms measured at the Mallik 5L-38 well, Northwest Territories, Canada, indicates that a significant part of the sonic waveform's amplitude loss is due to a source-coupling effect. All amplitude analyses of sonic waveforms should include the effect of source coupling in order to accurately characterize the formation's intrinsic attenuation.

A combined analytical and numerical analysis of the flow-acoustic coupling in a cavity-pipe system

NASA Astrophysics Data System (ADS)

Langthjem, Mikael A.; Nakano, Masami

2018-05-01

The generation of sound by flow through a closed, cylindrical cavity (expansion chamber) accommodated with a long tailpipe is investigated analytically and numerically. The sound generation is due to self-sustained flow oscillations in the cavity. These oscillations may, in turn, generate standing (resonant) acoustic waves in the tailpipe. The main interest of the paper is in the interaction between these two sound sources. An analytical, approximate solution of the acoustic part of the problem is obtained via the method of matched asymptotic expansions. The sound-generating flow is represented by a discrete vortex method, based on axisymmetric vortex rings. It is demonstrated through numerical examples that inclusion of acoustic feedback from the tailpipe is essential for a good representation of the sound characteristics.

Rankine cycle load limiting through use of a recuperator bypass

DOEpatents

Ernst, Timothy C.

2011-08-16

A system for converting heat from an engine into work includes a boiler coupled to a heat source for transferring heat to a working fluid, a turbine that transforms the heat into work, a condenser that transforms the working fluid into liquid, a recuperator with one flow path that routes working fluid from the turbine to the condenser, and another flow path that routes liquid working fluid from the condenser to the boiler, the recuperator being configured to transfer heat to the liquid working fluid, and a bypass valve in parallel with the second flow path. The bypass valve is movable between a closed position, permitting flow through the second flow path and an opened position, under high engine load conditions, bypassing the second flow path.

Electronic Excitation of Furan by Low Energy Electrons

NASA Astrophysics Data System (ADS)

Hargreaves, Leigh R.; Khakoo, Murtadha A.; Lopes, Maria Cristina A.; da Costa, Romarly; Bettega, Marcio H. F.; Lima, Marco A. P.

2011-10-01

We present absolute differential cross section (DCS) measurements and calculations of electron impact excitation of the lowest lying triplet 3B2 and 3A1 electronic states of furan. The incident electron energy range of the present study was 5-15eV. The experimental data were normalized to the elastic DCS data of. The cross sections were determined by unfolding electron energy loss spectra, using an open source data analysis package and the spectroscopic assignments of. The calculations employ a Multichannel Schwinger method with a 9-state closed coupling CI configuration including polarized pseudo-potentials. The preliminary theoretical results show reasonable agreement with experiment below 10eV, but differ at higher energies. Funded by the US NSF and the Brazilian funding agencies CNPq, CAPES and FAPESP.

Coupled analysis on landscape pattern and hydrological processes in Yanhe watershed of China.

PubMed

Li, J; Zhou, Z X

2015-02-01

As a typical experimental Soil and Water Conservation District, Yanhe watershed has long been plagued by soil erosion due to severe human disturbances. Exerting remote sensing (RS) and geographic information system (GIS) technology, this paper firstly analyzed and simulated ecological hydrological process in Yanhe watershed based on SWAT model, constructed a comprehensive landscape indices which was closely related to soil erosion, and reflected the coupling relationship between regional landscape pattern change and soil erosion. The results are as follows: (1) Areas of different land use types remained relatively stable from 1990 to 2000 and then changed drastically from 2000 to 2010, which was characterized by lawn expansion and cultivated land shrinkage. (2) In terms of the spatial heterogeneity of hydrological response unit (HRUs), the correlation coefficient of seven selected landscape indices and runoff was very small, and cannot pass all significant testing. But correlation between the indices and sediment yield except for Total Core Area (TCA) and Interspersion and Juxtaposition Index (IJI) was remarkable. (3) According to 'the source-sink' theory of soil erosion, new landscape index-slope-HRU landscape index (SHLI) was built, and reflected the relationship between landscape pattern and soil erosion processes to a certain extent. (4) Coupling relationship between SHLI in 2010 and annual sediment was very prominent. In the sub-basin scale, SHLI has obvious regional differentiation from annual sediment. Copyright © 2014 Elsevier B.V. All rights reserved.

H- radio frequency source development at the Spallation Neutron Source.

PubMed

Welton, R F; Dudnikov, V G; Gawne, K R; Han, B X; Murray, S N; Pennisi, T R; Roseberry, R T; Santana, M; Stockli, M P; Turvey, M W

2012-02-01

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ∼38 mA peak current in the linac and an availability of ∼90%. H(-) beam pulses (∼1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ∼60 kW) of a copper antenna that has been encased with a thickness of ∼0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ∼99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ∼75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance∕installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ∼100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Photon pair source via two coupling single quantum emitters

NASA Astrophysics Data System (ADS)

Peng, Yong-Gang; Zheng, Yu-Jun

2015-10-01

We study the two coupling two-level single molecules driven by an external field as a photon pair source. The probability of emitting two photons, P2, is employed to describe the photon pair source quality in a short time, and the correlation coefficient RAB is employed to describe the photon pair source quality in a long time limit. The results demonstrate that the coupling single quantum emitters can be considered as a stable photon pair source. Project supported by the National Natural Science Foundation of China (Grand Nos. 91021009, 21073110, and 11374191), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2013AQ020), the Postdoctoral Science Foundation of China (Grant No. 2013M531584), the Doctoral Program of Higher Education of China (Grant Nos. 20130131110005 and 20130131120006), and the Taishan Scholarship Project of Shandong Province, China.

Minding the close relationship.

PubMed

Harvey, J H; Omarzu, J

1997-01-01

In this theoretical analysis, we argue that a process referred to as minding is essential for a couple to feel mutually close and satisfied in a close relationship over a long period Minding represents a package of mutual self-disclosure, other forms of goal-oriented behavior aimed at facilitating the relationship, and attributions about self's and other's motivations, intentions, and Mort in the relationship. Self-disclosure and attribution activities in minding are aimed at getting to know the other, trying to understand the other's motivations and deeper disposition as they pertain to the relationship, and showing respect and acceptance for knowledge gained about other. We link the concept of minding to other major ideas and literatures about how couples achieve closeness: self-disclosure and social penetration, intimacy, empathy and empathic accuracy, and love and self-expansion. We argue that the minding process articulated here has not previously been delineated and that it is a useful composite notion about essential steps in bonding among humans. We also argue that the minding concept stretches our understanding of the interface of attribution and close relationships. We present research possibilities and implications and consider possible alternative positions and counter arguments about the merits of the minding idea for close relationship satisfaction.

Electron impact excitation of the n = 2 to n = 3 transition in atomic hydrogen near threshold

NASA Astrophysics Data System (ADS)

Hata, J.; Morgan, L. A.; McDowell, M. R. C.

1980-06-01

Close-coupling calculations of electron impact excitation of the n = 2 to n = 3 transition of atomic hydrogen at energies below the n = 4 threshold are presented. The algebraic variational close-coupling code of Morgan (1980) with an eighteen-state basis was used to obtain cross sections at eight impact energies from 2.04 to 2.45 eV, and calculations in a six-state close-coupling model were compared with the six-state calculations of Burke et al. (1967). The six-state values are found to be in satisfactory agreement with the exception of the singlet contribution to the 2s-3s transition. Near the n = 3 threshold the cross section obtained in the full calculation is found to be almost a factor of 2 lower than that predicted by Johnson (1972), thus explaining in part the discrepancy between Johnson's results and experiments on hydrogen plasmas. Estimates of rate coefficients based on the cross sections and assuming a Maxwellian velocity distribution, however, are shown to remain in disagreement with experiment.

Field stabilization studies for a radio frequency quadrupole accelerator

NASA Astrophysics Data System (ADS)

Gaur, R.; Kumar, V.

2014-07-01

The Radio Frequency Quadrupole (RFQ) linear accelerator is an accelerator that efficiently focuses, bunches and accelerates a high intensity DC beam from an ion source, for various applications. Unlike other conventional RF linear accelerators, the electromagnetic mode used for its operation is not the lowest frequency mode supported by the structure. In a four vane type RFQ, there are several undesired electromagnetic modes having frequency close to that of the operating mode. While designing an RFQ accelerator, care must be taken to ensure that the frequencies of these nearby modes are sufficiently separated from the operating mode. If the undesired nearby modes have frequencies close to the operating mode, the electromagnetic field pattern in the presence of geometrical errors will not be stabilized to the desired field profile, and will be perturbed by the nearby modes. This will affect the beam dynamics and reduce the beam transmission. In this paper, we present a detailed study of the electromagnetic modes supported, which is followed by calculations for implementation of suitable techniques to make the desired operating mode stable against mixing with unwanted modes for an RFQ being designed for the proposed Indian Spallation Neutron Source (ISNS) project at Raja Ramanna Centre for Advanced Technology, Indore. Resonant coupling scheme, along with dipole stabilization rods has been proposed to increase the mode separation. The paper discusses the details of a generalized optimization procedure that has been used for the design of mode stabilization scheme.

Seismic moulin tremor

NASA Astrophysics Data System (ADS)

Roeoesli, Claudia; Walter, Fabian; Ampuero, Jean-Paul; Kissling, Edi

2016-08-01

Through glacial moulins, meltwater is routed from the glacier surface to its base. Moulins are a main feature feeding subglacial drainage systems and thus influencing basal motion and ice dynamics, but their geometry remains poorly known. Here we show that analysis of the seismic wavefield generated by water falling into a moulin can help constrain its geometry. We present modeling results of hour-long seimic tremors emitted from a vertical moulin shaft, observed with a seismometer array installed at the surface of the Greenland Ice Sheet. The tremor was triggered when the moulin water level exceeded a certain height, which we associate with the threshold for the waterfall to hit directly the surface of the moulin water column. The amplitude of the tremor signal changed over each tremor episode, in close relation to the amount of inflowing water. The tremor spectrum features multiple prominent peaks, whose characteristic frequencies are distributed like the resonant modes of a semiopen organ pipe and were found to depend on the moulin water level, consistent with a source composed of resonant tube waves (water pressure waves coupled to elastic deformation of the moulin walls) along the water-filled moulin pipe. Analysis of surface particle motions lends further support to this interpretation. The seismic wavefield was modeled as a superposition of sustained wave radiation by pressure sources on the side walls and at the bottom of the moulin. The former was found to dominate the wave field at close distance and the latter at large distance to the moulin.

Closed-Form 3-D Localization for Single Source in Uniform Circular Array with a Center Sensor

NASA Astrophysics Data System (ADS)

Bae, Eun-Hyon; Lee, Kyun-Kyung

A novel closed-form algorithm is presented for estimating the 3-D location (azimuth angle, elevation angle, and range) of a single source in a uniform circular array (UCA) with a center sensor. Based on the centrosymmetry of the UCA and noncircularity of the source, the proposed algorithm decouples and estimates the 2-D direction of arrival (DOA), i.e. azimuth and elevation angles, and then estimates the range of the source. Notwithstanding a low computational complexity, the proposed algorithm provides an estimation performance close to that of the benchmark estimator 3-D MUSIC.

Source memory for action in young and older adults: self vs. close or unknown others.

PubMed

Rosa, Nicole M; Gutchess, Angela H

2011-09-01

The present study examines source memory for actions (e.g., placing items in a suitcase). For both young and older adult participants, source memory for actions performed by the self was better than memory for actions performed by either a known (close) or unknown other. In addition, neither young nor older adults were more likely to confuse self with close others than with unknown others. Results suggest an advantage in source memory for actions performed by the self compared to others, possibly associated with sensorimotor cues that are relatively preserved in aging.

Mutual caring of elderly Korean couples.

PubMed

Ahn, Taesung; Kim, Kwibun

2007-01-01

The article described the experiences of elderly couples caring for each other using ethnographic methodology. Ten couples were interviewed in depth. The presence of a support system was found to be the primary requirement of elderly couples. Three taxonomies comprised the support system: (a) desire for respect in care, (b) desire for reliance, and (c) expectation. The close linkage and interaction of desire for care, desire for reliance, and expectations were confirmed. The findings suggested establishing a holistic support network for these elders.

Time Delay Effect in a Living Coupled Oscillator System with the Plasmodium of Physarum polycephalum

NASA Astrophysics Data System (ADS)

Takamatsu, Atsuko; Fujii, Teruo; Endo, Isao

2000-08-01

A living coupled oscillator system was constructed by a cell patterning method with a plasmodial slime mold, in which parameters such as coupling strength and distance between the oscillators can be systematically controlled. Rich oscillation phenomena between the two-coupled oscillators, namely, desynchronizing and antiphase/in-phase synchronization were observed according to these parameters. Both experimental and theoretical approaches showed that these phenomena are closely related to the time delay effect in interactions between the oscillators.

Closed-channel contribution in the BCS-BEC crossover regime of an ultracold Fermi gas with an orbital Feshbach resonance

NASA Astrophysics Data System (ADS)

Mondal, S.; Inotani, D.; Ohashi, Y.

2018-03-01

We theoretically investigate strong-coupling properties of an ultracold Fermi gas with an orbital Feshbach resonance (OFR). Including tunable pairing interaction associated with an OFR within the framework of the strong-coupling theory developed by Nozières and Schmitt-Rink (NSR), we examine the occupation of the closed channel. We show that, although the importance of the closed channel is characteristic of the system with an OFR, the occupation number of the closed channel is found to actually be very small at the superfluid phase transition temperature T c, in the whole BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover region, when we use the scattering parameters for an ultracold 173Yb Fermi gas. The occupation of the closed channel increases with increasing the temperature above T c, which is more remarkable for a stronger pairing interaction. We also present a prescription to remove effects of an experimentally inaccessible deep bound state from the NSR formalism, which we meet when we theoretically deal with a 173Yb Fermi gas with an OFR.

Capacitively coupled pickup in MCP-based photodetectors using a conductive metallic anode

NASA Astrophysics Data System (ADS)

Angelico, E.; Seiss, T.; Adams, B.; Elagin, A.; Frisch, H.; Spieglan, E.

2017-02-01

We have designed and tested a robust 20×20 cm2 thin metal film internal anode capacitively coupled to an external array of signal pads or micro-strips for use in fast microchannel plate photodetectors. The internal anode, in this case a 10 nm-thick NiCr film deposited on a 96% pure Al2O3 3 mm-thick ceramic plate and connected to HV ground, provides the return path for the electron cascade charge. The multi-channel pickup array consists of a printed-circuit card or glass plate with metal signal pickups on one side and the signal ground plane on the other. The pickup can be put in close proximity to the bottom outer surface of the sealed photodetector, with no electrical connections through the photodetector hermetic vacuum package other than a single ground connection to the internal anode. Two pickup patterns were tested using a small commercial MCP-PMT as the signal source: 1) parallel 50 Ω 25-cm-long micro-strips with an analog bandwidth of 1.5 GHz, and 2) a 20×20 cm2 array of 2-dimensional square 'pads' with sides of 1.27 cm or 2.54 cm. The rise-time of the fast input pulse is maintained for both pickup patterns. For the pad pattern, we observe 80% of the directly coupled amplitude. For the strip pattern we measure 34% of the directly coupled amplitude on the central strip of a broadened signal. The physical decoupling of the photodetector from the pickup pattern allows easy customization for different applications while maintaining high analog bandwidth.

Uniform and nonuniform V-shaped planar arrays for 2-D direction-of-arrival estimation

NASA Astrophysics Data System (ADS)

Filik, T.; Tuncer, T. E.

2009-10-01

In this paper, isotropic and directional uniform and nonuniform V-shaped arrays are considered for azimuth and elevation direction-of-arrival (DOA) angle estimation simultaneously. It is shown that the uniform isotropic V-shaped arrays (UI V arrays) have no angle coupling between the azimuth and elevation DOA. The design of the UI V arrays is investigated, and closed form expressions are presented for the parameters of the UI V arrays and nonuniform V arrays. These expressions allow one to find the isotropic V angle for different array types. The DOA performance of the UI V array is compared with the uniform circular array (UCA) for correlated signals and in case of mutual coupling between array elements. The modeling error for the sensor positions is also investigated. It is shown that V array and circular array have similar robustness for the position errors while the performance of UI V array is better than the UCA for correlated source signals and when there is mutual coupling. Nonuniform V-shaped isotropic arrays are investigated which allow good DOA performance with limited number of sensors. Furthermore, a new design method for the directional V-shaped arrays is proposed. This method is based on the Cramer-Rao Bound for joint estimation where the angle coupling effect between the azimuth and elevation DOA angles is taken into account. The design method finds an optimum angle between the linear subarrays of the V array. The proposed method can be used to obtain directional arrays with significantly better DOA performance.

Recommended design and fabrication sequence of AMTEC test assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schock, A.; Kumar, V.; Noravian, H.

1998-01-01

A series of previous OSC papers described: 1) a novel methodology for the coupled thermal, fluid flow, and electrical analysis of multitube AMTEC (Alkali Metal Thermal-to-Electric Conversion) cells; 2) the application of that methodology to determine the effect of numerous design variations on the cell{close_quote}s performance, leading to selection and performance characterization of an OSC-recommended cell design; and 3) the design, analysis, and characterization of an OSC-generated power system design combining sixteen of the above AMTEC cells with two or three GPHS (General Purpose Heat Source) radioisotope heat source modules, and the applicability of those power systems to future spacemore » missions ({ital e.g.} Pluto Express and Europa Orbiter) under consideration by NASA. The OSC system design studies demonstrated the critical importance of the thermal insulation subsystem, and culminated in a design in which the eight AMTEC cells on each end of the heat source stack are embedded in Min-K fibrous insulation, and the Min-K and the GPHS modules are surrounded by graded-length Mo multifoil insulation. The present paper depicts the OSC-recommended AMTEC cell and generator designs, and identifies the need for an electrically heated (scaled-down but otherwise prototypic) test assembly for the experimental validation of the generator{close_quote}s system performance predictions. It then describes the design of an OSC-recommended test assembly consisting of an electrical heater enclosed in a graphite box to simulate the radioisotope heat source, four series-connected prototypic AMTEC cells of the OSC-recommended configuration, and a prototypic hybrid insulation package consisting of Min-K and graded-length Mo multifoils. Finally, the paper describes and illustrates an OSC-recommended detailed fabrication sequence and procedure for the above cell and test assembly. That fabrication procedure is being implemented by AMPS, Inc. with the support of DOE{close_quote}s Oak Ridge and Mound Laboratories, and the Air Force Phillips Laboratory (AFPL) will test the performance of the assembly over a range of input thermal powers and output voltages. The experimentally measured performance will be compared with the results of OSC analyses of the same insulated test assembly over the same range of operating parameters. {copyright} {ital 1998 American Institute of Physics.}« less

Optical Spectroscopy Of Charged Quantum Dot Molecules

NASA Astrophysics Data System (ADS)

Scheibner, M.; Bracker, A. S.; Stinaff, E. A.; Doty, M. F.; Gammon, D.; Ponomarev, I. V.; Reinecke, T. L.; Korenev, V. L.

2007-04-01

Coupling between two closely spaced quantum dots is observed by means of photoluminescence spectroscopy. Hole coupling is realized by rational crystal growth and heterostructure design. We identify molecular resonances of different excitonic charge states, including the important case of a doubly charged quantum dot molecule.

Coupled spin and electron-phonon interaction at the Tl/Si(111) surface from relativistic first-principles calculations

NASA Astrophysics Data System (ADS)

Garcia-Goiricelaya, Peio; Gurtubay, Idoia G.; Eiguren, Asier

2018-05-01

We investigate the role played by the electron spin and the spin-orbit interaction in the exceptional electron-phonon coupling at the Tl/Si(111) surface. Our first-principles calculations demonstrate that the particular spin pattern of this system dominates the whole low-energy electron-phonon physics, which is remarkably explained by forbidden spin-spin scattering channels. In particular, we show that the strength of the electron-phonon coupling appears drastically weakened for surface states close to the K ¯ and K'¯ valleys, which is unambiguously attributed to the spin polarization through the associated modulation due to the spinor overlaps. However, close to the Γ ¯ point, the particular spin pattern in this area is less effective in damping the electron-phonon matrix elements, and the result is an exceptional strength of the electron-phonon coupling parameter λ ˜1.4 . These results are rationalized by a simple model for the electron-phonon matrix elements including the spinor terms.

PARALLEL MEASUREMENT AND MODELING OF TRANSPORT IN THE DARHT II BEAMLINE ON ETA II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chambers, F W; Raymond, B A; Falabella, S

To successfully tune the DARHT II transport beamline requires the close coupling of a model of the beam transport and the measurement of the beam observables as the beam conditions and magnet settings are varied. For the ETA II experiment using the DARHT II beamline components this was achieved using the SUICIDE (Simple User Interface Connecting to an Integrated Data Environment) data analysis environment and the FITS (Fully Integrated Transport Simulation) model. The SUICIDE environment has direct access to the experimental beam transport data at acquisition and the FITS predictions of the transport for immediate comparison. The FITS model ismore » coupled into the control system where it can read magnet current settings for real time modeling. We find this integrated coupling is essential for model verification and the successful development of a tuning aid for the efficient convergence on a useable tune. We show the real time comparisons of simulation and experiment and explore the successes and limitations of this close coupled approach.« less

Tsunami Ionospheric warning and Ionospheric seismology

NASA Astrophysics Data System (ADS)

Lognonne, Philippe; Rolland, Lucie; Rakoto, Virgile; Coisson, Pierdavide; Occhipinti, Giovanni; Larmat, Carene; Walwer, Damien; Astafyeva, Elvira; Hebert, Helene; Okal, Emile; Makela, Jonathan

2014-05-01

The last decade demonstrated that seismic waves and tsunamis are coupled to the ionosphere. Observations of Total Electron Content (TEC) and airglow perturbations of unique quality and amplitude were made during the Tohoku, 2011 giant Japan quake, and observations of much lower tsunamis down to a few cm in sea uplift are now routinely done, including for the Kuril 2006, Samoa 2009, Chili 2010, Haida Gwai 2012 tsunamis. This new branch of seismology is now mature enough to tackle the new challenge associated to the inversion of these data, with either the goal to provide from these data maps or profile of the earth surface vertical displacement (and therefore crucial information for tsunami warning system) or inversion, with ground and ionospheric data set, of the various parameters (atmospheric sound speed, viscosity, collision frequencies) controlling the coupling between the surface, lower atmosphere and the ionosphere. We first present the state of the art in the modeling of the tsunami-atmospheric coupling, including in terms of slight perturbation in the tsunami phase and group velocity and dependance of the coupling strength with local time, ocean depth and season. We then show the confrontation of modelled signals with observations. For tsunami, this is made with the different type of measurement having proven ionospheric tsunami detection over the last 5 years (ground and space GPS, Airglow), while we focus on GPS and GOCE observation for seismic waves. These observation systems allowed to track the propagation of the signal from the ground (with GPS and seismometers) to the neutral atmosphere (with infrasound sensors and GOCE drag measurement) to the ionosphere (with GPS TEC and airglow among other ionospheric sounding techniques). Modelling with different techniques (normal modes, spectral element methods, finite differences) are used and shown. While the fits of the waveform are generally very good, we analyse the differences and draw direction of future studies and improvements, enabling the integration of lateral variations of the solid earth, bathymetry or atmosphere, finite model sources, non-linearity of the waves and better attenuation and coupling processes. All these effects are revealed by phase or amplitude discrepancies in selected observations. We then present goals and first results of source inversions, with a focus on estimations of the sea level uplift location and amplitude, either by using GPS networks close from the epicentre or, for tsunamis, GPS of the Hawaii Islands.

Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

NASA Technical Reports Server (NTRS)

Rengarajan, Sembiam

2012-01-01

Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside. The traveling wave planar slot array consists of a long feed waveguide containing resonant-centered inclined coupling slots in the broad wall, coupling power into an array of stacked radiating waveguides orthogonal to it. The radiating waveguides consist of longitudinal offset radiating slots in a standing wave configuration. For the traveling wave feed of a planar slot array, one has to design the tilt angle and length of each coupling slot such that the amplitude and phase of excitation of each radiating waveguide are close to the desired values. The coupling slot spacing is chosen for an appropriate beam squint. Scattering matrix parameters of resonant coupling slots are used in the design process to produce appropriate excitations of radiating waveguides with constraints placed only on amplitudes. Since the radiating slots in each radiating waveguide are designed to produce a certain total admittance, the scattering (S) matrix of each coupling slot is reduced to a 2x2 matrix. Elements of each 2x2 S-matrix and the amount of coupling into the corresponding radiating waveguide are expressed in terms of the element S11. S matrices are converted into transmission (T) matrices, and the T matrices are multiplied to cascade the coupling slots and waveguide sections, starting from the load end and proceeding towards the source. While the use of non-resonant coupling slots may provide an additional degree of freedom in the design, resonant coupling slots simplify the design process. The amplitude of the wave going to the load is set at unity. The S11 parameter, r of the coupling slot closest to the load, is assigned an arbitrary value. A larger value of r will reduce the power dissipated in the load while increasing the reflection coefficient at the input port. It is now possible to obtain the excitation of the radiating waveguide closest to the load and the coefficients of the wave incident and reflected at the input port of this coupling slot. The next coupling slot parameter, r , is chosen to realize the excitation of that radiating waveguide. One continues this process moving towards the source, until all the coupling slot parameters r and hence the S11 parameter of the 4-port coupler, r, are known for each coupling slot. The goal is to produce the desired array aperture distribution in the feed direction. From an interpolation of the computed moment method data for the slot parameters, all the coupling slot tilt angles and lengths are obtained. From the excitations of the radiating waveguides computed from the coupling values, radiating slot parameters may be obtained so as to attain the desired total normalized slot admittances. This process yields the radiating slot parameters, offsets, and lengths. The design is repeated by choosing different values of r for the last coupling slot until the percentage of power dissipated in the load and the input reflection coefficient values are satisfactory. Numerical results computed for the radiation pattern, the tilt angles and lengths of coupling slots, and excitation phases of the radiating waveguides, are presented for an array with uniform amplitude excitation. The design process has been validated using computer simulations. This design procedure is valid for non-uniform amplitude excitations as well.

Observation of a Rayleigh Wave Induced by Infrasonic Elephant Vocalizations: a Possible Communication Mode?

NASA Astrophysics Data System (ADS)

Gunther, R.; O'Connell-Rodwell, C. E.; Klemperer, S.; Rodwell, T. C.; Haines, S.; Goldman, M.; Evans, J. R.

2003-12-01

A variety of animals such as arthropods, amphibians, reptiles, fish and rodents communicate by creating and sensing ground vibrations rather than, or in addition to, sound waves. There is evidence that this may be the case for elephants as well. We set out to characterize the Rayleigh wave generated by near-source coupling during elephant low frequency rumble vocalizations (25 Hz lasting 3-7 seconds), using standard engineering-scale seismology equipment. We used a 60-channel GeometricsT seismograph to record data from vertical and horizontal geophones and from microphones, placed along a 168-m cable near Salinas, CA. Seismic wave-speed for body waves (1400 m/s) and surface waves (440 m/s) and the air-wave velocity (340 m/s) were established using a sledgehammer source. Trained elephants vocalized on command at one end of our seismic recording spread. The vocalization was strongest at 25 to 28 Hz (with strong higher harmonics), with a duration of 3 to 4 seconds, and repeated multiple times with separations of 2 to 5 seconds. Unlike an explosive seismic source, the duration of the elephant vocalization is tens of times longer than the characteristic period of the source, lasting far longer than the total propagation time along our seismic recording spread (less than 500 ms), so that different propagating modes cannot be separated by different arrival times. Unlike a VibroseisTM sweep, the elephant rumble is relatively monotonic with no characteristic onset, ruling out the use of deconvolution techniques to recognize the signals. Using a semblance technique applied to linear moveouts on narrow-bandpass-filtered data, coupled with forward modeling, we demonstrate that the complex waves observed are the interference of an air wave and a Rayleigh wave traveling at the appropriate velocities. The Rayleigh wave appears to be generated at or close to the elephant, either by coupling through the elephant's body or through the air near the body to the ground. In our experiments, the amplitudes of both the elephant-coupled Rayleigh wave and the elephant-driven airwave had decayed to almost ambient noise levels at the end of our 168-m-long recording spread. This was most likely due to the high ambient-noise levels during our experiment. Free-ranging African elephants have been shown to respond to low-frequency calls of other elephants at ranges of 2 km with an ideal outer limit of 10 km. Because a surface wave decays at only 1/r, we speculate that wild elephants may detect the Rayleigh waves of other elephants via bone conduction or somatosensory reception or both, and hence may communicate at greater distances than possible using infrasonic calls transmitted through the atmosphere.

Absolute cascade-free cross-sections for the 2S to 2P transition in Zn(+) using electron-energy-loss and merged-beams methods

NASA Technical Reports Server (NTRS)

Smith, Steven J.; Man, K.-F.; Chutjian, A.; Mawhorter, R. J.; Williams, I. D.

1991-01-01

Absolute cascade-free excitation cross-sections in an ion have been measured for the resonance 2S to 2P transition in Zn(+) using electron-energy-loss and merged electron-ion beams methods. Measurements were carried out at electron energies of below threshold to 6 times threshold. Comparisons are made with 2-, 5-, and 15-state close-coupling and distorted-wave theories. There is good agreement between experiment and the 15-state close-coupling cross-sections over the energy range of the calculations.

Broadening of the R(0) and P(2) Lines in the 13CO Fundamental by Helium Atoms from 300 K down to 12 K: Measurements and Comparison with Close-Coupling Calculations

NASA Technical Reports Server (NTRS)

Thibault, F.; Mantz, A. W.; Claveau, C.; Valentin, A.; Hurtmans, D.

2007-01-01

We present measurements of He-broadening parameters for the R(0) and O(2) lines in the fundamental band of 13CO at different temperatures between 12K and room temperature. The broadening parameters are determined, taking into account confinement narrowing, by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The pressure broadening cross sections are deduced and compared to close-coupling calculations and earlier results obtained for rotational transitions of 12 CO.

Quantum phase transition in dimerised spin-1/2 chains

NASA Astrophysics Data System (ADS)

Das, Aparajita; Bhadra, Sreeparna; Saha, Sonali

2015-11-01

Quantum phase transition in dimerised antiferromagnetic Heisenberg spin chain has been studied. A staircase structure in the variation of concurrence within strongly coupled pairs with that of external magnetic field has been observed indicating multiple critical (or critical like) points. Emergence of entanglement due to external magnetic field or magnetic entanglement is observed for weakly coupled spin pairs too in the same dimer chain. Though closed dimerised isotropic XXX Heisenberg chains with different dimer strengths were mainly explored, analogous studies on open chains as well as closed anisotropic (XX interaction) chains with tilted external magnetic field have also been studied.

Coupling Meteorology, Metal Concentrations, and Pb Isotopes for Source Attribution in Archived Precipitation Samples

EPA Science Inventory

A technique that couples lead (Pb) isotopes and multi-element concentrations with meteorological analysis was used to assess source contributions to precipitation samples at the Bondville, Illinois USA National Trends Network (NTN) site. Precipitation samples collected over a 16 ...

Scalar-tensor theory of gravitation with negative coupling constant

NASA Technical Reports Server (NTRS)

Smalley, L. L.; Eby, P. B.

1976-01-01

The possibility of a Brans-Dicke scalar-tensor gravitation theory with a negative coupling constant is considered. The admissibility of a negative-coupling theory is investigated, and a simplified cosmological solution is obtained which allows a negative derivative of the gravitation constant. It is concluded that a Brans-Dicke theory with a negative coupling constant can be a viable alternative to general relativity and that a large negative value for the coupling constant seems to bring the original scalar-tensor theory into close agreement with perihelion-precession results in view of recent observations of small solar oblateness.

Plasmon-Exciton Coupling Interaction for Surface Catalytic Reactions.

PubMed

Wang, Jingang; Lin, Weihua; Xu, Xuefeng; Ma, Fengcai; Sun, Mengtao

2018-05-01

In this review, we firstly reveal the physical principle of plasmon-exciton coupling interaction with steady absorption spectroscopy, and ultrafast transition absorption spectroscopy, based on the pump-prop technology. Secondly, we introduce the fabrication of electro-optical device of two-dimensional semiconductor-nanostructure noble metals hybrid, based on the plasmon-exciton coupling interactions. Thirdly, we introduce the applications of plasmon-exciton coupling interaction in the field of surface catalytic reactions. Lastly, the perspective of plasmon-exciton coupling interaction and applications closed this review. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Symbolic joint entropy reveals the coupling of various brain regions

NASA Astrophysics Data System (ADS)

Ma, Xiaofei; Huang, Xiaolin; Du, Sidan; Liu, Hongxing; Ning, Xinbao

2018-01-01

The convergence and divergence of oscillatory behavior of different brain regions are very important for the procedure of information processing. Measurements of coupling or correlation are very useful to study the difference of brain activities. In this study, EEG signals were collected from ten subjects under two conditions, i.e. eyes closed state and idle with eyes open. We propose a nonlinear algorithm, symbolic joint entropy, to compare the coupling strength among the frontal, temporal, parietal and occipital lobes and between two different states. Instead of decomposing the EEG into different frequency bands (theta, alpha, beta, gamma etc.), the novel algorithm is to investigate the coupling from the entire spectrum of brain wave activities above 4Hz. The coupling coefficients in two states with different time delay steps are compared and the group statistics are presented as well. We find that the coupling coefficient of eyes open state with delay consistently lower than that of eyes close state across the group except for one subject, whereas the results without delay are not consistent. The differences between two brain states with non-zero delay can reveal the intrinsic inter-region coupling better. We also use the well-known Hénon map data to validate the algorithm proposed in this paper. The result shows that the method is robust and has a great potential for other physiologic time series.

Phonon coupling in optical transitions for singlet-triplet pairs of bound excitons in semiconductors

NASA Astrophysics Data System (ADS)

Pistol, M. E.; Monemar, B.

1986-05-01

A model is presented for the observed strong difference in selection rules for coupling of phonons in the one-phonon sideband of optical spectra related to bound excitons in semiconductors. The present treatment is specialized to the case of a closely spaced pair of singlet-triplet character as the lowest electronic states, as is common for bound excitons associated with neutral complexes in materials like GaP and Si. The optical transition for the singlet bound-exciton state is found to couple strongly only to symmetric A1 modes. The triplet state has a similar coupling strength to A1 modes, but in addition strong contributions are found for replicas corresponding to high-density-of-states phonons TAX, LAX, and TOX. This can be explained by a treatment of particle-phonon coupling beyond the ordinary adiabatic approximation. A weak mixing between the singlet and triplet states is mediated by the phonon coupling, as described in first-order perturbation theory. The model derived in this work, for such phonon-induced mixing of closely spaced electronic states, is shown to explain the observed phonon coupling for several bound-exciton systems of singlet-triplet character in GaP. In addition, the observed oscillator strength of the forbidden triplet state may be explained as partly derived from phonon-induced mixing with the singlet state, which has a much larger oscillator strength.

Self-closing shielded container for use with radioactive materials

DOEpatents

Smith, Jay E.

1984-01-01

A container for storage of radioactive material comprising a container body nd a closure member. The closure member being coupled to the container body to enable the closure body to move automatically from a first position (e.g., closed) to a second position (open).

Self-closing shielded container for use with radioactive materials

DOEpatents

Smith, J.E.

A container for storage of radioactive material comprises a container body and a closure member. The closure member is coupled to the container body to enable the closure body to move automatically from a first position (e.g., closed) to a second position (open).

DHA-Containing Oilseed: A Timely Solution for the Sustainability Issues Surrounding Fish Oil Sources of the Health-Benefitting Long-Chain Omega-3 Oils

PubMed Central

Kitessa, Soressa M.; Abeywardena, Mahinda; Wijesundera, Chakra; Nichols, Peter D.

2014-01-01

Benefits of long-chain (≥C20) omega-3 oils (LC omega-3 oils) for reduction of the risk of a range of disorders are well documented. The benefits result from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); optimal intake levels of these bioactive fatty acids for maintenance of normal health and prevention of diseases have been developed and adopted by national and international health agencies and science bodies. These developments have led to increased consumer demand for LC omega-3 oils and, coupled with increasing global population, will impact on future sustainable supply of fish. Seafood supply from aquaculture has risen over the past decades and it relies on harvest of wild catch fisheries also for its fish oil needs. Alternate sources of LC omega-3 oils are being pursued, including genetically modified soybean rich in shorter-chain stearidonic acid (SDA, 18:4ω3). However, neither oils from traditional oilseeds such as linseed, nor the SDA soybean oil have shown efficient conversion to DHA. A recent breakthrough has seen the demonstration of a land plant-based oil enriched in DHA, and with omega-6 PUFA levels close to that occurring in marine sources of EPA and DHA. We review alternative sources of DHA supply with emphasis on the need for land plant oils containing EPA and DHA. PMID:24858407

DHA-containing oilseed: a timely solution for the sustainability issues surrounding fish oil sources of the health-benefitting long-chain omega-3 oils.

PubMed

Kitessa, Soressa M; Abeywardena, Mahinda; Wijesundera, Chakra; Nichols, Peter D

2014-05-22

Benefits of long-chain (≥C20) omega-3 oils (LC omega-3 oils) for reduction of the risk of a range of disorders are well documented. The benefits result from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); optimal intake levels of these bioactive fatty acids for maintenance of normal health and prevention of diseases have been developed and adopted by national and international health agencies and science bodies. These developments have led to increased consumer demand for LC omega-3 oils and, coupled with increasing global population, will impact on future sustainable supply of fish. Seafood supply from aquaculture has risen over the past decades and it relies on harvest of wild catch fisheries also for its fish oil needs. Alternate sources of LC omega-3 oils are being pursued, including genetically modified soybean rich in shorter-chain stearidonic acid (SDA, 18:4ω3). However, neither oils from traditional oilseeds such as linseed, nor the SDA soybean oil have shown efficient conversion to DHA. A recent breakthrough has seen the demonstration of a land plant-based oil enriched in DHA, and with omega-6 PUFA levels close to that occurring in marine sources of EPA and DHA. We review alternative sources of DHA supply with emphasis on the need for land plant oils containing EPA and DHA.

Ocean to land moisture transport is reflected in sea surface salinity

NASA Astrophysics Data System (ADS)

Schmitt, R. W.; Schanze, J. J.; Li, L.; Ummenhofer, C.

2016-02-01

The ocean has a much larger water cycle than the land, with global ocean evaporation of 13 Sverdrups being 10 times larger than the sum of all river flows. This disparity and the different dynamics of dry surfaces, have led to an unfortunate disconnect between terrestrial hydrologists and oceanographers. Here we show that there is in fact a close coupling between the water cycles of ocean and land. In both cases there is much local recycling of moisture, since it does not travel far in the atmosphere. We argue that the most important water cycle variable is the net export (or import) of water from (to) an area. Over the open ocean this is just evaporation minus precipitation (E-P). The "P vs E" plot is a valuable tool for identifying the source and sink regions of the water cycle. The subtropical high pressure systems are the source regions of the water cycle, with a global net export of 4.5 Sv. The three sinks are the ITCZ in the tropics, the high latitude subpolar lows, and the land, all at about 1.5 Sv, though the subpolar lows do receive more water than the tropics, where high rainfall is maintained by much local recycling. Of course, the signature of E-P in the open ocean is the sea surface salinity (SSS), as only net freshwater fluxes can create salinity variations. With the land receiving 1/3 of the oceanic export, we should expect close coupling between terrestrial rainfall and the salinity of nearby oceans, and SSS variations have indeed been found to be valuable for seasonal rainfall forecasts on land. The remarkable 3-6 month lead of winter-spring SSS over summer rainfall appears to be mediated by the recycling process on land through soil moisture. When soil moisture is high, terrestrial regions can become more oceanic-like, with solar heating energizing evaporation and leading to down-stream propagation of the moisture signal (the "brown ocean" effect). The correlation of high SSS with high rainfall promises to be a very valuable seasonal prediction tool for a variety of regions around the world.

Modeling deep brain stimulation: point source approximation versus realistic representation of the electrode

NASA Astrophysics Data System (ADS)

Zhang, Tianhe C.; Grill, Warren M.

2010-12-01

Deep brain stimulation (DBS) has emerged as an effective treatment for movement disorders; however, the fundamental mechanisms by which DBS works are not well understood. Computational models of DBS can provide insights into these fundamental mechanisms and typically require two steps: calculation of the electrical potentials generated by DBS and, subsequently, determination of the effects of the extracellular potentials on neurons. The objective of this study was to assess the validity of using a point source electrode to approximate the DBS electrode when calculating the thresholds and spatial distribution of activation of a surrounding population of model neurons in response to monopolar DBS. Extracellular potentials in a homogenous isotropic volume conductor were calculated using either a point current source or a geometrically accurate finite element model of the Medtronic DBS 3389 lead. These extracellular potentials were coupled to populations of model axons, and thresholds and spatial distributions were determined for different electrode geometries and axon orientations. Median threshold differences between DBS and point source electrodes for individual axons varied between -20.5% and 9.5% across all orientations, monopolar polarities and electrode geometries utilizing the DBS 3389 electrode. Differences in the percentage of axons activated at a given amplitude by the point source electrode and the DBS electrode were between -9.0% and 12.6% across all monopolar configurations tested. The differences in activation between the DBS and point source electrodes occurred primarily in regions close to conductor-insulator interfaces and around the insulating tip of the DBS electrode. The robustness of the point source approximation in modeling several special cases—tissue anisotropy, a long active electrode and bipolar stimulation—was also examined. Under the conditions considered, the point source was shown to be a valid approximation for predicting excitation of populations of neurons in response to DBS.

Connecting source aggregating areas with distributive regions via Optimal Transportation theory.

NASA Astrophysics Data System (ADS)

Lanzoni, S.; Putti, M.

2016-12-01

We study the application of Optimal Transport (OT) theory to the transfer of water and sediments from a distributed aggregating source to a distributing area connected by a erodible hillslope. Starting from the Monge-Kantorovich equations, We derive a global energy functional that nonlinearly combines the cost of constructing the drainage network over the entire domain and the cost of water and sediment transportation through the network. It can be shown that the minimization of this functional is equivalent to the infinite time solution of a system of diffusion partial differential equations coupled with transient ordinary differential equations, that closely resemble the classical conservation laws of water and sediments mass and momentum. We present several numerical simulations applied to realstic test cases. For example, the solution of the proposed model forms network configurations that share strong similiratities with rill channels formed on an hillslope. At a larger scale, we obtain promising results in simulating the network patterns that ensure a progressive and continuous transition from a drainage drainage area to a distributive receiving region.

Mineralogical Approaches to Sourcing Pipes and Figurines from the Eastern Woodlands, U.S.A.

USGS Publications Warehouse

Wisseman, S.U.; Moore, D.M.; Hughes, R.E.; Hynes, M.R.; Emerson, T.E.

2002-01-01

Provenance studies of stone artifacts often rely heavily upon chemical techniques such as neutron activation analysis. However, stone specimens with very similar chemical composition can have different mineralogies (distinctive crystalline structures as well as variations within the same mineral) that are not revealed by multielemental techniques. Because mineralogical techniques are often cheap and usually nondestructive, beginning with mineralogy allows the researcher to gain valuable information and then to be selective about how many samples are submitted for expensive and somewhat destructive chemical analysis, thus conserving both valuable samples and funds. Our University of Illinois team of archaeologists and geologists employs Portable Infrared Mineral Analyzer (PIMA) spectroscopy, X-ray diffraction (XRD), and Sequential acid dissolution/XRD/Inductively coupled plasma (SAD-XRD-ICP) analyses. Two case studies of Hopewellian pipes and Mississippian figurines illustrate this mineralogical approach. The results for both studies identify sources relatively close to the sites where the artifacts were recovered: Sterling, Illinois (rather than Ohio) for the (Hopewell) pipes and Missouri (rather than Arkansas or Oklahoma) for the Cahokia figurines. ?? 2002 Wiley Periodicals, Inc.

The injection of microorganisms into an atmospheric pressure rf-driven microplasma

NASA Astrophysics Data System (ADS)

Maguire, P. D.; Mahony, C. M. O.; Diver, D.; Mariotti, D.; Bennet, E.; Potts, H.; McDowell, D. A.

2013-09-01

The introduction of living organisms, such as bacteria, into atmospheric pressure microplasmas offers a unique means to study certain physical mechanisms in individual microorganisms and also help understand the impact of macroscopic entities and liquid droplets on plasma characteristics. We present the characterization of an RF-APD operating at 13.56 MHz and containing microorganisms in liquid droplets emitted from a nebulizer, with the spray entrained in a gas flow by a gas shroud and passed into the plasma source. We report successful microorganism injection and transmission through the plasma with stable plasma operation of at least one hour. Diagnostics include RF electrical characterization, optical emission spectrometry and electrostatic deflection to investigate microorganism charging. A close-coupled Impedans Octiv VI probe indicates source efficiencies of 10 to 15%. The introduction of the droplets/microorganisms results in increased plasma conductivity and reduced capacitance, due to their impact on electron density and temperature. An electrical model will be presented based on diagnostic data and deflection studies with input from simulations of charged aerosol diffusion and evaporation. Engineering and Physical Sciences Research Council EP/K006088, EP/K006142.

Manipulating Smith-Purcell Emission with Babinet Metasurfaces

NASA Astrophysics Data System (ADS)

Wang, Zuojia; Yao, Kan; Chen, Min; Chen, Hongsheng; Liu, Yongmin

2016-10-01

Swift electrons moving closely parallel to a periodic grating produce far-field radiation of light, which is known as the Smith-Purcell effect. In this letter, we demonstrate that designer Babinet metasurfaces composed of C -aperture resonators offer a powerful control over the polarization state of the Smith-Purcell emission, which can hardly be achieved via traditional gratings. By coupling the intrinsically nonradiative energy bound at the source current sheet to the out-of-plane electric dipole and in-plane magnetic dipole of the C -aperture resonator, we are able to excite cross-polarized light thanks to the bianisotropic nature of the metasurface. The polarization direction of the emitted light is aligned with the orientation of the C -aperture resonator. Furthermore, the efficiency of the Smith-Purcell emission from Babinet metasurfaces is significantly increased by 84%, in comparison with the case of conventional gratings. These findings not only open up a new way to manipulate the electron-beam-induced emission in the near-field region but also promise compact, tunable, and efficient light sources and particle detectors.

Manipulating Smith-Purcell Emission with Babinet Metasurfaces.

PubMed

Wang, Zuojia; Yao, Kan; Chen, Min; Chen, Hongsheng; Liu, Yongmin

2016-10-07

Swift electrons moving closely parallel to a periodic grating produce far-field radiation of light, which is known as the Smith-Purcell effect. In this letter, we demonstrate that designer Babinet metasurfaces composed of C-aperture resonators offer a powerful control over the polarization state of the Smith-Purcell emission, which can hardly be achieved via traditional gratings. By coupling the intrinsically nonradiative energy bound at the source current sheet to the out-of-plane electric dipole and in-plane magnetic dipole of the C-aperture resonator, we are able to excite cross-polarized light thanks to the bianisotropic nature of the metasurface. The polarization direction of the emitted light is aligned with the orientation of the C-aperture resonator. Furthermore, the efficiency of the Smith-Purcell emission from Babinet metasurfaces is significantly increased by 84%, in comparison with the case of conventional gratings. These findings not only open up a new way to manipulate the electron-beam-induced emission in the near-field region but also promise compact, tunable, and efficient light sources and particle detectors.

Observation of EIA in closed and open caesium atomic system

NASA Astrophysics Data System (ADS)

Zhao, Jian-Ming; Zhao, Yan-Ting; Huang, Tao; Xiao, Lian-Tuan; Jia, Suo-Tang

2005-04-01

We present an experimental study on electromagnetically induced absorption (EIA) in the closed transition of a degenerate two-level Cs atomic system. The coupling and probe lasers coupled with the transition 6S1/2F=4 → 6P3/2F'=5 of caesium atom. The signal of EIA was obtained and the frequency detuning and intensity effect of the pumping laser were experimentally investigated. The EIA signal in 6S1/2 F=4 → 6P3/2 F'=4 and 6S1/2 F=4 → 6P3/2 F'=3 open transitions was also obtained. As the repumping laser couples with the transition of 6S1/2 F=3 → 6P3/2 F'=4, the EIA signal is increased due to the hyperfine optical pumping.

Axionic landscape for Higgs coupling near-criticality

NASA Astrophysics Data System (ADS)

Cline, James M.; Espinosa, José R.

2018-02-01

The measured value of the Higgs quartic coupling λ is peculiarly close to the critical value above which the Higgs potential becomes unstable, when extrapolated to high scales by renormalization group running. It is tempting to speculate that there is an anthropic reason behind this near-criticality. We show how an axionic field can provide a landscape of vacuum states in which λ scans. These states are populated during inflation to create a multiverse with different quartic couplings, with a probability distribution P that can be computed. If P is peaked in the anthropically forbidden region of Higgs instability, then the most probable universe compatible with observers would be close to the boundary, as observed. We discuss three scenarios depending on the Higgs vacuum selection mechanism: decay by quantum tunneling, by thermal fluctuations, or by inflationary fluctuations.

Methane Emissions from Kuwait: long-term measurement, mobile plume mapping and isotopic characterisation

NASA Astrophysics Data System (ADS)

al-Shalaan, Aalia; Lowry, David; Fisher, Rebecca; Zazzeri, Giulia; Alsarawi, Mohammad; Nisbet, Euan

2017-04-01

National and EDGAR inventories suggest that the dominant sources of methane in Kuwait are leaks from gas flaring and distribution (92%) and landfills (5%),with additional smaller emissions from sewage (wastewater) treatment and ruminant animals. New measurements during 2015 and 2016 suggest that the inventories differ greatly from observations. Regular weekly bag samples have been collected from 3 sites in Kuwait, one NW of the city, one to the SE and one in the city from the rooftop of Kuwait College of Science. These take turns to have the highest recorded mole fractions, depending on wind direction. Associated with higher mole fraction is a consistent depletion in 13C of methane, pointing to a national source mix with 13C of -54.8‰. This is significantly different from the calculation using inventories that suggest a mix of -51.3‰. Mobile plume identification using a Picarro G2301 analyser, coupled with Tedlar bag sampling for isotopic analysis (Zazzeri et al., 2015), reveals that by far the largest observed source of methane in Kuwait is from landfill sites (13C of -57‰), with smaller contributions from fossil fuel industry (-51‰), wastewater treatment (-50‰) and ruminant animals (cows, -62‰; camels -60‰, sheep -64‰). Many of these isotopic signatures are close to those observed for the same source categories in other countries, for example landfill emission signatures have the same range as those calculated for UK and Hong Kong (-60 to -55‰), even to the level that older closed and capped landfills emit smaller amounts of methane at more enriched values (-55 to -50‰), due to small % of topsoil oxidation. Our findings suggest that many more top down measurements must be made to verify emissions inventories, particularly in middle eastern countries where a significant proportion of emissions are unverified calculations of fossil fuel emissions. Zazzeri, G. et al. (2015) Plume mapping and isotopic characterization of anthropogenic methane sources, Atmospheric Environment, 110, 151-162, doi.org/10.1016/j.atmosenv.2015.03.029

Dynamic Clamp in Cardiac and Neuronal Systems Using RTXI

PubMed Central

Ortega, Francis A.; Butera, Robert J.; Christini, David J.; White, John A.; Dorval, Alan D.

2016-01-01

The injection of computer-simulated conductances through the dynamic clamp technique has allowed researchers to probe the intercellular and intracellular dynamics of cardiac and neuronal systems with great precision. By coupling computational models to biological systems, dynamic clamp has become a proven tool in electrophysiology with many applications, such as generating hybrid networks in neurons or simulating channelopathies in cardiomyocytes. While its applications are broad, the approach is straightforward: synthesizing traditional patch clamp, computational modeling, and closed-loop feedback control to simulate a cellular conductance. Here, we present two example applications: artificial blocking of the inward rectifier potassium current in a cardiomyocyte and coupling of a biological neuron to a virtual neuron through a virtual synapse. The design and implementation of the necessary software to administer these dynamic clamp experiments can be difficult. In this chapter, we provide an overview of designing and implementing a dynamic clamp experiment using the Real-Time eXperiment Interface (RTXI), an open- source software system tailored for real-time biological experiments. We present two ways to achieve this using RTXI’s modular format, through the creation of a custom user-made module and through existing modules found in RTXI’s online library. PMID:25023319

Design principles and optimal performance for molecular motors under realistic constraints

NASA Astrophysics Data System (ADS)

Tu, Yuhai; Cao, Yuansheng

2018-02-01

The performance of a molecular motor, characterized by its power output and energy efficiency, is investigated in the motor design space spanned by the stepping rate function and the motor-track interaction potential. Analytic results and simulations show that a gating mechanism that restricts forward stepping in a narrow window in configuration space is needed for generating high power at physiologically relevant loads. By deriving general thermodynamics laws for nonequilibrium motors, we find that the maximum torque (force) at stall is less than its theoretical limit for any realistic motor-track interactions due to speed fluctuations. Our study reveals a tradeoff for the motor-track interaction: while a strong interaction generates a high power output for forward steps, it also leads to a higher probability of wasteful spontaneous back steps. Our analysis and simulations show that this tradeoff sets a fundamental limit to the maximum motor efficiency in the presence of spontaneous back steps, i.e., loose-coupling. Balancing this tradeoff leads to an optimal design of the motor-track interaction for achieving a maximum efficiency close to 1 for realistic motors that are not perfectly coupled with the energy source. Comparison with existing data and suggestions for future experiments are discussed.

Implantable apparatus for localized heating of tissue

DOEpatents

Doss, James D.

1987-01-01

With the object of repetitively treating deep-seated, inoperable tumors by hyperthermia as well as locally heating other internal tissue masses repetitively, a receiving antenna, transmission line, and electrode arrangment are implanted completely within the patient's body, with the receiving antenna just under the surface of the skin and with the electrode arrangement being located so as to most effectively heat the tissue to be treated. An external, transmitting antenna, driven by an external radio-frequency energy source, is closely coupled to the implanted receiving antenna so that the energy coupled across the air-skin interface provides electromagnetic energy suitable for heating the tissue in the vicinity of the implanted electrodes. The resulting increase in tissue temperature may be estimated by an indirect measurement of the decrease in tissue resistivity in the heated region. This change in resistivity appears as a change in the loading of the receiving antenna which can be measured by either determining the change in the phase relationship between the voltage and the current appearing on the transmitting antenna or by measuring the change in the magnitude of the impedance thereof. Optionally, multiple electrode arrays may be activated or inactivated by the application of magnetic fields to operate implanted magnetic reed switches.

Implantable apparatus for localized heating of tissue

DOEpatents

Doss, J.D.

1985-05-20

With the object of repetitively treating deep-seated, inoperable tumors by hyperthermia as well as locally heating other internal tissue masses repetitively, a receiving antenna, transmission line and electrode arrangement are implanted completely within the patient's body, with the receiving antenna just under the surface of the skin and with the electrode arrangement being located so as to most effectively heat the tissue to be treated. An external, transmitting antenna, driven by an external radio-frequency energy source, is closely coupled to the implanted receiving antenna so that the energy coupled across the air-skin interface provides electromagnetic energy suitable for heating the tissue in the vicinity of the implanted electrodes. The resulting increase in tissue temperature may be estimated by an indirect measurement of the decrease in tissue resistivity in the heat region. This change in resistivity appears as a change in the loading of the receiving antenna which can be measured by either determining the change in the phase relationship between the voltage and the current appearing on the transmitting antenna or by measuring the change in the magnitude of the impedance thereof. Optionally, multiple electrode arrays may be activated or inactivated by the application of magnetic fields to operate implanted magnetic reed swtiches. 5 figs.

Thin-layer chromatography and mass spectrometry coupled using proximal probe thermal desorption with electrospray or atmospheric pressure chemical ionization.

PubMed

Ovchinnikova, Olga S; Van Berkel, Gary J

2010-06-30

An atmospheric pressure proximal probe thermal desorption sampling method coupled with secondary ionization by electrospray or atmospheric pressure chemical ionization was demonstrated for the mass spectrometric analysis of a diverse set of compounds (dyestuffs, pharmaceuticals, explosives and pesticides) separated on various high-performance thin-layer chromatography plates. Line scans along or through development lanes on the plates were carried out by moving the plate relative to a stationary heated probe positioned close to or just touching the stationary phase surface. Vapors of the compounds thermally desorbed from the surface were drawn into the ionization region of a combined electrospray ionization/atmospheric pressure chemical ionization source where they merged with reagent ions and/or charged droplets from a corona discharge or an electrospray emitter and were ionized. The ionized components were then drawn through the atmospheric pressure sampling orifice into the vacuum region of a triple quadrupole mass spectrometer and detected using full scan, single ion monitoring, or selected reaction monitoring mode. Studies of variable parameters and performance metrics including the proximal probe temperature, gas flow rate into the ionization region, surface scan speed, read-out resolution, detection limits, and surface type are discussed.

Kinetics of Melting and Dissolution in Lunar Materials

NASA Technical Reports Server (NTRS)

Hess, Paul C.

2002-01-01

An understanding of the petrogenesis of lunar magmas, particularly mare basalts and the parent magmas to the Mg-rich suite, remains an unfulfilled goal. The fact is not surprising given the complexity of the problem. On the Moon, the source region for lunar magmas is not primitive mantle but rather a series of cumulate rocks that vary widely in both minerology and major and minor element contents. The stratigraphy of the cumulate mantle is not likely to be very regular given that the culumate pile is formed initially in an unstable configuration and subsequent thermal and compositional heterogeneities on a number of length scales. These lithologic heterogeneities, the large range of pressures and temperatures over which melts are generated on the Moon, and the close juxtaposition of cumulate rock with widely varying solidii introduce significant complications to the nature of the melting relations that control melt generation. These factors, coupled with the likelihood that polybaric fractional melting of varying efficiencies ultimately control the composition of planetary progress, are ample reasons why the lunar magmas remain the enigma they are. To make progress, phase equilibria studies must be coupled with a detailed understanding of the time scales and the dynamics of crystal and melt reequilibration processes.

Prediction of break-out sound from a rectangular cavity via an elastically mounted panel.

PubMed

Wang, Gang; Li, Wen L; Du, Jingtao; Li, Wanyou

2016-02-01

The break-out sound from a cavity via an elastically mounted panel is predicted in this paper. The vibroacoustic system model is derived based on the so-called spectro-geometric method in which the solution over each sub-domain is invariably expressed as a modified Fourier series expansion. Unlike the traditional modal superposition methods, the continuity of the normal velocities is faithfully enforced on the interfaces between the flexible panel and the (interior and exterior) acoustic media. A fully coupled vibro-acoustic system is obtained by taking into account the strong coupling between the vibration of the elastic panel and the sound fields on the both sides. The typical time-consuming calculations of quadruple integrals encountered in determining the sound power radiation from a panel has been effectively avoided by reducing them, via discrete cosine transform, into a number of single integrals which are subsequently calculated analytically in a closed form. Several numerical examples are presented to validate the system model, understand the effects on the sound transmissions of panel mounting conditions, and demonstrate the dependence on the size of source room of the "measured" transmission loss.

Conceptual design of a high-speed electromagnetic switch for a modified flux-coupling-type SFCL and its application in renewable energy system.

PubMed

Chen, Lei; Chen, Hongkun; Yang, Jun; Shu, Zhengyu; He, Huiwen; Shu, Xin

2016-01-01

The modified flux-coupling-type superconducting fault current (SFCL) is a high-efficient electrical auxiliary device, whose basic function is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch. In this paper, the high-speed switch is based on electromagnetic repulsion mechanism, and its conceptual design is carried out to promote the application of the modified SFCL. Regarding that the switch which is consisting of a mobile copper disc, two fixed opening and closing coils, the computational method for the electromagnetic force is discussed, and also the dynamic mathematical model including circuit equation, magnetic field equation as well as mechanical motion equation is theoretically deduced. According to the mathematical modeling and calculation of characteristic parameters, a feasible design scheme is presented, and the high-speed switch's response time can be less than 0.5 ms. For that the modified SFCL is equipped with this high-speed switch, the SFCL's application in a 10 kV micro-grid system with multiple renewable energy sources are assessed in the MATLAB software. The simulations are well able to affirm the SFCL's performance behaviors.

Cortisol stress resonance in the laboratory is associated with inter-couple diurnal cortisol covariation in daily life.

PubMed

Engert, Veronika; Ragsdale, Amy M; Singer, Tania

2018-02-01

In laboratory environments individuals may display empathic cortisol stress responses merely from observing another experience psychosocial stress. Moreover, within couples, women synchronize their own to their partners' stress-induced cortisol release. We investigated whether a woman's tendency to experience such cortisol stress resonance in a controlled laboratory task is associated with the degree to which her and her partner's diurnal cortisol levels covary in a naturalistic environment. Such habitual cortisol covariation may be a pathway via which close relationships influence health outcomes. Forty-four men completed the Trier Social Stress Test while their female partners observed the situation, either via "real-life" (one-way mirror) or "virtual" (video) observation modality. Later, the couples collected diurnal cortisol samples over two weekdays. Hierarchical linear modeling indicated that the degree to which couples covaried in their daily cortisol secretion was associated with the female partner's cortisol stress resonance in the laboratory, and that this association was stronger if stress resonance was assessed in the "real-life" observation condition. Specifically, women with higher cortisol stress resonance were more closely linked to their partner's diurnal cortisol secretion. Neither momentary partner presence during sampling nor relationship duration or quality accounted for the association. By showing that covariation in the laboratory has ecological validity in naturalistic conditions, these results make an important methodological contribution to the study of dyadic processes. Given that close relationships exert immense influence over individual health outcomes, understanding the association between acute and chronic physiological linkage may provide important insight into the mechanisms by which close relationships impact well-being. Copyright © 2018 Elsevier Inc. All rights reserved.

Correlation characteristics of phase and amplitude chimeras in an ensemble of nonlocally coupled maps

NASA Astrophysics Data System (ADS)

Vadivasova, T. E.; Strelkova, G. I.; Bogomolov, S. A.; Anishchenko, V. S.

2017-01-01

Correlation characteristics of chimera states have been calculated using the coefficient of mutual correlation of elements in a closed-ring ensemble of nonlocally coupled chaotic maps. Quantitative differences between the coefficients of mutual correlation for phase and amplitude chimeras are established for the first time.

Modeling Blast Loading on Buried Reinforced Concrete Structures with Zapotec

DOE PAGES

Bessette, Greg C.

2008-01-01

A coupled Euler-Lagrange solution approach is used to model the response of a buried reinforced concrete structure subjected to a close-in detonation of a high explosive charge. The coupling algorithm is discussed along with a set of benchmark calculations involving detonations in clay and sand.

17O nuclear quadrupole coupling constants of water bound to a metal ion: A gadolinium(III) case study

NASA Astrophysics Data System (ADS)

Yazyev, Oleg V.; Helm, Lothar

2006-08-01

Rotational correlation times of metal ion aqua complexes can be determined from O17 NMR relaxation rates if the quadrupole coupling constant of the bound water oxygen-17 nucleus is known. The rotational correlation time is an important parameter for the efficiency of Gd3+ complexes as magnetic resonance imaging contrast agents. Using a combination of density functional theory with classical and Car-Parrinello molecular dynamics simulations we performed a computational study of the O17 quadrupole coupling constants in model aqua ions and the [Gd(DOTA)(H2O)]- complex used in clinical diagnostics. For the inner sphere water molecule in the [Gd(DOTA)(H2O)]- complex the determined quadrupole coupling parameter χ√1+η2/3 of 8.7MHz is very similar to that of the liquid water (9.0MHz ). Very close values were also predicted for the the homoleptic aqua ions of Gd3+ and Ca2+. We conclude that the O17 quadrupole coupling parameters of water molecules coordinated to closed shell and lanthanide metal ions are similar to water molecules in the liquid state.

Bidirectional buck boost converter

DOEpatents

Esser, Albert Andreas Maria

1998-03-31

A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

Bidirectional buck boost converter

DOEpatents

Esser, A.A.M.

1998-03-31

A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero. 20 figs.

Driver circuit for solid state light sources

DOEpatents

Palmer, Fred; Denvir, Kerry; Allen, Steven

2016-02-16

A driver circuit for a light source including one or more solid state light sources, a luminaire including the same, and a method of so driving the solid state light sources are provided. The driver circuit includes a rectifier circuit that receives an alternating current (AC) input voltage and provides a rectified AC voltage. The driver circuit also includes a switching converter circuit coupled to the light source. The switching converter circuit provides a direct current (DC) output to the light source in response to the rectified AC voltage. The driver circuit also includes a mixing circuit, coupled to the light source, to switch current through at least one solid state light source of the light source in response to each of a plurality of consecutive half-waves of the rectified AC voltage.

Normal-Mode Splitting in a Weakly Coupled Optomechanical System

NASA Astrophysics Data System (ADS)

Rossi, Massimiliano; Kralj, Nenad; Zippilli, Stefano; Natali, Riccardo; Borrielli, Antonio; Pandraud, Gregory; Serra, Enrico; Di Giuseppe, Giovanni; Vitali, David

2018-02-01

Normal-mode splitting is the most evident signature of strong coupling between two interacting subsystems. It occurs when two subsystems exchange energy between themselves faster than they dissipate it to the environment. Here we experimentally show that a weakly coupled optomechanical system at room temperature can manifest normal-mode splitting when the pump field fluctuations are antisquashed by a phase-sensitive feedback loop operating close to its instability threshold. Under these conditions the optical cavity exhibits an effectively reduced decay rate, so that the system is effectively promoted to the strong coupling regime.

Energetic (above 60 eV) atmospheric photoelectrons

NASA Technical Reports Server (NTRS)

Winningham, J. D.; Decker, D. T.; Kozyra, J. U.; Nagy, A. F.; Jasperse, J. R.

1989-01-01

Data from low altitude plasma instrument (LAPI) on Dynamics Explorer 2 document a population of high-energy (up to 800 eV) atmospheric photoelectrons that has not been reported in the published literature. The source of these photoelectrons is postulated to be the soft X-ray portion of the whole sun spectrum. This conclusion is supported by sunrise-sunset characteristics that track those of the classical (below 60 eV) EUV-produced photoelectrons, and theoretical results from two models that incorporate the soft X-ray portion of the solar spectrum. The models include K-shell ionization effects and predict peaks in the photoelectron spectrum due to Auger electrons emitted from oxygen and nitrogen. The peak for nitrogen is observed as predicted, but the peak for oxygen is barely observable. Excellent quantitative agreement is achieved between theory and experiment by using reasonable adjustments to the few published soft X-ray spectra based on solar activity. The upflowing energetic photoelectrons provide a heretofore unknown source of electrons to the magnetosphere. They occur whenever and wherever the sun is up, that is, at all invariant latitudes. Their density is low, but they are steady and ubiquitous. If scattering and trapping occur on closed field lines, then photoelectrons could contribute as a significant particle source and thus represent a new facet of magnetosphere-ionosphere coupling.

Measurement and analysis of time-domain characteristics of corona-generated radio interference from a single positive corona source

NASA Astrophysics Data System (ADS)

Li, Xuebao; Li, Dayong; Chen, Bo; Cui, Xiang; Lu, Tiebing; Li, Yinfei

2018-04-01

The corona-generated electromagnetic interference commonly known as radio interference (RI) has become a limiting factor for the design of high voltage direct current transmission lines. In this paper, a time-domain measurement system is developed to measure the time-domain characteristics of corona-generated RI from a single corona source under a positive corona source. In the experiments, the corona current pulses are synchronously measured through coupling capacitors. The one-to-one relationship between the corona current pulse and measured RI voltage pulse is observed. The statistical characteristics of pulse parameters are analyzed, and the correlations between the corona current pulse and RI voltage pulse in the time-domain and frequency-domain are analyzed. Depending on the measured corona current pulses, the time-domain waveform of corona-generated RI is calculated on the basis of the propagation model of corona current on the conductor, the dipolar model for electric field calculation, and the antenna model for inducing voltage calculation. The well matched results between measured and simulated waveforms of RI voltage can show the validity of the measurement and calculation method presented in this paper, which also further show the close correlation between corona current and corona-generated RI.

Assessing the impacts of assimilating IASI and MOPITT CO retrievals using CESM-CAM-chem and DART

NASA Astrophysics Data System (ADS)

Barré, Jérôme; Gaubert, Benjamin; Arellano, Avelino F. J.; Worden, Helen M.; Edwards, David P.; Deeter, Merritt N.; Anderson, Jeffrey L.; Raeder, Kevin; Collins, Nancy; Tilmes, Simone; Francis, Gene; Clerbaux, Cathy; Emmons, Louisa K.; Pfister, Gabriele G.; Coheur, Pierre-François; Hurtmans, Daniel

2015-10-01

We show the results and evaluation with independent measurements from assimilating both MOPITT (Measurements Of Pollution In The Troposphere) and IASI (Infrared Atmospheric Sounding Interferometer) retrieved profiles into the Community Earth System Model (CESM). We used the Data Assimilation Research Testbed ensemble Kalman filter technique, with the full atmospheric chemistry CESM component Community Atmospheric Model with Chemistry. We first discuss the methodology and evaluation of the current data assimilation system with coupled meteorology and chemistry data assimilation. The different capabilities of MOPITT and IASI retrievals are highlighted, with particular attention to instrument vertical sensitivity and coverage and how these impact the analyses. MOPITT and IASI CO retrievals mostly constrain the CO fields close to the main anthropogenic, biogenic, and biomass burning CO sources. In the case of IASI CO assimilation, we also observe constraints on CO far from the sources. During the simulation time period (June and July 2008), CO assimilation of both instruments strongly improves the atmospheric CO state as compared to independent observations, with the higher spatial coverage of IASI providing better results on the global scale. However, the enhanced sensitivity of multispectral MOPITT observations to near surface CO over the main source regions provides synergistic effects at regional scales.

The local density of optical states of a metasurface

NASA Astrophysics Data System (ADS)

Lunnemann, Per; Koenderink, A. Femius

2016-02-01

While metamaterials are often desirable for near-field functions, such as perfect lensing, or cloaking, they are often quantified by their response to plane waves from the far field. Here, we present a theoretical analysis of the local density of states near lattices of discrete magnetic scatterers, i.e., the response to near field excitation by a point source. Based on a pointdipole theory using Ewald summation and an array scanning method, we can swiftly and semi-analytically evaluate the local density of states (LDOS) for magnetoelectric point sources in front of an infinite two-dimensional (2D) lattice composed of arbitrary magnetoelectric dipole scatterers. The method takes into account radiation damping as well as all retarded electrodynamic interactions in a self-consistent manner. We show that a lattice of magnetic scatterers evidences characteristic Drexhage oscillations. However, the oscillations are phase shifted relative to the electrically scattering lattice consistent with the difference expected for reflection off homogeneous magnetic respectively electric mirrors. Furthermore, we identify in which source-surface separation regimes the metasurface may be treated as a homogeneous interface, and in which homogenization fails. A strong frequency and in-plane position dependence of the LDOS close to the lattice reveals coupling to guided modes supported by the lattice.

Fuel injection system and method of operating the same for an engine

DOEpatents

Topinka, Jennifer Ann [Niskayuna, NY; DeLancey, James Peter [Corinth, NY; Primus, Roy James [Niskayuna, NY; Pintgen, Florian Peter [Niskayuna, NY

2011-02-15

A fuel injector is coupled to an engine. The fuel injector includes an injection opening configured to vary in cross-section between a open state and a fully closed state. The fuel injector is configured to provide a plurality of discrete commanded fuel injections into an engine cylinder by modulating the size of the injection opening without completely closing the opening to the fully closed state.

High Power LaB6 Plasma Source Performance for the Lockheed Martin Compact Fusion Reactor Experiment

NASA Astrophysics Data System (ADS)

Heinrich, Jonathon

2016-10-01

Lockheed Martin's Compact Fusion Reactor (CFR) concept is a linear encapsulated ring cusp. Due to the complex field geometry, plasma injection into the device requires careful consideration. A high power thermionic plasma source (>0.25MW; >10A/cm2) has been developed with consideration to phase space for optimal coupling. We present the performance of the plasma source, comparison with alternative plasma sources, and plasma coupling with the CFR field configuration. ©2016 Lockheed Martin Corporation. All Rights Reserved.

Synthesis of the carbocyclic core of the cornexistins by ring-closing metathesis.

PubMed

Clark, J Stephen; Marlin, Frederic; Nay, Bastien; Wilson, Claire

2003-01-09

An advanced intermediate in the synthesis of the phytotoxins cornexistin and hydroxycornexistin has been synthesized. Sequential palladium-mediated sp(2)-sp(3) fragment coupling and ring-closing diene metathesis have been used to construct the nine-membered carbocyclic core found in the natural products. [reaction--see text

Self-closing shielded container for use with radioactive materials

DOEpatents

Smith, J.E.

1984-10-16

A container is described for storage of radioactive material comprising a container body and a closure member. The closure member being coupled to the container body to enable the closure body to move automatically from a first position (e.g., closed) to a second position (open). 1 fig.

Evolvable circuit with transistor-level reconfigurability

NASA Technical Reports Server (NTRS)

Stoica, Adrian (Inventor); Salazar-Lazaro, Carlos Harold (Inventor)

2004-01-01

An evolvable circuit includes a plurality of reconfigurable switches, a plurality of transistors within a region of the circuit, the plurality of transistors having terminals, the plurality of transistors being coupled between a power source terminal and a power sink terminal so as to be capable of admitting power between the power source terminal and the power sink terminal, the plurality of transistors being coupled so that every transistor terminal to transistor terminal coupling within the region of the circuit comprises a reconfigurable switch.

Evolutionary Technique for Automated Synthesis of Electronic Circuits

NASA Technical Reports Server (NTRS)

Stoica, Adrian (Inventor); Salazar-Lazaro, Carlos Harold (Inventor)

2007-01-01

An evolvable circuit includes a plurality of reconfigurable switches, a plurality of transistors within a region of the circuit, the plurality of transistors having terminals, the plurality of transistors being coupled between a power source terminal and a power sink terminal so as to be capable of admitting power between the power source terminal and the power sink terminal, the plurality of transistors being coupled so that every transistor to transistor terminal coupling within the region of the circuit comprises a reconfigurable switch.

Comparative bioinformatics analyses and profiling of lysosome-related organelle proteomes

NASA Astrophysics Data System (ADS)

Hu, Zhang-Zhi; Valencia, Julio C.; Huang, Hongzhan; Chi, An; Shabanowitz, Jeffrey; Hearing, Vincent J.; Appella, Ettore; Wu, Cathy

2007-01-01

Complete and accurate profiling of cellular organelle proteomes, while challenging, is important for the understanding of detailed cellular processes at the organelle level. Mass spectrometry technologies coupled with bioinformatics analysis provide an effective approach for protein identification and functional interpretation of organelle proteomes. In this study, we have compiled human organelle reference datasets from large-scale proteomic studies and protein databases for seven lysosome-related organelles (LROs), as well as the endoplasmic reticulum and mitochondria, for comparative organelle proteome analysis. Heterogeneous sources of human organelle proteins and rodent homologs are mapped to human UniProtKB protein entries based on ID and/or peptide mappings, followed by functional annotation and categorization using the iProXpress proteomic expression analysis system. Cataloging organelle proteomes allows close examination of both shared and unique proteins among various LROs and reveals their functional relevance. The proteomic comparisons show that LROs are a closely related family of organelles. The shared proteins indicate the dynamic and hybrid nature of LROs, while the unique transmembrane proteins may represent additional candidate marker proteins for LROs. This comparative analysis, therefore, provides a basis for hypothesis formulation and experimental validation of organelle proteins and their functional roles.

Low-energy electron scattering from atomic hydrogen. I. Ionization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Childers, J.G.; James, K.E. Jr.; Bray, Igor

2004-02-01

Absolute doubly differential cross sections for the ionization of atomic hydrogen by electron impact have been measured at energies ranging from near threshold to intermediate values. The measurements are normalized to the accurate differential cross section for the electron-impact excitation of the H 1 {sup 2}S{yields}2 {sup 2}S+2 {sup 2}P transition. These measurements were made possible through the use of a moveable target source which enables the collection of hydrogen energy loss spectra free of all backgrounds. The measurements cover the incident electron energy range of 14.6-40 eV and scattering angles from 12 deg. to 127 deg., and are inmore » very good agreement with the results of the latest theoretical models--the convergent close-coupling model and the exterior complex scaling model.« less

Highlights of theoretical progress related to the International Magnetospheric Study

NASA Technical Reports Server (NTRS)

Hill, T. W.

1982-01-01

U.S. theoretical research efforts have addressed three areas within the International Magnetospheric Study. The first, solar wind/magnetosphere interaction, is presently concerned with the suggestion that magnetic merging may predominantly occur near the polar cusps rather than near the subsolar point. Mechanisms have been proposed for noncollisional diffusion of solar wind plasma across the closed magnetopause entailed by such a phenomenon. The second area considers the importance to magnetotail dynamics of a continuous source of solar wind plasma, and of sporadic plasma loss associated with an unsteady convection cycle. In the third area, the electrodynamic magnetosphere/ionosphere interaction, an advanced state has been reached in the understanding of the relevant physics, with respect both to coupling in the subauroral region and the large scale structure of auroral zone electric fields parallel, and perpendicular to, the magnetic field.

Resonant Polarization Spectroscopy for Hot X-ray Plasmas

DOE PAGES

Chen, Guo -Xin

2016-04-28

X-ray line polarization spectroscopy is a method of choice for probing hot plasma conditions. The precise roles of resonant structures in this method have not been realized and fully understood. With a sophisticated relativistic close coupling Dirac R-matrix calculation of polarized radiation of the quadrupole magnetic M2 line at 2.717 Å in Ba 46+, we revealed the nature of resonant structures in x-ray line polarization spectroscopy. We found that signatures with a heavy resonance forest imprinting on polarization may be used for a sensitive new spectroscopic method. The resonant polarization spectrum was used to determine or constrain the directional beammore » electron distribution of the laboratory Ba plasma. Lastly, our results provide a start of resonant polarization spectroscopy as a method for diagnostics of laboratory, fusion and astrophysical plasma source conditions.« less

Diode-quad bridge circuit means

NASA Technical Reports Server (NTRS)

Harrison, D. R.; Dimeff, J. (Inventor)

1975-01-01

Diode-quad bridge circuit means is described for use as a transducer circuit or as a discriminator circuit. It includes: (1) a diode bridge having first, second, third, and fourth bridge terminals consecutively coupled together by four diodes polarized in circulating relationship; (2) a first impedance connected between the second bridge terminal and a circuit ground; (3) a second impedance connected between the fourth bridge terminal and the circuit ground; (4) a signal source having a first source terminal capacitively coupled to the first and third bridge terminals, and a second source terminal connected to the circuit ground; and (5) an output terminal coupled to the first bridge terminal and at which an output signal may be taken.

Henry Barton Jacobs, William Osler's intimate friend

PubMed Central

2017-01-01

William Osler was considered a universal friend by physicians of his era but, as with most people, his intimate friends were few. Henry Barton Jacobs became a close friend as one of the “latchkeyers” who lived next door to the Oslers in Baltimore, and the friendship intensified after Jacobs married Mary Sloan Frick Garrett, the fabulously wealthy widow of a former patient. The couples stayed close after the Oslers moved to Oxford, vacationing together and corresponding frequently. The couple friendship between the Oslers and the Jacobses benefited American medicine in specific ways, including the care of patients with tuberculosis and the care of children. PMID:28127152

Tsunami Generation from Asteroid Airburst and Ocean Impact and Van Dorn Effect

NASA Technical Reports Server (NTRS)

Robertson, Darrel

2016-01-01

Airburst - In the simulations explored energy from the airburst couples very weakly with the water making tsunami dangerous over a shorter distance than the blast for asteroid sizes up to the maximum expected size that will still airburst (approx.250MT). Future areas of investigation: - Low entry angle airbursts create more cylindrical blasts and might couple more efficiently - Bursts very close to the ground will increase coupling - Inclusion of thermosphere (>80km altitude) may show some plume collapse effects over a large area although with much less pressure center dot Ocean Impact - Asteroid creates large cavity in ocean. Cavity backfills creating central jet. Oscillation between the cavity and jet sends out tsunami wave packet. - For deep ocean impact waves are deep water waves (Phase speed = 2x Group speed) - If the tsunami propagation and inundation calculations are correct for the small (<250MT) asteroids in these simulations where they impact deep ocean basins, the resulting tsunami is not a significant hazard unless particularly close to vulnerable communities. Future work: - Shallow ocean impact. - Effect of continental shelf and beach profiles - Tsunami vs. blast damage radii for impacts close to populated areas - Larger asteroids below presumed threshold of global effects (Ø200 - 800m).

Closed-form Static Analysis with Inertia Relief and Displacement-Dependent Loads Using a MSC/NASTRAN DMAP Alter

NASA Technical Reports Server (NTRS)

Barnett, Alan R.; Widrick, Timothy W.; Ludwiczak, Damian R.

1995-01-01

Solving for the displacements of free-free coupled systems acted upon by static loads is commonly performed throughout the aerospace industry. Many times, these problems are solved using static analysis with inertia relief. This solution technique allows for a free-free static analysis by balancing the applied loads with inertia loads generated by the applied loads. For some engineering applications, the displacements of the free-free coupled system induce additional static loads. Hence, the applied loads are equal to the original loads plus displacement-dependent loads. Solving for the final displacements of such systems is commonly performed using iterative solution techniques. Unfortunately, these techniques can be time-consuming and labor-intensive. Since the coupled system equations for free-free systems with displacement-dependent loads can be written in closed-form, it is advantageous to solve for the displacements in this manner. Implementing closed-form equations in static analysis with inertia relief is analogous to implementing transfer functions in dynamic analysis. Using a MSC/NASTRAN DMAP Alter, displacement-dependent loads have been included in static analysis with inertia relief. Such an Alter has been used successfully to solve efficiently a common aerospace problem typically solved using an iterative technique.

The energy balance in coronal holes and average quiet-sun regions

NASA Technical Reports Server (NTRS)

Raymond, J. C.; Doyle, J. G.

1981-01-01

Emission measure curves are presented for average coronal hole and quiet-sun spectra taken during the Skylab mission by Vernazza and Reeves (1978), and the curves are used to discuss the energy balance in each region. Close-coupling calculations are used for the Be sequence, assuming a 10 level ion; for B sequence ions mainly distorted wave calculations in an 11 level ion are used, but close-coupling cross sections are used for some ions; for C and Mg sequence ions, distorted wave calculations are used with 15 and 10 level ions, respectively, and close-coupling results are used for Li-like ions with two levels. Results are presented and include the following: the coronal hole spectrum shows a smaller slope in the emission measure distribution, consistent with the expected outflow effects. It is concluded that the simple constant pressure models of static coronal loops of constant cross section are basically able to match the observed emission measure distribution of the average quiet sun between 1,000,000 and 10,000,000 K. However, the cell center and network distributions are respectively steeper and shallower than predicted by the detailed cooling curve.

Analytical close-to-source investigation for an isotropic point source in an unbounded, anisotropically scattering medium

NASA Astrophysics Data System (ADS)

Rinzema, Kees; ten Bosch, Jaap J.; Ferwerda, Hedzer A.; Hoenders, Bernhard J.

1995-01-01

The diffusion approximation, which is often used to describe the propagation of light in biological tissues, is only good at a sufficient distance from sources and boundaries. Light- tissue interaction is however most intense in the region close to the source. It would therefore be interesting to study this region more closely. Although scattering in biological tissues is predominantly forward peaked, explicit solutions to the transport equation have only been obtained in the case of isotropic scattering. Particularly, for the case of an isotropic point source in an unbounded, isotropically scattering medium the solution is well known. We show that this problem can also be solved analytically if the scattering is no longer isotropic, while everything else remains the same.

High flow, low mobile weight quick disconnect system

NASA Technical Reports Server (NTRS)

Smith, Ronn G. (Inventor); Nagy, Jr., Zoltan Frank (Inventor); Moszczienski, Joseph Roch (Inventor)

2010-01-01

A fluid coupling device and coupling system that may start and stop the flow of a fluid is disclosed. In some embodiments, first and second couplings are provided having an actuator coupled with each of the couplings. The couplings and actuators may be detachable to provide quick disconnect features and, in some embodiments, provide unitary actuation for the actuators of the coupling device to facilitate connection in mobile applications. Actuation may occur as the two couplings and actuators are engaged and disengaged and may occur by rotational actuation of the actuators. Rotational actuation can be provided to ensure flow through the coupling device, which in some embodiments may further provide an offset venturi feature. Upon disengagement, a compression element such as a compression spring can be provided to return the actuators to a closed position. Some embodiments further provide a seal external to the actuators and provided at incipient engagement of the couplings.

Virtual environment display for a 3D audio room simulation

NASA Astrophysics Data System (ADS)

Chapin, William L.; Foster, Scott

1992-06-01

Recent developments in virtual 3D audio and synthetic aural environments have produced a complex acoustical room simulation. The acoustical simulation models a room with walls, ceiling, and floor of selected sound reflecting/absorbing characteristics and unlimited independent localizable sound sources. This non-visual acoustic simulation, implemented with 4 audio ConvolvotronsTM by Crystal River Engineering and coupled to the listener with a Poihemus IsotrakTM, tracking the listener's head position and orientation, and stereo headphones returning binaural sound, is quite compelling to most listeners with eyes closed. This immersive effect should be reinforced when properly integrated into a full, multi-sensory virtual environment presentation. This paper discusses the design of an interactive, visual virtual environment, complementing the acoustic model and specified to: 1) allow the listener to freely move about the space, a room of manipulable size, shape, and audio character, while interactively relocating the sound sources; 2) reinforce the listener's feeling of telepresence into the acoustical environment with visual and proprioceptive sensations; 3) enhance the audio with the graphic and interactive components, rather than overwhelm or reduce it; and 4) serve as a research testbed and technology transfer demonstration. The hardware/software design of two demonstration systems, one installed and one portable, are discussed through the development of four iterative configurations. The installed system implements a head-coupled, wide-angle, stereo-optic tracker/viewer and multi-computer simulation control. The portable demonstration system implements a head-mounted wide-angle, stereo-optic display, separate head and pointer electro-magnetic position trackers, a heterogeneous parallel graphics processing system, and object oriented C++ program code.

The potential of mild testicular heating as a safe, effective and reversible contraceptive method for men.

PubMed

Mieusset, R; Bujan, L

1994-08-01

A preliminary assessment of the contraceptive efficacy of a daily mild increase (1-2 degrees C) in testicular temperature during waking hours is reported in nine couples using two techniques of non-surgical fixation of the testes close to the inguinal canal. With technique 1, immobilization was achieved by passing the penis and the empty scrotum through a hole made in close-fitting underwear; there was one pregnancy, from a man who stopped the heating after 7 weeks, for 42 cycles of exposure in three couples. With technique 2, immobilization was achieved by adding a ring of soft material surrounding the hole in the underwear; there was no pregnancy for 117 cycles of exposure in six couples. Reversibility and safety were assessed. These preliminary results suggest that a daily mild increase in testicular temperature could be a potential contraceptive method for men.

Line Coupling Effects in the Isotropic Raman Spectra of N2: A Quantum Calculation at Room Temperature

NASA Technical Reports Server (NTRS)

Thibault, Franck; Boulet, Christian; Ma, Qiancheng

2014-01-01

We present quantum calculations of the relaxation matrix for the Q branch of N2 at room temperature using a recently proposed N2-N2 rigid rotor potential. Close coupling calculations were complemented by coupled states studies at high energies and provide about 10200 two-body state-to state cross sections from which the needed one-body cross-sections may be obtained. For such temperatures, convergence has to be thoroughly analyzed since such conditions are close to the limit of current computational feasibility. This has been done using complementary calculations based on the energy corrected sudden formalism. Agreement of these quantum predictions with experimental data is good, but the main goal of this work is to provide a benchmark relaxation matrix for testing more approximate methods which remain of a great utility for complex molecular systems at room (and higher) temperatures.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zammit, Mark C.; Fursa, Dmitry V.; Savage, Jeremy S.

Starting from first principles, this tutorial describes the development of the adiabatic-nuclei convergent close-coupling (CCC) method and its application to electron and (single-centre) positron scattering from diatomic molecules. In this paper, we give full details of the single-centre expansion CCC method, namely the formulation of the molecular target structure; solving the momentum-space coupled-channel Lippmann-Schwinger equation; deriving adiabatic-nuclei cross sections and calculatingmore » $V$-matrix elements. Selected results are presented for electron and positron scattering from molecular hydrogen H$$_2$$ and electron scattering from the vibrationally excited molecular hydrogen ion H$$_2^+$$ and its isotopologues (D$$_2^+$$, T$$_2^+$$, HD$^+$, HT$^+$ and TD$^+$). Finally, convergence in both the close-coupling (target state) and projectile partial-wave expansions of fixed-nuclei electron- and positron-molecule scattering calculations is demonstrated over a broad energy-range and discussed in detail. In general the CCC results are in good agreement with experiments.« less

CCC calculated integrated cross sections of electron-H2 scattering

NASA Astrophysics Data System (ADS)

Zammit, Mark; Fursa, Dmitry; Savage, Jeremy; Bray, Igor

2016-09-01

Recently we applied the molecular convergent close-coupling (CCC) method to electron scattering from molecular hydrogen H2. Convergence of the major integrated cross sections has been explicitly demonstrated in the fixed-nuclei approximation by increasing the number of H2 target states in the close-coupling expansion from 9 to 491. The calculations have been performed using a projectile partial wave expansion with maximum orbital angular momentum Lmax = 8 and total orbital angular momentum projections | M | <= 8 . Coupling to the ionization continuum is modeled via a large pseudo state expansion, which we found is required to obtain reliable elastic and excitation cross sections. Here we present benchmark elastic, single-ionization, electronic excitation and total integrated cross sections over a broad energy range (0.1 to 300 eV) and compare with available experiment and previous calculations. Los Alamos National Laboratory and Curtin University.

Coculturing with endothelial cells promotes in vitro maturation and electrical coupling of human embryonic stem cell-derived cardiomyocytes.

PubMed

Pasquier, Jennifer; Gupta, Renuka; Rioult, Damien; Hoarau-Véchot, Jessica; Courjaret, Raphael; Machaca, Khaled; Al Suwaidi, Jassim; Stanley, Edouard G; Rafii, Shahin; Elliott, David A; Abi Khalil, Charbel; Rafii, Arash

2017-06-01

Pluripotent human embryonic stem cells (hESC) are a promising source of repopulating cardiomyocytes. We hypothesized that we could improve maturation of cardiomyocytes and facilitate electrical interconnections by creating a model that more closely resembles heart tissue; that is, containing both endothelial cells (ECs) and cardiomyocytes. We induced cardiomyocyte differentiation in the coculture of an hESC line expressing the cardiac reporter NKX2.5-green fluorescent protein (GFP), and an Akt-activated EC line (E4 + ECs). We quantified spontaneous beating rates, synchrony, and coordination between different cardiomyocyte clusters using confocal imaging of Fura Red-detected calcium transients and computer-assisted image analysis. After 8 days in culture, 94% ± 6% of the NKX2-5GFP + cells were beating when hESCs embryonic bodies were plated on E4 + ECs compared with 34% ± 12.9% for controls consisting of hESCs cultured on BD Matrigel (BD Biosciences) without ECs at Day 11 in culture. The spatial organization of beating areas in cocultures was different. The GFP + cardiomyocytes were close to the E4 + ECs. The average beats/min of the cardiomyocytes in coculture was faster and closer to physiologic heart rates compared with controls (50 ± 14 [n = 13] vs 25 ± 9 [n = 8]; p < 0.05). The coculture with ECs led to synchronized beating relying on the endothelial network, as illustrated by the loss of synchronization upon the disruption of endothelial bridges. The coculturing of differentiating cardiomyocytes with Akt-activated ECs but not EC-conditioned media results in (1) improved efficiency of the cardiomyocyte differentiation protocol and (2) increased maturity leading to better intercellular coupling with improved chronotropy and synchrony. Copyright © 2017. Published by Elsevier Inc.

Low Frequency Electromagnetic Pulse and Explosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sweeney, J J

2011-02-01

This paper reviews and summarizes prior work related to low frequency (< 100 Hz) EMP (ElectroMagnetic Pulse) observed from explosions. It focuses on how EMP signals might, or might not, be useful in monitoring underground nuclear tests, based on the limits of detection, and physical understanding of these signals. In summary: (1) Both chemical and nuclear explosions produce an EMP. (2) The amplitude of the EMP from underground explosions is at least two orders of magnitude lower than from above ground explosions and higher frequency components of the signal are rapidly attenuated due to ground conductivity. (3) In general, inmore » the near field, that is distances (r) of less than 10s of kilometers from the source, the amplitude of the EMP decays approximately as 1/r{sup 3}, which practically limits EMP applications to very close (<{approx}1km) distances. (4) One computational model suggests that the EMP from a decoupled nuclear explosion may be enhanced over the fully coupled case. This has not been validated with laboratory or field data. (5) The magnitude of the EMP from an underground nuclear explosion is about two orders of magnitude larger than that from a chemical explosion, and has a larger component of higher frequencies. In principle these differences might be used to discriminate a nuclear from a chemical explosion using sensors at very close (<{approx}1 km) distances. (6) Arming and firing systems (e.g. detonators, exploding bridge wires) can also produce an EMP from any type of explosion. (7) To develop the understanding needed to apply low frequency EMP to nuclear explosion monitoring, it is recommended to carry out a series of controlled underground chemical explosions with a variety of sizes, emplacements (e.g. fully coupled and decoupled), and arming and firing systems.« less

Marine self potential and CSEM measurements using an autonomous underwater vehicle

NASA Astrophysics Data System (ADS)

Constable, S.; Kowalczyk, P.; Bloomer, S.

2017-12-01

Marine self potential (SP) and controlled source EM (CSEM) measurements are commonly made using instruments towed close to the seafloor, which requires dedicated ship time, is limited to slow speeds, and is subject to navigation errors of 5 to 10 m. An alternative is to mount SP and CSEM sensors on an autonomous underwater vehicle (AUV). We tested this with a pilot study in the Iheya area of the Okinawa Trough, off Japan, using an ISE Explorer-class AUV operated by Fukada Salvage and Marine Works and equipped with a Scripps CSEM receiver system. Parts of this prospect have documented hydrothermal venting and seafloor massive sulfide (SMS) deposits. CSEM signals were generated by deploying battery-powered seafloor transmitters, which emitted 20 amps, alternately every 30 seconds on orthogonal, 10 m antennas. CSEM signals were recorded by 3-axis AC-coupled sensors on the AUV as it flew a pattern 70 m above the seafloor around the transmitters. By transmitting two slightly different frequencies, two or more transmitters can broadcast simultaneously. Measurements were made at the same time using DC-coupled electric field amplifiers, from which self potentials were estimated using regularized inversion, yielding negative anomalies of 10 to 25 mV. Modeling suggests that the anomalies are localized and close to the seafloor. Apparent conductivities as high as 30 S/m were fit to the CSEM data, which strongly suggests that SMS mineralization is associated with the SP anomalies, although it is possible the causative mechanism is at least partly due to hydrothermal venting. In either case, we have demonstrated that AUV-mounted instrument systems are an efficient, effective, and low noise means of collecting marine CSEM and SP data. The entire data set was collected in a single day on station with a 10-hour AUV deployment.

Modelling the Effects of Electrical Coupling between Unmyelinated Axons of Brainstem Neurons Controlling Rhythmic Activity

PubMed Central

Hull, Michael J.; Soffe, Stephen R.; Willshaw, David J.; Roberts, Alan

2015-01-01

Gap junctions between fine unmyelinated axons can electrically couple groups of brain neurons to synchronise firing and contribute to rhythmic activity. To explore the distribution and significance of electrical coupling, we modelled a well analysed, small population of brainstem neurons which drive swimming in young frog tadpoles. A passive network of 30 multicompartmental neurons with unmyelinated axons was used to infer that: axon-axon gap junctions close to the soma gave the best match to experimentally measured coupling coefficients; axon diameter had a strong influence on coupling; most neurons were coupled indirectly via the axons of other neurons. When active channels were added, gap junctions could make action potential propagation along the thin axons unreliable. Increased sodium and decreased potassium channel densities in the initial axon segment improved action potential propagation. Modelling suggested that the single spike firing to step current injection observed in whole-cell recordings is not a cellular property but a dynamic consequence of shunting resulting from electrical coupling. Without electrical coupling, firing of the population during depolarising current was unsynchronised; with coupling, the population showed synchronous recruitment and rhythmic firing. When activated instead by increasing levels of modelled sensory pathway input, the population without electrical coupling was recruited incrementally to unpatterned activity. However, when coupled, the population was recruited all-or-none at threshold into a rhythmic swimming pattern: the tadpole “decided” to swim. Modelling emphasises uncertainties about fine unmyelinated axon physiology but, when informed by biological data, makes general predictions about gap junctions: locations close to the soma; relatively small numbers; many indirect connections between neurons; cause of action potential propagation failure in fine axons; misleading alteration of intrinsic firing properties. Modelling also indicates that electrical coupling within a population can synchronize recruitment of neurons and their pacemaker firing during rhythmic activity. PMID:25954930

Generalized analytical solutions to sequentially coupled multi-species advective-dispersive transport equations in a finite domain subject to an arbitrary time-dependent source boundary condition

NASA Astrophysics Data System (ADS)

Chen, Jui-Sheng; Liu, Chen-Wuing; Liang, Ching-Ping; Lai, Keng-Hsin

2012-08-01

SummaryMulti-species advective-dispersive transport equations sequentially coupled with first-order decay reactions are widely used to describe the transport and fate of the decay chain contaminants such as radionuclide, chlorinated solvents, and nitrogen. Although researchers attempted to present various types of methods for analytically solving this transport equation system, the currently available solutions are mostly limited to an infinite or a semi-infinite domain. A generalized analytical solution for the coupled multi-species transport problem in a finite domain associated with an arbitrary time-dependent source boundary is not available in the published literature. In this study, we first derive generalized analytical solutions for this transport problem in a finite domain involving arbitrary number of species subject to an arbitrary time-dependent source boundary. Subsequently, we adopt these derived generalized analytical solutions to obtain explicit analytical solutions for a special-case transport scenario involving an exponentially decaying Bateman type time-dependent source boundary. We test the derived special-case solutions against the previously published coupled 4-species transport solution and the corresponding numerical solution with coupled 10-species transport to conduct the solution verification. Finally, we compare the new analytical solutions derived for a finite domain against the published analytical solutions derived for a semi-infinite domain to illustrate the effect of the exit boundary condition on coupled multi-species transport with an exponential decaying source boundary. The results show noticeable discrepancies between the breakthrough curves of all the species in the immediate vicinity of the exit boundary obtained from the analytical solutions for a finite domain and a semi-infinite domain for the dispersion-dominated condition.

Relationship Factors and Couples' Engagement in Sun Protection

ERIC Educational Resources Information Center

Manne, S. L.; Coups, E. J.; Kashy, D. A.

2016-01-01

Individuals may be more motivated to adopt health practices if they consider the benefits of these behaviors for their close relationships. The goal of this study was to examine couple concordance with sun protection and use the interdependence and communal coping theory to evaluate the role of relationship factors in sun protection. One hundred…

Tandem robot control system and method for controlling mobile robots in tandem

DOEpatents

Hayward, David R.; Buttz, James H.; Shirey, David L.

2002-01-01

A control system for controlling mobile robots provides a way to control mobile robots, connected in tandem with coupling devices, to navigate across difficult terrain or in closed spaces. The mobile robots can be controlled cooperatively as a coupled system in linked mode or controlled individually as separate robots.

Coupling sensing to crop models for closed-loop plant production in advanced life support systems

NASA Astrophysics Data System (ADS)

Cavazzoni, James; Ling, Peter P.

1999-01-01

We present a conceptual framework for coupling sensing to crop models for closed-loop analysis of plant production for NASA's program in advanced life support. Crop status may be monitored through non-destructive observations, while models may be independently applied to crop production planning and decision support. To achieve coupling, environmental variables and observations are linked to mode inputs and outputs, and monitoring results compared with model predictions of plant growth and development. The information thus provided may be useful in diagnosing problems with the plant growth system, or as a feedback to the model for evaluation of plant scheduling and potential yield. In this paper, we demonstrate this coupling using machine vision sensing of canopy height and top projected canopy area, and the CROPGRO crop growth model. Model simulations and scenarios are used for illustration. We also compare model predictions of the machine vision variables with data from soybean experiments conducted at New Jersey Agriculture Experiment Station Horticulture Greenhouse Facility, Rutgers University. Model simulations produce reasonable agreement with the available data, supporting our illustration.

Magnetospheric electrons

NASA Technical Reports Server (NTRS)

Coroniti, F. V.; Thorne, R. M.

1972-01-01

Coupling of source, transport, and sink processes produces a fairly accurate model for the macroscopic structure and dynamics of magnetospheric electrons. Auroral electrons are controlled by convective transport from a plasma sheet source coupled with a precipitation loss due to whistler and electrostatic plasma turbulence. Outer and inner zone electrons are governed by radial diffusion transport from convection and acceleration sources external to the plasmapause and by parasitic precipitation losses arising from cyclotron and Landau interactions with whistler and ion cyclotron turbulence.

Surface emission determination of volatile organic compounds (VOC) from a closed industrial waste landfill using a self-designed static flux chamber.

PubMed

Gallego, E; Perales, J F; Roca, F J; Guardino, X

2014-02-01

Closed landfills can be a source of VOC and odorous nuisances to their atmospheric surroundings. A self-designed cylindrical air flux chamber was used to measure VOC surface emissions in a closed industrial landfill located in Cerdanyola del Vallès, Catalonia, Spain. The two main objectives of the study were the evaluation of the performance of the chamber setup in typical measurement conditions and the determination of the emission rates of 60 different VOC from that industrial landfill, generating a valuable database that can be useful in future studies related to industrial landfill management. Triplicate samples were taken in five selected sampling points. VOC were sampled dynamically using multi-sorbent bed tubes (Carbotrap, Carbopack X, Carboxen 569) connected to SKC AirCheck 2000 pumps. The analysis was performed by automatic thermal desorption coupled with a capillary gas chromatograph/mass spectrometry detector. The emission rates of sixty VOC were calculated for each sampling point in an effort to characterize surface emissions. To calculate average, minimum and maximum emission values for each VOC, the results were analyzed by three different methods: Global, Kriging and Tributary area. Global and Tributary area methodologies presented similar values, with total VOC emissions of 237 ± 48 and 222 ± 46 g day(-1), respectively; however, Kriging values were lower, 77 ± 17 gd ay(-1). The main contributors to the total emission rate were aldehydes (nonanal and decanal), acetic acid, ketones (acetone), aromatic hydrocarbons and alcohols. Most aromatic hydrocarbon (except benzene, naphthalene and methylnaphthalenes) and aldehyde emission rates exhibited strong correlations with the rest of VOC of their family, indicating a possible common source of these compounds. B:T ratio obtained from the emission rates of the studied landfill suggested that the factors that regulate aromatic hydrocarbon distributions in the landfill emissions are different from the ones from urban areas. Environmental conditions (atmospheric pressure, temperature and relative humidity) did not alter the pollutant emission fluxes. © 2013.

The role of stress on close relationships and marital satisfaction.

PubMed

Randall, Ashley K; Bodenmann, Guy

2009-03-01

Stress is a concept that has received increased attention in marital research during the last decade, showing that it plays an important role in understanding the quality and stability of close relationships. Evidence suggests that stress is a threat to marital satisfaction and its longevity. Research has been based upon theoretical models of stress in close relationships, specifically family stress models [e.g., Hill, R. (1958). Generic features of families under stress. Social Casework, 39, 139-150.; McCubbin, H. I., & Patterson, J. M. (1983). Family transitions: Adaptation to stress. In H. I. McCubbin & C. R. Figley (Eds.), Stress and the family: Coping with normative transitions (Vol. 2, pp. 5-25). New York: Brunner/Mazel] and couple's stress model's proposed by Karney, Story, and Bradbury [Karney, B. R., Story, L. B., & Bradbury, T. N. (2005). Marriages in context: Interactions between chronic an acute stress among newlyweds. In T. A. Revenson, K. Kayser, & G. Bodenmann (Eds.), Couples coping with stress: Emerging perspectives on dyadic coping (pp.13-32). American Psychological Association: Washington, D.C.] and Bodenmann [Bodenmann, G. (1995). A systemic-transactional conceptualization of stress and coping in couples. Swiss Journal of Psychology, 54, 34-49.; Bodenmann, G. (2005). Dyadic coping and its significant for marital functioning. In T. Revenson, K. Kayser, & G. Bodenmann (Eds.), Couples coping with stress: Emerging perspectives on dyadic coping (pp.33-50). American Psychological Association: Washington, D.C.]. In this review we: (1) examine the various theoretical models of stress, (2) analyze and summarize the typologies relating to stress models (internal versus external, major versus minor, acute versus chronic), and (3) summarize findings from stress research in couples that has practical significance and may inspire clinical work. Future directions in research and clincial significance are suggested.

700 W blue fiber-coupled diode-laser emitting at 450 nm

NASA Astrophysics Data System (ADS)

Balck, A.; Baumann, M.; Malchus, J.; Chacko, R. V.; Marfels, S.; Witte, U.; Dinakaran, D.; Ocylok, S.; Weinbach, M.; Bachert, C.; Kösters, A.; Krause, V.; König, H.; Lell, A.; Stojetz, B.; Löffler, A.; Strauss, U.

2018-02-01

A high-power blue laser source was long-awaited for processing materials with low absorption in the near infrared (NIR) spectral range like copper or gold. Due to the huge progress of GaN-based semiconductors, the performance of blue diode-lasers has made a major step forward recently. With the availability of unprecedented power levels at cw-operating blue diode-lasers emitting at 450 nm, it was possible to set up a high-power diode-laser in the blue spectral range to address these conventional laser applications and probably beyond that to establish completely new utilizations for lasers. Within the scope of the research project "BlauLas", funded within the German photonic initiative "EFFILAS" [8] by the German Federal Ministry of Education and Research (BMBF), Laserline in cooperation with OSRAM aims to realize a cw fiber-coupled diode-laser exceeding 1 kW blue laser power. In this paper the conceptual design and experimental results of a 700 W blue fiber-coupled diode-laser are presented. Initially a close look had to be taken on the mounting techniques of the semiconductors to serve the requirements of the GaN laser diodes. Early samples were used for extensive long term tests to investigate degradation processes. With first functional laser-modules we set up fiber-coupled laser-systems for further testing. Besides adaption of well-known optical concepts a main task within the development of the laser system was the selection and examination of suitable materials and assembling in order to minimize degradation and reach adequate lifetimes. We realized R&D blue lasersystems with lifetimes above 5,000 h, which enable first application experiments on processing of various materials as well as experiments on conversion to white-light.

Computational models for the study of heart-lung interactions in mammals.

PubMed

Ben-Tal, Alona

2012-01-01

The operation and regulation of the lungs and the heart are closely related. This is evident when examining the anatomy within the thorax cavity, in the brainstem and in the aortic and carotid arteries where chemoreceptors and baroreceptors, which provide feedback affecting the regulation of both organs, are concentrated. This is also evident in phenomena such as respiratory sinus arrhythmia where the heart rate increases during inspiration and decreases during expiration, in other types of synchronization between the heart and the lungs known as cardioventilatory coupling and in the association between heart failure and sleep apnea where breathing is interrupted periodically by periods of no-breathing. The full implication and physiological significance of the cardiorespiratory coupling under normal, pathological, or extreme physiological conditions are still unknown and are subject to ongoing investigation both experimentally and theoretically using mathematical models. This article reviews mathematical models that take heart-lung interactions into account. The main ideas behind low dimensional, phenomenological models for the study of the heart-lung synchronization and sleep apnea are described first. Higher dimensions, physiology-based models are described next. These models can vary widely in detail and scope and are characterized by the way the heart-lung interaction is taken into account: via gas exchange, via the central nervous system, via the mechanical interactions, and via time delays. The article emphasizes the need for the integration of the different sources of heart-lung coupling as well as the different mathematical approaches. Copyright © 2011 Wiley Periodicals, Inc.

Automatic treatment of the variance estimation bias in TRIPOLI-4 criticality calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumonteil, E.; Malvagi, F.

2012-07-01

The central limit (CLT) theorem States conditions under which the mean of a sufficiently large number of independent random variables, each with finite mean and variance, will be approximately normally distributed. The use of Monte Carlo transport codes, such as Tripoli4, relies on those conditions. While these are verified in protection applications (the cycles provide independent measurements of fluxes and related quantities), the hypothesis of independent estimates/cycles is broken in criticality mode. Indeed the power iteration technique used in this mode couples a generation to its progeny. Often, after what is called 'source convergence' this coupling almost disappears (the solutionmore » is closed to equilibrium) but for loosely coupled systems, such as for PWR or large nuclear cores, the equilibrium is never found, or at least may take time to reach, and the variance estimation such as allowed by the CLT is under-evaluated. In this paper we first propose, by the mean of two different methods, to evaluate the typical correlation length, as measured in cycles number, and then use this information to diagnose correlation problems and to provide an improved variance estimation. Those two methods are based on Fourier spectral decomposition and on the lag k autocorrelation calculation. A theoretical modeling of the autocorrelation function, based on Gauss-Markov stochastic processes, will also be presented. Tests will be performed with Tripoli4 on a PWR pin cell. (authors)« less

Chimera-type states induced by local coupling

NASA Astrophysics Data System (ADS)

Clerc, M. G.; Coulibaly, S.; Ferré, M. A.; García-Ñustes, M. A.; Rojas, R. G.

2016-05-01

Coupled oscillators can exhibit complex self-organization behavior such as phase turbulence, spatiotemporal intermittency, and chimera states. The latter corresponds to a coexistence of coherent and incoherent states apparently promoted by nonlocal or global coupling. Here we investigate the existence, stability properties, and bifurcation diagram of chimera-type states in a system with local coupling without different time scales. Based on a model of a chain of nonlinear oscillators coupled to adjacent neighbors, we identify the required attributes to observe these states: local coupling and bistability between a stationary and an oscillatory state close to a homoclinic bifurcation. The local coupling prevents the incoherent state from invading the coherent one, allowing concurrently the existence of a family of chimera states, which are organized by a homoclinic snaking bifurcation diagram.

Coupled hydrological and biogeochemical processes controlling variability of nitrogen species in streamflow during autumn in an upland forest

USGS Publications Warehouse

Sebestyen, Stephen D.; Shanley, James B.; Boyer, Elizabeth W.; Kendall, Carol; Doctor, Daniel H.

2014-01-01

Autumn is a season of dynamic change in forest streams of the northeastern United States due to effects of leaf fall on both hydrology and biogeochemistry. Few studies have explored how interactions of biogeochemical transformations, various nitrogen sources, and catchment flow paths affect stream nitrogen variation during autumn. To provide more information on this critical period, we studied (1) the timing, duration, and magnitude of changes to stream nitrate, dissolved organic nitrogen (DON), and ammonium concentrations; (2) changes in nitrate sources and cycling; and (3) source areas of the landscape that most influence stream nitrogen. We collected samples at higher temporal resolution for a longer duration than typical studies of stream nitrogen during autumn. This sampling scheme encompassed the patterns and extremes that occurred during base flow and stormflow events of autumn. Base flow nitrate concentrations decreased by an order of magnitude from 5.4 to 0.7 µmol L−1 during the week when most leaves fell from deciduous trees. Changes to rates of biogeochemical transformations during autumn base flow explained the low nitrate concentrations; in-stream transformations retained up to 72% of the nitrate that entered a stream reach. A decrease of in-stream nitrification coupled with heterotrophic nitrate cycling were primary factors in the seasonal nitrate decline. The period of low nitrate concentrations ended with a storm event in which stream nitrate concentrations increased by 25-fold. In the ensuing weeks, peak stormflow nitrate concentrations progressively decreased over closely spaced, yet similarly sized events. Most stormflow nitrate originated from nitrification in near-stream areas with occasional, large inputs of unprocessed atmospheric nitrate, which has rarely been reported for nonsnowmelt events. A maximum input of 33% unprocessed atmospheric nitrate to the stream occurred during one event. Large inputs of unprocessed atmospheric nitrate show direct and rapid effects on forest streams that may be widespread, although undocumented, throughout nitrogen-polluted temperate forests. In contrast to a week-long nitrate decline during peak autumn litterfall, base flow DON concentrations increased after leaf fall and remained high for 2 months. Dissolved organic nitrogen was hydrologically flushed to the stream from riparian soils during stormflow. In contrast to distinct seasonal changes in base flow nitrate and DON concentrations, ammonium concentrations were typically at or below the detection limit, similar to the rest of the year. Our findings reveal couplings among catchment flow paths, nutrient sources, and transformations that control seasonal extremes of stream nitrogen in forested landscapes.

Intimacy and Relationship Processes in Couples’ Psychosocial Adaptation to Cancer

PubMed Central

Manne, Sharon; Badr, Hoda

2015-01-01

The authors highlighted the importance of viewing cancer from a relationship perspective. This perspective not only considers the marital relationship as a resource that individual partners draw upon but also highlights the importance of focusing attention onto the relationship and engaging in communication behaviors aimed at sustaining and/or enhancing the relationship during stressful times. On the basis of existing conceptualizations, empiric research on couples and cancer, and the authors’ perspective on the literature, they formulated the relationship intimacy model of couples’ psychosocial adaptation to cancer as a first step toward building a framework for researchers and clinicians to inform their work in this area. The model proposes that patients and their partners engage in behaviors that either promote or undermine the level of closeness in their relationship and that the closeness of the marital relationship is an important determinant of patient and partner psychologic adaptation to cancer. Preliminary data from a couples’ intimacy-enhancing intervention for breast cancer patients and their partners supported the model. Of the 25 couples who consented to participate in the intervention and completed the preintervention surveys, 15 couples completed all 5 sessions, and 12 couples completed the follow-up survey. The current results suggested that the intervention improved patient and partner perceptions of the closeness of their relationship and reduced their distress. The authors also discuss limitations of the relationship intimacy model as well as future directions for empiric and clinical research on couples’ psychosocial adaptation to cancer. PMID:18428202

Source time functions of large Mexican subduction earthquakes, morphology of the Benioff Zone, age of the plate, and their tectonic implications

NASA Astrophysics Data System (ADS)

Singh, S. K.; Mortera, F.

1991-12-01

We study source parameters of large, shallow Mexican subduction zone earthquakes (95°W to 106°W) which occurred between 1928 and 1986 by modeling the P waves recorded on Galitzin-Wilip seismograph in DeBilt (DBN), Holland. For post-1962 events the source parameters retrieved from DBN seismograms alone agree well with those obtained from long-period World-Wide Standardized Seismograph Network records, giving us confidence in our results for pre-1962 events. All earthquakes are shallow (H˜10 to 20 km). With few exceptions the sources in Oaxaca (95°W to 99°W) are very simple. To the northwest of 99°W they are simple as well as complex. The ratio of surface wave to body wave seismic moment (Mos/MoP), which is a measure of long- to short-period radiation, is smaller in Oaxaca (˜ 1.5±0.5) than in the regions northwest of 99°W (˜3.1±1.3). These results suggest a change in the plate interface characteristics near 99°W. The sharp change in the rupture mode and the intersection of the O'Gorman Fracture Zone (OFZ) with the trench occur near 99°W. Two strike-slip events offshore, close to OFZ, suggest a segmentation of the subducting plate near 99°W. The age of the plate near the trench in Oaxaca is not well known; it is possible that it does not increase continuously from northwest to southeast in the region but jumps across 99°W. If so, then the older age of the subducted plate southeast of 99°W may be the cause of the distinct rupture mode of the Oaxaca earthquakes. The length of the Benioff zone, which is greatest below Oaxaca ( ≈ 400 km) and decreases toward the northwest, can be explained by the correlation between the length of the subducted slab and the product of the lithosphere age and convergence rate. The relative complexity of sources, the weaker background seismicity, and the lesser number of aftershocks northwest of Oaxaca may be explained by a stronger interface coupling resulting from subduction of younger oceanic slabs (˜5 to 13 m.y. old) in this region. This, however, explains neither larger Mos/MoP values northwest of Oaxaca nor the low stress drop estimates obtained from the analysis of near-field strong-motion data for the Michoacan earthquake of 1985, both of which indicate weaker coupling of the interface. Thus the issue of whether subduction of very young plates (≤ 10 m.y. old) results in strong or weak coupling remains unsolved from the presently available Mexican data.

Compliant, low profile, independently releasing, non-protruding and genderless docking system for robotic modules

NASA Technical Reports Server (NTRS)

Khoshnevis, Behrokh (Inventor)

2010-01-01

An apparatus for coupling with a mating coupling module to facilitate the joining of two disjoined structures without requiring precise alignment between the disjoined structures during the coupling of them may include a rotating drive mechanism, a hollow cylindrical body operatively connected to the rotating drive mechanism, wherein the hollow cylindrical body has at least one internal spiral channel, and at least one connector claw positioned within the hollow cylindrical body and guided by the internal spiral channel, wherein the at least one connector claw is configured to extend outwardly from the coupling module to engage the mating coupling module when brought in close proximity but not necessarily in precise alignment with the mating coupling module.

Sound source localization and segregation with internally coupled ears: the treefrog model

PubMed Central

Christensen-Dalsgaard, Jakob

2016-01-01

Acoustic signaling plays key roles in mediating many of the reproductive and social behaviors of anurans (frogs and toads). Moreover, acoustic signaling often occurs at night, in structurally complex habitats, such as densely vegetated ponds, and in dense breeding choruses characterized by high levels of background noise and acoustic clutter. Fundamental to anuran behavior is the ability of the auditory system to determine accurately the location from where sounds originate in space (sound source localization) and to assign specific sounds in the complex acoustic milieu of a chorus to their correct sources (sound source segregation). Here, we review anatomical, biophysical, neurophysiological, and behavioral studies aimed at identifying how the internally coupled ears of frogs contribute to sound source localization and segregation. Our review focuses on treefrogs in the genus Hyla, as they are the most thoroughly studied frogs in terms of sound source localization and segregation. They also represent promising model systems for future work aimed at understanding better how internally coupled ears contribute to sound source localization and segregation. We conclude our review by enumerating directions for future research on these animals that will require the collaborative efforts of biologists, physicists, and roboticists. PMID:27730384

Simulation Study of Near-Surface Coupling of Nuclear Devices vs. Equivalent High-Explosive Charges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fournier, Kevin B; Walton, Otis R; Benjamin, Russ

2014-09-29

A computational study was performed to examine the differences in near-surface ground-waves and air-blast waves generated by high-explosive energy sources and those generated by much higher energy - density low - yield nuclear sources. The study examined the effect of explosive-source emplacement (i.e., height-of-burst, HOB, or depth-of-burial, DOB) over a range from depths of -35m to heights of 20m, for explosions with an explosive yield of 1-kt . The chemical explosive was modeled by a JWL equation-of-state model for a ~14m diameter sphere of ANFO (~1,200,000kg – 1 k t equivalent yield ), and the high-energy-density source was modeled asmore » a one tonne (1000 kg) plasma of ‘Iron-gas’ (utilizing LLNL’s tabular equation-of-state database, LEOS) in a 2m diameter sphere, with a total internal-energy content equivalent to 1 k t . A consistent equivalent-yield coupling-factor approach was developed to compare the behavior of the two sources. The results indicate that the equivalent-yield coupling-factor for air-blasts from 1 k t ANFO explosions varies monotonically and continuously from a nearly perfec t reflected wave off of the ground surface for a HOB ≈ 20m, to a coupling factor of nearly zero at DOB ≈ -25m. The nuclear air - blast coupling curve, on the other hand, remained nearly equal to a perfectly reflected wave all the way down to HOB’s very near zero, and then quickly dropped to a value near zero for explosions with a DOB ≈ -10m. The near - surface ground - wave traveling horizontally out from the explosive source region to distances of 100’s of meters exhibited equivalent - yield coupling - factors t hat varied nearly linearly with HOB/DOB for the simulated ANFO explosive source, going from a value near zero at HOB ≈ 5m to nearly one at DOB ≈ -25m. The nuclear-source generated near-surface ground wave coupling-factor remained near zero for almost all HOB’s greater than zero, and then appeared to vary nearly - linearly with depth-of-burial until it reached a value of one at a DOB between 15m and 20m. These simulations confirm the expected result that the variation of coupling to the ground, or the air, change s much more rapidly with emplacement location for a high-energy-density (i.e., nuclear-like) explosive source than it does for relatively low - energy - density chemical explosive sources. The Energy Partitioning, Energy Coupling (EPEC) platform at LLNL utilizes laser energy from one quad (i.e. 4-laser beams) of the 192 - beam NIF Laser bank to deliver ~10kJ of energy to 1mg of silver in a hohlraum creating an effective small-explosive ‘source’ with an energy density comparable to those in low-yield nuclear devices. Such experiments have the potential to provide direct experimental confirmation of the simulation results obtained in this study, at a physical scale (and time-scale) which is a factor of 1000 smaller than the spatial- or temporal-scales typically encountered when dealing with nuclear explosions.« less

Symmetry Breaking and Optical Negative Index of Closed Nanorings

NASA Astrophysics Data System (ADS)

Kante, Boubacar; Park, Yong-Shik; O'Brien, Kevin; Shuldman, Daniel; Lanzillotti-Kimura, Norberto; Wong, Zi; Yin, Xiaobo; Zhang, Xiang; UC Berkeley Team

2013-03-01

We report the first experimental demonstration of broadband negative-index metamaterial made solely of closed metallic nanorings. Using symmetry breaking that negatively couples the discrete nanorings, we measured negative phase delay in our composite chess metamaterial. Our approach open avenues towards topological nanophotonics with on demand linear and non-linear responses.

Emission performance of ceramic preconverters evaluated by FTP and Euro Stage III emission test cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Locker, R.J.; Then, P.M.; Zink, U.

1996-09-01

Preconverters and close-coupled main converters are viewed as key components in advanced emission systems to help the auto industry comply with tightened emission regulations in North America and Europe. Due to their close position to the exhaust manifold when compared to current main catalysts, the mechanical and thermal durability requirements on such close-coupled converters are significantly increased. A set of representative preconverter systems, with respect to back pressure and surface area, ceramic and metal substrate material was exposed to a 100 hour engine aging cycle, which is equivalent to approximately 80,000 kilometers under European driving conditions. This aging cycle ismore » used by the German Autoconsortium (ZDAKW). In order to address the high thermal load in a close-coupled position, the preconverter inlet gas temperature has been elevated to a maximum of 950 C at stoichiometry. Maximum preconverter midbed temperature has been found close to 1,000 C. State-of-the-art catalytic coatings were used on the preconverters (Pd-only) and main converters (Trimetal). Emission tests using the new European test cycle (EDC 99), as well as the FTP 75 test cycle have been used to evaluate the catalytic performance. These tests were done during the aging at 20, 60 and 100 hours on the preconverters alone and on the combination of pre- and main converters. The impact of air injection has been studied on the complete preconverter/mainconverter system. The Celcor XT{trademark} ceramic preconverter proved mechanically and catalytically intact during the severe 100 hour aging cycle. The metallic and ceramic preconverter systems demonstrated equivalent catalytic performance.« less

Don't Panic! Closed String Tachyons in ALE Spacetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverstein, Eva M

2001-08-20

We consider closed string tachyons localized at the fixed points of noncompact nonsupersymmetric orbifolds. We argue that tachyon condensation drives these orbifolds to flat space or supersymmetric ALE spaces. The decay proceeds via an expanding shell of dilaton gradients and curvature which interpolates between two regions of distinct angular geometry. The string coupling remains weak throughout. For small tachyon VEVs, evidence comes from quiver theories on D-branes probes, in which deformations by twisted couplings smoothly connect non-supersymmetric orbifolds to supersymmetric orbifolds of reduced order. For large tachyon VEVs, evidence comes from worldsheet RG flow and spacetime gravity. For C{sup 2}/Z{submore » n}, we exhibit infinite sequences of transitions producing SUSY ALE spaces via twisted closed string condensation from non-supersymmetric ALE spaces. In a T-dual description this provides a mechanism for creating NS5-branes via closed string tachyon condensation similar to the creation of D-branes via open string tachyon condensation. We also apply our results to recent duality conjectures involving fluxbranes and the type 0 string.« less

Solid state light source driver establishing buck or boost operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmer, Fred

A solid state light source driver circuit that operates in either a buck convertor or a boost convertor configuration is provided. The driver circuit includes a controller, a boost switch circuit and a buck switch circuit, each coupled to the controller, and a feedback circuit, coupled to the light source. The feedback circuit provides feedback to the controller, representing a DC output of the driver circuit. The controller controls the boost switch circuit and the buck switch circuit in response to the feedback signal, to regulate current to the light source. The controller places the driver circuit in its boostmore » converter configuration when the DC output is less than a rectified AC voltage coupled to the driver circuit at an input node. The controller places the driver circuit in its buck converter configuration when the DC output is greater than the rectified AC voltage at the input node.« less

Coupling of Algal Biofuel Production with Wastewater

PubMed Central

Panwar, Amit; Bisht, Tara Singh; Tamta, Sushma

2014-01-01

Microalgae have gained enormous consideration from scientific community worldwide emerging as a viable feedstock for a renewable energy source virtually being carbon neutral, high lipid content, and comparatively more advantageous to other sources of biofuels. Although microalgae are seen as a valuable source in majority part of the world for production of biofuels and bioproducts, still they are unable to accomplish sustainable large-scale algal biofuel production. Wastewater has organic and inorganic supplements required for algal growth. The coupling of microalgae with wastewater is an effective way of waste remediation and a cost-effective microalgal biofuel production. In this review article, we will primarily discuss the possibilities and current scenario regarding coupling of microalgal cultivation with biofuel production emphasizing recent progress in this area. PMID:24982930

Methods for solid electrolyte interphase formation and anode pre-lithiation of lithium ion capacitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raman, Santhanam; Xi, Xiaomei; Ye, Xiang-Rong

A method of pre-doping an anode of an energy storage device can include immersing the anode and a dopant source in an electrolyte, and coupling a substantially constant current between the anode and the dopant source. A method of pre-doping an anode of an energy storage device can include immersing the anode and a dopant source in an electrolyte, and coupling a substantially constant voltage across the anode and the dopant source. An energy storage device can include an anode having a lithium ion pre-doping level of about 60% to about 90%.

Fiber-coupled pillar array as a highly pure and stable single-photon source

NASA Astrophysics Data System (ADS)

Odashima, S.; Sasakura, H.; Nakajima, H.; Kumano, H.

2017-12-01

A highly pure and stable single-photon source is prepared that comprises a well-designed pillar array, in which each pillar contains only a few InAs quantum dots. A nano-pillar in this array is in direct contact with a fiber end surface and cooled in a liquid-He bath. Auto-correlation measurements show that this source provides an average g(2)(0) value of 0.0174 in the measured excitation-power range. This photon source and fiber coupling are quite rigid against external disturbances such as cooling-heating cycles and vibration, with long-term stability.

Microcavities coupled to multilevel atoms

NASA Astrophysics Data System (ADS)

Schmid, Sandra Isabelle; Evers, Jörg

2011-11-01

A three-level atom in the Λ configuration coupled to a microcavity is studied. The two transitions of the atom are assumed to couple to different counterpropagating mode pairs in the cavity. We analyze the dynamics both in the strong-coupling and the bad-cavity limits. We find that, compared to a two-level setup, the third atomic state and the additional control field modes crucially modify the system dynamics and enable more advanced control schemes. All results are explained using appropriate dressed-state and eigenmode representations. As potential applications, we discuss optical switching and turnstile operations and detection of particles close to the resonator surface.

Electro-mechanical energy conversion system having a permanent magnet machine with stator, resonant transfer link and energy converter controls

DOEpatents

Skeist, S. Merrill; Baker, Richard H.

2006-01-10

An electro-mechanical energy conversion system coupled between an energy source and an energy load comprising an energy converter device including a permanent magnet induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer to control the flow of power or energy through the permanent magnetic induction machine.

Application of USNRC NUREG/CR-6661 and draft DG-1108 to evolutionary and advanced reactor designs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang 'Apollo', Chen

2006-07-01

For the seismic design of evolutionary and advanced nuclear reactor power plants, there are definite financial advantages in the application of USNRC NUREG/CR-6661 and draft Regulatory Guide DG-1108. NUREG/CR-6661, 'Benchmark Program for the Evaluation of Methods to Analyze Non-Classically Damped Coupled Systems', was by Brookhaven National Laboratory (BNL) for the USNRC, and Draft Regulatory Guide DG-1108 is the proposed revision to the current Regulatory Guide (RG) 1.92, Revision 1, 'Combining Modal Responses and Spatial Components in Seismic Response Analysis'. The draft Regulatory Guide DG-1108 is available at http://members.cox.net/apolloconsulting, which also provides a link to the USNRC ADAMS site to searchmore » for NUREG/CR-6661 in text file or image file. The draft Regulatory Guide DG-1108 removes unnecessary conservatism in the modal combinations for closely spaced modes in seismic response spectrum analysis. Its application will be very helpful in coupled seismic analysis for structures and heavy equipment to reduce seismic responses and in piping system seismic design. In the NUREG/CR-6661 benchmark program, which investigated coupled seismic analysis of structures and equipment or piping systems with different damping values, three of the four participants applied the complex mode solution method to handle different damping values for structures, equipment, and piping systems. The fourth participant applied the classical normal mode method with equivalent weighted damping values to handle differences in structural, equipment, and piping system damping values. Coupled analysis will reduce the equipment responses when equipment, or piping system and structure are in or close to resonance. However, this reduction in responses occurs only if the realistic DG-1108 modal response combination method is applied, because closely spaced modes will be produced when structure and equipment or piping systems are in or close to resonance. Otherwise, the conservatism in the current Regulatory Guide 1.92, Revision 1, will overshadow the advantage of coupled analysis. All four participants applied the realistic modal combination method of DG-1108. Consequently, more realistic and reduced responses were obtained. (authors)« less

Study of the Forced Response of a Clamped Circular Plate Coupled to a Uni-Dimensional Acoustic Cavity

NASA Astrophysics Data System (ADS)

Curà, F.; Curti, G.; Mantovani, M.

1996-03-01

The subject of this paper is an experimental and analytical study of a structural-acoustical coupling problem. To simplify the issue, the analytical model considered here consists of a uni-dimensional acoustic cavity coupled to a one-degree-of-freedom system (mass, spring and damper). An harmonic excitation force is applied to the mass of the oscillator. In the theoretical analysis, the uni-dimensional cavity is subjected, in correspondence of its end sections, to boundary conditions, which are either the usual ones (closed or open ended) or those deriving from the coupling with the oscillator. This simple model proved to be very useful to investigate the influence of the variation of both the geometrical parameters (i.e., the length of the cavity) and the physical parameters (i.e., mass, damping coefficient and stiffness of the oscillator). The analytical results are compared to those obtained experimentally on a real coupled system, consisting of a cavity enclosed by an acoustically rigid steel cylinder, closed at one end by a movable, acoustically rigid piston and at the other end by a flexible plate, clamped around its edge by the cylinder. Thus the length of the cavity can be varied by simply moving the rigid piston.

Source Parameters from Full Moment Tensor Inversions of Potentially Induced Earthquakes in Western Canada

NASA Astrophysics Data System (ADS)

Wang, R.; Gu, Y. J.; Schultz, R.; Kim, A.; Chen, Y.

2015-12-01

During the past four years, the number of earthquakes with magnitudes greater than three has substantially increased in the southern section of Western Canada Sedimentary Basin (WCSB). While some of these events are likely associated with tectonic forces, especially along the foothills of the Canadian Rockies, a significant fraction occurred in previously quiescent regions and has been linked to waste water disposal or hydraulic fracturing. A proper assessment of the origin and source properties of these 'induced earthquakes' requires careful analyses and modeling of regional broadband data, which steadily improved during the past 8 years due to recent establishments of regional broadband seismic networks such as CRANE, RAVEN and TD. Several earthquakes, especially those close to fracking activities (e.g. Fox creek town, Alberta) are analyzed. Our preliminary full moment tensor inversion results show maximum horizontal compressional orientations (P-axis) along the northeast-southwest orientation, which agree with the regional stress directions from borehole breakout data and the P-axis of historical events. The decomposition of those moment tensors shows evidence of strike-slip mechanism with near vertical fault plane solutions, which are comparable to the focal mechanisms of injection induced earthquakes in Oklahoma. Minimal isotropic components have been observed, while a modest percentage of compensated-linear-vector-dipole (CLVD) components, which have been linked to fluid migraition, may be required to match the waveforms. To further evaluate the non-double-couple components, we compare the outcomes of full, deviatoric and pure double couple (DC) inversions using multiple frequency ranges and phases. Improved location and depth information from a novel grid search greatly assists the identification and classification of earthquakes in potential connection with fluid injection or extraction. Overall, a systematic comparison of the source attributes of intermediate-sized earthquakes present a new window into the nature of potentially induced earthquakes in the WCSB.

Monopolar electrosurgery through single-port laparoscopy: a potential hidden hazard for bowel burns.

PubMed

Abu-Rafea, Basim; Vilos, George A; Al-Obeed, Omar; AlSheikh, Abdulmalik; Vilos, Angelos G; Al-Mandeel, Hazem

2011-01-01

Surveys indicate that up to 90% of general surgeons and gynecologists use monopolar radiofrequency during laparoscopy and 18% have experienced visceral burns. Monopolar electrosurgery compared with other energy sources is associated with unique characteristics and inherent risks and complications caused by inadvertent direct or capacitive coupling or insulation failure of instruments. These dangers become particularly important with the reemergence of single-port laparoscopy, which requires close proximity and crossing of multiple intraabdominal instruments outside the surgeon's field of view. To determine the effects of monopolar electrosurgery on various tissues/organs during simulated single-port laparoscopic surgery in vitro and in vivo. Simulation in a dry laboratory with fresh sheep liver, pig bowel and bowel in an anesthetized dog (Canadian Classification II-3). University-affiliated teaching hospital and animal facilities. We used Valleylab Force 2 and FX electrosurgical generators at clinically used power outputs of 40 to 60 watts, and both high- and low-voltage (coagulation and cut) waveforms and commercially-available single-port devices. The effect on tissue was recorded by pictures and video camera and graded visually and histologically with hematoxylin and eosin stains. During activation of any standard monopolar laparoscopic instrument (scissors, coagulating electrode, etc), capacitive coupled currents resulting in visible tissue burn (blanching) caused by other adjacent cold instrument (graspers, etc) including metallic suction-irrigation cannulas and the laparoscope itself were noted. Histopathologic study confirmed transmural thermal damage extending to the mucosa of small bowel, even in the presence of mild serosa blanching. With prolonged activation of the electrosurgical generator, the capacitive coupled corona discharge burned the insulation and caused rapid insulation breakdown of the electrode instrument resulting in direct coupling (sparking, arcing) to adjacent cold instruments and more severe burning to the contacted tissue/organ. During single-port laparoscopy and use of monopolar radiofrequency, the proximity and crossing of multiple instruments generate capacitive or direct coupled currents, which may cause visceral burns. Copyright © 2011 AAGL. Published by Elsevier Inc. All rights reserved.

Dynamics of the Transition Corona

NASA Technical Reports Server (NTRS)

Masson, Sophie; McCauley, Patrick; Golub, Leon; Reeves, Katharine K.; DeLuca, Edward E.

2014-01-01

Magnetic reconnection between the open and closed magnetic fields in the corona is believed to play a crucial role in the corona/heliosphere coupling. At large scale, the exchange of open/closed connectivity is expected to occur in pseudo-streamer (PS) structures. However, there is neither clear observational evidence of how such coupling occurs in PSs, nor evidence for how the magnetic reconnection evolves. Using a newly developed technique, we enhance the off-limb magnetic fine structures observed with the Atmospheric Imaging Assembly and identify a PS-like feature located close to the northern coronal hole. We first identify that the magnetic topology associated with the observation is a PS, null-point (NP) related topology bounded by the open field. By comparing the magnetic field configuration with the extreme ultraviolet (EUV) emission regions, we determined that most of the magnetic flux associated with plasma emission are small loops below the PS basic NP and open field bounding the PS topology. In order to interpret the evolution of the PS, we referred to a three-dimensional MHD interchange reconnection modeling the exchange of connectivity between small closed loops and the open field. The observed PS fine structures follow the dynamics of the magnetic field before and after reconnecting at the NP obtained by the interchange model. Moreover, the pattern of the EUV plasma emission is the same as the shape of the expected plasma emission location derived from the simulation. These morphological and dynamical similarities between the PS observations and the results from the simulation strongly suggest that the evolution of the PS, and in particular the opening/closing of the field, occurs via interchange/slipping reconnection at the basic NP of the PS. Besides identifying the mechanism at work in the large-scale coupling between the open and closed fields, our results highlight that interchange reconnection in PSs is a gradual physical process that differs from the impulsive reconnection of the solar-jet model.

Development of procedure for measurement of Pb isotope ratios in seawater by application of seaFAST sample pre-treatment system and Sector Field Inductively Coupled Plasma Mass Spectrometry

NASA Astrophysics Data System (ADS)

Vassileva, Emilia; Wysocka, Irena

2016-12-01

Anthropogenic Pb in the oceans, derived from high-temperature industrial processes, fuel combustion and incineration can have an isotopic signature distinct from naturally occurring Pb, supplied by rock weathering. To identify the different pollution sources accurately and to quantify their relative contributions, Pb isotope ratios are widely used. Due to the high salt content (approximately 3.5% of total dissolved solids) and very low levels of Pb (typically from 1 to 100 ng L- 1) in seawater the determination of Pb isotope ratios requires preliminary matrix separation and analyte preconcentration. An analytical protocol for the measurements of Pb isotope ratios in seawater combining seaFAST sample pre-treatment system and Sector Field Inductively Coupled Plasma Mass Spectrometry (SF ICP-MS) was developed. The application of seaFAST system was advantageous, because of its completely closed working cycle and small volumes of chemicals introduced in pre-treatment step, resulting in very low detection limits and procedural blanks. The preconcentration/matrix separation step was also of crucial importance for minimizing the isobaric and matrix interferences, coming from the seawater. In order to differentiate between anthropogenic and natural Pb sources, particular attention was paid to the determination of 204Pb isotope because of its implication in some geological interpretations. The validation of the analytical procedure was effectuated according to the recommendations of the ISO/IEC 17025 standard. The method was validated by processing the common Pb isotope reference material NIST SRM 981. All major sources of uncertainty were identified and propagated together following the ISO/GUM guidelines. The estimation of the total uncertainty associated to each measurement result was fundamental tool for sorting the main sources of possible biases. The developed analytical procedure was applied to the coastal and open seawater samples, collected in different regions of the world and revealed that the procedure is applicable for the measurement of Pb isotope ratios in seawater with combined uncertainty adequate to discuss the origin of Pb pollution in the ocean.

Coupled Source-to-Sink and Geodynamic Modeling of Extensional Basins: A Case Study of the Gulf of Corinth, Greece.

NASA Astrophysics Data System (ADS)

Smithells, R. A.

2015-12-01

Many studies investigate rift evolution with geodynamic models, giving insight into the architecture and morphology of extensional basins. Recent advances in modeling allow better temporal and spatial resolution in surface processes when coupled with geodynamic processes, allowing modeling the interactions between sediment erosion and deposition with rift development. Here we use a combination of dynamic forward modeling and landscape evolution models to determine feedback and interaction of sediment erosion and deposition with rift development and fault localization. The Gulf of Corinth is an ideal basin to study the effect of surface processes on rifting because it can be considered a closed system for sediment erosion and deposition. It is a young rift, not affected by subsequent overprinting and there is a large amount of data from offshore seismic surveys and onshore fieldwork to constrain its evolution. We reconstruct paleo topography of the catchment area by removing the effects of fault activity and sediment erosion. The reconstructed topography is used to model different scenarios for landscape evolution and the results determine the relative importance of regional and fault related uplift and subsidence on the drainage evolution in the Gulf of Corinth. The landscape models are also used to constrain source area and total amount of sediment eroded from the catchment area. The eroded onshore volume and the amount of sediment deposited offshore are compared in order to reconstruct the source-to-sink balance for the Gulf of Corinth. Our results constrain the evolution of the catchment area and timings of drainage reversals that occurred in the fluvial systems of the Gulf of Corinth. Coupled forward tectonic-surface process modeling is used to investigate feedback between rift formation and the surface processes and to determine its role in developing asymmetry and fault migration in an extensional setting. In this study we investigate the effect of a mature sediment routing system on rift development. Our models show that migrating fault activity may be triggered by migration of sediment deposition filling the accommodation space provided by the associated half grabens. The asymmetric development of the rift can be explained by the preferred erosion and deposition of the southern flank of the Gulf of Corinth.

The precarious couple effect: verbally inhibited men + critical, disinhibited women = bad chemistry.

PubMed

Swann, William B; Rentfrow, Peter J; Gosling, Samuel D

2003-12-01

When critical, verbally disinhibited women are paired with verbally inhibited men, relationship quality suffers, rendering the relationship precarious. This effect theoretically emerges when (a). verbally disinhibited women pair with relatively inhibited men (man-more-inhibited couples) and (b). the disinhibition of women in man-more-inhibited couples amplifies women's criticalness and alienates men. Three studies (Ns=437, 300, and 564) provided evidence that relationship quality suffered in man-more-inhibited couples; a 4th study (N=168) showed that the criticalness of women in man-more-inhibited couples did indeed undermine relationship quality. Implications for understanding the impact of gender expectations on relationships and for integrating behavioral and personological approaches to close relationships are discussed.

Microsystem enabled photovoltaic modules and systems

DOEpatents

Nielson, Gregory N.; Sweatt, William C.; Okandan, Murat

2017-09-12

A photovoltaic (PV) module includes an absorber layer coupled to an optic layer. The absorber layer includes an array of PV elements. The optic layer includes a close-packed array of Keplerian telescope elements, each corresponding to one of an array of pupil elements. The Keplerian telescope substantially couple radiation that is incident on their objective surfaces into the corresponding pupil elements. Each pupil element relays radiation that is coupled into it from the corresponding Keplerian telescope element into the corresponding PV element.

Infrared fixed point of SU(2) gauge theory with six flavors

NASA Astrophysics Data System (ADS)

Leino, Viljami; Rummukainen, Kari; Suorsa, Joni; Tuominen, Kimmo; Tähtinen, Sara

2018-06-01

We compute the running of the coupling in SU(2) gauge theory with six fermions in the fundamental representation of the gauge group. We find strong evidence that this theory has an infrared stable fixed point at strong coupling and measure also the anomalous dimension of the fermion mass operator at the fixed point. This theory therefore likely lies close to the boundary of the conformal window and will display novel infrared dynamics if coupled with the electroweak sector of the Standard Model.

Summary of low-speed longitudinal aerodynamics of two powered close-coupled wing-canard fighter configurations. [conducted in Langley C/STOL tunnel

NASA Technical Reports Server (NTRS)

Paulson, J. W., Jr.; Thomas, J. L.

1979-01-01

Investigations of the low speed longitudinal characteristics of two powered close coupled wing-canard fighter configurations are discussed. Data obtained at angles of attack from -2 deg to 42 deg, Mach numbers from 0.12 to 0.20, nozzle and flap deflections from 0 deg to 40 deg, and thrust coefficients from 0 to 2.0, to represent both high angle of attack subsonic maneuvering characteristics and conventional takeoff and landing characteristics are examined. Data obtained with the nozzles deflected either 60 deg or 90 deg and the flaps deflected 60 deg to represent vertical or short takeoff and landing characteristics are discussed.

Hot gas filter and system assembly

DOEpatents

Lippert, Thomas Edwin; Palmer, Kathryn Miles; Bruck, Gerald Joseph; Alvin, Mary Anne; Smeltzer, Eugene E.; Bachovchin, Dennis Michael

1999-01-01

A filter element for separating fine dirty particles from a hot gas. The filter element comprises a first porous wall and a second porous wall. Each porous wall has an outer surface and an inner surface. The first and second porous walls being coupled together thereby forming a substantially closed figure and open at one end. The open end is formed to be coupled to a hot gas clean up system support structure. The first and second porous walls define a channel beginning at the open end and terminate at the closed end through which a filtered clean gas can flow through and out into the clean gas side of a hot gas clean up system.

Hot gas filter and system assembly

DOEpatents

Lippert, T.E.; Palmer, K.M.; Bruck, G.J.; Alvin, M.A.; Smeltzer, E.E.; Bachovchin, D.M.

1999-08-31

A filter element is described for separating fine dirty particles from a hot gas. The filter element comprises a first porous wall and a second porous wall. Each porous wall has an outer surface and an inner surface. The first and second porous walls being coupled together thereby forming a substantially closed figure and open at one end. The open end is formed to be coupled to a hot gas clean up system support structure. The first and second porous walls define a channel beginning at the open end and terminate at the closed end through which a filtered clean gas can flow through and out into the clean gas side of a hot gas clean up system. 8 figs.

Mechanism of interlayer exchange in magnetic multilayers

NASA Astrophysics Data System (ADS)

Slonczewski, J. C.

1993-09-01

The spin-current method is used to calculate the oscillatory exchange energy that couples two semi-infinite ferromagnets with exchange-split parabolic bands which are joined by a nonmagnetic metallic spacer. A closed asymptotic formula extends the previous RKKY-type formula to the case in which the ferromagnets and spacer have different Fermi vectors. The predicted amplitude of oscillatory coupling increases steeply with Fermi vector or electron density in the spacer, as do the experimental trends reported by Parkin. Numerical computations relevant to iron support this closed formula and show that the amplitude of the biquadratic ( J2 cos 2θ) and higher-order corrections to the conventional - J1 cos θ form of energy is less than 2%.

Convergent close coupling versus the generalized Sturmian function approach: Wave-function analysis

NASA Astrophysics Data System (ADS)

Ambrosio, M.; Mitnik, D. M.; Gasaneo, G.; Randazzo, J. M.; Kadyrov, A. S.; Fursa, D. V.; Bray, I.

2015-11-01

We compare the physical information contained in the Temkin-Poet (TP) scattering wave function representing electron-impact ionization of hydrogen, calculated by the convergent close-coupling (CCC) and generalized Sturmian function (GSF) methodologies. The idea is to show that the ionization cross section can be extracted from the wave functions themselves. Using two different procedures based on hyperspherical Sturmian functions we show that the transition amplitudes contained in both GSF and CCC scattering functions lead to similar single-differential cross sections. The single-continuum channels were also a subject of the present studies, and we show that the elastic and excitation amplitudes are essentially the same as well.

Closed-form solutions for a class of optimal quadratic regulator problems with terminal constraints

NASA Technical Reports Server (NTRS)

Juang, J.-N.; Turner, J. D.; Chun, H. M.

1984-01-01

Closed-form solutions are derived for coupled Riccati-like matrix differential equations describing the solution of a class of optimal finite time quadratic regulator problems with terminal constraints. Analytical solutions are obtained for the feedback gains and the closed-loop response trajectory. A computational procedure is presented which introduces new variables for efficient computation of the terminal control law. Two examples are given to illustrate the validity and usefulness of the theory.

Alternate energy source usage for in situ heat treatment processes

DOEpatents

Stone, Jr., Francis Marion; Goodwin, Charles R [League City, TX; Richard, Jr., James

2011-03-22

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one system for providing power to one or more subsurface heaters is described herein. The system may include an intermittent power source; a transformer coupled to the intermittent power source, and a tap controller coupled to the transformer. The transformer may be configured to transform power from the intermittent power source to power with appropriate operating parameters for the heaters. The tap controller may be configured to monitor and control the transformer so that a constant voltage is provided to the heaters from the transformer regardless of the load of the heaters and the power output provided by the intermittent power source.

Radiation source with shaped emission

DOEpatents

Kubiak, Glenn D.; Sweatt, William C.

2003-05-13

Employing a source of radiation, such as an electric discharge source, that is equipped with a capillary region configured into some predetermined shape, such as an arc or slit, can significantly improve the amount of flux delivered to the lithographic wafers while maintaining high efficiency. The source is particularly suited for photolithography systems that employs a ringfield camera. The invention permits the condenser which delivers critical illumination to the reticle to be simplified from five or more reflective elements to a total of three or four reflective elements thereby increasing condenser efficiency. It maximizes the flux delivered and maintains a high coupling efficiency. This architecture couples EUV radiation from the discharge source into a ring field lithography camera.

C5-C12 volatile organic compounds at roadside, residential, and background locations in Ankara, Turkey: temporal and spatial variations and sources.

PubMed

Kuntasal, Oznur Oğuz; Kilavuz, Seda Aslan; Karman, Deniz; Wang, Daniel; Tuncel, Gürdal

2013-10-01

Concentrations of 91 volatile organic compounds (VOCs) ranging from C5 to C12 were measured at three sites in Ankara, the capital of Turkey, in the summer of 2003 and winter of 2004. Samples were collected at roadside, residential and background stations at consecutive 4-hr intervals over a 24-hr period for six weeks in each season. Air samples were collected onto cartridges packed with Tenax TA and Carbopack B resins and analyzed by thermal desorption, followed by gas chromatography coupled to a mass selective detector (GC/MSD). Time resolved data provided information on ambient levels, temporal and spatial variations and sources of VOCs in Ankara. Toluene is the most abundant compound at all sites with and average concentration of 13.1 ?g m(-3). The mean concentrations of benzene are 12.6, 5.2, and 2.4 ?g m(-3) during winter at roadside, residential and background stations, respectively. Diurnal variation in the data together with toluene to benzene concentration ratio (T:B) that is close to 2.0 indicated the influence of traffic related emissions at residential and roadside stations during winter season. Higher T:B ratio observed at residential and background stations during summer period and correlation analysis indicated additional VOC sources. Temporal variations and low m,p-xylene to ethylbenzene ratio (mpX:E) indicated that transported air mass is the major VOC source influencing VOC concentrations measured at the background station.

4D volcano gravimetry

USGS Publications Warehouse

Battaglia, Maurizio; Gottsmann, J.; Carbone, D.; Fernandez, J.

2008-01-01

Time-dependent gravimetric measurements can detect subsurface processes long before magma flow leads to earthquakes or other eruption precursors. The ability of gravity measurements to detect subsurface mass flow is greatly enhanced if gravity measurements are analyzed and modeled with ground-deformation data. Obtaining the maximum information from microgravity studies requires careful evaluation of the layout of network benchmarks, the gravity environmental signal, and the coupling between gravity changes and crustal deformation. When changes in the system under study are fast (hours to weeks), as in hydrothermal systems and restless volcanoes, continuous gravity observations at selected sites can help to capture many details of the dynamics of the intrusive sources. Despite the instrumental effects, mainly caused by atmospheric temperature, results from monitoring at Mt. Etna volcano show that continuous measurements are a powerful tool for monitoring and studying volcanoes.Several analytical and numerical mathematical models can beused to fit gravity and deformation data. Analytical models offer a closed-form description of the volcanic source. In principle, this allows one to readily infer the relative importance of the source parameters. In active volcanic sites such as Long Valley caldera (California, U.S.A.) and Campi Flegrei (Italy), careful use of analytical models and high-quality data sets has produced good results. However, the simplifications that make analytical models tractable might result in misleading volcanological inter-pretations, particularly when the real crust surrounding the source is far from the homogeneous/ isotropic assumption. Using numerical models allows consideration of more realistic descriptions of the sources and of the crust where they are located (e.g., vertical and lateral mechanical discontinuities, complex source geometries, and topography). Applications at Teide volcano (Tenerife) and Campi Flegrei demonstrate the importance of this more realistic description in gravity calculations. ?? 2008 Society of Exploration Geophysicists. All rights reserved.

Soliton-impurity interaction in two Ablowitz-Ladik chains with different coupling

NASA Astrophysics Data System (ADS)

Kamburova, R. S.; Primatarowa, M. T.

2014-12-01

The interaction of solitons with point defects in a system of coupled Ablowitz- Ladik (AL) chains is studied numerically. The system is a discrete analog of coupled nonlinear Schrodinger equations. Two types of interchain coupling are investigated: one which admits reduction of the system to the standard integrable AL model (dispersive coupling) and one which couples opposite sites of the chains and does not admit reduction to the AL model (nondispersive coupling). The action of the two coupling types is additive and they can compensate each other in some cases. We have obtained that the single-peak bound soliton-defect solution (attractive impurity) is stable against perturbations, while the double-peak bound soliton-defect solution (repulsive impurity) is unstable and can be easily destroyed. Linear point defects do not influence the period of energy transfer and it is close to the period for the homogeneous case.

Strong Coupling Expansion of the Generating Functional for Gauge Systems on a Lattice with Arbitrary Sources

NASA Astrophysics Data System (ADS)

Hoek, Jaap

1983-02-01

A set of programs to calculate algebraically the generating functional (free energy) of a gauge system with arbitrary external sources on a lattice has been developed. It makes use of the strong coupling expansion. For theories with the standard Tr(UUU †U †) action results have been obtained up to fourth order.

Studies on the coupling transformer to improve the performance of microwave ion source.

PubMed

Misra, Anuraag; Pandit, V S

2014-06-01

A 2.45 GHz microwave ion source has been developed and installed at the Variable Energy Cyclotron Centre to produce high intensity proton beam. It is operational and has already produced more than 12 mA of proton beam with just 350 W of microwave power. In order to optimize the coupling of microwave power to the plasma, a maximally flat matching transformer has been used. In this paper, we first describe an analytical method to design the matching transformer and then present the results of rigorous simulation performed using ANSYS HFSS code to understand the effect of different parameters on the transformed impedance and reflection and transmission coefficients. Based on the simulation results, we have chosen two different coupling transformers which are double ridged waveguides with ridge widths of 24 mm and 48 mm. We have fabricated these transformers and performed experiments to study the influence of these transformers on the coupling of microwave to plasma and extracted beam current from the ion source.

Studies on the coupling transformer to improve the performance of microwave ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Misra, Anuraag, E-mail: pandit@vecc.gov.in, E-mail: vspandit12@gmail.com, E-mail: anuraag@vecc.gov.in; Pandit, V. S., E-mail: pandit@vecc.gov.in, E-mail: vspandit12@gmail.com, E-mail: anuraag@vecc.gov.in

A 2.45 GHz microwave ion source has been developed and installed at the Variable Energy Cyclotron Centre to produce high intensity proton beam. It is operational and has already produced more than 12 mA of proton beam with just 350 W of microwave power. In order to optimize the coupling of microwave power to the plasma, a maximally flat matching transformer has been used. In this paper, we first describe an analytical method to design the matching transformer and then present the results of rigorous simulation performed using ANSYS HFSS code to understand the effect of different parameters on themore » transformed impedance and reflection and transmission coefficients. Based on the simulation results, we have chosen two different coupling transformers which are double ridged waveguides with ridge widths of 24 mm and 48 mm. We have fabricated these transformers and performed experiments to study the influence of these transformers on the coupling of microwave to plasma and extracted beam current from the ion source.« less

Interferometric source of multi-color, multi-beam entangled photons with mirror and mixer

DOEpatents

Dress, William B.; Kisner, Roger A.; Richards, Roger K.

2004-06-01

53 Systems and methods are described for an interferometric source of multi-color, multi-beam entangled photons. An apparatus includes: a multi-refringent device optically coupled to a source of coherent energy, the multi-refringent device providing a beam of multi-color entangled photons; a condenser device optically coupled to the multi-refringent device, the condenser device i) including a mirror and a mixer and ii) converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; a tunable phase adjuster optically coupled to the condenser device, the tunable phase adjuster changing a phase of at least a portion of the converged multi-color entangled photon beam to generate a first interferometeric multi-color entangled photon beam; and a beam splitter optically coupled to the condenser device, the beam splitter combining the first interferometeric multi-color entangled photon beam with a second interferometric multi-color entangled photon beam.

Electrical system for pulse-width modulated control of a power inverter using phase-shifted carrier signals and related operating methods

DOEpatents

Welchko, Brian A [Torrance, CA

2012-02-14

Systems and methods are provided for pulse-width modulated control of power inverter using phase-shifted carrier signals. An electrical system comprises an energy source and a motor. The motor has a first set of windings and a second set of windings, which are electrically isolated from each other. An inverter module is coupled between the energy source and the motor and comprises a first set of phase legs coupled to the first set of windings and a second set of phase legs coupled to the second set of windings. A controller is coupled to the inverter module and is configured to achieve a desired power flow between the energy source and the motor by modulating the first set of phase legs using a first carrier signal and modulating the second set of phase legs using a second carrier signal. The second carrier signal is phase-shifted relative to the first carrier signal.

Efficient Approaches for Evaluating the Planar Microstrip Green's Function and its Applications to the Analysis of Microstrip Antennas.

NASA Astrophysics Data System (ADS)

Barkeshli, Sina

A relatively simple and efficient closed form asymptotic representation of the microstrip dyadic surface Green's function is developed. The large parameter in this asymptotic development is proportional to the lateral separation between the source and field points along the planar microstrip configuration. Surprisingly, this asymptotic solution remains accurate even for very small (almost two tenths of a wavelength) lateral separation of the source and field points. The present asymptotic Green's function will thus allow a very efficient calculation of the currents excited on microstrip antenna patches/feed lines and monolithic millimeter and microwave integrated circuit (MIMIC) elements based on a moment method (MM) solution of an integral equation for these currents. The kernal of the latter integral equation is the present asymptotic form of the microstrip Green's function. It is noted that the conventional Sommerfeld integral representation of the microstrip surface Green's function is very poorly convergent when used in this MM formulation. In addition, an efficient exact steepest descent path integral form employing a radially propagating representation of the microstrip dyadic Green's function is also derived which exhibits a relatively faster convergence when compared to the conventional Sommerfeld integral representation. The same steepest descent form could also be obtained by deforming the integration contour of the conventional Sommerfeld representation; however, the radially propagating integral representation exhibits better convergence properties for laterally separated source and field points even before the steepest descent path of integration is used. Numerical results based on the efficient closed form asymptotic solution for the microstrip surface Green's function developed in this work are presented for the mutual coupling between a pair of dipoles on a single layer grounded dielectric slab. The accuracy of the latter calculations is confirmed by comparison with results based on an exact integral representation for that Green's function.

Oak tree-rings record spatial-temporal pollution trends from different sources in Terni (Central Italy).

PubMed

Perone, A; Cocozza, C; Cherubini, P; Bachmann, O; Guillong, M; Lasserre, B; Marchetti, M; Tognetti, R

2018-02-01

Monitoring atmospheric pollution in industrial areas near urban center is essential to infer past levels of contamination and to evaluate the impact for environmental health and safety. The main aim of this study was to understand if the chemical composition of tree-ring wood can be used for monitoring spatial-temporal variability of pollutants in Terni, Central Italy, one of the most polluted towns in Italy. Tree cores were taken from 32 downy oaks (Quercus pubescens) located at different distances from several pollutant sources, including a large steel factory. Trace element (Cr, Co, Cu, Pb, Hg, Mo, Ni, Tl, W, U, V, and Zn) index in tree-ring wood was determined using high-resolution laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We hypothesized that the presence of contaminants detected in tree-rings reflected industrial activities over time. The accumulation of contaminants in tree-rings was affected by anthropogenic activities in the period 1958-2009, though signals varied in intensity with the distance of trees from the industrial plant. A stronger limitation of tree growth was observed in the proximity of the industrial plant in comparison with other pollutant sources. Levels of Cr, Ni, Mo, V, U and W increased in tree-ring profiles of trees close to the steel factory, especially during the 80's and 90's, in correspondence to a peak of pollution in this period, as recorded by air quality monitoring stations. Uranium contents in our tree-rings were difficult to explain, while the higher contents of Cu, Hg, Pb, and Tl could be related to the contaminants released from an incinerator located close to the industrial plant. The accumulation of contaminants in tree-rings reflected the historical variation of environmental pollution in the considered urban context. Copyright © 2017 Elsevier Ltd. All rights reserved.

An efficient closed-form solution for acoustic emission source location in three-dimensional structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xibing; Dong, Longjun, E-mail: csudlj@163.com; Australian Centre for Geomechanics, The University of Western Australia, Crawley, 6009

This paper presents an efficient closed-form solution (ECS) for acoustic emission(AE) source location in three-dimensional structures using time difference of arrival (TDOA) measurements from N receivers, N ≥ 6. The nonlinear location equations of TDOA are simplified to linear equations. The unique analytical solution of AE sources for unknown velocity system is obtained by solving the linear equations. The proposed ECS method successfully solved the problems of location errors resulting from measured deviations of velocity as well as the existence and multiplicity of solutions induced by calculations of square roots in existed close-form methods.

Development of a dedicated ethanol ultra-low emission vehicle (ULEV): Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dodge, L.; Bourn, G.; Callahan, T.

The objective of this project was to develop a commercially competitive vehicle powered by ethanol (or an ethanol blend) that can meet California`s ultra-low emission vehicle (ULEV) standards and equivalent corporate average fuel economy (CAFE) energy efficiency for a light-duty passenger car application. The definition of commercially competitive is independent of fuel cost, but does include technical requirements for competitive power, performance, refueling times, vehicle range, driveability, fuel handling safety, and overall emissions performance. This report summarizes the fourth and final phase of this project, and also the overall project. The focus of this report is the technology used tomore » develop a dedicated ethanol-fueled ULEV, and the emissions results documenting ULV performance. Some of the details for the control system and hardware changes are presented in two appendices that are SAE papers. The demonstrator vehicle has a number of advanced technological features, but it is currently configured with standard original equipment manufacturer (OEM) under-engine catalysts. Close-coupled catalysts would improve emissions results further, but no close-coupled catalysts were available for this testing. Recently, close-coupled catalysts were obtained, but installation and testing will be performed in the future. This report also briefly summarizes work in several other related areas that supported the demonstrator vehicle work.« less

The cooperative voltage sensor motion that gates a potassium channel.

PubMed

Pathak, Medha; Kurtz, Lisa; Tombola, Francesco; Isacoff, Ehud

2005-01-01

The four arginine-rich S4 helices of a voltage-gated channel move outward through the membrane in response to depolarization, opening and closing gates to generate a transient ionic current. Coupling of voltage sensing to gating was originally thought to operate with the S4s moving independently from an inward/resting to an outward/activated conformation, so that when all four S4s are activated, the gates are driven to open or closed. However, S4 has also been found to influence the cooperative opening step (Smith-Maxwell et al., 1998a), suggesting a more complex mechanism of coupling. Using fluorescence to monitor structural rearrangements in a Shaker channel mutant, the ILT channel (Ledwell and Aldrich, 1999), that energetically isolates the steps of activation from the cooperative opening step, we find that opening is accompanied by a previously unknown and cooperative movement of S4. This gating motion of S4 appears to be coupled to the internal S6 gate and to two forms of slow inactivation. Our results suggest that S4 plays a direct role in gating. While large transmembrane rearrangements of S4 may be required to unlock the gating machinery, as proposed before, it appears to be the gating motion of S4 that drives the gates to open and close.

The Cooperative Voltage Sensor Motion that Gates a Potassium Channel

PubMed Central

Pathak, Medha; Kurtz, Lisa; Tombola, Francesco; Isacoff, Ehud

2005-01-01

The four arginine-rich S4 helices of a voltage-gated channel move outward through the membrane in response to depolarization, opening and closing gates to generate a transient ionic current. Coupling of voltage sensing to gating was originally thought to operate with the S4s moving independently from an inward/resting to an outward/activated conformation, so that when all four S4s are activated, the gates are driven to open or closed. However, S4 has also been found to influence the cooperative opening step (Smith-Maxwell et al., 1998a), suggesting a more complex mechanism of coupling. Using fluorescence to monitor structural rearrangements in a Shaker channel mutant, the ILT channel (Ledwell and Aldrich, 1999), that energetically isolates the steps of activation from the cooperative opening step, we find that opening is accompanied by a previously unknown and cooperative movement of S4. This gating motion of S4 appears to be coupled to the internal S6 gate and to two forms of slow inactivation. Our results suggest that S4 plays a direct role in gating. While large transmembrane rearrangements of S4 may be required to unlock the gating machinery, as proposed before, it appears to be the gating motion of S4 that drives the gates to open and close. PMID:15623895

Energetics of subdomain movements and fluorescence probe solvation environment change in ATP-bound myosin.

PubMed

Harris, Michael J; Woo, Hyung-June

2008-11-01

Energetics of conformational changes experienced by an ATP-bound myosin head detached from actin was studied by all-atom explicit water umbrella sampling simulations. The statistics of coupling between large scale domain movements and smaller scale structural features were examined, including the closing of the ATP binding pocket, and a number of key hydrogen bond formations shown to play roles in structural and biochemical studies. The statistics for the ATP binding pocket open/close transition show an evolution of the relative stability from the open state in the early stages of the recovery stroke to the stable closed state after the stroke. The change in solvation environment of the fluorescence probe Trp507 (scallop numbering; 501 in Dictyostelium discoideum) indicates that the probe faithfully reflects the closing of the binding pocket as previously shown in experimental studies, while being directly coupled to roughly the early half of the overall large scale conformational change of the converter domain rotation. The free energy change of this solvation environment change, in particular, is -1.3 kcal/mol, in close agreement with experimental estimates. In addition, our results provide direct molecular level data allowing for interpretations of the fluorescence experiments of myosin conformational change in terms of the de-solvation of Trp side chain.

Marital Therapy with Older Couples.

ERIC Educational Resources Information Center

Qualls, Sara Honn

1993-01-01

Presents basic information concerning normal aging that therapists need to understand sources of conflict and distress in older or caregiving couples. Describes unique aspects of assessment and intervention with older couples. Examines marital satisfaction across life span, including factors that alter marital functioning, developmental tasks and…

Electron-impact ionization of atomic hydrogen at incident electron energies of 15.6, 17.6, 25, and 40 eV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Childers, J. G.; James, K. E.; Hughes, M.

2003-09-01

Absolute doubly differential cross sections for the electron-impact ionization of atomic hydrogen have been measured from near threshold to intermediate energies. The measurements are calibrated to the well-established, accurate differential cross section for electron-impact excitation of the atomic hydrogen transition H(1{sup 2}S{yields}2{sup 2}S+2{sup 2}P). In these experiments background secondary electrons are suppressed by moving the atomic hydrogen target source to and from the collision region. Measurements cover the incident electron energy range of 14.6-40 eV, for scattering angles of 10 degree sign -120 degree sign and are found to be in very good agreement with the results of the mostmore » advanced theoretical models--the convergent close-coupling model and the exterior complex scaling model.« less

Load positioning system with gravity compensation

NASA Technical Reports Server (NTRS)

Hollow, R. H.

1984-01-01

A load positioning system with gravity compensation has a servomotor, position sensing feedback potentiometer and velocity sensing tachometer in a conventional closed loop servo arrangement to cause a lead screw and a ball nut to vertically position a load. Gravity compensating components comprise the DC motor, gears, which couple torque from the motor to the lead screw, and constant current power supply. The constant weight of the load applied to the lead screw via the ball nut tend to cause the lead screw to rotate, the constant torque of which is opposed by the constant torque produced by the motor when fed from the constant current source. The constant current is preset as required by the potentiometer to effect equilibration of the load which thereby enables the positioning servomotor to see the load as weightless under both static and dynamic conditions. Positioning acceleration and velocity performance are therefore symmetrical.

Developmental mechanisms facilitating the evolution of bills and quills

PubMed Central

Schneider, Richard A

2005-01-01

Beaks and feathers epitomize inimitable avian traits. Within individuals and across species there exists astounding diversity in the size, shape, arrangement, and colour of beaks and feathers in association with various functional adaptations. What has enabled the concomitantly divergent evolution of beaks and feathers? The common denominator may lie in their developmental programmes. As revealed through recent transplant experiments using quail and duck embryos, the developmental programme for each structure utilizes mesenchyme as a dominant source of species-specific patterning information, acts as a module of closely coupled molecular and histogenic events, and operates with a high degree of spatial and temporal plasticity. By synergizing these three features, the developmental programmes underlying beaks and feathers likely have the essential potential to react spontaneously to novel conditions and new gene functions, and as a consequence are well equipped to generate and accommodate innovative phenotypes during the course of evolution. PMID:16313392

A method of measuring the effective thermal conductivity of thermoplastic foams

NASA Astrophysics Data System (ADS)

Asséko, André Chateau Akué; Cosson, Benoit; Chaki, Salim; Duborper, Clément; Lacrampe, Marie-France; Krawczak, Patricia

2017-10-01

An inverse method for determining the in-plane effective thermal conductivity of porous thermoplastics was implemented by coupling infrared thermography experiments and numerical solution of heat transfer in straight fins having temperature-dependent convective heat transfer coefficient. The obtained effective thermal conductivity values were compared with previous results obtained using a numerical solution based on periodic homogenization techniques (NSHT) in which the microstructure heterogeneity of extruded polymeric polyethylene (PE) foam in which pores are filled with air with different levels of open and closed porosity was taken into account and Transient Plane Source Technique (TPS) in order to verify the accuracy of the proposed method. The new method proposed in the present study is in good agreement with both NSHT and TPS. It is also applicable to structural materials such as composites, e.g. unidirectional fiber-reinforced plastics, where heat transfer is very different according to the fiber direction (parallel or transverse to the fibers).

Search for exotic short-range interactions using paramagnetic insulators

DOE PAGES

Chu, Pinghan; Weisman, E.; Liu, C. -Y.; ...

2015-05-26

We describe a proposed experimental search for exotic spin-coupled interactions using a solid-state paramagnetic insulator. The experiment is sensitive to the net magnetization induced by the exotic interaction between the unpaired insulator electrons with a dense, nonmagnetic mass in close proximity. An existing experiment has been used to set limits on the electric dipole moment of the electron by probing the magnetization induced in a cryogenic gadolinium gallium garnet sample on application of a strong electric field. With suitable additions, including a movable source mass, this experiment can be used to explore “monopole-dipole” forces on polarized electrons with unique ormore » unprecedented sensitivity. As a result, the solid-state, nonmagnetic construction, combined with the low-noise conditions and extremely sensitive magnetometry available at cryogenic temperatures could lead to a sensitivity over 10 orders of magnitude greater than exiting limits in the range below 1 mm.« less

Dimension reduction for stochastic dynamical systems forced onto a manifold by large drift: a constructive approach with examples from theoretical biology

NASA Astrophysics Data System (ADS)

Parsons, Todd L.; Rogers, Tim

2017-10-01

Systems composed of large numbers of interacting agents often admit an effective coarse-grained description in terms of a multidimensional stochastic dynamical system, driven by small-amplitude intrinsic noise. In applications to biological, ecological, chemical and social dynamics it is common for these models to posses quantities that are approximately conserved on short timescales, in which case system trajectories are observed to remain close to some lower-dimensional subspace. Here, we derive explicit and general formulae for a reduced-dimension description of such processes that is exact in the limit of small noise and well-separated slow and fast dynamics. The Michaelis-Menten law of enzyme-catalysed reactions, and the link between the Lotka-Volterra and Wright-Fisher processes are explored as a simple worked examples. Extensions of the method are presented for infinite dimensional systems and processes coupled to non-Gaussian noise sources.

Transport model of controlled molecular rectifier showing unusual negative differential resistance effect.

PubMed

Granhen, Ewerton Ramos; Reis, Marcos Allan Leite; Souza, Fabrício M; Del Nero, Jordan

2010-12-01

We investigate theoretically the charge accumulated Q in a three-terminal molecular device in the presence of an external electric field. Our approach is based on ab initio Hartree-Fock and density functional theory methodology contained in Gaussian package. Our main finding is a negative differential resistance (NDR) in the charge Q as a function of an external electric field. To explain this NDR effect we apply a phenomenological capacitive model based on a quite general system composed of many localized levels (that can be LUMOs of a molecule) coupled to source and drain. The capacitance accounts for charging effects that can result in Coulomb blockade (CB) in the transport. We show that this CB effect gives rise to a NDR for a suitable set of phenomenological parameters, like tunneling rates and charging energies. The NDR profile obtained in both ab initio and phenomenological methodologies are in close agreement.

Gum and deposit formation from jet-turbine and diesel fuels at 130C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayo, F.R.; Lan, Bosco Y.

1986-01-01

The ultimate objective of this work is to devise an accelerated test to compare rates of soluble gum and deposit formation from jet-turbine and diesel fuels in storage and of hard deposits in engines. This paper describes rates of oxygen absorption and gum formation in air at 130 C. For a single fuel or hydrocarbon, the rate of gum formation is closely proportional to the oxygen absorbed, even when this rate varies with purification and additives. In general, pure hydrocarbons absorb oxygen much faster than the fuels, but the fuels and 2-ethylnaphthalene give more gum for the oxygen absorbed thanmore » the other pure hydrocarbons. Gum has two main sources; one appears to be associated with the chain termination mechanism in oxidation, the other coupling of fuel molecules in the absence of oxygen. Other possibilities are discussed.« less

Management of atmospheric pollutants from waste incineration processes: the case of Bozen.

PubMed

Ragazzi, Marco; Tirler, Werner; Angelucci, Giulio; Zardi, Dino; Rada, Elena Cristina

2013-03-01

This article presents the case study of a waste incinerator located in a region rich in natural and environmental resources, and close to the city of Bozen, where there are about 100,000 inhabitants. Local authorities paid special attention to the effect of the plant on human health and the surrounding environment. Indeed, among the measures adopted to control the emissions, in 2003 an automatic sampling system was installed specifically to monitor polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emissions during the complete operation time of the plant. The continuous sampling system was coupled directly to aerosol spectrometers for the determination of fine and ultra-fine particles in the emissions of the plant. The measurement results suggest that the waste incineration plant of Bozen is not a significant source of PCDD/F, or fine and ultra-fine particles. Immission measurements from other monitoring systems confirmed these results.

Growth of Bacterial Colonies

NASA Astrophysics Data System (ADS)

Warren, Mya; Hwa, Terence

2013-03-01

On hard agar gel, there is insufficient surface hydration for bacteria to swim or swarm. Instead, growth occurs in colonies of close-packed cells, which expand purely due to repulsive interactions: individual bacteria push each other out of the way through the force of their growth. In this way, bacterial colonies represent a new type of ``active'' granular matter. In this study, we investigate the physical, biochemical, and genetic elements that determine the static and dynamic aspects of this mode of bacterial growth for E. coli. We characterize the process of colony expansion empirically, and use discrete and continuum models to examine the extent to which our observations can be explained by the growth characteristics of non-communicating cells, coupled together by physical forces, nutrients, and waste products. Our results challenge the commonly accepted modes of bacterial colony growth and provide insight into sources of growth limitation in crowded bacterial communities.

Aluminium-gold reference material for the k0-standardisation of neutron activation analysis

NASA Astrophysics Data System (ADS)

Ingelbrecht, C.; Peetermans, F.; De Corte, F.; De Wispelaere, A.; Vandecasteele, C.; Courtijn, E.; D'Hondt, P.

1991-05-01

Gold is an excellent comparator material for the k0-standardisation of neutron activation analysis because of its convenient and well defined nuclear properties. The most suitable form for a reference material is a dilute aluminium-gold alloy, for which the self-shielding effect for neutrons is small. Castings of composition Al-0.1 wt.% Au were prepared by crucible-less levitation melting, which gives close control of ingot composition with minimal contamination of the melt. The alloy composition was checked using induction-coupled plasma source emission spectrometry. The homogeneity of the alloy was measured by neutron activation analysis and a relative standard deviation of the gold content of 0.30% was found (10 mg samples). Metallography revealed a homogeneous distribution of AuAl 2 particles. The alloy was certified as Reference Material CBNM-530, with certified gold mass fraction 0.100±0.002 wt.%.

Source characteristics and geological implications of the January 2016 induced earthquake swarm near Crooked Lake, Alberta

NASA Astrophysics Data System (ADS)

Wang, Ruijia; Gu, Yu Jeffrey; Schultz, Ryan; Zhang, Miao; Kim, Ahyi

2017-08-01

On 2016 January 12, an intraplate earthquake with an initial reported local magnitude (ML) of 4.8 shook the town of Fox Creek, Alberta. While there were no reported damages, this earthquake was widely felt by the local residents and suspected to be induced by the nearby hydraulic-fracturing (HF) operations. In this study, we determine the earthquake source parameters using moment tensor inversions, and then detect and locate the associated swarm using a waveform cross-correlation based method. The broad-band seismic recordings from regional arrays suggest a moment magnitude (M) 4.1 for this event, which is the largest in Alberta in the past decade. Similar to other recent M ∼ 3 earthquakes near Fox Creek, the 2016 January 12 earthquake exhibits a dominant strike-slip (strike = 184°) mechanism with limited non-double-couple components (∼22 per cent). This resolved focal mechanism, which is also supported by forward modelling and P-wave first motion analysis, indicates an NE-SW oriented compressional axis consistent with the maximum compressive horizontal stress orientations delineated from borehole breakouts. Further detection analysis on industry-contributed recordings unveils 1108 smaller events within 3 km radius of the epicentre of the main event, showing a close spatial-temporal relation to a nearby HF well. The majority of the detected events are located above the basement, comparable to the injection depth (3.5 km) on the Duvernay shale Formation. The spatial distribution of this earthquake cluster further suggests that (1) the source of the sequence is an N-S-striking fault system and (2) these earthquakes were induced by an HF well close to but different from the well that triggered a previous (January 2015) earthquake swarm. Reactivation of pre-existing, N-S oriented faults analogous to the Pine Creek fault zone, which was reported by earlier studies of active source seismic and aeromagnetic data, are likely responsible for the occurrence of the January 2016 earthquake swarm and other recent events in the Crooked Lake area.

Tube-wave seismic imaging

DOEpatents

Korneev, Valeri A [Lafayette, CA; Bakulin, Andrey [Houston, TX

2009-10-13

The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

Pulsed source of spectrally uncorrelated and indistinguishable photons at telecom wavelengths.

PubMed

Bruno, N; Martin, A; Guerreiro, T; Sanguinetti, B; Thew, R T

2014-07-14

We report on the generation of indistinguishable photon pairs at telecom wavelengths based on a type-II parametric down conversion process in a periodically poled potassium titanyl phosphate (PPKTP) crystal. The phase matching, pump laser characteristics and coupling geometry are optimised to obtain spectrally uncorrelated photons with high coupling efficiencies. Four photons are generated by a counter-propagating pump in the same crystal and anlysed via two photon interference experiments between photons from each pair source as well as joint spectral and g((2)) measurements. We obtain a spectral purity of 0.91 and coupling efficiencies around 90% for all four photons without any filtering. These pure indistinguishable photon sources at telecom wavelengths are perfectly adapted for quantum network demonstrations and other multi-photon protocols.

Tube-wave seismic imaging

DOEpatents

Korneev, Valeri A [LaFayette, CA

2009-05-05

The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

Evaluation of discrete frequency sound in closed-test-section wind tunnels

NASA Technical Reports Server (NTRS)

Mosher, Marianne

1990-01-01

The principal objective of this study is to assess the adequacy of linear acoustic theory with an impedance wall boundary condition for modeling the detailed sound field of an acoustic source in a duct. This study compares measurements and calculations of a simple acoustic source in a rectangular concrete duct lined with foam on the walls and anechoic end terminations. Measuring acoustic pressure for 12 wave numbers provides variation in frequency and absorption characteristics of the duct walls. The cases in this study contain low frequencies and low wall absorptions corresponding to measurements of low-frequency helicopter noise in a lined wind tunnel. This regime is particularly difficult to measure in wind tunnels due to high levels of the reverberant field relatively close to the source. Close to the source, where the interference of wall reflections is minimal, correlation is very good. Away from the source, correlation degrades, especially for the lower frequencies. Sensitivity studies show little effect on the predicted results for changes in impedance boundary condition values, source location, measurement location, temperature, and source model for variations spanning the expected measurement error.

Fiber-Coupled Cavity-QED Source of Identical Single Photons

NASA Astrophysics Data System (ADS)

Snijders, H.; Frey, J. A.; Norman, J.; Post, V. P.; Gossard, A. C.; Bowers, J. E.; van Exter, M. P.; Löffler, W.; Bouwmeester, D.

2018-03-01

We present a fully fiber-coupled source of high-fidelity single photons. An (In,Ga)As semiconductor quantum dot is embedded in an optical Fabry-Perot microcavity with a robust design and rigidly attached single-mode fibers, which enables through-fiber cross-polarized resonant laser excitation and photon extraction. Even without spectral filtering, we observe that the incident coherent light pulses are transformed into a stream of single photons with high purity (97%) and indistinguishability (90%), which is measured at an in-fiber brightness of 5% with an excellent cavity-mode-to-fiber coupling efficiency of 85%. Our results pave the way for fully fiber-integrated photonic quantum networks. Furthermore, our method is equally applicable to fiber-coupled solid-state cavity-QED-based photonic quantum gates.

Chameleon gravity, electrostatics, and kinematics in the outer galaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pourhasan, R.; Mann, R.B.; Afshordi, N.

2011-12-01

Light scalar fields are expected to arise in theories of high energy physics (such as string theory), and find phenomenological motivations in dark energy, dark matter, or neutrino physics. However, the coupling of light scalar fields to ordinary (or dark) matter is strongly constrained from laboratory, solar system, and astrophysical tests of the fifth force. One way to evade these constraints in dense environments is through the chameleon mechanism, where the field's mass steeply increases with ambient density. Consequently, the chameleonic force is only sourced by a thin shell near the surface of dense objects, which significantly reduces its magnitude.more » In this paper, we argue that thin-shell conditions are equivalent to ''conducting'' boundary conditions in electrostatics. As an application, we use the analogue of the method of images to calculate the back-reaction (or self-force) of an object around a spherical gravitational source. Using this method, we can explicitly compute the violation of the equivalence principle in the outskirts of galactic haloes (assuming an NFW dark matter profile): Intermediate mass satellites can be slower than their larger/smaller counterparts by as much as 10% close to a thin shell.« less

A reciprocity formulation for the EM scattering by an obstacle within a large open cavity

NASA Technical Reports Server (NTRS)

Pathak, Prabhakar H.; Burkholder, Robert J.

1993-01-01

A formulation based on a generalized reciprocity theorem is developed for analyzing the external high frequency EM scattering by a complex obstacle inside a relatively arbitrary open-ended waveguide cavity when it is illuminated by an external source. This formulation is also extended to include EM fields whose time dependence may be nonperiodic. A significant advantage of this formulation is that it allows one to break up the analysis into two independent parts; one deals with the waveguide cavity shape alone and the other with the obstacle alone. The external scattered field produced by the obstacle (in the presence of the waveguide cavity structure) is given in terms of a generalized reciprocity integral over a surface S(T) corresponding to the interior waveguide cavity cross section located conveniently but sufficiently close to the obstacle. Furthermore, the fields coupled into the cavity from the source in the exterior region generally need to propagate only one-way via the open front end (which is directly illuminated) to the interior surface S(T) in this approach, and not back, in order to find the external field scattered by the obstacle.

Weak-field limit of Kaluza-Klein models with spherically symmetric static scalar field: observational constraints

NASA Astrophysics Data System (ADS)

Zhuk, Alexander; Chopovsky, Alexey; Fakhr, Seyed Hossein; Shulga, Valerii; Wei, Han

2017-11-01

In a multidimensional Kaluza-Klein model with Ricci-flat internal space, we study the gravitational field in the weak-field limit. This field is created by two coupled sources. First, this is a point-like massive body which has a dust-like equation of state in the external space and an arbitrary parameter Ω of equation of state in the internal space. The second source is a static spherically symmetric massive scalar field centered at the origin where the point-like massive body is. The found perturbed metric coefficients are used to calculate the parameterized post-Newtonian (PPN) parameter γ . We define under which conditions γ can be very close to unity in accordance with the relativistic gravitational tests in the solar system. This can take place for both massive or massless scalar fields. For example, to have γ ≈ 1 in the solar system, the mass of scalar field should be μ ≳ 5.05× 10^{-49}g ˜ 2.83× 10^{-16}eV. In all cases, we arrive at the same conclusion that to be in agreement with the relativistic gravitational tests, the gravitating mass should have tension: Ω = - 1/2.

Intensity and temporal noise characteristics in femtosecond optical parametric amplifiers.

PubMed

Chen, Wei; Fan, Jintao; Ge, Aichen; Song, Huanyu; Song, Youjian; Liu, Bowen; Chai, Lu; Wang, Chingyue; Hu, Minglie

2017-12-11

We characterize the relative intensity noise (RIN) and relative timing jitter (RTJ) between the signal and pump pulses of optical parametric amplifiers (OPAs) seeded by three different seed sources. Compared to a white-light continuum (WLC) seeded- and an optical parametric generator (OPG) seeded OPA, the narrowband CW seeded OPA exhibits the lowest root-mean-square (RMS) RIN and RTJ of 0.79% and 0.32 fs, respectively, integrated from 1 kHz to the Nyquist frequency of 1.25 MHz. An improved numerical model based on a forward Maxwell equation (FME) is built to investigate the transfers of the pump and seed's noise to the resulting OPAs' intensity and temporal fluctuation. Both the experimental and numerical study indicate that the low level of noise from the narrowband CW seeded OPA is attributed to the elimination of the RIN and RTJ coupled from the noise of seed source, being one of the important contributions to RIN and timing jitter in the other two OPAs. The approach to achieve lower level of noise from this CW seeded OPA by driving it close to saturation is also discussed with the same numerical model.

Seasonal pathways of organic matter within the Avilés submarine canyon: Food web implications

NASA Astrophysics Data System (ADS)

Romero-Romero, Sonia; Molina-Ramírez, Axayacatl; Höfer, Juan; Duineveld, Gerard; Rumín-Caparrós, Aitor; Sanchez-Vidal, Anna; Canals, Miquel; Acuña, José Luis

2016-11-01

The transport and fate of organic matter (OM) sources within the Avilés submarine canyon (Cantabrian Sea, Southern Bay of Biscay) were studied using carbon and nitrogen stable isotope ratios. The isotopic composition of settling particles and deep bottom sediments closely resembled that of surface particulate OM, and there were no marked differences in the isotopic composition of settling particles inside and outside of the AC. This indicates that the Avilés Canyon (AC) receives inputs of sinking OM mostly from the upper water column and less through advective near-bottom down-canyon transport. Sinking OM fluxes are of marine and terrestrial origin in proportions which vary seasonally. Analysis of δ13C in the canyon fauna indicates a dependence on OM mainly produced by marine phytoplankton. A tight coupling of isotopic signatures between pelagic organisms and benthic suspension feeders reflects an active biological vertical transport of OM from the surface to the deep-sea. The food web presented seasonal variations in the trophic niche width and the amplitude of the primary carbon sources, reflecting seasonality in the availability of fresh particulate OM. Those seasonal changes are larger for benthic organisms of lower trophic levels.

Developing a Vacuum Electrospray Source To Implement Efficient Atmospheric Sampling for Miniature Ion Trap Mass Spectrometer.

PubMed

Yu, Quan; Zhang, Qian; Lu, Xinqiong; Qian, Xiang; Ni, Kai; Wang, Xiaohao

2017-12-05

The performance of a miniature mass spectrometer in atmospheric analysis is closely related to the design of its sampling system. In this study, a simplified vacuum electrospray ionization (VESI) source was developed based on a combination of several techniques, including the discontinuous atmospheric pressure interface, direct capillary sampling, and pneumatic-assisted electrospray. Pulsed air was used as a vital factor to facilitate the operation of electrospray ionization in the vacuum chamber. This VESI device can be used as an efficient atmospheric sampling interface when coupled with a miniature rectilinear ion trap (RIT) mass spectrometer. The developed VESI-RIT instrument enables regular ESI analysis of liquid, and its qualitative and quantitative capabilities have been characterized by using various solution samples. A limit of detection of 8 ppb could be attained for arginine in a methanol solution. In addition, extractive electrospray ionization of organic compounds can be implemented by using the same VESI device, as long as the gas analytes are injected with the pulsed auxiliary air. This methodology can extend the use of the proposed VESI technique to rapid and online analysis of gaseous and volatile samples.

Closed-Form Evaluation of Mutual Coupling in a Planar Array of Circular Apertures

NASA Technical Reports Server (NTRS)

Bailey, M. C.

1996-01-01

The integral expression for the mutual admittance between circular apertures in a planar array is evaluated in closed form. Very good accuracy is realized when compared with values that were obtained by numerical integration. Utilization of this closed-form expression, for all element pairs that are separated by more than one element spacing, yields extremely accurate results and significantly reduces the computation time that is required to analyze the performance of a large electronically scanning antenna array.

X-ray compass for determining device orientation

DOEpatents

Da Silva, Luiz B.; Matthews, Dennis L.; Fitch, Joseph P.; Everett, Matthew J.; Colston, Billy W.; Stone, Gary F.

1999-01-01

An apparatus and method for determining the orientation of a device with respect to an x-ray source. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source.

X-ray compass for determining device orientation

DOEpatents

Da Silva, L.B.; Matthews, D.L.; Fitch, J.P.; Everett, M.J.; Colston, B.W.; Stone, G.F.

1999-06-15

An apparatus and method for determining the orientation of a device with respect to an x-ray source are disclosed. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source. 25 figs.

Active Control of Fan Noise: Feasibility Study. Volume 6; Theoretical Analysis for Coupling of Active Noise Control Actuator Ring Sources to an Annular Duct with Flow

NASA Technical Reports Server (NTRS)

Kraft, R. E.

1996-01-01

The objective of this effort is to develop an analytical model for the coupling of active noise control (ANC) piston-type actuators that are mounted flush to the inner and outer walls of an annular duct to the modes in the duct generated by the actuator motion. The analysis will be used to couple the ANC actuators to the modal analysis propagation computer program for the annular duct, to predict the effects of active suppression of fan-generated engine noise sources. This combined program will then be available to assist in the design or evaluation of ANC systems in fan engine annular exhaust ducts. An analysis has been developed to predict the modes generated in an annular duct due to the coupling of flush-mounted ring actuators on the inner and outer walls of the duct. The analysis has been combined with a previous analysis for the coupling of modes to a cylindrical duct in a FORTRAN computer program to perform the computations. The method includes the effects of uniform mean flow in the duct. The program can be used for design or evaluation purposes for active noise control hardware for turbofan engines. Predictions for some sample cases modeled after the geometry of the NASA Lewis ANC Fan indicate very efficient coupling in both the inlet and exhaust ducts for the m = 6 spinning mode at frequencies where only a single radial mode is cut-on. Radial mode content in higher order cut-off modes at the source plane and the required actuator displacement amplitude to achieve 110 dB SPL levels in the desired mode were predicted. Equivalent cases with and without flow were examined for the cylindrical and annular geometry, and little difference was found for a duct flow Mach number of 0.1. The actuator ring coupling program will be adapted as a subroutine to the cylindrical duct modal analysis and the exhaust duct modal analysis. This will allow the fan source to be defined in terms of characteristic modes at the fan source plane and predict the propagation to the arbitrarily-located ANC source plane. The actuator velocities can then be determined to generate the anti-phase mode. The resulting combined fan source/ANC pressure can then be calculated at any desired wall sensor position. The actuator velocities can be determined manually or using a simulation of a control system feedback loop. This will provide a very useful ANC system design and evaluation tool.

Measurements of the Optical Performance of Prototype TES Bolometers for SAFARI

NASA Astrophysics Data System (ADS)

Audley, M. D.; de Lange, G.; Ranjan, M.; Gao, J.-R.; Khosropanah, P.; Ridder, M. L.; Mauskopf, P. D.; Morozov, D.; Doherty, S.; Trappe, N.; Withington, S.

2014-09-01

We have measured the optical response of prototype detectors for SAFARI, the far-infrared imaging spectrometer for the SPICA satellite. SAFARI's three bolometer arrays, coupled with a Fourier transform spectrometer, will provide images of a 2'×2' field of view with spectral information over the wavelength range 34-210 μm. Each horn-coupled bolometer consists of a transition edge sensor (TES), with a transition temperature close to 100 mK, and a thin-film Ta absorber on a thermally-isolated silicon nitride membrane. SAFARI requires extremely sensitive detectors ( NEP˜2×10-19 W/), with correspondingly low saturation powers (˜5 fW), to take advantage of SPICA's cooled optics. To meet the challenge of testing such sensitive detectors we have constructed an ultra-low background test facility based on a cryogen-free high-capacity dilution refrigerator, paying careful attention to stray-light exclusion, shielding, and vibration isolation. For optical measurements the system contains internal cold (3-30 K) and hot (˜300 K) black-body calibration sources, as well as a light pipe for external illumination. We discuss our measurements of high optical efficiency in prototype SAFARI detectors and describe recent improvements to the test facility that will enable us to test the full SAFARI focal-plane arrays.

Experimental bandstructure of the 5 d transition metal oxide IrO2

NASA Astrophysics Data System (ADS)

Kawasaki, Jason; Nie, Yuefeng; Uchida, Masaki; Schlom, Darrell; Shen, Kyle

2015-03-01

In the 5 d iridium oxides the close energy scales of spin-orbit coupling and electron-electron correlations lead to emergent quantum phenomena. Much research has focused on the ternary iridium oxides, e.g. the Ruddlesden-Poppers An + 1BnO3 n + 1 , which exhibit behavior from metal to antiferromagnetic insulator ground states, share common features with the cuprates, and may host a number of topological phases. The binary rutile IrO2 is another important 5 d oxide, which has technological importance for spintronics due to its large spin Hall effect and also applications in catalysis. IrO2 is expected to share similar physics as its perovskite-based cousins; however, due to bond-length distortions of the IrO6 octahedra in the rutile structure, the extent of similarities remains an open question. Here we use angle-resolved photoemission spectroscopy to perform momentum-resolved measurements of the electronic structure of IrO2 . IrO2 thin films were grown by molecular beam epitaxy on TiO2 (110) substrates using an Ir e-beam source and distilled ozone. Films were subsequently transferred through ultrahigh vacuum to a connected ARPES system. Combined with first-principles calculations we explore the interplay of spin-orbit coupling and correlations in IrO2 .

Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) Final Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, R.

2016-01-01

The extensive coverage of low clouds over the subtropical eastern oceans greatly impacts the current climate. In addition, the response of low clouds to changes in atmospheric greenhouse gases and aerosols is a major source of uncertainty, which thwarts accurate prediction of future climate change. Low clouds are poorly simulated in climate models, partly due to inadequate long-term simultaneous observations of their macrophysical and microphysical structure, radiative effects, and associated aerosol distribution in regions where their impact is greatest. The thickness and extent of subtropical low clouds is dependent on tight couplings between surface fluxes of heat and moisture, radiativemore » cooling, boundary layer turbulence, and precipitation (much of which evaporates before reaching the ocean surface and is closely connected to the abundance of cloud condensation nuclei). These couplings have been documented as a result of past field programs and model studies. However, extensive research is still required to achieve a quantitative understanding sufficient for developing parameterizations, which adequately predict aerosol indirect effects and low cloud response to climate perturbations. This is especially true of the interactions between clouds, aerosol, and precipitation. These processes take place in an ever-changing synoptic environment that can confound interpretation of short time period observations.« less

A sensitivity-based approach to optimize the surface treatment of a low-height tramway noise barrier

NASA Astrophysics Data System (ADS)

Jolibois, Alexandre

Transportation noise has become a main nuisance in urban areas, in the industrialized world and across the world, to the point that according to the World Health Organization 65% of the European population is exposed to excessive noise and 20% to night-time levels that may harm their health. There is therefore a need to find new ways to mitigate transportation noise in urban areas. In this work, a possible device to achieve this goal is studied: a low-height noise barrier. It consists of a barrier typically less than one meter high placed close to the source, designed to decrease significantly the noise level for nearby pedestrians and cyclists. A numerical method which optimizes the surface treatment of a low-height barrier in order to increase its insertion loss is presented. Tramway noise barriers are especially studied since the noise sources are in this case close to the ground and would be attenuated more by the barrier. The acoustic behavior of the surface treatment is modeled via its admittance. It can be itself described by a few parameters (flow resistivity, geometrical dimensions...), which can then be optimized. It is proposed to couple porous layers and micro-perforated panel (MPP) resonators in order to take advantage of their different acoustic properties. Moreover, the optimization is achieved using a sensitivity-based method, since in this framework the gradient of the attenuation can be evaluated accurately and efficiently. Several shapes are considered: half-cylinder, quarter-cylinder, straight wall, T-shape and square shape. In the case of a half-cylindrical geometry, a semi-analytical solution for the sound field in terms of a series of cylindrical waves is derived, which simplifies the sensitivity calculation and optimization process. The boundary element method (BEM) is used to evaluate the attenuation for the remaining shapes, and in this case the sensitivity is evaluated using the adjoint state approach. For all considered geometries, it is found that placing an absorbing treatment close to the source is indeed necessary to attenuate the multiple re ections happening between the tramway and the barrier, and that a tuned MPP resonator on the top of the barrier can yield better performance than a uniform absorbent treatment. More advanced numerical modeling and scale model measurements seem to confirm these results.

Electron capture in collisions of S4+ with helium

NASA Astrophysics Data System (ADS)

Wang, J. G.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Stancil, P. C.; Zygelman, B.

2002-07-01

Charge transfer due to collisions of ground-state S4+(3s2 1S) ions with helium is investigated for energies between 0.1 meV u-1 and 10 MeV u-1. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained utilizing the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling (AOCC), classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. Previous data are limited to a calculation of the total SEC rate coefficient using the Landau-Zener model that is, in comparison to the results presented here, three orders of magnitude smaller. The MOCC SEC cross sections at low energy reveal a multichannel interference effect. True double capture is also investigated with the AOCC and CTMC approaches while autoionizing double capture and transfer ionization (TI) is explored with CTMC. SEC is found to be the dominant process except for E>200 keV u-1 when TI becomes the primary capture channel. Astrophysical implications are briefly discussed.

Laser-fiber coupling by means of a silicon micro-optical bench and a self-aligned soldering process

NASA Astrophysics Data System (ADS)

Schmidt, Jan P.; Cordes, A.; Mueller, Joerg; Burkhardt, Hans

1995-02-01

The alignment of laser diodes to monomode fibers has to meet extremely close tolerances for a low coupling loss. Typically < 0.5 micrometers in lateral and vertical direction and less than two degrees in angle deviation are allowed for a coupling loss below 2 dB. Presently such close tolerances can only be met by gluing or soldering both components on separate base plates and combining them via piezoactivated alignment monitoring the output of the circuit and then gluing them using UV-hardening epoxies. Such a procedure is not very economical and not useful for mass applications. This paper presents the principle and realization of a silicon micro-optical bench for laser-fiber-coupling, which avoids the above mentioned disadvantages. The micro-optical bench is realized using well controlled plasma etching processes to transfer the guiding patterns for the laser and the fiber into the silicon substrate, keeping geometry tolerances below +/- 0.5 micrometers in lateral and vertical direction. Mounting the laser diode by means of a self-aligned soldering process, an additional contribution to the precise alignment of the laser is further improved.

Integrable subsectors from holography

NASA Astrophysics Data System (ADS)

de Mello Koch, Robert; Kim, Minkyoo; Van Zyl, Hendrik J. R.

2018-05-01

We consider operators in N=4 super Yang-Mills theory dual to closed string states propagating on a class of LLM geometries. The LLM geometries we consider are specified by a boundary condition that is a set of black rings on the LLM plane. When projected to the LLM plane, the closed strings are polygons with all corners lying on the outer edge of a single ring. The large N limit of correlators of these operators receives contributions from non-planar diagrams even for the leading large N dynamics. Our interest in these fluctuations is because a previous weak coupling analysis argues that the net effect of summing the huge set of non-planar diagrams, is a simple rescaling of the 't Hooft coupling. We carry out some nontrivial checks of this proposal. Using the su(2|2)2 symmetry we determine the two magnon S-matrix and demonstrate that it agrees, up to two loops, with a weak coupling computation performed in the CFT. We also compute the first finite size corrections to both the magnon and the dyonic magnon by constructing solutions to the Nambu-Goto action that carry finite angular momentum. These finite size computations constitute a strong coupling confirmation of the proposal.

Couple stress fluid flow in a rotating channel with peristalsis

NASA Astrophysics Data System (ADS)

Abd elmaboud, Y.; Abdelsalam, Sara I.; Mekheimer, Kh. S.

2018-04-01

This article describes a new model for obtaining closed-form semi-analytical solutions of peristaltic flow induced by sinusoidal wave trains propagating with constant speed on the walls of a two-dimensional rotating infinite channel. The channel rotates with a constant angular speed about the z - axis and is filled with couple stress fluid. The governing equations of the channel deformation and the flow rate inside the channel are derived using the lubrication theory approach. The resulting equations are solved, using the homotopy perturbation method (HPM), for exact solutions to the longitudinal velocity distribution, pressure gradient, flow rate due to secondary velocity, and pressure rise per wavelength. The effect of various values of physical parameters, such as, Taylor's number and couple stress parameter, together with some interesting features of peristaltic flow are discussed through graphs. The trapping phenomenon is investigated for different values of parameters under consideration. It is shown that Taylor's number and the couple stress parameter have an increasing effect on the longitudinal velocity distribution till half of the channel, on the flow rate due to secondary velocity, and on the number of closed streamlines circulating the bolus.

Closing in on the radiative weak chiral couplings

NASA Astrophysics Data System (ADS)

Cappiello, Luigi; Catà, Oscar; D'Ambrosio, Giancarlo

2018-03-01

We point out that, given the current experimental status of radiative kaon decays, a subclass of the O (p^4) counterterms of the weak chiral lagrangian can be determined in closed form. This involves in a decisive way the decay K^± → π ^± π ^0 l^+ l^-, currently being measured at CERN by the NA48/2 and NA62 collaborations. We show that consistency with other radiative kaon decay measurements leads to a rather clean prediction for the {O}(p^4) weak couplings entering this decay mode. This results in a characteristic pattern for the interference Dalitz plot, susceptible to be tested already with the limited statistics available at NA48/2. We also provide the first analysis of K_S→ π ^+π ^-γ ^*, which will be measured by LHCb and will help reduce (together with the related K_L decay) the experimental uncertainty on the radiative weak chiral couplings. A precise experimental determination of the {O}(p^4) weak couplings is important in order to assess the validity of the existing theoretical models in a conclusive way. We briefly comment on the current theoretical situation and discuss the merits of the different theoretical approaches.

A unified diabatic description for electron transfer reactions, isomerization reactions, proton transfer reactions, and aromaticity.

PubMed

Reimers, Jeffrey R; McKemmish, Laura K; McKenzie, Ross H; Hush, Noel S

2015-10-14

While diabatic approaches are ubiquitous for the understanding of electron-transfer reactions and have been mooted as being of general relevance, alternate applications have not been able to unify the same wide range of observed spectroscopic and kinetic properties. The cause of this is identified as the fundamentally different orbital configurations involved: charge-transfer phenomena involve typically either 1 or 3 electrons in two orbitals whereas most reactions are typically closed shell. As a result, two vibrationally coupled electronic states depict charge-transfer scenarios whereas three coupled states arise for closed-shell reactions of non-degenerate molecules and seven states for the reactions implicated in the aromaticity of benzene. Previous diabatic treatments of closed-shell processes have considered only two arbitrarily chosen states as being critical, mapping these states to those for electron transfer. We show that such effective two-state diabatic models are feasible but involve renormalized electronic coupling and vibrational coupling parameters, with this renormalization being property dependent. With this caveat, diabatic models are shown to provide excellent descriptions of the spectroscopy and kinetics of the ammonia inversion reaction, proton transfer in N2H7(+), and aromaticity in benzene. This allows for the development of a single simple theory that can semi-quantitatively describe all of these chemical phenomena, as well as of course electron-transfer reactions. It forms a basis for understanding many technologically relevant aspects of chemical reactions, condensed-matter physics, chemical quantum entanglement, nanotechnology, and natural or artificial solar energy capture and conversion.

Electrocatalytic cermet sensor

DOEpatents

Shoemaker, E.L.; Vogt, M.C.

1998-06-30

A sensor is described for O{sub 2} and CO{sub 2} gases. The gas sensor includes a plurality of layers driven by a cyclic voltage to generate a unique plot characteristic of the gas in contact with the sensor. The plurality of layers includes an alumina substrate, a reference electrode source of anions, a lower electrical reference electrode of Pt coupled to the reference source of anions, a solid electrolyte containing tungsten and coupled to the lower reference electrode, a buffer layer for preventing flow of Pt ions into the solid electrolyte and an upper catalytically active Pt electrode coupled to the buffer layer. 16 figs.

Electrocatalytic cermet sensor

DOEpatents

Shoemaker, Erika L.; Vogt, Michael C.

1998-01-01

A sensor for O.sub.2 and CO.sub.2 gases. The gas sensor includes a plurality of layers driven by a cyclic voltage to generate a unique plot characteristic of the gas in contact with the sensor. The plurality of layers includes an alumina substrate, a reference electrode source of anions, a lower electrical reference electrode of Pt coupled to the reference source of anions, a solid electrolyte containing tungsten and coupled to the lower reference electrode, a buffer layer for preventing flow of Pt ions into the solid electrolyte and an upper catalytically active Pt electrode coupled to the buffer layer.

The structural coupling between ATPase activation and recovery stroke in the myosin II motor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koppole, Sampath; Smith, Jeremy C; Fischer, S.

2007-07-01

Before the myosin motor head can perform the next power stroke, it undergoes a large conformational transition in which the converter domain, bearing the lever arm, rotates {approx} 65{sup o}. Simultaneous with this 'recovery stroke', myosin activates its ATPase function by closing the Switch-2 loop over the bound ATP. This coupling between the motions of the converter domain and of the 40 {angstrom}-distant Switch-2 loop is essential to avoid unproductive ATP hydrolysis. The coupling mechanism is determined here by finding a series of optimized intermediates between crystallographic end structures of the recovery stroke (Dictyostelium discoideum), yielding movies of the transitionmore » at atomic detail. The successive formation of two hydrogen bonds by the Switch-2 loop is correlated with the successive see-saw motions of the relay and SH1 helices that hold the converter domain. SH1 helix and Switch-2 loop communicate via a highly conserved loop that wedges against the SH1-helix upon Switch-2 closing.« less

Charge Exchange of Ne^9+ for X-ray Emission

NASA Astrophysics Data System (ADS)

Lyons, David

2016-01-01

Using the molecular-orbital close-coupling (MOCC) method, single electron capture (SEC) cross sections were computed for Ne^9+ colliding with H.Potential energies and nonadiabatic couplings were calculated and used to obtain the MOCC cross sections which are final-quantum-state-resolved including a separation of singlet and triplet states. Atomic-orbital close-coupling, classical trajectory Monte Carlo, and multichannel Landau-Zener (MCLZ) calculations are also performed. Cross sections for more complicated targets including He, H2, N2, H2O, CO, and CO2, were obtained with the MCLZ method. The SEC results are compared with experimental and other theoretical data, where available. The SEC cross sections are being used in cascade models to predict X-ray emission spectra relevant to solar systemand astrophysical environments.D. Lyons, R. S. Cumbee, P. D. Mullen, P. C. Stancil (UGA), D. R. Schultz (UNT), P. Liebermann (Wuppertal Univ.),R. Buenker (NCSU).This work was partially supported by NASA grant NNX09AC46G.

The structural coupling between ATPase activation and recovery stroke in the myosin II motor.

PubMed

Koppole, Sampath; Smith, Jeremy C; Fischer, Stefan

2007-07-01

Before the myosin motor head can perform the next power stroke, it undergoes a large conformational transition in which the converter domain, bearing the lever arm, rotates approximately 65 degrees . Simultaneous with this "recovery stroke," myosin activates its ATPase function by closing the Switch-2 loop over the bound ATP. This coupling between the motions of the converter domain and of the 40 A-distant Switch-2 loop is essential to avoid unproductive ATP hydrolysis. The coupling mechanism is determined here by finding a series of optimized intermediates between crystallographic end structures of the recovery stroke (Dictyostelium discoideum), yielding movies of the transition at atomic detail. The successive formation of two hydrogen bonds by the Switch-2 loop is correlated with the successive see-saw motions of the relay and SH1 helices that hold the converter domain. SH1 helix and Switch-2 loop communicate via a highly conserved loop that wedges against the SH1-helix upon Switch-2 closing.

Touch increases autonomic coupling between romantic partners

PubMed Central

Chatel-Goldman, Jonas; Congedo, Marco; Jutten, Christian; Schwartz, Jean-Luc

2014-01-01

Interpersonal touch is of paramount importance in human social bonding and close relationships, allowing a unique channel for affect communication. So far the effect of touch on human physiology has been studied at an individual level. The present study aims at extending the study of affective touch from isolated individuals to truly interacting dyads. We have designed an ecological paradigm where romantic partners interact only via touch and we manipulate their empathic states. Simultaneously, we collected their autonomic activity (skin conductance, pulse, respiration). Fourteen couples participated to the experiment. We found that interpersonal touch increased coupling of electrodermal activity between the interacting partners, regardless the intensity and valence of the emotion felt. In addition, physical touch induced strong and reliable changes in physiological states within individuals. These results support an instrumental role of interpersonal touch for affective support in close relationships. Furthermore, they suggest that touch alone allows the emergence of a somatovisceral resonance between interacting individuals, which in turn is likely to form the prerequisites for emotional contagion and empathy. PMID:24734009

High-power fiber-coupled 100W visible spectrum diode lasers for display applications

NASA Astrophysics Data System (ADS)

Unger, Andreas; Küster, Matthias; Köhler, Bernd; Biesenbach, Jens

2013-02-01

Diode lasers in the blue and red spectral range are the most promising light sources for upcoming high-brightness digital projectors in cinemas and large venue displays. They combine improved efficiency, longer lifetime and a greatly improved color space compared to traditional xenon light sources. In this paper we report on high-power visible diode laser sources to serve the demands of this emerging market. A unique electro-optical platform enables scalable fiber coupled sources at 638 nm with an output power of up to 100 W from a 400 μm NA0.22 fiber. For the blue diode laser we demonstrate scalable sources from 5 W to 100 W from a 400 μm NA0.22 fiber.

Radiatively coupled thermionic and thermoelectric power system concept

NASA Technical Reports Server (NTRS)

Shimada, K.; Ewell, R.

1981-01-01

The study presented showed that the large power systems (about 100 kW) utilizing radiatively coupled thermionic or thermoelectric converters could be designed so that the power subsystem could be contained in a Space Shuttle bay as a part of an electrically propelled spacecraft. The radiatively coupled system requires a large number of individual converters since the transferred heat is smaller than with the conductively coupled system, but the advantages of the new system indicates merit for further study. The advantages are (1) good electrical isolation between converters and the heat source, (2) physical separation of converters from the heat source (making the system fabrication manageable), and (3) elimination of radiator heat pipes, which are required in an all-heat-pipe power system. In addition, the specific weight of the radiatively coupled power systems favorably compares with that of the all-heat-pipe systems.

Wireless power using magnetic resonance coupling for neural sensing applications

NASA Astrophysics Data System (ADS)

Yoon, Hargsoon; Kim, Hyunjung; Choi, Sang H.; Sanford, Larry D.; Geddis, Demetris; Lee, Kunik; Kim, Jaehwan; Song, Kyo D.

2012-04-01

Various wireless power transfer systems based on electromagnetic coupling have been investigated and applied in many biomedical applications including functional electrical stimulation systems and physiological sensing in humans and animals. By integrating wireless power transfer modules with wireless communication devices, electronic systems can deliver data and control system operation in untethered freely-moving conditions without requiring access through the skin, a potential source of infection. In this presentation, we will discuss a wireless power transfer module using magnetic resonance coupling that is specifically designed for neural sensing systems and in-vivo animal models. This research presents simple experimental set-ups and circuit models of magnetic resonance coupling modules and discusses advantages and concerns involved in positioning and sizing of source and receiver coils compared to conventional inductive coupling devices. Furthermore, the potential concern of tissue heating in the brain during operation of the wireless power transfer systems will also be addressed.

The Central Role of the Mississippi River and its Delta in the Oceanography, Ecology and Economy of the Gulf of Mexico: A Synthesis

NASA Astrophysics Data System (ADS)

Kolker, A.; Chu, P. Y.; Taylor, C.; Roberts, B. J.; Renfro, A. A.; Peyronnin, N.; Fitzpatrick, C.

2017-12-01

While it has long been recognized that the Mississippi River is the largest source of freshwater, nutrients and sediments to the Gulf of Mexico, many questions remain unanswered about the impacts of the material on oceanography of the system. Here we report on the results of a regional synthesis study that examined how the Mississippi River and its delta influence the oceanography, ecology and the economy of the Gulf of Mexico. By employing a series of expert-opinion working groups, and using multi-dimensional numerical physical oceanographic models coupled to in-situ environmental data, this project is working to quantify how variability in discharge, meteorological forcings, and seasonal conditions influence the spatial distribution of the Mississippi River plume and its influence. Results collected to date indicate that the dimensions of the river plume are closely coupled to discharge, but in a non-linear fashion, that incorporates fluxes, flow distributions, offshore and meteorological forcings in the context of the local bathymetry. Ongoing research is using these human and numerical tools to help further elucidate the impacts of this river on the biogeochemistry of the region, and the distribution of key macrofauna. Further work by this team is examining how the delta's impacts on the ecology of the region, and the role that the delta plays as both a source of material for key offshore fauna, and a barrier to dispersal. This information is being used to help further the development of a research agenda for the northern Gulf of Mexico that will be useful through the mid-21st century.

Toward more efficient fabrication of high-density 2-D VCSEL arrays for spatial redundancy and/or multi-level signal communication

NASA Astrophysics Data System (ADS)

Roscher, Hendrik; Gerlach, Philipp; Khan, Faisal Nadeem; Kroner, Andrea; Stach, Martin; Weigl, Alexander; Michalzik, Rainer

2006-04-01

We present flip-chip attached high-speed VCSELs in 2-D arrays with record-high intra-cell packing densities. The advances of VCSEL array technology toward improved thermal performance and more efficient fabrication are reviewed, and the introduction of self-aligned features to these devices is pointed out. The structure of close-spaced wedge-shaped VCSELs is discussed and their static and dynamic characteristics are presented including an examination of the modal structure by near-field measurements. The lasers flip-chip bonded to a silicon-based test platform exhibit 3-dB and 10-dB bandwidths of 7.7 GHz and 9.8 GHz, respectively. Open 12.5 Gbit/s two-level eye patterns are demonstrated. We discuss the uses of high packing densities for the increase of the total amount of data throughput an array can deliver in the course of its life. One such approach is to provide up to two backup VCSELs per fiber channel that can extend the lifetimes of parallel transmitters through redundancy of light sources. Another is to increase the information density by using multiple VCSELs per 50 μm core diameter multimode fiber to generate more complex signals. A novel scheme using three butt-coupled VCSELs per fiber for the generation of four-level signals in the optical domain is proposed. First experiments are demonstrated using two VCSELs butt-coupled to the same standard glass fiber, each modulated with two-level signals to produce four-level signals at the photoreceiver. A four-level direct modulation of one VCSEL within a triple of devices produced first 20.6 Gbit/s (10.3 Gsymbols/s) four-level eyes, leaving two VCSELs as backup sources.

Interactions of toroidally coupled tearing modes in the KSTAR tokamak

NASA Astrophysics Data System (ADS)

Kim, Gnan; Yun, Gunsu S.; Woo, Minho; Park, Hyeon K.; KSTAR Team2, the

2018-03-01

The evolutions of toroidally coupled radially-distant and radially-adjacent tearing modes are visualized in 2D in detail on the Korea superconducting tokamak for advanced research. The coupled tearing modes are in-phase on the out-board mid-plane and become destabilized or compete with each other depending on their spatial separation. When two coupled tearing modes are far apart, both are increasingly destabilized. On the other hand, when they become close to each other, one becomes stabilized while the other becomes destabilized. In such cases, an additional tearing mode is often formed on outer rational flux surface and the three tearing modes compete. The competitions suggest that spatial overlap (merging) of coupled magnetic islands is difficult.

Indistinguishable and efficient single photons from a quantum dot in a planar nanobeam waveguide

NASA Astrophysics Data System (ADS)

KiršanskÄ--, Gabija; Thyrrestrup, Henri; Daveau, Raphaël S.; Dreeßen, Chris L.; Pregnolato, Tommaso; Midolo, Leonardo; Tighineanu, Petru; Javadi, Alisa; Stobbe, Søren; Schott, Rüdiger; Ludwig, Arne; Wieck, Andreas D.; Park, Suk In; Song, Jin D.; Kuhlmann, Andreas V.; Söllner, Immo; Löbl, Matthias C.; Warburton, Richard J.; Lodahl, Peter

2017-10-01

We demonstrate a high-purity source of indistinguishable single photons using a quantum dot embedded in a nanophotonic waveguide. The source features a near-unity internal coupling efficiency and the collected photons are efficiently coupled off chip by implementing a taper that adiabatically couples the photons to an optical fiber. By quasiresonant excitation of the quantum dot, we measure a single-photon purity larger than 99.4 % and a photon indistinguishability of up to 94 ±1 % by using p -shell excitation combined with spectral filtering to reduce photon jitter. A temperature-dependent study allows pinpointing the residual decoherence processes, notably the effect of phonon broadening. Strict resonant excitation is implemented as well as another means of suppressing photon jitter, and the additional complexity of suppressing the excitation laser source is addressed. The paper opens a clear pathway towards the long-standing goal of a fully deterministic source of indistinguishable photons, which is integrated on a planar photonic chip.

COSMOLOGY OF CHAMELEONS WITH POWER-LAW COUPLINGS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mota, David F.; Winther, Hans A.

2011-05-20

In chameleon field theories, a scalar field can couple to matter with gravitational strength and still evade local gravity constraints due to a combination of self-interactions and the couplings to matter. Originally, these theories were proposed with a constant coupling to matter; however, the chameleon mechanism also extends to the case where the coupling becomes field dependent. We study the cosmology of chameleon models with power-law couplings and power-law potentials. It is found that these generalized chameleons, when viable, have a background expansion very close to {Lambda}CDM, but can in some special cases enhance the growth of the linear perturbationsmore » at low redshifts. For the models we consider, it is found that this region of the parameter space is ruled out by local gravity constraints. Imposing a coupling to dark matter only, the local constraints are avoided, and it is possible to have observable signatures on the linear matter perturbations.« less

Androgynous, Reconfigurable Closed Loop Feedback Controlled Low Impact Docking System With Load Sensing Electromagnetic Capture Ring

NASA Technical Reports Server (NTRS)

Lewis, James L. (Inventor); Carroll, Monty B. (Inventor); Morales, Ray H. (Inventor); Le, Thang D. (Inventor)

2002-01-01

The present invention relates to a fully androgynous, reconfigurable closed loop feedback controlled low impact docking system with load sensing electromagnetic capture ring. The docking system of the present invention preferably comprises two Docking- assemblies, each docking assembly comprising a load sensing ring having an outer face, one of more electromagnets, one or more load cells coupled to said load sensing ring. The docking assembly further comprises a plurality of actuator arms coupled to said load sensing ring and capable of dynamically adjusting the orientation of said load sensing ring and a reconfigurable closed loop control system capable of analyzing signals originating from said plurality of load cells and of outputting real time control for each of the actuators. The docking assembly of the present invention incorporates an active load sensing system to automatically dynamically adjust the load sensing ring during capture instead of requiring significant force to push and realign the ring.

Chromosomal Arrangement of Phosphorelay Genes Couples Sporulation and DNA Replication.

PubMed

Narula, Jatin; Kuchina, Anna; Lee, Dong-Yeon D; Fujita, Masaya; Süel, Gürol M; Igoshin, Oleg A

2015-07-16

Genes encoding proteins in a common regulatory network are frequently located close to one another on the chromosome to facilitate co-regulation or couple gene expression to growth rate. Contrasting with these observations, here, we demonstrate a functional role for the arrangement of Bacillus subtilis sporulation network genes on opposite sides of the chromosome. We show that the arrangement of two sporulation network genes, one located close to the origin and the other close to the terminus, leads to a transient gene dosage imbalance during chromosome replication. This imbalance is detected by the sporulation network to produce cell-cycle coordinated pulses of the sporulation master regulator Spo0A∼P. This pulsed response allows cells to decide between sporulation and continued vegetative growth during each cell cycle spent in starvation. The simplicity of this coordination mechanism suggests that it may be widely applicable in a variety of gene regulatory and stress-response settings. VIDEO ABSTRACT. Copyright © 2015 Elsevier Inc. All rights reserved.

Shared Relationship Efficacy of Dyad Can Increase Life Satisfaction in Close Relationships: Multilevel Study

PubMed Central

Ito, Kenichi; Yoshida, Toshikazu

2016-01-01

Characteristics of relationship itself play an important role in determining well-being of individuals who participate in the relationship. We used efficacy expectations mutually shared between close friends or romantic partners as a characteristic of relationship and investigated its impact on their life satisfaction. In Study 1, we conducted a cross-sectional study among 137 pairs of close same-sex friends to test whether the efficacy expectations shared between friends are associated with levels of life satisfaction. In Study 2, we conducted a longitudinal study among 114 heterosexual romantic couples to test predictive validity of the efficacy expectations shared between couples predict levels of life satisfaction 2 month later. In both studies we found a consistent result that as degrees of the efficacy expectations shared between individuals in a relationship increased, the degree of their life satisfaction also increased. Underlying mechanisms that explain how characteristics of relationship itself increase life satisfaction are discussed. PMID:27437946

Formation of Circumbinary Planets in a Dead Zone

NASA Astrophysics Data System (ADS)

Martin, Rebecca G.; Armitage, Philip J.; Alexander, Richard D.

2013-08-01

Circumbinary planets have been observed at orbital radii where binary perturbations may have significant effects on the gas disk structure, on planetesimal velocity dispersion, and on the coupling between turbulence and planetesimals. Here, we note that the impact of all of these effects on planet formation is qualitatively altered if the circumbinary disk structure is layered, with a non-turbulent midplane layer (dead zone) and strongly turbulent surface layers. For close binaries, we find that the dead zone typically extends from a radius close to the inner disk edge up to a radius of around 10-20 AU from the center of mass of the binary. The peak in the surface density occurs within the dead zone, far from the inner disk edge, close to the snow line, and may act as a trap for aerodynamically coupled solids. We suggest that circumbinary planet formation may be easier near this preferential location than for disks around single stars. However, dead zones around wide binaries are less likely, and hence planet formation may be more difficult there.

Closed-Loop Control of Humidification for Artifact Reduction in Capacitive ECG Measurements.

PubMed

Leicht, Lennart; Eilebrecht, Benjamin; Weyer, Soren; Leonhardt, Steffen; Teichmann, Daniel

2017-04-01

Recording biosignals without the need for direct skin contact offers new opportunities for ubiquitous health monitoring. Electrodes with capacitive coupling have been shown to be suitable for the monitoring of electrical potentials on the body surface, in particular ECG. However, due to triboelectric charge generation and motion artifacts, signal and thus diagnostic quality is inferior to galvanic coupling. Active closed-loop humidification of capacitive electrodes is proposed in this work as a new concept to improve signal quality. A capacitive ECG recording system integrated into a common car seat is presented. It can regulate the micro climate at the interface of electrode and patient by actively dispensing water vapour and monitoring humidity in a closed-loop approach. As a regenerative water reservoir, silica gel is used. The system was evaluated with respect to subjective and objective ECG signal quality. Active humidification was found to have a significant positive effect in case of previously poor quality. Also, it had no diminishing effect in case of already good signal quality.

Concerted Dynamic Motions of an FABP4 Model and Its Ligands Revealed by Microsecond Molecular Dynamics Simulations

PubMed Central

2015-01-01

In this work, we investigate the dynamic motions of fatty acid binding protein 4 (FABP4) in the absence and presence of a ligand by explicitly solvated all-atom molecular dynamics simulations. The dynamics of one ligand-free FABP4 and four ligand-bound FABP4s is compared via multiple 1.2 μs simulations. In our simulations, the protein interconverts between the open and closed states. Ligand-free FABP4 prefers the closed state, whereas ligand binding induces a conformational transition to the open state. Coupled with opening and closing of FABP4, the ligand adopts distinct binding modes, which are identified and compared with crystal structures. The concerted dynamics of protein and ligand suggests that there may exist multiple FABP4–ligand binding conformations. Thus, this work provides details about how ligand binding affects the conformational preference of FABP4 and how ligand binding is coupled with a conformational change of FABP4 at an atomic level. PMID:25231537

Concerted dynamic motions of an FABP4 model and its ligands revealed by microsecond molecular dynamics simulations.

PubMed

Li, Yan; Li, Xiang; Dong, Zigang

2014-10-14

In this work, we investigate the dynamic motions of fatty acid binding protein 4 (FABP4) in the absence and presence of a ligand by explicitly solvated all-atom molecular dynamics simulations. The dynamics of one ligand-free FABP4 and four ligand-bound FABP4s is compared via multiple 1.2 μs simulations. In our simulations, the protein interconverts between the open and closed states. Ligand-free FABP4 prefers the closed state, whereas ligand binding induces a conformational transition to the open state. Coupled with opening and closing of FABP4, the ligand adopts distinct binding modes, which are identified and compared with crystal structures. The concerted dynamics of protein and ligand suggests that there may exist multiple FABP4-ligand binding conformations. Thus, this work provides details about how ligand binding affects the conformational preference of FABP4 and how ligand binding is coupled with a conformational change of FABP4 at an atomic level.

Spatial layout optimization design of multi-type LEDs lighting source based on photoelectrothermal coupling theory

NASA Astrophysics Data System (ADS)

Xue, Lingyun; Li, Guang; Chen, Qingguang; Rao, Huanle; Xu, Ping

2018-03-01

Multiple LED-based spectral synthesis technology has been widely used in the fields of solar simulator, color mixing, and artificial lighting of plant factory and so on. Generally, amounts of LEDs are spatially arranged with compact layout to obtain the high power density output. Mutual thermal spreading among LEDs will produce the coupled thermal effect which will additionally increase the junction temperature of LED. Affected by the Photoelectric thermal coupling effect of LED, the spectrum of LED will shift and luminous efficiency will decrease. Correspondingly, the spectral synthesis result will mismatch. Therefore, thermal management of LED spatial layout plays an important role for multi-LEDs light source system. In the paper, the thermal dissipation network topology model considering the mutual thermal spreading effect among the LEDs is proposed for multi-LEDs system with various types of power. The junction temperature increment cased by the thermal coupling has the great relation with the spatial arrangement. To minimize the thermal coupling effect, an optimized method of LED spatial layout for the specific light source structure is presented and analyzed. The results showed that layout of LED with high-power are arranged in the corner and low-power in the center. Finally, according to this method, it is convenient to determine the spatial layout of LEDs in a system having any kind of light source structure, and has the advantages of being universally applicable to facilitate adjustment.

CC, CS, and IOS generalized phenomenological cross sections for atom--diatom mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitz, D.E.; Kouri, D.J.; Evans, D.

1981-05-01

Close coupled expressions for phenomenological cross sections which describe transport properties of atom--diatom mixtures are obtained in the total-J coupling scheme and are related to the bracket integrals of kinetic theory. Coupled states and infinite order sudden expressions for the generalized phenomenological cross sections using initial, final, and average l-labeling are also given. Particular care is taken to use a phase convention for the CS and IOS approximations which is consistent with the Arthurs--Dalgarno formalism and which gives the correct behavior of degeneracy averaged differential cross sections.

R-matrix calculations for electron-impact excitation of C(+), N(2+), and O(3+) including fine structure

NASA Technical Reports Server (NTRS)

Luo, D.; Pradhan, A. K.

1990-01-01

The new R-matrix package for comprehensive close-coupling calculations for electron scattering with the first three ions in the boron isoelectronic sequence, the astrophysically significant C(+), N(2+), and O(3+), is presented. The collision strengths are calculated in the LS coupling approximation, as well as in pair-coupling scheme, for the transitions among the fine-structure sublevels. Calculations are carried out at a large number of energies in order to study the detailed effects of autoionizing resonances.

Theory of one-dimensional hopping motion of a heavy particle interacting with phonons by different couplings

NASA Astrophysics Data System (ADS)

Itai, K.

1987-02-01

Two models which describe one-dimensional hopping motion of a heavy particle interacting with phonons are discussed. Model A corresponds to hopping in 1D metals or to the polaron problem. In model B the momentum dependence of the particle-phonon coupling is proportional to k-1/2. The scaling equations show that only in model B does localization occur for a coupling larger than a critical value. In the localization region this model shows close analogy to the Caldeira-Leggett model for macroscopic quantum tunneling.

Different states of the transient luminous phenomena in Hessdalen valley, Norway.

NASA Astrophysics Data System (ADS)

Hauge, B. G.; Montebugnoli, S.

2012-04-01

The transient luminous phenomena's in Hessdalen valley has at least been observed for 200 years, since 1811, when the priest Jacob T. Krogh did the first written documentation. The valley is located in the middle of Norway, isolated and with sub arctic climate. The former mining district has no more than 140 inhabitants, and the deep mines are closed and filled with water. The valley has been under scientific surveillance since 1998 when the first automated and remote controlled observatory was put into action. Today a Norwegian, Italian and French collaboration runs 3 different research stations inside the valley. Each year a scientific field campaign establishes 4 temporary bases in the mountains, and up to 100 students and researchers man these bases for up to 14 days in september when the moon is down. The Hessdalen phenomena is not easy to detect, and approximately only 20 observations is done each year. The work done the last 14 years suggests that the phenomenon has different states, at least 6 detected so far. The states are so different that to se a coupling between them is difficult. New work done into dusty plasma physics suggest that the different phenomena's may be of the same origin, since the ionized grains of dusty plasma can change states from weakly coupled (gaseous) to crystalline, altering shape/formation and leading to different phenomena. Optical spectrometry from 2007 suggested that the luminous phenomena consisted of burning air and dust from the valley. Work done by G.S Paiva and C.A Taft suggests that radon decay from closed mines may be the mechanism that ionizes dust and triggers this phenomena. The 6 different main states of the Hessdalen phenomena, Doublet, Fireball, Plasma ray, Dust cloud, Flash and Invisible state is described and discussed. Investigation of the atmosphere inside the Hessdalen valley with low frequency directional RADAR, reveals large areas of ionized matter, giving a reflecting area big enough to saturate the input of the radar receiver. Together with long living time, ground analysis and radio active measurements, do not support the radon decay theory, and other forms of ionizing mechanisms must be investigated. The phenomenon's energy source is still not revealed, and the question of internal or external power source is also unexplained.

A stochastic particle method for the investigation of turbulence/chemistry interactions in large-eddy simulations of turbulent reacting flows

NASA Astrophysics Data System (ADS)

Ferrero, Pietro

The main objective of this work is to investigate the effects of the coupling between the turbulent fluctuations and the highly non-linear chemical source terms in the context of large-eddy simulations of turbulent reacting flows. To this aim we implement the filtered mass density function (FMDF) methodology on an existing finite volume (FV) fluid dynamics solver. The FMDF provides additional statistical sub-grid scale (SGS) information about the thermochemical state of the flow - species mass fractions and enthalpy - which would not be available otherwise. The core of the methodology involves solving a transport equation for the FMDF by means of a stochastic, grid-free, Lagrangian particle procedure. Any moments of the distribution can be obtained by taking ensemble averages of the particles. The main advantage of this strategy is that the chemical source terms appear in closed form so that the effects of turbulent fluctuations on these terms are already accounted for and do not need to be modeled. We first validate and demonstrate the consistency of our implementation by comparing the results of the hybrid FV/FMDF procedure against model-free LES for temporally developing, non-reacting mixing layers. Consistency requires that, for non-reacting cases, the two solvers should yield identical solutions. We investigate the sensitivity of the FMDF solution on the most relevant numerical parameters, such as the number of particles per cell and the size of the ensemble domain. Next, we apply the FMDF modeling strategy to the simulation of chemically reacting, two- and three-dimensional temporally developing mixing layers and compare the results against both DNS and model-free LES. We clearly show that, when the turbulence/chemistry interaction is accounted for with the FMDF methodology, the results are in much better agreement to the DNS data. Finally, we perform two- and three-dimensional simulations of high Reynolds number, spatially developing, chemically reacting mixing layers, with the intent of reproducing a set of experimental results obtained at the California Institute of Technology. The mean temperature rise calculated by the hybrid FV/FMDF solver, which is associated with the amount of product formed, lies very close to the experimental profile. Conversely, when the effects of turbulence/chemistry coupling are ignored, the simulations clearly over predict the amount of product that is formed.

Thallium isotope variations in seawater and hydrogenetic, diagenetic, and hydrothermal ferromanganese deposits

USGS Publications Warehouse

Rehkamper, M.; Frank, M.; Hein, J.R.; Porcelli, D.; Halliday, A.; Ingri, J.; Liebetrau, V.

2002-01-01

Results are presented for the first in-depth investigation of TI isotope variations in marine materials. The TI isotopic measurements were conducted by multiple collector-inductively coupled plasma mass spectrometry for a comprehensive suite of hydrogenetic ferromanganese crusts, diagenetic Fe-Mn nodules, hydrothermal manganese deposits and seawater samples. The natural variability of TI isotope compositions in these samples exceeds the analytical reproducibility (?? 0.05???) by more than a factor of 40. Hydrogenetic Fe-Mn crusts have ??205TI of + 10 to + 14, whereas seawater is characterized by values as low as -8 (??205TI represents the deviation of the 205TI/203TI ratio of a sample from the NIST SRM 997 TI isotope standard in parts per 104). This ~ 2??? difference in isotope composition is thought to result from the isotope fractionation that accompanies the adsorption of TI onto ferromanganese particles. An equilibrium fractionation factor of ?? ~ 1.0021 is calculated for this process. Ferromanganese nodules and hydrothermal manganese deposits have variable TI isotope compositions that range between the values obtained for seawater and hydrogenetic Fe-Mn crusts. The variability in ??205TI in diagenetic nodules appears to be caused by the adsorption of TI from pore fluids, which act as a closed-system reservoir with a TI isotope composition that is inferred to be similar to seawater. Nodules with ??205TI values similar to seawater are found if the scavenging of TI is nearly quantitative. Hydrothermal manganese deposits display a positive correlation between ??205TI and Mn/Fe. This trend is thought to be due to the derivation of TI from distinct hydrothermal sources. Deposits with low Mn/Fe ratios and low ??205TI are produced by the adsorption of TI from fluids that are sampled close to hydrothermal sources. Such fluids have low Mn/Fe ratios and relatively high temperatures, such that only minor isotope fractionation occurs during adsorption. Hydrothermal manganese deposits with high Mn/Fe and high ??205Ti are generated by scavenging of TI from colder, more distal hydrothermal fluids. Under such conditions, adsorption is associated with significant isotope fractionation, and this produces deposits with higher ??205TI values coupled with high Mn/Fe. ?? 2002 Elsevier Science B.V. All rights reserved.

Maritime Mobile Force Protection (MMFP) Program

DTIC Science & Technology

2010-05-28

to draw or write on the screen.  Thin design has a starting weight of 4.65lbs.  Capture handwriting : scrawl onscreen with the included dockable...Will say “Past CPA” if CPA has already occurred. Range at CPA DDD Yards Range at Closest Point of Approach to HVU Closing Speed DDD knots Speed of...closing to HVU, if greater than or equal to zero. Will say “Opening” if the closing speed is less than zero. Data Source Radar, AIS, Correlated Source

Generator voltage stabilisation for series-hybrid electric vehicles.

PubMed

Stewart, P; Gladwin, D; Stewart, J; Cowley, R

2008-04-01

This paper presents a controller for use in speed control of an internal combustion engine for series-hybrid electric vehicle applications. Particular reference is made to the stability of the rectified DC link voltage under load disturbance. In the system under consideration, the primary power source is a four-cylinder normally aspirated gasoline internal combustion engine, which is mechanically coupled to a three-phase permanent magnet AC generator. The generated AC voltage is subsequently rectified to supply a lead-acid battery, and permanent magnet traction motors via three-phase full bridge power electronic inverters. Two complementary performance objectives exist. Firstly to maintain the internal combustion engine at its optimal operating point, and secondly to supply a stable 42 V supply to the traction drive inverters. Achievement of these goals minimises the transient energy storage requirements at the DC link, with a consequent reduction in both weight and cost. These objectives imply constant velocity operation of the internal combustion engine under external load disturbances and changes in both operating conditions and vehicle speed set-points. An electronically operated throttle allows closed loop engine velocity control. System time delays and nonlinearities render closed loop control design extremely problematic. A model-based controller is designed and shown to be effective in controlling the DC link voltage, resulting in the well-conditioned operation of the hybrid vehicle.

Hybrid nanostructures of well-organized arrays of colloidal quantum dots and a self-assembled monolayer of gold nanoparticles for enhanced fluorescence

NASA Astrophysics Data System (ADS)

Liu, Xiaoying; McBride, Sean P.; Jaeger, Heinrich M.; Nealey, Paul F.

2016-07-01

Hybrid nanomaterials comprised of well-organized arrays of colloidal semiconductor quantum dots (QDs) in close proximity to metal nanoparticles (NPs) represent an appealing system for high-performance, spectrum-tunable photon sources with controlled photoluminescence. Experimental realization of such materials requires well-defined QD arrays and precisely controlled QD-metal interspacing. This long-standing challenge is tackled through a strategy that synergistically combines lateral confinement and vertical stacking. Lithographically generated nanoscale patterns with tailored surface chemistry confine the QDs into well-organized arrays with high selectivity through chemical pattern directed assembly, while subsequent coating with a monolayer of close-packed Au NPs introduces the plasmonic component for fluorescence enhancement. The results show uniform fluorescence emission in large-area ordered arrays for the fabricated QD structures and demonstrate five-fold fluorescence amplification for red, yellow, and green QDs in the presence of the Au NP monolayer. Encapsulation of QDs with a silica shell is shown to extend the design space for reliable QD/metal coupling with stronger enhancement of 11 times through the tuning of QD-metal spatial separation. This approach provides new opportunities for designing hybrid nanomaterials with tailored array structures and multiple functionalities for applications such as multiplexed optical coding, color display, and quantum transduction.

Method and system for a gas tube-based current source high voltage direct current transmission system

DOEpatents

She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

2017-08-29

A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

An air-coupled actuator array for active modal control of timpani

NASA Astrophysics Data System (ADS)

Rollow, Douglas; Sparrow, Victor W.; Swanson, David C.

2005-09-01

The timbral characteristics of kettledrums can be described by a modal formulation of the vibration of a thin, air-loaded membrane. Modification of the modal time history can be brought about with the use of a control system which has independent influence on each structural mode. By replacing the usual kettle with a shallow chamber and a planar array of piston sources, a modal controller is created when driving the sources in appropriate linear combinations. A theoretical formulation of active control of structural vibration by means of fluid-coupled actuators is expressed, and a Boundary Element simulation provides insight to the coupled modes, independence of control, and constraints due to the geometry of the chamber. Advantages and limitations of this type of control source to general problems in actively controlled musical instruments are explored.

MODULES FOR EXPERIMENTS IN STELLAR ASTROPHYSICS (MESA): BINARIES, PULSATIONS, AND EXPLOSIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paxton, Bill; Bildsten, Lars; Cantiello, Matteo

We substantially update the capabilities of the open-source software instrument Modules for Experiments in Stellar Astrophysics (MESA). MESA can now simultaneously evolve an interacting pair of differentially rotating stars undergoing transfer and loss of mass and angular momentum, greatly enhancing the prior ability to model binary evolution. New MESA capabilities in fully coupled calculation of nuclear networks with hundreds of isotopes now allow MESA to accurately simulate the advanced burning stages needed to construct supernova progenitor models. Implicit hydrodynamics with shocks can now be treated with MESA, enabling modeling of the entire massive star lifecycle, from pre-main-sequence evolution to themore » onset of core collapse and nucleosynthesis from the resulting explosion. Coupling of the GYRE non-adiabatic pulsation instrument with MESA allows for new explorations of the instability strips for massive stars while also accelerating the astrophysical use of asteroseismology data. We improve the treatment of mass accretion, giving more accurate and robust near-surface profiles. A new MESA capability to calculate weak reaction rates “on-the-fly” from input nuclear data allows better simulation of accretion induced collapse of massive white dwarfs and the fate of some massive stars. We discuss the ongoing challenge of chemical diffusion in the strongly coupled plasma regime, and exhibit improvements in MESA that now allow for the simulation of radiative levitation of heavy elements in hot stars. We close by noting that the MESA software infrastructure provides bit-for-bit consistency for all results across all the supported platforms, a profound enabling capability for accelerating MESA's development.« less

Temporal dynamics of biogeochemical processes at the Norman Landfill site

USGS Publications Warehouse

Arora, Bhavna; Mohanty, Binayak P.; McGuire, Jennifer T.; Cozzarelli, Isabelle M.

2013-01-01

The temporal variability observed in redox sensitive species in groundwater can be attributed to coupled hydrological, geochemical, and microbial processes. These controlling processes are typically nonstationary, and distributed across various time scales. Therefore, the purpose of this study is to investigate biogeochemical data sets from a municipal landfill site to identify the dominant modes of variation and determine the physical controls that become significant at different time scales. Data on hydraulic head, specific conductance, δ2H, chloride, sulfate, nitrate, and nonvolatile dissolved organic carbon were collected between 1998 and 2000 at three wells at the Norman Landfill site in Norman, OK. Wavelet analysis on this geochemical data set indicates that variations in concentrations of reactive and conservative solutes are strongly coupled to hydrologic variability (water table elevation and precipitation) at 8 month scales, and to individual eco-hydrogeologic framework (such as seasonality of vegetation, surface-groundwater dynamics) at 16 month scales. Apart from hydrologic variations, temporal variability in sulfate concentrations can be associated with different sources (FeS cycling, recharge events) and sinks (uptake by vegetation) depending on the well location and proximity to the leachate plume. Results suggest that nitrate concentrations show multiscale behavior across temporal scales for different well locations, and dominant variability in dissolved organic carbon for a closed municipal landfill can be larger than 2 years due to its decomposition and changing content. A conceptual framework that explains the variability in chemical concentrations at different time scales as a function of hydrologic processes, site-specific interactions, and/or coupled biogeochemical effects is also presented.

Upper bound on the Abelian gauge coupling from asymptotic safety

NASA Astrophysics Data System (ADS)

Eichhorn, Astrid; Versteegen, Fleur

2018-01-01

We explore the impact of asymptotically safe quantum gravity on the Abelian gauge coupling in a model including a charged scalar, confirming indications that asymptotically safe quantum fluctuations of gravity could trigger a power-law running towards a free fixed point for the gauge coupling above the Planck scale. Simultaneously, quantum gravity fluctuations balance against matter fluctuations to generate an interacting fixed point, which acts as a boundary of the basin of attraction of the free fixed point. This enforces an upper bound on the infrared value of the Abelian gauge coupling. In the regime of gravity couplings which in our approximation also allows for a prediction of the top quark and Higgs mass close to the experimental value [1], we obtain an upper bound approximately 35% above the infrared value of the hypercharge coupling in the Standard Model.

Cross-Regional Assessment Of Coupling And Variability In Precipitation-Runoff Relationships

NASA Astrophysics Data System (ADS)

Carey, S. K.; Tetzlaff, D.; Soulsby, C.; Buttle, J. M.; Laudon, H.; McDonnell, J. J.; McGuire, K. J.; Seibert, J.; Shanley, J. B.

2011-12-01

The higher mid-latitudes of the northern hemisphere are particularly sensitive to change due to the important role the zero-degree isotherm plays in the phase of precipitation and intermediate storage as snow. An international inter-catchment comparison program North-Watch seeks to improve our understanding of the sensitivity of northern catchments to change by examining their hydrological and biogeochemical variability and response. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). For this study, 8 catchments with 10 continuous years of daily precipitation and runoff data were selected to assess the seasonal coupling of rainfall and runoff and the memory effect of runoff events on the hydrograph at different time scales. To assess the coupling and synchroneity of precipitation, continuous wavelet transforms and wavelet coherence were used. Wavelet spectra identified the relative importance of both annual versus seasonal flows while wavelet coherence was applied to identify over different time scales along the 10-year window how well precipitation and runoff were coupled. For example, while on a given day, precipitation may be closely coupled to runoff, a wet year may not necessarily be a high runoff year in catchments with large storage. Assessing different averaging periods in the variation of daily flows highlights the importance of seasonality in runoff response and the relative influence of rain versus snowmelt on flow magnitude and variability. Wet catchments with limited seasonal precipitation variability (Strontian, Girnock) have precipitation signals more closely coupled with runoff, whereas dryer catchments dominated by snow (Wolf Creek, Krycklan) have strongly coupling only during freshet. Most catchments with highly seasonal precipitation show strong intermittent coupling during their wet season. At longer time scales, some catchments do not exhibit coupling in their input-output relations, which is related to catchment storage.

The S-Web Model for the Sources of the Slow Solar Wind

NASA Technical Reports Server (NTRS)

Antiochos, Spiro K.; Karpen, Judith T.; DeVore, C. Richard

2012-01-01

Models for the origin of the slow solar wind must account for two seemingly contradictory observations: The slow wind has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow wind has large angular width, up to 60 degrees, suggesting that its source extends far from the open-closed boundary. We describe a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices (the S-Web) and quasi-separatrix layers in the heliosphere. We discuss the dynamics of the S-Web model and its implications for present observations and for the upcoming observations from Solar Orbiter and Solar Probe Plus.

A semi-empirical approach for the modelling and analysis of microvibration sources on-board spacecraft

NASA Astrophysics Data System (ADS)

Addari, Daniele

The term microvibrations generally refers to accelerations in the order of micro-gs and which manifest in a bandwidth from a few Hz up to say 500-1000 Hz. The need to accurately characterise this small disturbances acting on-board modern satellites, thus allowing the design of dedicated minimisation and control systems, is nowadays a major concern for the success of some space missions. The main issues related to microvibrations are the feasibility to analytically describe the microvibration sources using a series of analysis tools and test experiments and the prediction of how the dynamics of the microvibration sources couple with those of the satellite structure. In this thesis, a methodology to facilitate the modelling of these phenomena is described. Two aspects are investigated: the characterisation of the microvibration sources with a semi-empirical procedure which allows derivation of the dynamic mass properties of the source, also including the gyroscopic effect, with a significantly simpler test configuration and lower computational effort compared to traditional approaches; and the modelling of the coupled dynamics when the source is mounted on a representative supporting structure of a spacecraft, including the passive and active effects of the source, which allows prediction of the structure response at any location. The methodology has been defined conducting an extensive study, both experimental and numerical, on a reaction wheel assembly, as this is usually identified as the main contributory factor among all microvibration sources. The contributions to the state-of-the-art made during this work include: i) the development of a cantilever configured reaction wheel analytical model able to reproduce all the configurations in which the mechanism may operate and inclusive of the gyroscopic effect; ii) the reformulation of the coupling theory which allows retrieving the dynamic mass of a microvibration source over a wide range of frequencies and speeds, by means of the experimental data obtained from measurements of the forces generated when the source is rigidly secured on a dynamometric platform and measurements of the accelerations at the source mounting interface in a freefree suspended boundary condition; iii) a practical example of coupling between a reaction wheel and a honeycomb structural panel, where the coupled loads and the panel response have been estimated using the mathematical model and compared with test results, obtained during the physical microvibration testing of the structural panel, showing a good level of agreement when the gyroscopic effect is also taken into account.

Behaviour and design considerations for continuous flow closed-open-closed liquid microchannels.

PubMed

Melin, Jessica; van der Wijngaart, Wouter; Stemme, Göran

2005-06-01

This paper introduces a method of combining open and closed microchannels in a single component in a novel way which couples the benefits of both open and closed microfluidic systems and introduces interesting on-chip microfluidic behaviour. Fluid behaviour in such a component, based on continuous pressure driven flow and surface tension, is discussed in terms of cross sectional flow behaviour, robustness, flow-pressure performance, and its application to microfluidic interfacing. The closed-open-closed microchannel possesses the versatility of upstream and downstream closed microfluidics along with open fluidic direct access. The device has the advantage of eliminating gas bubbles present upstream when these enter the open channel section. The unique behaviour of this device opens the door to applications including direct liquid sample interfacing without the need for additional and bulky sample tubing.

Head-mounted LED for optogenetic experiments of freely-behaving animal

NASA Astrophysics Data System (ADS)

Kwon, Ki Yong; Gnade, Andrew G.; Rush, Alexander D.; Patten, Craig D.

2016-03-01

Recent developments in optogenetics have demonstrated the ability to target specific types of neurons with sub-millisecond temporal precision via direct optical stimulation of genetically modified neurons in the brain. In most applications, the beam of a laser is coupled to an optical fiber, which guides and delivers the optical power to the region of interest. Light emitting diodes (LEDs) are an alternative light source for optogenetics and they provide many advantages over a laser based system including cost, size, illumination stability, and fast modulation. Their compact size and low power consumption make LEDs suitable light sources for a wireless optogenetic stimulation system. However, the coupling efficiency of an LED's output light into an optical fiber is lower than a laser due to its noncollimated output light. In typical chronic optogenetic experiment, the output of the light source is transmitted to the brain through a patch cable and a fiber stub implant, and this configuration requires two fiber-to-fiber couplings. Attenuation within the patch cable is potential source of optical power loss. In this study, we report and characterize a recently developed light delivery method for freely-behaving animal experiments. We have developed a head-mounted light source that maximizes the coupling efficiency of an LED light source by eliminating the need for a fiber optic cable. This miniaturized LED is designed to couple directly to the fiber stub implant. Depending on the desired optical power output, the head-mounted LED can be controlled by either a tethered (high power) or battery-powered wireless (moderate power) controller. In the tethered system, the LED is controlled through 40 gauge micro coaxial cable which is thinner, more flexible, and more durable than a fiber optic cable. The battery-powered wireless system uses either infrared or radio frequency transmission to achieve real-time control. Optical, electrical, mechanical, and thermal characteristics of the head-mounted LED were evaluated.

40 CFR 98.430 - Definition of the source category.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Contained in Pre-Charged Equipment or Closed-Cell Foams § 98.430 Definition of the source category. (a) The...-cell foams, consists of any entity that imports or exports pre-charged equipment that contains a fluorinated GHG, and any entity that imports or exports closed-cell foams that contain a fluorinated GHG. ...

40 CFR 98.430 - Definition of the source category.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Contained in Pre-Charged Equipment or Closed-Cell Foams § 98.430 Definition of the source category. (a) The...-cell foams, consists of any entity that imports or exports pre-charged equipment that contains a fluorinated GHG, and any entity that imports or exports closed-cell foams that contain a fluorinated GHG. ...

40 CFR 98.430 - Definition of the source category.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Contained in Pre-Charged Equipment or Closed-Cell Foams § 98.430 Definition of the source category. (a) The...-cell foams, consists of any entity that imports or exports pre-charged equipment that contains a fluorinated GHG, and any entity that imports or exports closed-cell foams that contain a fluorinated GHG. ...

40 CFR 98.430 - Definition of the source category.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Contained in Pre-Charged Equipment or Closed-Cell Foams § 98.430 Definition of the source category. (a) The...-cell foams, consists of any entity that imports or exports pre-charged equipment that contains a fluorinated GHG, and any entity that imports or exports closed-cell foams that contain a fluorinated GHG. ...

Protected Quantum Computation with Multiple Resonators in Ultrastrong Coupling Circuit QED

NASA Astrophysics Data System (ADS)

Nataf, Pierre; Ciuti, Cristiano

2011-11-01

We investigate theoretically the dynamical behavior of a qubit obtained with the two ground eigenstates of an ultrastrong coupling circuit-QED system consisting of a finite number of Josephson fluxonium atoms inductively coupled to a transmission line resonator. We show a universal set of quantum gates by using multiple transmission line resonators (each resonator represents a single qubit). We discuss the intrinsic “anisotropic” nature of noise sources for fluxonium artificial atoms. Through a master equation treatment with colored noise and many-level dynamics, we prove that, for a general class of anisotropic noise sources, the coherence time of the qubit and the fidelity of the quantum operations can be dramatically improved in an optimal regime of ultrastrong coupling, where the ground state is an entangled photonic “cat” state.

Vacuum stress energy density and its gravitational implications

NASA Astrophysics Data System (ADS)

Estrada, Ricardo; Fulling, Stephen A.; Kaplan, Lev; Kirsten, Klaus; Liu, Zhonghai; Milton, Kimball A.

2008-04-01

In nongravitational physics the local density of energy is often regarded as merely a bookkeeping device; only total energy has an experimental meaning—and it is only modulo a constant term. But in general relativity the local stress-energy tensor is the source term in Einstein's equation. In closed universes, and those with Kaluza-Klein dimensions, theoretical consistency demands that quantum vacuum energy should exist and have gravitational effects, although there are no boundary materials giving rise to that energy by van der Waals interactions. In the lab there are boundaries, and in general the energy density has a nonintegrable singularity as a boundary is approached (for idealized boundary conditions). As pointed out long ago by Candelas and Deutsch, in this situation there is doubt about the viability of the semiclassical Einstein equation. Our goal is to show that the divergences in the linearized Einstein equation can be renormalized to yield a plausible approximation to the finite theory that presumably exists for realistic boundary conditions. For a scalar field with Dirichlet or Neumann boundary conditions inside a rectangular parallelepiped, we have calculated by the method of images all components of the stress tensor, for all values of the conformal coupling parameter and an exponential ultraviolet cutoff parameter. The qualitative features of contributions from various classes of closed classical paths are noted. Then the Estrada-Kanwal distributional theory of asymptotics, particularly the moment expansion, is used to show that the linearized Einstein equation with the stress-energy near a plane boundary as source converges to a consistent theory when the cutoff is removed. This paper reports work in progress on a project combining researchers in Texas, Louisiana and Oklahoma. It is supported by NSF Grants PHY-0554849 and PHY-0554926.

Plasma wall interaction and its implication in an all tungsten divertor tokamak

NASA Astrophysics Data System (ADS)

Neu, R.; Balden, M.; Bobkov, V.; Dux, R.; Gruber, O.; Herrmann, A.; Kallenbach, A.; Kaufmann, M.; Maggi, C. F.; Maier, H.; Müller, H. W.; Pütterich, T.; Pugno, R.; Rohde, V.; Sips, A. C. C.; Stober, J.; Suttrop, W.; Angioni, C.; Atanasiu, C. V.; Becker, W.; Behler, K.; Behringer, K.; Bergmann, A.; Bertoncelli, T.; Bilato, R.; Bottino, A.; Brambilla, M.; Braun, F.; Buhler, A.; Chankin, A.; Conway, G.; Coster, D. P.; de Marné, P.; Dietrich, S.; Dimova, K.; Drube, R.; Eich, T.; Engelhardt, K.; Fahrbach, H.-U.; Fantz, U.; Fattorini, L.; Fink, J.; Fischer, R.; Flaws, A.; Franzen, P.; Fuchs, J. C.; Gál, K.; García Muñoz, M.; Gemisic-Adamov, M.; Giannone, L.; Gori, S.; da Graca, S.; Greuner, H.; Gude, A.; Günter, S.; Haas, G.; Harhausen, J.; Heinemann, B.; Hicks, N.; Hobirk, J.; Holtum, D.; Hopf, C.; Horton, L.; Huart, M.; Igochine, V.; Kálvin, S.; Kardaun, O.; Kick, M.; Kocsis, G.; Kollotzek, H.; Konz, C.; Krieger, K.; Kurki-Suonio, T.; Kurzan, B.; Lackner, K.; Lang, P. T.; Lauber, P.; Laux, M.; Likonen, J.; Liu, L.; Lohs, A.; Mank, K.; Manini, A.; Manso, M.-E.; Maraschek, M.; Martin, P.; Martin, Y.; Mayer, M.; McCarthy, P.; McCormick, K.; Meister, H.; Meo, F.; Merkel, P.; Merkel, R.; Mertens, V.; Merz, F.; Meyer, H.; Mlynek, M.; Monaco, F.; Murmann, H.; Neu, G.; Neuhauser, J.; Nold, B.; Noterdaeme, J.-M.; Pautasso, G.; Pereverzev, G.; Poli, E.; Püschel, M.; Raupp, G.; Reich, M.; Reiter, B.; Ribeiro, T.; Riedl, R.; Roth, J.; Rott, M.; Ryter, F.; Sandmann, W.; Santos, J.; Sassenberg, K.; Scarabosio, A.; Schall, G.; Schirmer, J.; Schmid, A.; Schneider, W.; Schramm, G.; Schrittwieser, R.; Schustereder, W.; Schweinzer, J.; Schweizer, S.; Scott, B.; Seidel, U.; Serra, F.; Sertoli, M.; Sigalov, A.; Silva, A.; Speth, E.; Stäbler, A.; Steuer, K.-H.; Strumberger, E.; Tardini, G.; Tichmann, C.; Treutterer, W.; Tröster, C.; Urso, L.; Vainonen-Ahlgren, E.; Varela, P.; Vermare, L.; Wagner, D.; Wischmeier, M.; Wolfrum, E.; Würsching, E.; Yadikin, D.; Yu, Q.; Zasche, D.; Zehetbauer, T.; Zilker, M.; Zohm, H.

2007-12-01

ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of the last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It was found that the large He content in the plasma, resulting from DC glow discharges for conditioning, leads to a confinement reduction. After the change to D glow for inter-shot conditioning, the He content quickly dropped and, in parallel, the usual H-Mode confinement with H factors close to one was achieved. After the initial conditioning phase, oxygen concentrations similar to that in previous campaigns with boronizations could be achieved. Despite the removal of all macroscopic carbon sources, no strong change in C influxes and C content could be observed so far. The W concentrations are similar to the ones measured previously in discharges with old boronization and only partial coverage of the surfaces with W. Concomitantly it is found that although the W erosion flux in the divertor is larger than the W sources in the main chamber in most of the scenarios, it plays only a minor role for the W content in the main plasma. For large antenna distances and strong gas puffing, ICRH power coupling could be optimized to reduce the W influxes. This allowed a similar increase of stored energy as yielded with comparable beam power. However, a strong increase of radiated power and a loss of H-Mode was observed for conditions with high temperature edge plasma close to the antennas. The use of ECRH allowed keeping the central peaking of the W concentration low and even phases of improved H-modes have already been achieved.

Battery-powered pulsed high density inductively coupled plasma source for pre-ionization in laboratory astrophysics experiments.

PubMed

Chaplin, Vernon H; Bellan, Paul M

2015-07-01

An electrically floating radiofrequency (RF) pre-ionization plasma source has been developed to enable neutral gas breakdown at lower pressures and to access new experimental regimes in the Caltech laboratory astrophysics experiments. The source uses a customized 13.56 MHz class D RF power amplifier that is powered by AA batteries, allowing it to safely float at 3-6 kV with the electrodes of the high voltage pulsed power experiments. The amplifier, which is capable of 3 kW output power in pulsed (<1 ms) operation, couples electrical energy to the plasma through an antenna external to the 1.1 cm radius discharge tube. By comparing the predictions of a global equilibrium discharge model with the measured scalings of plasma density with RF power input and axial magnetic field strength, we demonstrate that inductive coupling (rather than capacitive coupling or wave damping) is the dominant energy transfer mechanism. Peak ion densities exceeding 5 × 10(19) m(-3) in argon gas at 30 mTorr have been achieved with and without a background field. Installation of the pre-ionization source on a magnetohydrodynamically driven jet experiment reduced the breakdown time and jitter and allowed for the creation of hotter, faster argon plasma jets than was previously possible.

Predictability and Coupled Dynamics of MJO During DYNAMO

DTIC Science & Technology

2013-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Predictability and Coupled Dynamics of MJO During DYNAMO ... DYNAMO time period. APPROACH We are working as a team to study MJO dynamics and predictability using several models as team members of the ONR DRI...associated with the DYNAMO experiment. This is a fundamentally collaborative proposal that involves close collaboration with Dr. Hyodae Seo of the

Coupling Considerations in Assembly Language

DTIC Science & Technology

2018-01-05

report discusses coupling issues arising in assembly language source code, as contrasted to similar issues arising in high order language (HOL...Warfare Center Weapons Division (NAWCWD) require compliance with DO-178B and DO-178C, which contain guidelines relating to data and control coupling. The...considered unknown, but its effect on development and maintenance will serve as indicators on whether the coupling measure is high or low. Both

A SIMS Study of Sulfur Isotopes of Accessory Pyrites Associated with Barites from Methane Cold Seeps in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Morelli, E. C.; Aharon, P.

2017-12-01

Bacteria and archaea associated with seeps can fix methane from sublimating gas hydrates through coupled bacterial sulfate reduction/ anaerobic methane oxidation (BSR/AMO) and prevent outgassing to the atmosphere. The occurrence of such microbial processes has been established on the basis of the sulfur isotope compositions of microbial byproducts (pyrites; FeS2) that reflect the degree of fractionation between SO4 and FeS2 via the production of the H2S intermediate phase. BSR/AMO coupling has been discerned in accessory sulfides associated with carbonates from gas hydrate sites. Whether BSR/AMO coupling is also active in barites, another ubiquitous product of gas hydrate sublimation, has so far been overlooked. Here we present results of a new sulfur isotope study of accessory sulfides in barites associated with gas hydrates at the threshold of stability occurring on the Gulf of Mexico slope. Using a fractionation factor of 1.009 and a seawater δ34SSO4 value of 20.3‰ and assuming a Rayleigh distillation closed system model for marine sulfide precipitation, pyrites from barite gas seeps are predicted to exhibit a range of δ34S values (about -1‰ to 20‰ CDT) as the pool of sulfate is continuously depleted. Actual δ34S values could fall outside of the predicted range because the system in question is likely only partially closed and kinetic fractionations are likely. δ34S of accessory pyrites from three Garden Banks Lease Block 382 (510 - 640m water depth) and one Mississippi Canyon Lease Block 929 (590m) barite samples have been determined using an ims-1290 Secondary Ion Mass Spectrometer (SIMS). Two Garden Banks samples and one Mississippi Canyon sample reveal a spread of values from 5.30 ± 0.04 to 25.90 ± 0.09 (‰ CDT), which follow the predicted trend for gas seeps and indicate the source of fractionation is likely from the coupled BSR/AMO process. One Garden Banks sample yields a wide spread of values from -26.2 ± 0.05 to 20.5 ± 0.4 (‰ CDT). The negative values are unexpected because such values typically suggest a sole contribution by BSR. This sample was the youngest (12.8 ± 0.6 yrs versus 21.5 ± 1.9 to 44.23 ± 2.92 yrs) at time of collection, and thus some of the negative values could reflect kinetic effects governed by the BSR pathway or anaerobic bacterial disproportionation (BDS) of elemental sulfur.

Plasma characteristics of direct current enhanced cylindrical inductively coupled plasma source

NASA Astrophysics Data System (ADS)

Yue, HUA; Jian, SONG; Zeyu, HAO; Chunsheng, REN

2018-06-01

Experimental results of a direct current enhanced inductively coupled plasma (DCE-ICP) source which consists of a typical cylindrical ICP source and a plate-to-grid DC electrode are reported. With the use of this new source, the plasma characteristic parameters, namely, electron density, electron temperature and plasma uniformity, are measured by Langmuir floating double probe. It is found that DC discharge enhances the electron density and decreases the electron temperature, dramatically. Moreover, the plasma uniformity is obviously improved with the operation of DC and radio frequency (RF) hybrid discharge. Furthermore, the nonlinear enhancement effect of electron density with DC + RF hybrid discharge is confirmed. The presented observation indicates that the DCE-ICP source provides an effective method to obtain high-density uniform plasma, which is desirable for practical industrial applications.

Suitability of ARES for simulating tactical burst EMP environments. Topical report, 15 January-1 April 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holst, D.W.

The possibility of using the ARES to evaluate source region coupling in tactical systems is discussed. A 'tactical' source region is defined and the environment at the inner edge of this source region is determined for a 50 kt burst at a range of 1.2 km. The time and amplitude characteristics of the ARES pulse are compared with those from the selected environment. Coupling of the ARES and the source region fields into a short monopole antenna and small loop are compared. These objects are representative of those found in tactical systems. Based upon these results suggestions are made formore » augmenting and supplementing testing in the ARES to obtain responses representative of the source region.« less

Experimental demonstration of single-mode fiber coupling over relatively strong turbulence with adaptive optics.

PubMed

Chen, Mo; Liu, Chao; Xian, Hao

2015-10-10

High-speed free-space optical communication systems using fiber-optic components can greatly improve the stability of the system and simplify the structure. However, propagation through atmospheric turbulence degrades the spatial coherence of the signal beam and limits the single-mode fiber (SMF) coupling efficiency. In this paper, we analyze the influence of the atmospheric turbulence on the SMF coupling efficiency over various turbulences. The results show that the SMF coupling efficiency drops from 81% without phase distortion to 10% when phase root mean square value equals 0.3λ. The simulations of SMF coupling with adaptive optics (AO) indicate that it is inevitable to compensate the high-order aberrations for SMF coupling over relatively strong turbulence. The SMF coupling efficiency experiments, using an AO system with a 137-element deformable mirror and a Hartmann-Shack wavefront sensor, obtain average coupling efficiency increasing from 1.3% in open loop to 46.1% in closed loop under a relatively strong turbulence, D/r₀=15.1.

Discrete ordinates-Monte Carlo coupling: A comparison of techniques in NERVA radiation analysis

NASA Technical Reports Server (NTRS)

Lindstrom, D. G.; Normand, E.; Wilcox, A. D.

1972-01-01

In the radiation analysis of the NERVA nuclear rocket system, two-dimensional discrete ordinates calculations are sufficient to provide detail in the pressure vessel and reactor assembly. Other parts of the system, however, require three-dimensional Monte Carlo analyses. To use these two methods in a single analysis, a means of coupling was developed whereby the results of a discrete ordinates calculation can be used to produce source data for a Monte Carlo calculation. Several techniques for producing source detail were investigated. Results of calculations on the NERVA system are compared and limitations and advantages of the coupling techniques discussed.

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor)

2000-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Network based management for multiplexed electric vehicle charging

DOEpatents

Gadh, Rajit; Chung, Ching Yen; Qui, Li

2017-04-11

A system for multiplexing charging of electric vehicles, comprising a server coupled to a plurality of charging control modules over a network. Each of said charging modules being connected to a voltage source such that each charging control module is configured to regulate distribution of voltage from the voltage source to an electric vehicle coupled to the charging control module. Data collection and control software is provided on the server for identifying a plurality of electric vehicles coupled to the plurality of charging control modules and selectively distributing charging of the plurality of charging control modules to multiplex distribution of voltage to the plurality of electric vehicles.

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor); Mattes, Brenton L. (Inventor); Charnetski, Clark J. (Inventor)

1999-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Development of Vertical Cable Seismic System for Hydrothermal Deposit Survey (2) - Feasibility Study

NASA Astrophysics Data System (ADS)

Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Mikada, H.; Takekawa, J.; Shimura, T.

2010-12-01

In 2009, Ministry of Education, Culture, Sports, Science and Technology(MEXT) started the survey system development for Hydrothermal deposit. We proposed the Vertical Cable Seismic (VCS), the reflection seismic survey with vertical cable above seabottom. VCS has the following advantages for hydrothermal deposit survey. . (1) VCS is an effective high-resolution 3D seismic survey within limited area. (2) It achieves high-resolution image because the sensors are closely located to the target. (3) It avoids the coupling problems between sensor and seabottom that cause serious damage of seismic data quality. (4) Various types of marine source are applicable with VCS such as sea-surface source (air gun, water gun etc.) , deep-towed or ocean bottom sources. (5) Autonomous recording system. Our first experiment of 2D/3D VCS surveys has been carried out in Lake Biwa, JAPAN. in November 2009. The 2D VCS data processing follows the walk-away VSP, including wave field separation and depth migration. The result gives clearer image than the conventional surface seismic. Prestack depth migration is applied to 3D data to obtain good quality 3D depth volume. Uncertainty of the source/receiver poisons in water causes the serious problem of the imaging. We used several transducer/transponder to estimate these positions. The VCS seismic records themselves can also provide sensor position using the first break of each trace and we calibrate the positions. We are currently developing the autonomous recording VCS system and planning the trial experiment in actual ocean to establish the way of deployment/recovery and the examine the position through the current flow in November, 2010. The second VCS survey will planned over the actual hydrothermal deposit with deep-towed source in February, 2011.

One way coupling of CMAQ and a road source dispersion model for fine scale air pollution predictions

PubMed Central

Beevers, Sean D.; Kitwiroon, Nutthida; Williams, Martin L.; Carslaw, David C.

2012-01-01

In this paper we have coupled the CMAQ and ADMS air quality models to predict hourly concentrations of NOX, NO2 and O3 for London at a spatial scale of 20 m × 20 m. Model evaluation has demonstrated reasonable agreement with measurements from 80 monitoring sites in London. For NO2 the model evaluation statistics gave 73% of the hourly concentrations within a factor of two of observations, a mean bias of −4.7 ppb and normalised mean bias of −0.17, a RMSE value of 17.7 and an r value of 0.58. The equivalent results for O3 were 61% (FAC2), 2.8 ppb (MB), 0.15 (NMB), 12.1 (RMSE) and 0.64 (r). Analysis of the errors in the model predictions by hour of the week showed the need for improvements in predicting the magnitude of road transport related NOX emissions as well as the hourly emissions scaling in the model. These findings are consistent with recent evidence of UK road transport NOX emissions, reported elsewhere. The predictions of wind speed using the WRF model also influenced the model results and contributed to the daytime over prediction of NOX concentrations at the central London background site at Kensington and Chelsea. An investigation of the use of a simple NO–NO2–O3 chemistry scheme showed good performance close to road sources, and this is also consistent with previous studies. The coupling of the two models raises an issue of emissions double counting. Here, we have put forward a pragmatic solution to this problem with the result that a median double counting error of 0.42% exists across 39 roadside sites in London. Finally, whilst the model can be improved, the current results show promise and demonstrate that the use of a combination of regional scale and local scale models can provide a practical modelling tool for policy development at intergovernmental, national and local authority level, as well as for use in epidemiological studies. PMID:23471172

Non-Double-Couple Component Analysis of Induced Microearthquakes in the Val D'Agri Basin (Italy)

NASA Astrophysics Data System (ADS)

Roselli, P.; Improta, L.; Saccorotti, G.

2017-12-01

In recent years it has become accepted that earthquake source can attain significant Non-Double-Couple (NDC) components. Among the driving factors of deviation from normal double-couple (DC) mechanisms there is the opening/closing of fracture networks and the activation of pre-existing faults by pore fluid pressure perturbations. This observation makes the thorough analysis of source mechanism of key importance for the understanding of withdrawal/injection induced seismicity from geothermal and hydrocarbon reservoirs, as well as of water reservoir induced seismicity. In addition to the DC component, seismic moment tensor can be decomposed into isotropic (ISO) and compensated linear vector dipole (CLVD) components. In this study we performed a careful analysis of the seismic moment tensor of induced microseismicity recorded in the Val d'Agri (Southern Apennines, Italy) focusing our attention on the NDC component. The Val d'Agri is a Quaternary extensional basin that hosts the largest onshore European oil field and a water reservoir (Pertusillo Lake impoundment) characterized by severe seasonal level oscillations. Our input data-set includes swarm-type induced micro-seismicity recorded between 2005-2006 by a high-performance network and accurately localized by a reservoir-scale local earthquake tomography. We analyze two different seismicity clusters: (i) a swarm of 69 earthquakes with 0.3 ≤ ML ≤ 1.8 induced by a wastewater disposal well of the oilfield during the initial daily injection tests (10 days); (ii) 526 earthquakes with -0.2 ≤ ML ≤ 2.7 induced by seasonal volume changes of the artificial lake. We perform the seismic moment tensor inversion by using HybridMT code. After a very accurate signal-to-noise selection and hand-made picking of P-pulses, we obtain %DC, %ISO, %CLVD for each event. DC and NDC components are analyzed and compared with the spatio-temporal distribution of seismicity, the local stress field, the injection parameters and the water level in the impoundment. We find significant NDC components and abrupt temporal variations in the %DC and %ISO components that appear linked to the extremely variable parameters of the injection tests into the disposal well.

Joint Application of Concentrations and Isotopic Signatures to Investigate the Global Atmospheric Carbon Monoxide Budget: Inverse Modeling Approach

NASA Astrophysics Data System (ADS)

Park, K.; Emmons, L. K.; Mak, J. E.

2007-12-01

Carbon monoxide is not only an important component for determining the atmospheric oxidizing capacity but also a key trace gas in the atmospheric chemistry of the Earth's background environment. The global CO cycle and its change are closely related to both the change of CO mixing ratio and the change of source strength. Previously, to estimate the global CO budget, most top-down estimation techniques have been applied the concentrations of CO solely. Since CO from certain sources has a unique isotopic signature, its isotopes provide additional information to constrain its sources. Thus, coupling the concentration and isotope fraction information enables to tightly constrain CO flux by its sources and allows better estimations on the global CO budget. MOZART4 (Model for Ozone And Related chemical Tracers), a 3-D global chemical transport model developed at NCAR, MPI for meteorology and NOAA/GFDL and is used to simulate the global CO concentration and its isotopic signature. Also, a tracer version of MOZART4 which tagged for C16O and C18O from each region and each source was developed to see their contributions to the atmosphere efficiently. Based on the nine-year- simulation results we analyze the influences of each source of CO to the isotopic signature and the concentration. Especially, the evaluations are focused on the oxygen isotope of CO (δ18O), which has not been extensively studied yet. To validate the model performance, CO concentrations and isotopic signatures measured from MPI, NIWA and our lab are compared to the modeled results. The MOZART4 reproduced observational data fairly well; especially in mid to high latitude northern hemisphere. Bayesian inversion techniques have been used to estimate the global CO budget with combining observed and modeled CO concentration. However, previous studies show significant differences in their estimations on CO source strengths. Because, in addition to the CO mixing ratio, isotopic signatures are independent tracers that contain the source information, jointly applying the isotope and the concentration information is expected to provide more precise optimization results in CO budget estimation. Our accumulated long-term CO isotope measurement data contribute to having more confidence of the inversions as well. Besides the benefit of adding isotope data on the inverse modeling, a trait of each isotope of CO (oxygen and carbon isotope) contains another advantageous use in the top-down estimation of the CO budget. δ18O and δ13C has a distinctive isotopic signature on a specific source; combustion sources such as a fossil fuel use show clearly different values from other natural sources in the δ18O signatures and the methane source can be easily separated by using δ13C information. Therefore, inversions of the two major sources of CO respond with different sensitivity for the different isotopes. To maximize the strengths of using isotope data in the inverse modeling analysis, various coupling schemes combining [CO], δ18O and δ13C have been investigated to enhance the credibility of the CO budget optimization.

Joint Application of Concentrations and Isotopic Signatures to Investigate the Global Atmospheric Carbon Monoxide Budget: Inverse Modeling Approach

NASA Astrophysics Data System (ADS)

Park, K.; Mak, J. E.; Emmons, L. K.

2008-12-01

Carbon monoxide is not only an important component for determining the atmospheric oxidizing capacity but also a key trace gas in the atmospheric chemistry of the Earth's background environment. The global CO cycle and its change are closely related to both the change of CO mixing ratio and the change of source strength. Previously, to estimate the global CO budget, most top-down estimation techniques have been applied the concentrations of CO solely. Since CO from certain sources has a unique isotopic signature, its isotopes provide additional information to constrain its sources. Thus, coupling the concentration and isotope fraction information enables to tightly constrain CO flux by its sources and allows better estimations on the global CO budget. MOZART4 (Model for Ozone And Related chemical Tracers), a 3-D global chemical transport model developed at NCAR, MPI for meteorology and NOAA/GFDL and is used to simulate the global CO concentration and its isotopic signature. Also, a tracer version of MOZART4 which tagged for C16O and C18O from each region and each source was developed to see their contributions to the atmosphere efficiently. Based on the nine-year-simulation results we analyze the influences of each source of CO to the isotopic signature and the concentration. Especially, the evaluations are focused on the oxygen isotope of CO (δ18O), which has not been extensively studied yet. To validate the model performance, CO concentrations and isotopic signatures measured from MPI, NIWA and our lab are compared to the modeled results. The MOZART4 reproduced observational data fairly well; especially in mid to high latitude northern hemisphere. Bayesian inversion techniques have been used to estimate the global CO budget with combining observed and modeled CO concentration. However, previous studies show significant differences in their estimations on CO source strengths. Because, in addition to the CO mixing ratio, isotopic signatures are independent tracers that contain the source information, jointly applying the isotope and the concentration information is expected to provide more precise optimization results in CO budget estimation. Our accumulated long-term CO isotope measurement data contribute to having more confidence of the inversions as well. Besides the benefit of adding isotope data on the inverse modeling, a trait of each isotope of CO (oxygen and carbon isotope) contains another advantageous use in the top-down estimation of the CO budget. δ18O and δ13C has a distinctive isotopic signature on a specific source; combustion sources such as a fossil fuel use show clearly different values from other natural sources in the δ18O signatures and the methane source can be easily separated by using δ13C information. Therefore, inversions of the two major sources of CO respond with different sensitivity for the different isotopes. To maximize the strengths of using isotope data in the inverse modeling analysis, various coupling schemes combining [CO], δ18O and δ13C have been investigated to enhance the credibility of the CO budget optimization.