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Sample records for cross-connected figure-eight null-flux

  1. Computer modeling and experimental verification of figure-eight-shaped null-flux coil suspension system

    SciTech Connect

    He, J.L.; Mulcahey, T.M.; Rote, D.M.; Kelly, T.

    1994-12-01

    This report discusses the computer modeling and experimental verification of the magnetic forces associated with a figure-eight-shaped null-flux coil suspension system. A set of computer codes called COILGDWY, were developed on the basis of the dynamic circuit model and verified by means of a laboratory model. The experimental verification was conducted with a rotating PVC drum, the surface of which held various types of figure-eight-shaped null-flux coils that interacted with a stationary permanent magnet. The transient and dynamic magnetic forces between the stationary magnet and the rotating conducting coils were measured and compared with results obtained from the computer model. Good agreement between the experimental results and computer simulations was obtained. The computer model can also be used to calculate magnetic forces in a large-scale magnetic-levitation system.

  2. Magnetic damping forces in figure-eight-shaped null-flux coil suspension systems

    SciTech Connect

    He, Jianliang; Coffey, H.

    1997-08-01

    This paper discusses magnetic damping forces in figure-eight-shaped null-flux coil suspension systems, focusing on the Holloman maglev rocket system. The paper also discusses simulating the damping plate, which is attached to the superconducting magnet by two short-circuited loop coils in the guideway. Closed-form formulas for the magnetic damping coefficient as functions of heave-and-sway displacements are derived by using a dynamic circuit model. These formulas are useful for dynamic stability studies.

  3. Study on figure-eight-shaped coil electrodynamic suspension magnetic levitation systems without cross-connection

    SciTech Connect

    Ribani, P.L.; Urbano, N.

    2000-01-01

    Two figure-eight-shaped coils for electrodynamic suspension (EDS) magnetic levitation (MAGLEV) systems without cross-connection are proposed and analyzed. The guideway coils are positioned under the MAGLEV vehicle; they are parallel to the horizontal plane. The interaction of a magnetic module on the vehicle, composed of three or four superconducting (SC) coils, with a guideway module, comprised of two figure-eight coils, is studied by means of the dynamic circuit theory. The currents in the SC coils are supposed to be constant in time while they move as a rigid body, with a constant velocity. Some results are presented and compared with those for a standard side-wall cross-connected system.

  4. Forces on a magnet moving past figure-eight coils

    SciTech Connect

    Mulcahy, T.H.; He, Jianliang; Rote, D.M.; Rossing, T.D.

    1993-03-01

    For the first time, the lift, drag, and guidance forces acting on a permanent magnet are measured as the magnet passes over different arrays of figure-eight (null-flux) coils. The experimental results are in good agreement with the predictions of dynamic circuit theory, which is used to explain more optimal coil arrays.

  5. Forces on a magnet moving past figure-eight coils

    SciTech Connect

    Mulcahy, T.M.; He, J.; Rote, D.M. ); Rossing, T.D. . Dept. of Physics)

    1993-11-01

    Considerable attention has been given to the magnetic levitation of vehicles over guideways consisting of periodically-spaced conducting coils. Examples of proposed guideway configurations include arrays of independent coils (''loop track''), interconnected coils (''ladder track''), two layers of coils (double-layer ''null-flux'' track), and figure-eight coils (single-layer ''null-flux'' track). Typically, widely-separated superconducting magnets are mounted in the vehicle. A system that achieves both lift and guidance from vertical figure-eight coils in the guideway sidewalls has been developed in Japan. This system, when well designed, can have a very large lift-to-drag ratio. The authors conducted an experimental and theoretical investigation of the lift, drag, and guidance forces on a permanent magnet moving close to various arrays of figure-eight coils. The measured time-histories of the forces provide a basis for the evaluation of electrodynamic models and codes developed to analyze the magnetic levitation of vehicles using the discrete suspension coils of the null-flux type. Good correlation was found between the experimental data and the predictions of the code COIL GDWY. The authors report some of the results and discuss their application to the design of maglev systems.

  6. Designing with null flux coils

    SciTech Connect

    Davey, K.R.

    1997-09-01

    Null flux were suggested by Danby and Powell in the late 1960`s as a useful means for realizing induced lift with little drag. As an array of alternating magnets is translated past a set of null flux coils, the currents induced in these coils act to vertically center the magnets on those coils. At present, one Japanese MAGLEV system company and two American-based companies are employing either null flux or flux eliminating coils in their design for high speed magnetically levitated transportation. The principle question addressed in paper is: what is the proper choice of coil length to magnet length in a null flux system? A generic analysis in the time and frequency domain is laid out with the intent of showing the optimal design specification in terms of coil parameters.

  7. Homochiral and meso figure eight knots and a Solomon link.

    PubMed

    Ponnuswamy, Nandhini; Cougnon, Fabien B L; Pantoş, G Dan; Sanders, Jeremy K M

    2014-06-11

    A homochiral naphthalenediimide-based building block forms in water a disulfide library of macrocycles containing topological isomers. We attempted to identify each of these isomers, and explored the mechanisms leading to their formation. The two most abundant species of the library were assigned as a topologically chiral Solomon link (60% of the library, as measured by high-performance liquid chromatography (HPLC)) and a topologically achiral figure eight knot (18% by HPLC), competing products with formally different geometries but remarkably similar 4-fold symmetries. In contrast, a racemic mixture of building blocks gives the near-quantitative formation of another new and more stable structure, assigned as a meso figure eight knot. Taken together, these results seem to uncover a correlation between the point chirality of the building block used and the topological chirality of the major structure formed. These and the earlier discovery of a trefoil knot also suggest that the number of rigid components in the building block may translate into corresponding knot symmetry and could set the basis of a new strategy for constructing complex topologies. PMID:24831779

  8. Approximate action-angle variables for the figure-eight and periodic three-body orbits.

    PubMed

    Šuvakov, Milovan; Dmitrašinović, V

    2011-05-01

    We use the maximally permutation-symmetric set of three-body coordinates that consist of the "hyper-radius" R=√[ρ(2)+λ(2)], the "rescaled area of the triangle" √[3]/2R(2) |ρ×λ|), and the (braiding) hyperangle Φ=arctan(2ρ·λ/λ(2)-ρ(2)) to analyze the "figure-eight" choreographic three-body motion discovered by Moore [Phys. Rev. Lett. 70, 3675 (1993)] in the Newtonian three-body problem. Here ρ,λ are the two Jacobi relative coordinate vectors. We show that the periodicity of this motion is closely related to the braiding hyperangle Φ. We construct an approximate integral of motion ̅G that together with the hyperangle Φ forms the action-angle pair of variables for this problem and show that it is the underlying cause of figure-eight motion's stability. We construct figure-eight orbits in two other attractive permutation-symmetric three-body potentials. We compare the figure-eight orbits in these three potentials and discuss their generic features, as well as their differences. We apply these variables to two new periodic, but nonchoreographic, orbits: One has a continuously rising Φ in time t, just like the figure-eight motion, but with a different, more complex, periodicity, whereas the other one has an oscillating Φ(t) temporal behavior. PMID:21728678

  9. DEVELOPMENT OF LOCOMOTOR ACTIVITY OF RAT PUPS IN FIGURE-EIGHT MAZES

    EPA Science Inventory

    In a series of four experiments, social and experiential factors that influence the development of motor activity in rat pups were examined. Motor activity was monitored from postnatal days 13 to 21 as photocell interruptions in figure-eight mazes and comparisons were made betwee...

  10. Continuity and stability of families of figure eight orbits with finite angular momentum

    NASA Astrophysics Data System (ADS)

    Nauenberg, Michael

    2007-01-01

    Numerical solutions are presented for a family of three dimensional periodic orbits with three equal masses which connects the classical circular orbit of Lagrange with the figure eight orbit discovered by C. Moore [Moore, C.: Phys. Rev. Lett. 70, 3675 3679 (1993); Chenciner, A., Montgomery, R.: Ann. Math. 152, 881 901 (2000)]. Each member of this family is an orbit with finite angular momentum that is periodic in a frame which rotates with frequency Ω around the horizontal symmetry axis of the figure eight orbit. Numerical solutions for figure eight shaped orbits with finite angular momentum were first reported in [Nauenberg, M.: Phys. Lett. 292, 93 99 (2001)], and mathematical proofs for the existence of such orbits were given in [Marchal, C.: Celest. Mech. Dyn. Astron. 78, 279 298 (2001)], and more recently in [Chenciner, A. et al.: Nonlinearity 18, 1407 1424 (2005)] where also some numerical solutions have been presented. Numerical evidence is given here that the family of such orbits is a continuous function of the rotation frequency Ω which varies between Ω = 0, for the planar figure eight orbit with intrinsic frequency ω, and Ω = ω for the circular Lagrange orbit. Similar numerical solutions are also found for n > 3 equal masses, where n is an odd integer, and an illustration is given for n = 21. Finite angular momentum orbits were also obtained numerically for rotations along the two other symmetry axis of the figure eight orbit [Nauenberg, M.: Phys. Lett. 292, 93 99 (2001)], and some new results are given here. A preliminary non-linear stability analysis of these orbits is given numerically, and some examples are given of nearby stable orbits which bifurcate from these families.

  11. Dynamic Stability of Lateral and Yawing Motions in the Double Null-Flux EDS System

    NASA Astrophysics Data System (ADS)

    Murai, Toshiaki; Yoshioka, Hiroshi; Sugino, Motohiko

    The double null-flux electro-dynamic suspension (EDS) in the superconducting maglev has the coupling lateral and yawing stiffness, which does not coincide with each other, so special attention should be paid to the dynamic stability of lateral and yawing motions. This paper describes their intrinsic dynamic stability by analyzing the lateral and yawing motions of bogie levitated by the double null-flux EDS.

  12. Noise-like pulse trapping in a figure-eight fiber laser.

    PubMed

    Luo, Ai-Ping; Luo, Zhi-Chao; Liu, Hao; Zheng, Xu-Wu; Ning, Qiu-Yi; Zhao, Nian; Chen, Wei-Cheng; Xu, Wen-Cheng

    2015-04-20

    We report on the trapping of noise-like pulse in a figure-eight fiber laser mode locked by nonlinear amplifier loop mirror (NALM). After achievement of noise-like vector pulse, it was found that the wavelength shift of the two resolved polarization components responsible for the pulse trapping was very sensitive to the cavity birefringence. By properly rotating the polarization controllers (PCs), the wavelength shift could be up to 4.8 nm, which is much larger than that of conventional soliton trapping. The observed results would shed some light on the fundamental physics of noise-like pulse as well as its vector features in fiber lasers. PMID:25969083

  13. Electromagnetic characteristics of eccentric figure-eight coils for transcranial magnetic stimulation: A numerical study

    NASA Astrophysics Data System (ADS)

    Kato, Takuya; Sekino, Masaki; Matsuzaki, Taiga; Nishikawa, Atsushi; Saitoh, Youichi; Ohsaki, Hiroyuki

    2012-04-01

    Repetitive transcranial magnetic stimulation (rTMS) is effective for treatment of several neurological and psychiatric diseases. We proposed an eccentric figure-eight coil, which induces strong eddy currents in the target brain tissue. In this study, numerical analyses were carried out to obtain magnetic field distribution of the eccentric figure-eight coil and eddy current in the brain. The analyses were performed with various coil design parameters, such as the outer and inner diameters and number of turns, to investigate the influence of these parameters on the coil characteristics. Increases in the inner diameter, outer diameter, and number of turns caused increases in the maximum eddy current densities. Coil inductance, working voltage, and heat generation also became higher with the increases in these design parameters. In order to develop a compact stimulator system for use at home, we need to obtain strong eddy current density, keeping the working voltage as low as possible. Our results show that it is effective to enlarge the outer diameter.

  14. Eddy current probe for nondestructive testing using cross-coupled figure-eight coils

    SciTech Connect

    Sasada, I.; Watanabe, N.

    1995-11-01

    It is shown that the pickup head consisting of cross-coupled figure-eight coils originally developed for the magnetostrictive torque sensor is well suited for the eddy current probe detecting small defects in a nonmagnetic conductive material. The probe is easily extended to a one dimensional array form, which substantially reduces number of times of scanning the targeted materials. The response of a single unit of the probe to a trough hole defect in an aluminum plate are presented. A half-way hole at the back of an aluminum plate of 1.2 mm in thickness was successfully detected from the front using this probe. A five-channel array was developed in which the excitation coil is shared by all the channel. A small through hole defect in an aluminum plate was detected clearly by a single scan with the array probe.

  15. Design approaches and parameters for magnetically levitated transport systems. [Null flux suspension (Maglev)

    SciTech Connect

    Danby, G.T.; Powell, J.R.

    1988-01-01

    Mechanically levitated transport system approaches are assessed with regard to thrust power needs, track cost, suspension stability, and safety. The null flux suspension appears as the favored approach, having the least thrust power requirements, highest stability, and lowest amount of track material. Various null flux configurations are described together with their operating parameters. The Linear Synchronous Motor (LSM) propulsion system is also described for propelling the suspended vehicles. Cryogenics and superconductivity aspects are discussed and the effect of high T/sub c/ superconductors evaluated. 13 refs., 16 figs., 2 tabs.

  16. Multiple noise-like pulsing of a figure-eight fibre laser

    NASA Astrophysics Data System (ADS)

    Pottiez, O.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernández-García, J. C.; González-García, A.; Durán-Sánchez, M.

    2014-01-01

    In this work we study multiple noise-like pulse generation in a 320 m long passively mode-locked erbium-doped figure-eight fibre laser in the normal net dispersion regime. The nonlinear optical loop mirror (NOLM) that is used as a mode locker operates through polarization asymmetry, which allows us to control its switching power by birefringence adjustments at the NOLM input, using a half-wave retarder (HWR). Over some range of the HWR orientation, a single noise-like pulse is observed in the cavity. Its peak power is adjustable as it remains clamped to the variable switching power, and its duration varies inversely between ˜5 and ˜22 ps. Beyond the HWR position, corresponding to the longest duration, the pulse splits into several noise-like pulses. These multiple pulses usually present a walkoff, however they can be synchronized through slight birefringence adjustments, although they are not evenly spaced in time. Up to 12 simultaneous noise-like pulses were observed experimentally, with a duration of ˜2 ns. Multiple pulsing and synchronization of the pulses are interpreted in terms of mechanisms of interaction between pulses. Multiple pulsing appears to be indirectly related to the peak power limiting effect of the NOLM.

  17. Two regimes of widely tuneable noise-like pulses from a figure-eight fibre laser

    NASA Astrophysics Data System (ADS)

    Pottiez, O.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernández-García, J. C.; González-García, A.; Durán-Sánchez, M.

    2014-10-01

    In this paper we study a dispersion-managed figure-eight fibre laser generating noise-like pulses with adjustable characteristics. Non-self-starting mode locking leads to the formation of a single noise-like pulse circulating in the cavity. Both the duration of the pulse and its spectral width can be adjusted by tuning the angle of wave retarders, in particular a half-wave retarder that controls the switching power of the polarization-imbalanced nonlinear optical loop mirror that is used as mode locker. Wave retarder tuning also allows observing an abrupt transition between two clearly distinct noise-like pulse regimes, one characterized by a long (> 1 ns) rectangular pulse envelope with a narrow spectrum and the other characterized by shorter sub-ns bell-shaped pulses whose Raman-enhanced spectrum extends far beyond the doped fibre gain spectrum. The existence of two distinct noise-like pulsing modes can be understood in terms of the periodic variation of the pulse spectrum along the cavity, which is able to shift the effective dispersion regime of the laser. By joining the tuning ranges of each regime, the noise-like pulse duration can be adjusted between 57 ps and 6.3 ns, and its bandwidth between 3.5 and 59 nm.

  18. Study of a figure-eight laser generating noise-like pulses with adjustable characteristics

    NASA Astrophysics Data System (ADS)

    Pottiez, O.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernandez-Garcia, J. C.

    2011-09-01

    In this work we study experimentally and numerically a passively mode-locked figure-eight fiber laser that includes a polarization-imbalanced Nonlinear Optical Loop Mirror (NOLM), whose switching power can be adjusted through a wave retarder plate. The laser emits broadband noise-like pulses with a bandwidth that can exceed 50 nm. The pulses are actually sub-nanosecond wave packets with an inner fine structure of sub-ps pulses with random amplitude and duration. The duration of the pulses as well as their spectral width can be adjusted through the variation of the NOLM switching power. Numerical simulations are in good agreement with experimental results, confirming in particular the strong dependence of the pulse properties on the value of the NOLM switching power, although NOLM switching alone does not explain the appearance of the noise-like pulsing mode. The properties of this kind of pulses, like their wide bandwidth and energy, make them attractive for applications like supercontinuum generation and metrology.

  19. Calculation of motion induced eddy current forces in null flux coils

    SciTech Connect

    Davey, K.; Morris, T.; Shaaf, J.; Rote, D.

    1995-11-01

    Time dependent motion induced eddy current forces can be quite difficult to compute. The movement of null flux coils between magnets is approached using a coupled boundary element-circuit approach to compute the forces on the structure. The technique involves treating the magnets as a separate circuit whose current is dictated by the product of the magnet thickness and the working coercivity. The mutual inductance between the windows of the moving null flux coil and the stationary equivalent magnet coil hold the key for predicting lift, guidance, and drag forces on the coil. The rate of change of these inductances with respect to position determines the forces and currents. A steady state approximation to these forces is derived in addition to a numerical simulation when the steady state assumption is invalid. The results compare favorably to laboratory results from a 4 ft. diameter experimental test wheel.

  20. Experimental investigation of pedestal suppression in a figure-eight fiber laser by including a polarization asymmetrical NOLM

    NASA Astrophysics Data System (ADS)

    Hernández-Escobar, E.; Bello-Jiménez, M.; Kuzin, E. A.; Ibarra-Escamilla, B.; Duran-Sánchez, M.; Díez, A.; Cruz, J. L.; Andrés, M. V.

    2016-03-01

    A polarization asymmetrical nonlinear optical loop mirror (NOLM) is investigated to perform pedestal-free optical pulses in a figure-eight laser (F8L). The results demonstrate that in the low-power regime the NOLM operates as a halfwave plate and the output polarization is orthogonal to the input one. However, at higher power level the polarization component parallel to the input appears, with a transmission that always begins from zero at low power, allowing the rejection of low-intensity components. Experimental results demonstrate that by employing this configuration we can obtain a contrast between the peak and continuous background higher that 40 dB.

  1. Effects of mop handle height on shoulder muscle activity and perceived exertion during floor mopping using a figure eight method

    PubMed Central

    WALLIUS, Mari-Anne; RISSANEN, Saara M.; BRAGGE, Timo; VARTIAINEN, Paavo; KARJALAINEN, Pasi A.; RÄSÄNEN, Kimmo; JÄRVELIN-PASANEN, Susanna

    2015-01-01

    The aim of this study was to investigate effects of mop handle height on electromyographic (EMG) activities of the shoulder muscles and perceived exertion for the shoulder area during floor mopping using a figure eight method. An experimental study with 13 cleaners was conducted using surface EMG and category ratio (CR-10) scale. EMG activity was recorded unilaterally from the upper trapezius, infraspinatus, anterior and middle deltoid muscles. Each subject performed four trials of mopping and each trial consisted of using a different mop handle height (mop adjustment at the level of shoulder, chin, nose and eye) in randomized order. EMG data were normalized to a percentage of maximal voluntary contraction (%MVC). The muscle activities were assessed by estimating the 10th, 50th and 90th percentiles of the amplitude probability distribution function (APDF) of the EMG signals and analysed by linear mixed model analysis. Results showed that shoulder muscle activity was significantly lower when the mop handle height was adjusted to shoulder level or chin level as compared to eye level. These findings were supported by subjective ratings of exertion. It seems that mop handle height adjustment between shoulder and chin level may be recommended as a basis for figure eight mopping. PMID:26423328

  2. Effects of mop handle height on shoulder muscle activity and perceived exertion during floor mopping using a figure eight method.

    PubMed

    Wallius, Mari-Anne; Rissanen, Saara M; Bragge, Timo; Vartiainen, Paavo; Karjalainen, Pasi A; Räsänen, Kimmo; Järvelin-Pasanen, Susanna

    2016-01-01

    The aim of this study was to investigate effects of mop handle height on electromyographic (EMG) activities of the shoulder muscles and perceived exertion for the shoulder area during floor mopping using a figure eight method. An experimental study with 13 cleaners was conducted using surface EMG and category ratio (CR-10) scale. EMG activity was recorded unilaterally from the upper trapezius, infraspinatus, anterior and middle deltoid muscles. Each subject performed four trials of mopping and each trial consisted of using a different mop handle height (mop adjustment at the level of shoulder, chin, nose and eye) in randomized order. EMG data were normalized to a percentage of maximal voluntary contraction (%MVC). The muscle activities were assessed by estimating the 10th, 50th and 90th percentiles of the amplitude probability distribution function (APDF) of the EMG signals and analysed by linear mixed model analysis. Results showed that shoulder muscle activity was significantly lower when the mop handle height was adjusted to shoulder level or chin level as compared to eye level. These findings were supported by subjective ratings of exertion. It seems that mop handle height adjustment between shoulder and chin level may be recommended as a basis for figure eight mopping. PMID:26423328

  3. Coexistence of harmonic soliton molecules and rectangular noise-like pulses in a figure-eight fiber laser.

    PubMed

    Huang, Yu-Qi; Hu, Zi-Ang; Cui, Hu; Luo, Zhi-Chao; Luo, Ai-Ping; Xu, Wen-Cheng

    2016-09-01

    We report the coexistence of high-order harmonic soliton molecules and rectangular noise-like pulses (NLP) in a figure-eight fiber laser mode-locked by a nonlinear amplifying loop mirror. The harmonic soliton molecule has a repetition rate of 936.6 MHz, corresponding to the 466th harmonics of the fundamental cavity repetition rate, with soliton separation of 16.5 ps. Meanwhile, the rectangular NLP operates at the fundamental repetition rate. In addition, these two types of pulses could be generated independently by manipulating the polarization controllers. The experimental results demonstrate an interesting operation regime of the fiber laser and contribute to enriching the dynamics of mode-locked pulses in fiber lasers. PMID:27607971

  4. Water Treatment Technology - Cross-Connections.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on cross connections provides instructional materials for two competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on cross connections terminology and control devices. For each…

  5. Generation and characterization of erbium-Raman noise-like pulses from a figure-eight fibre laser

    NASA Astrophysics Data System (ADS)

    Santiago-Hernandez, H.; Pottiez, O.; Paez-Aguirre, R.; Ibarra-Villalon, H. E.; Tenorio-Torres, A.; Duran-Sanchez, M.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernandez-Garcia, J. C.

    2015-04-01

    We report an experimental study of the noise-like pulses generated by a ~300 m long passively mode-locked erbium-doped figure-eight fibre laser. Non-self-starting mode locking yields the formation of ns scale bunches of sub-ps pulses. Depending on birefringence adjustments, noise-like pulses with a variety of temporal profiles and optical spectra are obtained. In particular, for some adjustments the Raman-enhanced spectrum reaches a 10 dB bandwidth of ~130 nm. For the first time to our knowledge, we extract information on the inner structure of the noise-like pulses, using a birefringent Sagnac interferometer as a spectral filter and a nonlinear optical loop mirror as an intensity filter. In particular we show that the different spectral components of the bunch are homogeneously distributed within the temporal envelope of the bunch, whereas the amplitude and/or the density of the sub-pulses present substantial variations along the envelope. In some cases, the analysis reveals the existence of an intermediate level of organization in the structure of the noise-like pulse, between the ns bunch and the sub-ps inner pulses, suggesting that these objects may be even more complex than previously recognized.

  6. Supercontinuum generation in a standard fiber pumped by noise-like pulses from a figure-eight fiber laser

    NASA Astrophysics Data System (ADS)

    Hernandez-Garcia, J. C.; Pottiez, O.; Estudillo-Ayala, J. M.

    2011-10-01

    We report the experimental study of broadband spectrum generation in a piece of standard fiber (SMF-28) using as the pump a train of noise-like pulses, or sub-nanosecond packets of sub-ps pulses with randomly varying amplitudes. The pulses are generated by an erbium-doped figure-eight fiber laser, and present a wide (˜50 nm) optical spectrum, which represents a significant advantage to seed the generation of new frequencies. Another advantage of the pulses is their relatively large energy, as they are made up of a large number of ultrashort pulses. After amplification with an Erbium Doped Fiber Amplifier (EDFA), the pulses were injected in a 0.75 km length of SMF-28 fiber. We obtained experimentally at the end of the fiber an out-put signal spectrum extending from 1530 nm to at least 1750 nm (the upper limit of the spectrum analyzer) for pump pulses with an average power of 20.4 mW, corresponding to a few kilowatts peak power. The spectral broadening is due to Raman self-frequency shift (SFS). It is noteworthy that the spectrum of the newly created frequencies was extremely uniform over the range of measurement. Considering that the Raman shift is directly related to the pump pulse duration, spectral flatness is a direct consequence of the random distribution of amplitudes and durations of the pulses in the packet. Finally, the results show the capabilities of noise-like pulses from a fiber laser for applications in supercontinuum generation based on nonlinear phenomena such as Raman SFS.

  7. Dual-keel electrodynamic Maglev system

    SciTech Connect

    He, Jianliang; Rote, D.M.; Wang, Zian; Coffey, H.T.

    1995-12-31

    This paper introduces a new concept for an electrodynamic-suspension maglev system that has a dual-keel arrangement. Each keel consists of a row of superconducting magnets aboard the vehicle. The keels move in troughs in the guideway that are each lined with pairs of figure-eight-shaped null-flux coils. Each pair of null-flux coils is cross-connected to produce null-flux suspension and guidance force. The cross-connected figure-eight null-flux coils in each trough are also energized by a three-phase power supply to produce propulsive force. Preliminary analysis shows that the new system has many advantages over other EDS systems in terms of system performance and dynamic stability.

  8. Switchable dual-pulse-shape mode-locked figure-eight all-PM fibre master oscillator with 0.5 W-level average output

    NASA Astrophysics Data System (ADS)

    Kobtsev, Sergey; Ivanenko, Aleksey; Fedotov, Yurii; Smirnov, Sergey V.; Golubtsov, Artur; Khripunov, Sergey

    2016-03-01

    For the first time a method for switching between generation of single- and double-scale pulses has been demonstrated in a mode-locked figure-eight NALM-based all-PM-fibre Yb master oscillator by adjustment of two pumps power. Introduction into a F8 configuration of a non-linear amplifying loop mirror with two active media not only ensured relatively high average output power of the master oscillator (> 0.5 W at 22-MHz repetition rate), but also allowed switching laser operation from one pulse type (single-scale with duration of <10 ps) to another - femtosecond clusters with envelope width of 16 ps and sub-pulse duration <200 fs.

  9. Analytical investigation of a figure-eight single-pulse all-fiber laser based on a nonlinear amplifying loop mirror

    SciTech Connect

    Salhi, M.; Amrani, F.; Leblond, H.; Sanchez, F.

    2010-10-15

    We establish analytically a master equation of a figure-eight all-fiber passively mode-locked laser. The nonlinear amplifying loop mirror (NALM) is used as an effective saturable absorber in order to generate short pulses. The master equation is of the cubic complex Ginzburg-Landau type, in which the coefficients explicitly depend on the characteristics of the cavity, in particular on the orientation of the polarizer, the coupling coefficient, and the length of the NALM. Single-pulse and continuous-wave (cw) solutions in both normal and anomalous dispersion are discussed analytically. In the anomalous dispersion situation, the equation governing the evolution of the system admits stable analytic pulse solutions. The pulse duration and energy are studied. The analysis provides domains in the space of the cavity parameters where energetic soliton and ultrashort pulses are obtained.

  10. Intelligent optical networking with photonic cross connections

    NASA Astrophysics Data System (ADS)

    Ceuppens, L.; Jerphagnon, Olivier L.; Lang, Jonathan; Banerjee, Ayan; Blumenthal, Daniel J.

    2002-09-01

    Optical amplification and dense wavelength division multiplexing (DWDM) have fundamentally changed optical transport networks. Now that these technologies are widely adopted, the bottleneck has moved from the outside line plant to nodal central offices, where electrical switching equipment has not kept pace. While OEO technology was (and still is) necessary for grooming and traffic aggregation, the transport network has dramatically changed, requiring a dramatic rethinking of how networks need to be designed and operated. While todays transport networks carry remarkable amounts of bandwidth, their optical layer is fundamentally static and provides for only simple point-to-point transport. Efficiently managing the growing number of wavelengths can only be achieved through a new breed of networking element. Photonic switching systems (PSS) can efficiently execute these functions because they are bit rate, wavelength, and protocol transparent. With their all-optical switch cores and interfaces, PSS can switch optical signals at various levels of granularity wavelength, sub band, and composite DWDM fiber levels. Though cross-connect systems with electrical switch cores are available, they perform these functions at very high capital costs and operational inefficiencies. This paper examines enabling technologies for deployment of intelligent optical transport networks (OTN), and takes a practical perspective on survivability architecture migration and implementation issues.

  11. Generation of dual-wavelength square pulse in a figure-eight erbium-doped fiber laser with ultra-large net-anomalous dispersion.

    PubMed

    Shao, Zhihua; Qiao, Xueguang; Rong, Qiangzhou; Su, Dan

    2015-08-01

    A type of wave-breaking-free mode-locked dual-wavelength square pulse was experimentally observed in a figure-eight erbium-doped fiber laser with ultra-large net-anomalous dispersion. A 2.7 km long single-mode fiber (SMF) was incorporated as a nonlinear optical loop mirror (NOLM) and provided largely nonlinear phase accumulation and anomalous dispersion, which enhanced the four-wave-mixing effect to improve the stability of the dual-wavelength operation. In the NOLM, the long SMF with small birefringence supported the Sagnac interference as a filter to manage the dual-wavelength lasing. The dual-wavelength operation was made switchable by adjusting the intra-cavity polarization loss and phase delay corresponding to two square pulses. When the pump power was increased, the duration of the square pulse increased continuously while the peak pulse power gradually decreased. This square-type pulse can potentially be utilized for signal transmission and sensing. PMID:26368084

  12. Experimental study to improve the focalization of a figure-eight coil of rTMS by using a highly conductive and highly permeable medium.

    PubMed

    Zhang, Shunqi; Yin, Tao; Liu, Zhipeng; Li, Ying; Jin, Jingna; Ma, Ren

    2013-05-01

    A method to improve the focalization of the repetitive transcranial magnetic stimulation figure-eight coil in a magnetic stimulation is presented in this paper. For the purpose of reducing the half width of the distribution curve, while improving the ratio of positive to negative electric field, a shield plate with a window and a magnetic conductor were adopted. The shield plate, which was made of highly conductive copper, focused the magnetic field into a smaller area. The magnetic inductor, which was made of highly permeable soft magnetic ferrite, strengthened the magnetic field. A group of experiments was conducted to validate the focalizing effect. Experimental results showed that the negative peak and the half width of the distribution curve reduced by using the shield plate and the magnetic conductor. Especially for to the Magstim 70 mm double coil, when the shield window was 30 × 60 mm, the ratio of positive to negative electric field could be increased 109%, while the half width of the distribution curve could be reduced about 55%. PMID:22531823

  13. Study of Japanese electrodynamic-suspension maglev systems

    NASA Astrophysics Data System (ADS)

    He, J. L.; Rote, D. M.; Coffey, H. T.

    1994-04-01

    This report presents the results of a study of the Japanese MLU magnetic levitation (maglev) system. The development of the MLU system is reviewed, and the dynamic circuit model then is introduced and applied to the figure-eight-shaped null-flux coil suspension system. Three different types of figure-eight-shaped null-flux suspension systems are discussed in detail: (1) the figure-eight-shaped null-flux coil suspension system without cross-connection; (2) the combined suspension and guidance system; and (3) the combined propulsion, levitation, and guidance system. The electrodynamic suspension maglev systems developed in Japan seem to be very promising and could result in a commercial application in the near future.

  14. Dual-keel electrodynamic maglev system

    SciTech Connect

    He, J.; Wang, Z.; Rote, D.M.; Coffey, H.T.; Hull, J.R.; Mulcahy, T.M.; Cai, Y.

    1995-12-31

    A propulsion and stabilization system with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle.

  15. Dual-keel electrodynamic maglev system

    DOEpatents

    He, Jianliang; Wang, Zian; Rote, Donald M.; Coffey, Howard T.; Hull, John R.; Mulcahy, Thomas M.; Cal, Yigang

    1996-01-01

    A propulsion and stabilization system with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle.

  16. Dual-keel electrodynamic maglev system

    DOEpatents

    He, J.L.; Wang, Z.; Rote, D.M.; Coffey, H.T.; Hull, J.R.; Mulcahy, T.M.; Cal, Y.

    1996-12-24

    A propulsion and stabilization system is disclosed with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle. 6 figs.

  17. Study of Japanese electrodynamic-suspension maglev systems

    SciTech Connect

    He, J.L.; Rote, D.M.; Coffey, H.T.

    1994-04-01

    This report presents the results of a study of the Japanese MLU magnetic-levitation (maglev) system. The development of the MLU system is reviewed, and the dynamic circuit model then is introduced and applied to the figure-eight-shaped null-flux coil suspension system. Three different types of figure-eight-shaped null-flux suspension systems are discussed in detail: (1) the figure-eight-shaped null-flux coil suspension system without cross-connection; (2) the combined suspension and guidance system; and (3) the combined propulsion, levitation, and guidance system. The electrodynamic-suspension maglev systems developed in Japan seem to be very promising and could result in a commercial application in the near future.

  18. Synthesis of dual-microring-resonator cross-connect filters

    NASA Astrophysics Data System (ADS)

    Emelett, S. J.; Soref, R. A.

    2005-06-01

    A new type of resonant, waveguided, 2 x 2 cross-connect optical filter is proposed and synthesized using a microwave filter analog. The optical passbands of the device are determined using 2D scattering matrix theory and the desired response is generated via a synthesis for a combined singly and doubly terminated circuit. This synthesis realizes the microring coupling coefficients necessary for maximally flat infrared spectral response. Closed-form analytical solutions are presented. Devices containing two, four, and six microrings were investigated.

  19. 78 FR 25577 - Safety Zone, Figure Eight Causeway Channel; Figure Eight Island, NC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-02

    ..., 2013. ADDRESSES: Documents mentioned in this preamble are part of docket . To view documents mentioned... Security FR Federal Register NPRM Notice of Proposed Rulemaking A. Regulatory History and Information The... this event were not provided to the Coast Guard until April 10, 2013. As such, it is impracticable...

  20. Cross-connection control of the potable water lines at Oak Ridge National Laboratory

    SciTech Connect

    Moore, R.M.

    1996-04-01

    A 1991 independent U.S. Department of Energy (DOE) audit of Oak Ridge National Laboratory (ORNL) identified the need for establishing a cross-connection control program for the potable and nonpotable water systems at the facility. An informal cross-connection policy had been in place for some time, but the formal implementation of a cross-connection program brought together individuals from the Quality Engineering and Inspection Section of the Office of Quality Programs and Inspection, Industrial Hygiene, Health Physics, Plant and Equipment Division, and the Atomic Trade and Labor Council. In January 1994 a Cross-Connection Control Committee was established at ORNL to identify potential and actual cross connections between potable and nonpotable water systems. Potable water is safe to drink, and nonpotable or process water (e.g., sewage, laboratory wastewater, cooling water, and tower water) is not intended for human consumption, washing of the body, or food preparation. The program is intended to conform with the Federal Safe Drinking Water Act Amendment of 1986 and with state and local regulations. Although the Occupational Safety and Health Administration addresses cross-connection functions, it does not define specific program requirements. The program at ORNL is designed to ensure that necessary recommendations are implemented to safeguard all internal and external potable water distribution lines. Program responsibilities include a thorough engineering assessment to (1) identify the potable water lines, (2) identify any existing or potential cross connections, and (3) inspect the integrity of the water lines. If any cross-connection deficiencies are found, corrective actions are initiated according to industry standards.

  1. Impact of SONET digital cross-connect system architecture on distributed restoration

    NASA Astrophysics Data System (ADS)

    Wu, Tsong-Ho; Kobrinski, Haim; Lakshman, T. V.

    1994-01-01

    The viability of distributed control restoration using Digital Cross-Connect Systems (DC's) depends on its capability for restoring services within specified time requirements, and its economics for providing restoration compared to other alternatives. In this paper, we report a Bellcore study for the impact of the DCS architecture on distributed restoration. This study concludes that currently proposed distributed control DCS self-healing schemes may not meet the 2-s restoration objective for large metropolitan Local Exchange Carrier's networks, regardless of the distributed algorithm used, if the present DCS system architecture which uses serial message processing and serial path cross-connection remains unchanged. This paper also discusses several DCS architecture enhancement options, including a parallel processing/cross-connect DCS architecture, which may improve the service restoration time.

  2. Impact of SONET digital cross-connect system architecture on distributed restoration

    SciTech Connect

    Wu, Tsong-ho; Kobrinski, H.; Lakshman, T.V. )

    1994-01-01

    The viability of distributed control restoration using Digital Cross-Connect Systems (DC's) depends on its capability for restoring services within specified time requirements, and its economics for providing restoration compared to other alternatives. In this paper, we report a Bellcore study for the impact of the DCS architecture on distributed restoration. This study concludes that currently proposed distributed control DCS self-healing schemes may not meet the 2-s restoration objective for large metropolitan Local Exchange Carrier's networks, regardless of the distributed algorithm used, if the present DCS system architecture which uses serial message processing and serial path cross-connection remains unchanged. This paper also discusses several DCS architecture enhancement options, including a parallel processing/cross-connect DCS architecture, which may improve the service restoration time. 20 refs.

  3. Multiwavelength line-rate-independent optical digital cross-connects based on low-gain fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Kuang; Way, Winston I.

    1994-09-01

    We experimentally demonstrated a multiwavelength, line-rate independent optical digital cross-connect system (DCS) by using cascaded low-gain erbium-doped fiber amplifiers as the switching elements in a dilated Benes architecture.

  4. Fiber-handling robot and optical connection mechanisms for automatic cross-connection of multiple optical connectors

    NASA Astrophysics Data System (ADS)

    Mizukami, Masato; Makihara, Mitsuhiro

    2013-07-01

    Conventionally, in intelligent buildings in a metropolitan area network and in small-scale facilities in the optical access network, optical connectors are joined manually using an optical connection board and a patch panel. In this manual connection approach, mistakes occur due to discrepancies between the actual physical settings of the connections and their management because these processes are independent. Moreover, manual cross-connection is time-consuming and expensive because maintenance personnel must be dispatched to remote places to correct mistakes. We have developed a fiber-handling robot and optical connection mechanisms for automatic cross-connection of multiple optical connectors, which are the key elements of automatic optical fiber cross-connect equipment. We evaluate the performance of the equipment, such as its optical characteristics and environmental specifications. We also devise new optical connection mechanisms that enable the automated optical fiber cross-connect module to handle and connect angled physical contact (APC) optical connector plugs. We evaluate the performance of the equipment, such as its optical characteristics. The evaluation results confirm that the automated optical fiber cross-connect equipment can connect APC connectors with low loss and high return loss, indicating that the automated optical fiber cross-connect equipment is suitable for practical use in intelligent buildings and optical access networks.

  5. Packaged and connectorized optical interconnect circuits for optoelectronic cross-connect switching

    NASA Astrophysics Data System (ADS)

    Popelek, Jan; Ai, Jun; Li, Yao

    1999-10-01

    Cross-connect switching is a common switching architecture for telecom and datacom applications. Large bandwidth O-E interface devices have recently been made commercially available. Small scale fast electronic switches and large scale optical interconnect circuits can be effectively used for handling large bandwidth O-E cross-connect switching. In this paper, we show two packaged and connectorized optical interconnect circuits. The first one is a 100 X 100 channel guided-wave circuit fully compatible, through MT array connectors, to O-E interface devices, such as Motorola OPTOBUSTM or Simens PAROLITM chips. The second one is a more scalable architecture which is a hybrid of free- space and fiber circuits. For demonstration purpose, a 256 X 256 channel hybrid circuit is shown. Key parameters, such as insertion loss, cross-talk, and bit-error-rate of these interconnect circuits are presented. Transmission and routing of video data are performed to demonstrate interconnect quality of various data links. Scalability of these demonstrated circuits to larger sizes are speculated.

  6. Evaluation of cross-connected waveguides as transfer standards of transmission at high millimetre-wave frequencies

    NASA Astrophysics Data System (ADS)

    Ridler, Nick; Clarke, Roland; Huang, Hui; Zinal, Sherko

    2016-08-01

    At the present time, transfer and verification standards of transmission coefficient (or, equivalently, transmission loss) are not readily available at high millimetre-wave frequencies (i.e. at frequencies ranging typically from 100 GHz to 300 GHz). In recent years, cross-connected waveguide devices have been proposed to provide calculable standards of transmission loss at these frequencies. This paper investigates the viability of these cross-connected waveguides as transfer standards of transmission for inter-laboratory measurement comparison exercises. This relates to their potential use in activities such as international key comparison exercises and measurement audit programmes. A trial inter-laboratory comparison involving four laboratories using two cross-connected waveguides in the WR-05 waveguide size (covering frequencies from 140 GHz to 220 GHz) is described and includes an analysis of the measurement results obtained during the comparison exercise.

  7. A continuous active monitoring approach to identify cross-connections between potable water and effluent distribution systems.

    PubMed

    Friedler, E; Alfiya, Y; Shaviv, A; Gilboa, Y; Harussi, Y; Raize, O

    2015-03-01

    A continuous active monitoring approach was developed for identification of cross-connections between potable water supply systems and treated wastewater effluent reuse distribution systems. The approach is based on monitoring the oxidation reduction potential (ORP) at the potable water system while injecting sulfite (a reducing agent) into the effluent line. A sharp decrease in the ORP of the potable water would indicate a cross-connection event. The approach was tested in batch experiments on treated municipal wastewater effluent of varying degree of treatment, and at dilution ratios of up to 1:100 (effluent/potable). The approach was then examined under continuous flow conditions, which simulated cross-connection events at various dilution ratios (up to 1:100). In the continuous runs, differences between the potable water ORP and the effluent-potable water mixture (containing sulfite as sodium bisulfite (SBS)) ORP were 450-630 mV. This suggests high potential for identifying a cross-connection event. Implementation of the approach includes adding sulfite to effluent used for agricultural irrigation; hence, possible effects on soil and on crops were studied in soil columns and pots planted with basil (Ocimum basilicum) as a model plant. No negative effects of sulfite addition to the irrigation effluent were observed in the irrigated soils and plants, and therefore, it could be safely implemented also in agricultural applications. PMID:25701471

  8. Cascaded active silicon microresonator array cross-connect circuits for WDM networks-on-chip

    NASA Astrophysics Data System (ADS)

    Poon, Andrew W.; Xu, Fang; Luo, Xianshu

    2008-02-01

    We propose a design of an optical switch on a silicon chip comprising a 5 × 5 array of cascaded waveguide-crossing-coupled microring resonator-based switches for photonic networks-on-chip applications. We adopt our recently demonstrated design of multimode-interference (MMI)-based wire waveguide crossings, instead of conventional plain waveguide crossings, for the merits of low loss and low crosstalk. The microring resonator is integrated with a lateral p-i-n diode for carrier-injection-based GHz-speed on-off switching. All 25 microring resonators are assumed to be identical within a relatively wide resonance line width. The optical circuit switch can employ a single wavelength channel or multiple wavelength channels that are spaced by the microring resonator free spectral range. We analyze the potential performance of the proposed photonic network in terms of (i) light path cross-connections loss budget, and (ii) DC on-off power consumption for establishing a light path. As a proof-of-concept, our initial experiments on cascaded passive silicon MMI-crossing-coupled microring resonators demonstrate 3.6-Gbit/s non-return-to-zero data transmissions at on- and off-resonance wavelengths.

  9. Improved method for survivable network design based on pre-cross-connected trails

    NASA Astrophysics Data System (ADS)

    Grue, Aden; Grover, Wayne D.

    2007-02-01

    Previous work developed the concept of 'pre-cross-connected trails' (PXTs), which are fully pre-connected linear structures of spare capacity used to protect one or more paths end-to-end. To date, the only approach for designing PXT-based restorable networks is a heuristic algorithm suited for the dynamic protection of demands as they arrive in a network. The heuristic can also be used as a 'green fields' planning algorithm for a known set of demands by running through the set and protecting them in order. In both cases, however, recent work has shown that the resulting PXT structures can be looping, as well as long and complex. While the capacity efficiency of the designs was high, the practicality of using such convoluted structures in any real network is doubtful. In this work we propose a semi-heuristic approach based on integer linear programming methods that allows important properties of the PXTs (such as length and degree of looping) to be tightly controlled. We also show how this method may be adapted to the dynamic protection of incrementally arriving random demands. Results show that even when PXTs are restricted to be totally non-looping and of much lower maximum length, we still attain capacity efficiencies near those of the original PXT design heuristic. A notable extra finding is that, in an efficient PXT network design in general, many PXTs are equivalent to standalone 1+1 APS arrangements for certain demand flows.

  10. Parallel and simultaneous spatial mode conversion using photorefractive crystal for photonic cross-connect

    NASA Astrophysics Data System (ADS)

    Zhao, Yanfeng; Okamoto, Atsushi; Maeda, Tomohiro; Hirasaki, Yuki; Tomita, Akihisa; Bunsen, Masatoshi

    2015-01-01

    In this paper, we present a novel technology for photonic cross-connect (PXC) in spatial mode domain for the realization of advanced and flexible optical transmission of spatial modes. The PXC is a kind of all -optical devices to switch highspeed optical signals for mode-division multiplexing (MDM) network and it is able to perform signal labeling in the spatial mode domain similar to current photonic switching in the wavelength domain. In addition, parallel and simultaneous mode conversion can be realized using multiplex holograms in a photorefractive crystal (PRC). In our experiment, during the recording process, a rewritable hologram is recorded in the PRC (LiNbO3) through the interference between the signal beam with certain input mode and the reference beam with the phase distribution of the desired output mode. Signal beams are generated by computer generated hologram (CGH) using a spatial light modulator (SLM) instead of an optical fiber emergent beam, and reference beams are generated by phase only modulation using another SLM. Subsequently, during the converting process, the input signal beam is converted into the desired output mode through the holographic diffract ion in the crystal and free-space propagation by an optical lens. By using phase code multiplexing method, parallel mode conversions can be realized. We performed an experiment on parallel mode conversions of several different conversion pairs. Signal beams and reference beams intersected in the PRC with an angle of 18.43 degree. The intensity distributions of converted modes were observed by CCD camera set on the Fourier plane. We confirmed that the two modes inter-conversion of LP11 with LP21 was successfully implemented.

  11. CMOS VLSI pilot and support chip for a liquid crystal on silicon 8x8 optical cross connect

    NASA Astrophysics Data System (ADS)

    Lelah, Alan; Vinouze, Bruno; Martel, Gilbert; Perez-Segovia, Tomas; Geoffroy, Philippe; Laval, Jean-Paul; Jayet, Philippe; Senn, Patrice; Gravey, Philippe; Wolffer, Nicole; Lever, Roger; Tan, Antione

    2001-12-01

    With the explosion of Internet and multi-service traffic, telecommunication transport networks today are turning to Wavelength Division Multiplexing. Optical cross-connects (OXCs) allow flexible rerouting of wavelength channels. It has been shown that 2-D free-space beam deflection by nematic liquid crystal gratings provide a good solution for the realization of optical switches in OXCs. Operating in the telecom 1.5 micrometers wavelength region they serve as an active holographic element. Liquid Crystal on Silicon (LCOS) combined with VLSI technologies allow the fabrication of large capacity, low cost and low consumption compact free-space switches. An N X N optical switch can be built by cascading two LCOS-based spatial light modulators (SLMs). The first part of the paper describes a circuit that provides the physical support as well as piloting circuitry for such SLMs. It is capable of piloting beams from a linear array of 8 incoming fibers towards a similar array of 8 outgoing fibers. The electrode command voltages are analog while the external interface as well as on-chip memory is digital. The chip has been implemented in a CMOS 0.5 (mu) process with 600,000 transistors while die size is 320 mm2 (80 mm2 active area).

  12. EVALUATION OF THE ABILITY OF CHLORINE TO INACTIVATE SELECTED ORGANISMS FROM THE BIOFILM OF A DRINKING WATER DISTRIBUTION SYSTEM SIMULATOR FOLLOWING A LONG-TERM WASTEWATER CROSS-CONNECTION

    EPA Science Inventory

    The drinking water distribution system simulator (DSS) from the U.S. EPA was operated with a direct cross-connection of 0.3% wastewater to system volume per day for 70 d. During the cross-connection, tap water, wastewater, and system discharge water were monitored to ensure that ...

  13. Design and fabrication of a compact chip-scale optical cross-connect enabled by photonic crystals for optical interconnects

    NASA Astrophysics Data System (ADS)

    Zablocki, Mathew Joseph

    As integrated circuits, such as microprocessors, are fabricated with higher yields and with increasing numbers of smaller and smaller transistors, the communication between discrete elements becomes as important as the elements themselves. The delays associated with signal distribution across the chip have become a limiting factor for processor speeds, and are primarily located within the global interconnect layers for intra-chip and inter-chip communication. Optical interconnects have the potential to relieve the restrictions set by the interconnect bottleneck by taking advantage of their reduced power demands for signal distribution and their lower propagation delays. The work within this dissertation discusses the design, fabrication and characterization of an ultra-compact photonic crystal optical switch for use within a transparent optical cross-connect (OXC). To reduce the size and power consumption of the switch, perturbations were made within the photonic crystal structure to achieve a degree of slow light, decreasing the group velocity of the propagating signals. Further, as a means to integrate the developed switch matrix to a microprocessor in order to serve as a chip's optical global interconnect, a process was developed to transfer the switch fabric to a new substrate as a silicon-nanomembrane (Si-NM). The developed transfer process allows the transfer and stacking of intricate photonic devices, such as the aforementioned switch matrix, to new material platforms and substrates that would be incompatible with typical complementary-metal-oxide-semiconductor CMOS processing. The developed Si-NM processing along with the developed switch matrix for a transparent OXC are significant steps toward implementing an optical interconnect network on a chip.

  14. Exploring Concepts from Abstract Algebra Using Variations of Generalized Woven Figure Eights

    ERIC Educational Resources Information Center

    Taylor, Tara; Knoll, Eva; Landry, Wendy

    2016-01-01

    Students often struggle with concepts from abstract algebra. Typical classes incorporate few ways to make the concepts concrete. Using a set of woven paper artifacts, this paper proposes a way to visualize and explore concepts (symmetries, groups, permutations, subgroups, etc.). The set of artifacts used to illustrate these concepts is derived…

  15. Effect of Correlations of Component Failures and Cross-Connections of EDGs on Seismically Induced Core Damages of a Multi-Unit Site

    NASA Astrophysics Data System (ADS)

    Muramatsu, Ken; Liu, Qiao; Uchiyama, Tomoaki

    Aiming at proposing effective applications of seismic probabilistic safety assessment (PSA) for design and risk management of nuclear facilities, we conducted a preliminary seismic PSA study for a multi-unit site to examine core damage frequency (CDF) and core damage sequences with consideration of the effect of correlations of component failures. In addition, we also examined the effectiveness of an accident management measure, namely, cross-connections of emergency diesel generators (EDGs) between adjacent units in this study. Twin BWR-5 units of the same design were hypothesized to be located at the same site in this study and the CDF as well as the accident sequences of this two-unit site were analyzed by using SECOM2, a system reliability analysis code for seismic PSA. The results showed that the calculated CDF was dependent on the assumptions on the correlations of component failures. When the rules for assigning correlation coefficients of component responses defined in the NUREG-1150 program were adopted, the CDF of a single unit, the CDF of this two-unit site (the frequency of core damages of at least one unit at this site) and the frequency of simultaneous core damages of both units increased by factors of about 1.3, 1.2 and 2.3, respectively. In addition, it might be possible that the simultaneous core damages of both units are caused by different accident sequence pairs as well as the same sequence pairs. When cross-connections of EDGs between two units were available, the CDF of a single unit, the CDF of this two-unit site as well as the frequency of simultaneous core damages of both units decreased. In addition, the CDF of this two-unit site was smaller than the CDF of a single unit site. These results show that cross-connections of EDGs might be beneficial for a multi-unit site if the rules for assigning correlation coefficients defined in NUREG-1150 program are reasonable.

  16. Optimization and efficient routing scenario of system using C-band: reconfigurable multiwavelength optical cross connect based on tunable fiber Bragg grating and optical circulator

    NASA Astrophysics Data System (ADS)

    Singh, Manpreet; Dewra, Sanjeev; Kaler, Rajinder S.

    2016-07-01

    The impact of physical parameters such as grating length, effective index of grating, and apodization on the performance of 5×5 reconfigurable multiwavelength optical cross connect based on tunable fiber Bragg grating and optical circulator in DWDM system with 0.8-nm channel spacing at 15×10 Gbps is evaluated. It is observed that least BER is achieved at the minimum input transmission power with specific values of grating length, effective index of grating, and apodization change of a T-FBG. It shows that BER increases as the values of T-FBG grating length, effective index of grating, and apodization decrease. The data can be transmitted over a distance of 60 km in the presence of fiber nonlinearities without optical amplifier and dispersion compensating techniques.

  17. UV-free red electroluminescence from the cross-connected p-ZnO:Cu nanobushes/n-GaN light emitting diode.

    PubMed

    Wang, Yumei; Han, Yibo; Han, Junbo; Zhang, Xianghui; Chen, Ying; Wang, Siliang; Wen, Li; Liu, Nishuang; Su, Jun; Li, Luying; Gao, Yihua

    2016-02-22

    A p-ZnO:Cu/n-GaN heterojunction light emitting diode (LED) is fabricated by growing cross-connected p-ZnO:Cu nanobushes on n-GaN film using chemical vapor deposition under oxygen-rich condition. This LED emits stable UV-free red light of 677 nm and 745 nm. The electroluminescence (EL) light of this LED is tuned from ultraviolet (UV) of ZnO/GaN to UV-free red by the electronic interfacial transition from the conduction band of n-GaN to the deep acceptor levels of p-ZnO:Cu. Both room temperature and low temperature (5K) photoluminescence spectra of ZnO:Cu indicate that the UV emission of ZnO is suppressed and the green emission is enhanced, which implies the formation of Cu-related deep levels introduced by intentionally doping Cu in ZnO. These deep levels help the EL red emission in the LED device. PMID:26907047

  18. Cross-Connections of Chemistry

    NASA Astrophysics Data System (ADS)

    Mason, Diana S.

    2002-02-01

    We are in desperate need of qualified chemistry teachers. Are the teachers who have biology, physics, or some psychology degrees qualified to teach chemistry? Have they taken enough chemistry to be prepared to teach outside their degree field? If remediation is necessary, what courses should be required? Attracting pre-service science teachers to the study of pure chemistry is not an easy task when more attractive course offerings are available. Maybe we should concentrate on cross-training in-service teachers by providing appropriate graduate courses to encourage them and bring them into the family. Many teachers with degrees outside the traditional discipline of chemistry have adequate backgrounds in the applications of chemistry. Requiring hours of undergraduate education before they enter the hallowed halls of the chemistry building as graduate students only serves to discourage a large segment of in-service teachers who wish to broaden their perspective. The National Science Education Standards make a compelling argument for connecting and integrating science courses for practicing teachers (3). We are at the crossroads. At a time when we so desperately need qualified chemistry teachers, shouldn't we be more open in our graduate teaching programs, inviting those with degrees in other disciplines to start on a graduate degree without insisting on undergraduate or survey coursework first? Many potential chemical education graduate students have a background in chemistry--it is just known by another name.

  19. Simulation Study to Improve Focalization of a Figure Eight Coil by Using a Conductive Shield Plate and a Ferromagnetic Block.

    PubMed

    Zhao, Chen; Zhang, Shunqi; Liu, Zhipeng; Yin, Tao

    2015-07-01

    A new method to improve the focalization and efficiency of the Figure of Eight (FOE) coil in rTMS is discussed in this paper. In order to decrease the half width of the distribution curve (HWDC), as well to increase the ratio of positive peak value to negative peak value (RPN) of the induced electric field, a shield plate with a window and a ferromagnetic block are assumed to enhance the positive peak value of the induced electrical field. The shield is made of highly conductive copper, and the block is made of highly permeable soft magnetic ferrite. A computer simulation is conducted on ANSYS® software to conduct the finite element analysis (FEA). Two comparing coefficients were set up to optimize the sizes of the shield window and the block. Simulation results show that a shield with a 60 mm × 30 mm sized window, together with a block 40 mm thick, can decrease the focal area of a FOE coil by 46.7%, while increasing the RPN by 135.9%. The block enhances the peak value of the electrical field induced by a shield-FOE by 8.4%. A real human head model was occupied in this paper to further verify our method. PMID:25594972

  20. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    DOEpatents

    Rote, Donald M.; He, Jianliang; Johnson, Larry R.

    1994-01-01

    A propulsion and stabilization system comprising a series of FIG. 8 coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the FIG. 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

  1. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    DOEpatents

    Rote, D.M.; He, Jianliang; Johnson, L.R.

    1992-01-01

    This report discusses a propulsion and stabilization system comprising a series of figure 8 coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the figure 8 coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension.

  2. Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles

    DOEpatents

    Rote, D.M.; He, J.; Johnson, L.R.

    1994-01-04

    A propulsion and stabilization system are described comprising a series of coils mounted vertically on the walls of the guideway to provide suspension, lateral guidance, and propulsion of a magnetically levitated vehicle. This system further allows for altering the magnetic field effects by changing the relative position of the loops comprising the coils either longitudinally and/or vertically with resulting changes in the propulsion, the vertical stability, and the suspension. 8 figures.

  3. Computation of magnetic suspension of maglev systems using dynamic circuit theory

    SciTech Connect

    He, J.L.; Rote, D.M.; Coffey, H.T.

    1991-01-01

    Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper. 15 refs., 7 figs., 1 tab.

  4. Computation of magnetic suspension of maglev systems using dynamic circuit theory

    NASA Technical Reports Server (NTRS)

    He, J. L.; Rote, D. M.; Coffey, H. T.

    1992-01-01

    Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper.

  5. Applications of the dynamic circuit theory to maglev suspension systems

    SciTech Connect

    He, Jian Liang; Rote, D.M.; Coffey, H.T.

    1993-11-01

    This paper discusses the applications of dynamic circuit theory to electrodynamic suspension EDS systems. In particular, the paper focuses on the loop-shaped coil and the figure-eight-shaped null-flux coil suspension systems. Mathematical models, including very general force expressions that can be used for the development of computer codes, are provided for each of these suspension systems. General applications and advantages of the dynamic circuit model are summarized. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many EDS maglev design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper to demonstrate the capability of the model.

  6. Microsecond regime optical cross connect: 32 port to 32 port scalable device

    NASA Astrophysics Data System (ADS)

    Lynn, Brittany; Miles, Alexander; Blanche, Pierre-Alexandre; Wissinger, John; Carothers, Daniel; Norwood, Robert A.; Peyghambarian, N.

    2014-03-01

    Presented here is a 32 × 32 optical switch for telecommunications applications capable of reconfiguring at speeds of up to 12 microseconds. The free space switching mechanism in this interconnect is a digital micromirror device (DMD) consisting of a 2D array of 10.8μm mirrors optimized for implementation at 1.55μm. Hinged along one axis, each micromirror is capable of accessing one of two positions in binary fashion. In general reflection based applications this corresponds to the ability to manifest only two display states with each mirror, but by employing this binary state system to display a set of binary amplitude holograms, we are able to access hundreds of distinct locations in space. We previously demonstrated a 7 × 7 switch employing this technology, providing a proof of concept device validating our initial design principles but exhibiting high insertion and wavelength dependent losses. The current system employs 1920 × 1080 DMD, allowing us to increase the number of accessible ports to 32 × 32. Adjustments in imaging, coupling component design and wavelength control were also made in order to improve the overall loss of the switch. This optical switch performs in a bit-rate and protocol independent manner, enabling its use across various network fabrics and data rates. Additionally, by employing a diffractive switching mechanism, we are able to implement a variety of ancillary features such as dynamic beam pick-off for monitoring purposes, beam division for multicasting applications and in situ attenuation control.

  7. Spatial light modulators for full cross-connections in optical networks

    NASA Technical Reports Server (NTRS)

    Juday, Richard D. (Inventor)

    2004-01-01

    A polarization-independent optical switch is disclosed for switching at least one incoming beam from at least one input source to at least one output drain. The switch includes a polarizing beam splitter to split each of the at least one incoming beam into a first input beam and a second input beam, wherein the first input beam and the second input beams are independently polarized; a wave plate optically coupled to the second input beam for converting the polarization of the second input beam to an appropriately polarized second input beam; a beam combiner optically coupled to the first input beam and the modified second input beam, wherein the beam combiner accepts the first input beam and the modified second input beam to produce a combined beam; the combined beam is invariant to the polarization state of the input source's polarization; and a controllable spatial light modulator optically coupled to the combined beam, wherein the combined beam is diffracted by the controllable spatial light modulator to place light at a plurality of output locations.

  8. 4x4 and 8x8 optical cross connect for optical fiber networks

    NASA Astrophysics Data System (ADS)

    Zickar, Michael; Noell, Wilfried; Marxer, Cornel; de Rooij, Nicolaas F.

    2004-08-01

    We report on a 4x4 optical matrix switch for telecom application. It consists of a 4x4 array of vertical mirrors that have the same pitch as the fibers of commercially available fiber ribbons (250 μm). This compact design enables a parallel assembly to optical components, which simplifies the time consuming and costly process for switches with larger pitch. Additionally, a small pitch leads to a short optical coupling length, which facilitates the integration of a suitable collimation system. However there are physical limitations for optical MEMS in conjunction with assembled micro-optics. The optical beam exiting a collimator diverges, the divergence angle is indirectly proportional to the beam waist and the coupling length increases quadratically. Our calculations show that for a pitch of 250 μm a mirror height of 100 μm is optimal. The mirrors are monolithically etched onto a platform etched during a previous step. No assembly of the mirrors to the actuators is needed. Alignment structures for the optical components are etched during the same step as the mirrors, which lead to self aligned structures. The platform is supported by 150 μm long torsion beams with sub-micron diameter. The electrostatic actuation voltage is given by a separate chip. The mirror moves out of the optical path when the platform is actuated and goes to the switching state if no voltage is applied. The first prototypes have been actuated at 200 V, which agrees with a CoventorWare simulation used for designing the device. Light was successfully switched with a 4x4 OXC. An 8x8 OXC is shown and electrostatically characterized.

  9. Performance enhancements of the CMCC"s national mesh network using the intelligent optical cross-connect switches

    NASA Astrophysics Data System (ADS)

    Gong, Qian; Xu, Rong; Lin, JinTong L.

    2004-04-01

    In the last five years, the traffic growth rate in China has been extremely fast. By 2005, the number of wired telephone customers is estimated to reach 220 to 260 million, while the number of expected cellular customers will reach 260 to 290 million. To meet these challenges, we will continue evolving with more wavelengths and higher speed. By evolving point-to-point WDM systems to OTN/ASON systems, we can eliminate the throughput bottleneck of network nodes caused by electronics, provide optical-layer bandwidth- management capability, provide scalability (which allows continuous traffic growth and network expansion), and provide reconfigurability (which allows semi-dynamic and dynamic optical networking). We can also simplify and speed up provisioning of high-speed circuits and services and offer fast network protection and restoration on the order of tens or hundreds of milliseconds to guarantee excellent network and service survivability. The CMCC (China Mobile Communication Company) will build its OTN network towards the ASON. The CMCC"s long-haul national network utilizing OXC has clearly becomes an intelligent network. It offers end-to-end point-and-click provisioning, shared mesh restoration with a few tens to a couple of hundred msec restoration times, re-provisioning of connections in the event of double failures and network capacity that is not optimally used. In this paper, first we present the CMCC network situation, The network planning tool will be introduced, Then we compare ring with mesh solution in terms of the cost, network performance, protection and restoration, network re-optimization. At last we derive a desired conclusion.

  10. Complex Rotating Waves and Long Transients in a Ring Network of Electrochemical Oscillators with Sparse Random Cross-Connections.

    PubMed

    Sebek, Michael; Tönjes, Ralf; Kiss, István Z

    2016-02-12

    We perform experiments and phase model simulations with a ring network of oscillatory electrochemical reactions to explore the effect of random connections and nonisochronicity of the interactions on the pattern formation. A few additional links facilitate the emergence of the fully synchronized state. With larger nonisochronicity, complex rotating waves or persistent irregular phase dynamics can derail the convergence to global synchronization. The observed long transients of irregular phase dynamics exemplify the possibility of a sudden onset of hypersynchronous behavior without any external stimulus or network reorganization. PMID:26919024

  11. THE EFFECT OF LONG TERM WASTEWATER CROSS-CONNECTION'S EFFECT ON THE BIOFILM OF A SIMULATED WATER DISTRIBUTION SYSTEM

    EPA Science Inventory

    Under the current regulations (CFR 503), Class B biosolids may be land applied with certain site restrictions. One method for achieving Class B status is to raise the pH of the sludge to >12 for a minimum of 2 hours with an alkaline material (normally lime). Alternately, a Clas...

  12. 77 FR 5185 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway Albermarle Sound to Sunset Beach...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-02

    ... Albermarle Sound to Sunset Beach, Scotts Hill, NC AGENCY: Coast Guard, DHS. ACTION: Notice of temporary... Figure Eight Beach Homeowners Association, who owns and operates the Figure Eight Swing Bridge across...

  13. Science 101: How Does the Motion of the Earth Affect Our View of the Sun?

    ERIC Educational Resources Information Center

    Robertson, Bill

    2014-01-01

    The question examined in this "Science 101" column was inspired by "Find Your School's Analemma" (in this issue). What causes the Sun's apparent position in the sky to trace a figure-eight pattern throughout one year? The analemma, or figure eight pattern that the Sun makes throughout the year, is due to two major…

  14. 77 FR 29618 - The Release of the Draft Environmental Impact Statement and the Announcement of a Public Hearing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-18

    ... Announcement of a Public Hearing for the Figure Eight Island Inlet and Shoreline Management Project, on Figure Eight Island, New Hanover County, NC AGENCY: Department of the Army, U.S. Army Corps of Engineers, DoD... feet of back barrier shoreline to protect residential homes and infrastructures along the central...

  15. 77 FR 29740 - Self-Regulatory Organizations; BOX Options Exchange LLC; Notice of Filing and Immediate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-18

    ... Connect'' fees are per physical connection and vary by size from the smallest (T-1) to the largest (CAT 6... Connect per T-3 350 Cross Connect per CAT 5, 5E, 6 \\8\\ 500 Monthly Hosting 200 Cross Connect per T-1 100 Cross Connect per T-3 200 Cross Connect per CAT 5, 5E, 6 250 Additionally, Back Office Trade...

  16. TRIMETHYLTIN-INDUCED HYPERACTIVITY: TIME COURSE AND PATTERN

    EPA Science Inventory

    Adult male Long-Evans rats were intubated with either 0,5,6, or 7 mg/kg trimethyltin chloride. Activity was measured for 1 hr in a figure-eight maze 2 hr after dosing (day 0) and again on days 4,8,16 and 32 after dosing. On days 49-51, activity was measured in a figure-eight maze...

  17. Study of lift enhancing mechanisms via comparison of two distinct flapping patterns in the dragonfly Sympetrum flaveolum

    NASA Astrophysics Data System (ADS)

    Chen, Y. H.; Skote, M.

    2015-03-01

    The computational fluid dynamic model of a live-sized dragonfly (Sympetrum flaveolum) hindwing is simulated according to the in-flight flapping motions measured in kinematic experiments. The flapping motion of the simulated wing is accomplished by dynamically re-gridding the wing-fluid mesh according to the established kinematic model for each flapping pattern. Comparisons between two distinct flapping patterns (double figure-eight and simple figure-eight) are studied via analysis of the aerodynamic forces and flow field structures. The result shows that additional lift is generated during supination and upstroke for the double figure-eight pattern, while maximum thrust is generated during pronation for the simple figure-eight pattern. In addition, through our comparisons of the different kinematics, we are able to reveal the mechanism behind the leading edge vortex stabilization prior to supination and the kinematic movement responsible for additional lift generation during supination. By increasing the translational deceleration during stroke-end rotations in the double figure-eight flapping pattern, a trailing edge vortex is formed which is stronger as compared to the single figure-eight flapping pattern, thus enhancing the lift.

  18. AUDITORY DEFICITS AND MOTOR DYSFUNCTION FOLLOWING IMINODIPROPIONITRILE ADMINISTRATION IN THE RAT

    EPA Science Inventory

    The behavioral effects of 3,3'-iminodipropionitrile (IDPN) were studied using reflex modification of the acoustic startle response and figure-eight maze activity. umber of experiments were conducted with separate groups of adult male Long Evans hooded rats exposed to saline, or 5...

  19. NEUROBEHAVIORAL EFFECTS OF TRIADIMEFON, A TRIAZOLE FUNGICIDE, IN MALE AND FEMALE RATS

    EPA Science Inventory

    Triadimefon is a widely used systemic fungicide, yet there is little published information on its effects in mammals. This study describes the effects of triadimefon in male and female rats using a functional observational battery (FOB), motor activity (measured in a figure-eight...

  20. Dragonfly (Sympetrum flaveolum) flight: Kinematic measurement and modelling

    NASA Astrophysics Data System (ADS)

    Chen, Y. H.; Skote, M.; Zhao, Y.; Huang, W. M.

    2013-07-01

    The kinematics of the flapping hindwing of the dragonfly Sympetrum flaveolum is investigated. Several tracking points along the leading edge and trailing edge of the hindwing are recorded and studied using high-speed videography. By applying more tracking points along the leading edge around the nodus, it is shown that the leading edge is not one rigid piece, but two pieces hinged at the nodus with physical constraint of forty degrees. Such arrangement also eases the difficulties in rotating the wing during pronation by bending the leading edge forward and flattening the wing. From the kinematic experiments, two flapping patterns of the dragonfly wing are revealed as a simple figure-eight and a double figure-eight flapping pattern. Kinematic modelling of the two flapping patterns is then established by transforming the flapping motions into angular rotations about the pivoting wing root in a local body-fixed spherical coordinate system.

  1. A symplectic integrator for the symmetry reduced and regularised planar 3-body problem with vanishing angular momentum

    NASA Astrophysics Data System (ADS)

    Rose, Danya; Dullin, Holger R.

    2013-10-01

    We construct an explicit reversible symplectic integrator for the planar 3-body problem with zero angular momentum. We start with a Hamiltonian of the planar 3-body problem that is globally regularised and fully symmetry reduced. This Hamiltonian is a sum of 10 polynomials each of which can be integrated exactly, and hence a symplectic integrator is constructed. The performance of the integrator is examined with three numerical examples: The figure eight, the Pythagorean orbit, and a periodic collision orbit.

  2. Nonblocking space wavelength networks with wave-mixing frequency conversion

    NASA Astrophysics Data System (ADS)

    Dasylva, Abel Clement; Montuno, Delfin Y.; Kodaypak, Prasad

    2002-06-01

    We describe what we believe to be new designs for all-optical cross connects, capable of wavelength conversion. They are based on two-dimensional, space-wavelength, Benes or Cantor topologies, and they exploit cascaded wave-mixing bulk frequency conversion. In these cross connects many channels at distinct frequencies can be simultaneously frequency translated in a common wave-mixing device, and a given lightpath may be converted many times between its input and output. The new wavelength-interchanging cross connects are nonblocking and require O{F log2 W[log2(FW)]n} wave-mixing converters, where n = 0, 1.

  3. Design Optimization for a Maglev System Employing Flux Eliminating Coils

    NASA Technical Reports Server (NTRS)

    Davey, Kent R.

    1996-01-01

    Flux eliminating coils have received no little attention over the past thirty years as an alternative for realizing lift in a MAGLEV system. When the magnets on board the vehicle are displaced from the equilibrium or null flux point of these coils, they induce current in those coils which act to restore the coil to its null flux or centerline position. The question being addressed in this paper is that of how to choose the best coil for a given system. What appears at first glance to be an innocent question is in fact one that is actually quite involved, encompassing both the global economics and physics of the system. The real key in analyzing that question is to derive an optimization index or functional which represents the cost of the system subject to constraints, the primary constraint being that the vehicle lift itself at a certain threshold speed. Outlined in this paper is one scenario for realizing a total system design which uses sequential quadratic programming techniques.

  4. Project W-320 high vacuum 241-AY-102 annulus ventilation system operability test report

    SciTech Connect

    Bailey, J.W.

    1998-03-12

    This report documents the test results of OTP-320-001, Tank 241-AY-102 Annulus Ventilation System Testing. Included in the appendices are: (1) Supporting documentation prepared to demonstrate the structural integrity of the tank at high annulus vacuum (<20 INWG), and (2) a report that identifies potential cross connections between the primary and annulus ventilation systems. These cross connections were verified to be eliminated prior to the start of testing.

  5. Application of portable fluorescence spectrophotometry for integrity testing of recycled water dual distribution systems.

    PubMed

    Hambly, Adam C; Henderson, Rita K; Baker, Andy; Stuetz, Richard M; Khan, Stuart J

    2015-01-01

    Water utilities supplying recycled water to households via a "third-pipe" or "dual reticulation" system have a need for a rapid, portable method to detect cross-connections within potable water reticulation networks. This study evaluates portable fluorimetry as a technique for cross-connection detection in the field. For the first time, an investigation of a full-scale dual reticulation water-recycling network has been carried out to identify cross-connections using a portable fluorimeter. We determined that this can be carried out with a 3 mL water sample, and unlike methods that are currently in use for cross-connection detection, can be achieved quickly without disruption to water flow or availability within the network. It was also revealed that fluorescence trigger values could be established with high levels of confidence by sampling less than 2.5% of the network. Fluorescence analysis was also able to uncover a single, real cross-connection event. As such, this paper is a fundamental demonstration of fluorescence as a reliable, highly portable technique for cross-connection detection within dual reticulation water recycling networks and further establishes the abilities of fluorescence devices as valuable field instruments for water quality monitoring. PMID:25506735

  6. Physiological modules for generating discrete and rhythmic movements: component analysis of EMG signals

    PubMed Central

    Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana Maria; Dan, Bernard; Cheron, Guy; McIntyre, Joseph

    2015-01-01

    A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the central nervous system (CNS) builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90°. To test for the effects of biomechanical constraints, movements were performed in the frontal-parallel or sagittal planes, corresponding to two different nominal flexion/abduction postures of the shoulder. In all cases we measured limb kinematics and surface electromyographic activity (EMG) signals for seven different muscles acting around the shoulder. We first performed principal component analysis (PCA) of the EMG signals on a movement-by-movement basis. We found a surprisingly consistent pattern of muscle groupings across movement types and movement planes, although we could detect systematic differences between the PCs derived from movements performed in each shoulder posture and between the principal components associated with the different orientations of the figure. Unexpectedly we found no systematic differences between the figure eights and the point-to-point movements. The first three principal components could be associated with a general co-contraction of all seven muscles plus two patterns of reciprocal activation. From these results, we surmise that both “discrete-rhythmic movements” such as the figure eight, and discrete point-to-point movement may be constructed from three different fundamental modules, one regulating the impedance of the limb over the time span of the movement and two others operating to generate movement, one aligned with the

  7. Flexible polyvinyl chloride neutron guides for transporting ultracold and very cold neutrons

    SciTech Connect

    Arzumanov, S. S. Bondarenko, L. N.; Geltenbort, P.; Morozov, V. I.; Nesvizhevsky, V. V.; Panin, Yu. N.; Strepetov, A. N.; Chuvilin, D. Yu.

    2011-12-15

    The transmission of ultracold neutrons (UCNs) through flexible polyvinyl chloride (PVC) tubes with lengths of up to 3 m and an internal diameter of 6-8 mm has been studied. High UCN transmission is found even for arbitrarily bent tubes (single bend, double bend, triple bend, figure eight, etc.). The transmission can be improved significantly by coating the inner surface of the tube with a thin layer of liquid fluorine polymer. The prospects of these neutron guides in fundamental and applied research are discussed.

  8. Wake-body resonance of long flexible structures is dominated by counterclockwise orbits.

    PubMed

    Bourguet, Rémi; Modarres-Sadeghi, Yahya; Karniadakis, George E; Triantafyllou, Michael S

    2011-09-23

    We identify a dominant mechanism in the interaction between a slender flexible structure undergoing free vibrations in sheared cross-flow and the vortices forming in its wake: energy is transferred from the fluid to the body under a resonance condition, defined as wake-body frequency synchronization close to a natural frequency of the structure; this condition occurs within a well-defined region of the span, which is dominated by counterclockwise, figure-eight orbits. Clockwise orbits are associated with damping fluid forces. PMID:22026858

  9. Knot undulator to generate linearly polarized photons with low on-axis power density.

    PubMed

    Qiao, S; Ma, Dewei; Feng, Donglai; Marks, S; Schlueter, R; Prestemon, S; Hussain, Z

    2009-08-01

    Heat load on beamline optics is a serious obstacle for devices designed to generate pure linearly polarized photons in third generation synchrotron radiation facilities. For permanent magnet undulators, this problem can be overcome by implementing a figure-eight design configuration. As yet there has been no good method to tackle this problem for electromagnetic elliptical undulators. Here, a novel design and operational mode is suggested, which can generate pure linearly polarized photons with very low on-axis heat load. Additionally, the minimum photon energy capability of linearly polarized photons can be significantly extended by this method. PMID:19725682

  10. REACTORS

    DOEpatents

    Spitzer, L. Jr.

    1961-10-01

    Thermonuclear reactors, methods, and apparatus are described for controlling and confining high temperature plasma. Main axial confining coils in combination with helical windings provide a rotational transform that avoids the necessity of a figure-eight shaped reactor tube. The helical windings provide a multipolar helical magnetic field transverse to the axis of the main axial confining coils so as to improve the effectiveness of the confining field by counteracting the tendency of the more central lines of force in the stellarator tube to exchange positions with the magnetic lines of force nearer the walls of the tube. (AEC)

  11. Effects of pulsed magnetic stimulation on isolated crayfish heart.

    PubMed

    Chiba, Atsushi; Inase, Masahiko

    2016-01-01

    Cardiac muscular contraction of the neurogenic heart that could be excited by pulsed magnetic stimulation (PMS) was investigated using preparation of the isolated crayfish heart. When a figure-eight magnetic coil was set over the isolated heart, cardiac contraction induced by a single PMS was not observed. Cardiac arrest occurred immediately after repetitive PMS and persisted for dozens of seconds depending on the number of stimuli. We concluded that PMS caused neuronal modulation in the neuronal network in the cardiac ganglion. PMID:25545190

  12. Unidirectional acoustic probe based on the particle velocity gradient.

    PubMed

    Yu, Shiduo; Fernández Comesaña, Daniel; Carrillo Pousa, Graciano; Yang, Yixin; Xu, Lingji

    2016-06-01

    This paper presents the foundations of a unidirectional acoustic probe based on the particle velocity gradient. Highly directional characteristics play a key role in reducing the influence of undesired acoustic sources. These characteristics can be achieved by using multiple acoustic sensors in a spatial gradient arrangement. Two particle velocity sensors possessing the figure eight directivity pattern were used in a first-order gradient configuration to yield a unidirectional probe that can reject most excitations originating from both sides and the rear. The effects of key parameters are thoroughly discussed, and the proposed theory is validated in practice. PMID:27369169

  13. The Stealth Biplane: a Proposal in Response to a Low Reynolds Number Station Keeping Mission

    NASA Technical Reports Server (NTRS)

    Walsh, Timothy E.; Flynn, Kevin T.; Donovan, Steven; Paul, Chris; Pangilinan, Harold; Padgett, John; Twomey, Daniel

    1990-01-01

    The Stealth Biplane is conceived and constructed to serve as a remotely piloted vehicle designed to navigate a low-level figure-eight course at a target Reynolds number of 100,000. This flight vehicle will combine the latest in lightweight radio controlled hardware in conjunction with current low Reynolds number aerodynamic research to demonstrate feasible operation in a variety of applications. These potential low Reynolds number applications include high altitude atmospheric sampling, search and rescue, and even law enforcement. Design specs and fabrication technique are discussed.

  14. Analysis of an electrodynamic maglev system

    SciTech Connect

    Davey, K.

    1999-09-01

    Electrodynamic systems (EDS's) for maglev have an advantage over electromagnetic systems (EMS's) in that the stability is built into the system. EDS's induce the currents used for levitation and guidance, while EMS's impose those currents with controlled feedback. The movement of a magnet over properly designed EDS coils results in forces to keep the system fixed in the lowest energy or null flux spot. In the past such systems have been examined through two-dimensional boundary element techniques. An approximation to the full three-dimensional time harmonic problem is obtained through LaPlace transform theory after using boundary element methods to predict the mutual coupling of the magnets with the track coils. The analytic solution offers helpful design and operation guidelines.

  15. Blended head analyses to reduce uncertainty in packer testing in fractured-rock boreholes

    NASA Astrophysics Data System (ADS)

    Quinn, Patryk; Parker, Beth L.; Cherry, John A.

    2016-02-01

    Open boreholes in fractured rock often cross-connect fractures with differing hydraulic head and the head differences between these fractures cause vertical flow in the water column. This cross-connection has potential to bias transmissivity ( T) values obtained from straddle packer tests. This study demonstrates how measurements of the blended head in the open-hole segments above and below the straddle-packer test interval can be used to correct packer tests for cross-connection effects. A pressure response observed in the open-hole segment above and/or below the packers isolating a test interval during a hydraulic test indicates short-circuiting of water from the injection interval through the vertically connected fracture network to the open-hole segments, resulting in the overestimation of T. A method is presented using blended head concepts to minimize this error using a trial-and-error procedure to determine the short-circuiting flow rate to account for the head conditions in the open-hole segments during each hydraulic test. Observed differences between the measured head and the calculated blended head in the open-hole segments above and below the test interval are attributed to cross-connection effects around the 1-m-long packers. The head and corrected T values determined from packer tests are used to estimate the flow in and out of the open hole at each of the intervals tested for assessing the cross-connection effects under open borehole conditions. Understanding open-hole flow dynamics gives insight about the potential for vertical cross connection of chemical constituents caused by the open hole.

  16. The Dynactin Complex Maintains the Integrity of Metaphasic Centrosomes to Ensure Transition to Anaphase*

    PubMed Central

    Ozaki, Yuko; Matsui, Hirotaka; Nagamachi, Akiko; Asou, Hiroya; Aki, Daisuke; Inaba, Toshiya

    2011-01-01

    The dynactin complex is required for activation of the dynein motor complex, which plays a critical role in various cell functions including mitosis. During metaphase, the dynein-dynactin complex removes spindle checkpoint proteins from kinetochores to facilitate the transition to anaphase. Three components (p150Glued, dynamitin, and p24) compose a key portion of the dynactin complex, termed the projecting arm. To investigate the roles of the dynactin complex in mitosis, we used RNA interference to down-regulate p24 and p150Glued in human cells. In response to p24 down-regulation, we observed cells with delayed metaphase in which chromosomes frequently align abnormally to resemble a “figure eight,” resulting in cell death. We attribute the figure eight chromosome alignment to impaired metaphasic centrosomes that lack spindle tension. Like p24, RNA interference of p150Glued also induces prometaphase and metaphase delays; however, most of these cells eventually enter anaphase and complete mitosis. Our findings suggest that although both p24 and p150Glued components of the dynactin complex contribute to mitotic progression, p24 also appears to play a role in metaphase centrosome integrity, helping to ensure the transition to anaphase. PMID:21163948

  17. Path Integration: Effect of Curved Path Complexity and Sensory System on Blindfolded Walking

    PubMed Central

    Koutakis, Panagiotis; Mukherjee, Mukul; Vallabhajosula, Srikant; Blanke, Daniel J.; Stergiou, Nicholas

    2012-01-01

    Path integration refers to the ability to integrate continuous information of the direction and distance travelled by the system relative to the origin. Previous studies have investigated path integration through blindfolded walking along simple paths such as straight line and triangles. However, limited knowledge exists regarding the role of path complexity in path integration. Moreover, little is known about how information from different sensory input systems (like vision and proprioception) contributes to accurate path integration. The purpose of the current study was to investigate how sensory information and curved path complexity affect path integration. Forty blindfolded participants had to accurately reproduce a curved path and return to the origin. They were divided into four groups that differed in the curved path, circle (simple) or figure-eight (complex), and received either visual (previously seen) or proprioceptive (previously guided) information about the path before they reproduced it. The dependent variables used were average trajectory error, walking speed, and distance travelled. The results indicated that (a) both groups that walked on a circular path and both groups that received visual information produced greater accuracy in reproducing the path. Moreover, the performance of the group that received proprioceptive information and later walked on a figure-eight path was less accurate than their corresponding circular group. The groups that had the visual information also walked faster compared to the group that had proprioceptive information. Results of the current study highlight the roles of different sensory inputs while performing blindfolded walking for path integration. PMID:22840893

  18. Characteristics of bowl-shaped coils for transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Yamamoto, Keita; Suyama, Momoko; Takiyama, Yoshihiro; Kim, Dongmin; Saitoh, Youichi; Sekino, Masaki

    2015-05-01

    Transcranial magnetic stimulation (TMS) has recently been used as a method for the treatment of neurological and psychiatric diseases. Daily TMS sessions can provide continuous therapeutic effectiveness, and the installation of TMS systems at patients' homes has been proposed. A figure-eight coil, which is normally used for TMS therapy, induces a highly localized electric field; however, it is challenging to achieve accurate coil positioning above the targeted brain area using this coil. In this paper, a bowl-shaped coil for stimulating a localized but wider area of the brain is proposed. The coil's electromagnetic characteristics were analyzed using finite element methods, and the analysis showed that the bowl-shaped coil induced electric fields in a wider area of the brain model than a figure-eight coil. The expanded distribution of the electric field led to greater robustness of the coil to the coil-positioning error. To improve the efficiency of the coil, the relationship between individual coil design parameters and the resulting coil characteristics was numerically analyzed. It was concluded that lengthening the outer spherical radius and narrowing the width of the coil were effective methods for obtaining a more effective and more uniform distribution of the electric field.

  19. Macromolecular knot in good and poor solvents: a Monte Carlo simulation.

    PubMed

    Sun, Huan-Quan; Zhang, Lu; Liao, Qi

    2010-09-30

    The probability and dimension of the simple macromolecular knots over a wide range of temperatures corresponding from good to poor solvents are investigated by Monte Carlo simulation. Macromolecular knots are modeled as rings of self-avoiding walks on a simple cubic lattice with the nearest neighbor attractions. We found that there is a minimum probability for the unknotted ring at a certain temperature. The size dependence of trivial, trefoil, and figure-eight knots on chain lengths and temperatures is presented. The simulation results for the size dependence on the knot's complication in different solvents are in good qualitative agreement with prediction of the scaling model proposed by Grosberg et al. The critical exponent for long chain is independent of the knot types based on the simulation results, although the mean square radius of gyration is influenced significantly by the knot types for a shorter length macromolecular ring. We calculated the ratio of the topological invariant p of trefoil knot and figure-eight knot and found that the ratio is approaching to 1.3 with the increasing of the chain length. PMID:20825151

  20. 76 FR 70199 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Notice of Filing of Proposed Rule...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-10

    ... data center to the client's chosen venue(s), in addition to the telco cross connect. These connections... equipment in the Exchange's data center, with additional carriers added at the request of a client. In order... telecommunication carriers with equipment in the Exchange's data center, one carrier has, to date, agreed to...

  1. 77 FR 39292 - Self-Regulatory Organizations; New York Stock Exchange LLC; Notice of Filing of Proposed Rule...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-02

    ... Exchange operates a data center in Mahwah, New Jersey (``data center'') from which it provides co- location services to Users. The Exchange's co-location services allow Users to rent space in the data center in... from the Exchange. Cabinet Cross Connects A User that has more than one cabinet within the data...

  2. 76 FR 70187 - Self-Regulatory Organizations; NASDAQ OMX PHLX LLC; Notice of Filing and Immediate Effectiveness...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-10

    ... Exchange's data center to the client's chosen venue(s), in addition to the telco cross connect. These... equipment in the Exchange's data center, with additional carriers added at the request of a client. In order... telecommunication carriers with equipment in the Exchange's data center, one carrier has, to date, agreed to...

  3. 77 FR 6520 - Airworthiness Directives; BAE SYSTEMS (OPERATIONS) LIMITED Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-08

    ... Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not affect intrastate aviation in... baggage bay fire bottles that can be misassembled such that two squib electrical connectors can be cross-connected. This proposed AD would require a general visual inspection of certain baggage bay fire...

  4. MICROBIAL GROWTH IN DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Drinking water is not sterile. Microbes are commonly found in delivered water. Some survive treatment, while others may be introduced due to cross connections, line breaks, or by other means. Biofilm forms in drinking water pipes when bacteria and other organisms adhere to pip...

  5. LAND USE AND SEASONAL EFFECTS ON URBAN STORMWATER RUNOFF MICROORGANISM CONCENTRATIONS

    EPA Science Inventory

    Stormwater samples collected from storm sewers draining small municipal separate storm sewer systems shown to be free of cross connections within an urban watershed dominated by a single land use were analyzed for pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) and i...

  6. WATERBORNE PATHOGEN INVASIONS: A CASE FOR WATER QUALITY PROTECTION IN DISTRIBUTION PROTECTION IN DISTRIBUTION

    EPA Science Inventory

    No degree of treatment will insure the delivery of a safe water supplyto the consumer's tap when the distribution system is subject to cross-connections water pressure losses, frequent line breaks, open reservoirs and infrastructure deterioration. n one recent U.S. outbreak, wate...

  7. 46 CFR 78.17-5 - Valves and closing appliances.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Valves and closing appliances. 78.17-5 Section 78.17-5..., Drills, and Inspections § 78.17-5 Valves and closing appliances. (a) It shall be the duty of the master to see that all valves, including cross connecting valves where fitted, and other appliances such...

  8. 47 CFR 69.112 - Direct-trunked transport.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... assigned to the lowest priced density pricing zone (zone 1) under an approved density pricing zone plan as... cross-connects for the transmission of switched traffic per office assigned to the lowest priced density pricing zone (zone 1). (g) In study areas in which the telephone company has implemented density...

  9. Backflow prevention and responsibilities of HVAC professionals

    SciTech Connect

    Towle, N.

    1996-09-01

    This article highlights the seriousness of backflow of harmful substances into potable water systems from cross-connections with other systems. Topics include backflow hazard examples, taking action, piping system surveys. The examples cited included schools, police station, hospitals, and a college. The contaminants included heat transfer fluids and corrosion inhibitors such as zinc chromate and ethylene glycol.

  10. The Advent of WDM and the All-Optical Network: A Reality Check.

    ERIC Educational Resources Information Center

    Lutkowitz, Mark

    1998-01-01

    Discussion of the telecommunications industry focuses on WDM (wavelength division multiplexing) as a solution for dealing with capacity constraints. Highlights include fiber optic technology; cross-connecting and switching wavelengths; SONET (Synchronous Optical Network) and wavelength networking; and optical TDM (Time Division Multiplexing). (LRW)

  11. 46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... instantaneous protection against short circuit for electrical-power circuits and control circuits, the... (parallel but cross-connected) power systems for the main steering gear by way of compliance with paragraph... subordinate parallel system is located at the steering-control station in the pilothouse; (2) Full power...

  12. 46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... instantaneous protection against short circuit for electrical-power circuits and control circuits, the... (parallel but cross-connected) power systems for the main steering gear by way of compliance with paragraph... subordinate parallel system is located at the steering-control station in the pilothouse; (2) Full power...

  13. 46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... instantaneous protection against short circuit for electrical-power circuits and control circuits, the... (parallel but cross-connected) power systems for the main steering gear by way of compliance with paragraph... subordinate parallel system is located at the steering-control station in the pilothouse; (2) Full power...

  14. 46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... instantaneous protection against short circuit for electrical-power circuits and control circuits, the... (parallel but cross-connected) power systems for the main steering gear by way of compliance with paragraph... subordinate parallel system is located at the steering-control station in the pilothouse; (2) Full power...

  15. 46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... instantaneous protection against short circuit for electrical-power circuits and control circuits, the... (parallel but cross-connected) power systems for the main steering gear by way of compliance with paragraph... subordinate parallel system is located at the steering-control station in the pilothouse; (2) Full power...

  16. Waterworks Operator Training Manual.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    Sixteen self-study waterworks operators training modules are provided. Module titles are the following: basic mathematics, basic chemistry, analysis procedures, microbiology, basic electricity, hydraulics, chlorination, plant operation, surface water, ground water, pumps, cross connections, distribution systems, safety, public relations, and…

  17. A new magnetic bar code system based on a magnetic anisotropy detection (abstract)

    NASA Astrophysics Data System (ADS)

    Sasada, I.; Watanabe, N.

    1996-04-01

    Magnetic bar codes can be used in unclean environments, where widely used optical bar code systems cannot be applied. Readout system for magnetic bar codes can also be made much simpler than optical ones. A new magnetic bar code system is proposed, in which binary information is coded in the sign of tilted angles of magnetic strips from a given standard direction. This scheme is unique compared to the conventional optical bar code, where width or space of the parallel pattern carries information, or an already reported magnetic bar code, where cross sectional shapes of pattern engraved in a ferromagnetic body carries information. Each of the magnetic strips brings about magnetic anisotropy due to its shape effect, hence angular dependent permeability in the proximity of the strip. The sign of the tilted angle of each magnetic strip is detected inductively through the angular dependent permeability by using a magnetic pickup head with a pair of cross-coupled figure-eight coils, where the sign of mutual inductance between the primary and the secondary figure-eight coil has one to one relationship to the sign of the tilted angle. Because the detection of the tilted angle is independent of scanning speed, variation in the scanning speed of the readout head does not affect the performance. In our preliminary study, the proposed magnetic bar code system was examined using pickup head consisting of a pair of cross-coupled 10-turn figure-eight coils which was embedded in a rectangular ferrite rod with cross-shape groove on the top surface of 6.5×3 mm dimension. The head was made thinner in the scanning direction to allow dense alignment of the pattern. Two kinds of pattern were made: the one was by aligning short amorphous wires (5 mm in length and 120 μm in diameter) on the plastic film and the other by using a thin (10 μm in thickness) copper film with tilted slits backed by an amorphous ribbon. These samples of magnetic bar code patterns were scanned with lift-off of

  18. The Circulation Pattern in Simulated Contact Binaries

    NASA Astrophysics Data System (ADS)

    Motl, Patrick M.; Frank, J.; Tohline, J. E.

    2006-06-01

    We present a three-dimensional hydrodynamical simulation of an initially symmetric (equal mass) binary where both components are marginally in contact. The simulation evolves the binary through approximately 150 orbital periods and within the first 20 orbits, a global velocity field is established that carries material between both components. In the equatorial plane, the flow is along a figure eight pattern with streams of material sliding past one another in the neighborhood of the inner Lagrange point. For our chosen equation of state, mass transfer is ultimately unstable in this binary though the growth time is long compared to the orbital period. We are therefore able to observe that the circulation pattern, once established, is quite close to steady state. We explore the role that similar steady state flows may play in real contact systems.

  19. On universal knot polynomials

    NASA Astrophysics Data System (ADS)

    Mironov, A.; Mkrtchyan, R.; Morozov, A.

    2016-02-01

    We present a universal knot polynomials for 2- and 3-strand torus knots in adjoint representation, by universalization of appropriate Rosso-Jones formula. According to universality, these polynomials coincide with adjoined colored HOMFLY and Kauffman polynomials at SL and SO/Sp lines on Vogel's plane, respectively and give their exceptional group's counterparts on exceptional line. We demonstrate that [m,n]=[n,m] topological invariance, when applicable, take place on the entire Vogel's plane. We also suggest the universal form of invariant of figure eight knot in adjoint representation, and suggest existence of such universalization for any knot in adjoint and its descendant representations. Properties of universal polynomials and applications of these results are discussed.

  20. Dynamics of noise-like pulsing at sub-ns scale in a passively mode-locked fiber laser.

    PubMed

    Santiago-Hernandez, H; Pottiez, O; Duran-Sanchez, M; Alvarez-Tamayo, R I; Lauterio-Cruz, J P; Hernandez-Garcia, J C; Ibarra-Escamilla, B; Kuzin, E A

    2015-07-27

    We report an original noise-like pulse dynamics observed in a figure-eight fiber laser, in which fragments are continually released from a main waveform that circulates in the cavity. Particularly, we report two representative cases of the dynamics: in the first case the released fragments drift away from the main bunch and decay over a fraction of the round-trip time, and then vanish suddenly; in the second case, the sub-packets drift without decaying over the complete cavity round-trip time, until they eventually merge again with the main waveform. The most intriguing result is that these fragments, as well as the main waveform, are formed of units with sub-ns duration and roughly the same energy. PMID:26367548

  1. Highly nonlinear fibers for very wideband supercontinuum generation

    NASA Astrophysics Data System (ADS)

    Grüner-Nielsen, Lars; Pálsdóttir, Bera

    2008-02-01

    Supercontinuum generation in highly nonlinear fibers (HNLF) pumped with femtosecond pulses is an area of large interest for applications such as broad band light sources, tunable femtosecond sources, frequency metrology, and fluorescence microscopy. In the last few years, a lot of focus has been put on optimizing photonics crystal fibers for supercontinuum application. In this paper, we will focus on conventional silica based HNLF, which e.g. have the advantage of precise dispersion control, and easy splicing to standard single mode fibers. We have performed a systematic experimental study of the effect of dispersion, of the HNLF as well as the input power to the HNLF. To pump the fiber we have build an femtosecond fiber laser consisting of a passive mode locked figure eight oscillator followed by an amplifier. The dispersion before coupling into the HNLF was optimized for broadest supercontinuum generation. Supercontinuum generation in both standard and polarization maintaining HNLF are studied.

  2. Overexpressed Arabidopsis Annexin4 accumulates in inclusion bodylike structures

    PubMed Central

    Khachatoorian, Careen; Ramirez, Rigoberto A.; Hernandez, Fernando; Serna, Raphael; Kwok, Ernest Y.

    2015-01-01

    Large protein complexes form in the cytosol of prokaryotes and eukaryotes as assemblies of functional enzymes or aggregates of misfolded proteins. Their roles in the cell range from critical components of metabolism to disease-causing agents. We have observed a novel structure in the cells of transgenic Arabidopsis thaliana that appears to be a form of inclusion body. These long, spindle-shaped structures form when Arabidopsis are transformed to express high levels of the protein Annexin4 fused to a fluorescent protein. These structures, previously named darts, are visible in all cells of the plant throughout development. Darts take on a variety of morphologies including rings and figure-eights. These structures are not associated with the endomembrane system and are not membrane bounded. Darts appear to be insoluble aggregates of protein analogous to bacterial inclusion bodies and eukaryotic aggresomes. Similar structures have not been observed in untransformed plants, suggesting darts are artifacts of transgenic overexpression. PMID:25818562

  3. The Penguin: a Low Reynolds Number Powered Glider for Station Keeping Missions

    NASA Technical Reports Server (NTRS)

    Costello, J. K.; Greene, D. W.; Lee, T. T.; Matier, P. T.; Mccarthy, T. R.; Mcguire, R. J.; Schuette, M. J.

    1990-01-01

    The Penguin is a low Reynolds number (approx. 100,000) remotely piloted vehicle (RPV). It was designed to fly three laps indoors around two pylons in a figure-eight course while maximizing loiter time. The Penguin's low Reynolds number mission is an important one currently being studied for possible future flights in the atmospheres of other planets and for specialized military missions. Although the Penguin's mission seemed quite simple at first, the challenges of such low Reynolds number flight have proven to be quite unique. In addition to the constraint of low Reynolds number flight, the aircraft had to be robust in its control, highly durable, and it had to carry a small instrument package. The Penguin's flight plan, concept, performance, aerodynamic design, weight estimation, structural design, propulsion, stability and control, and cost estimate is detailed.

  4. Spinal reflex evoked by a pair of opposing pulsed magnetic fields

    NASA Astrophysics Data System (ADS)

    Ueno, S.; Hiwaki, O.

    1991-04-01

    A noninvasive method of magnetic stimulation of the spinal roots was designed. The basic idea is to concentrate induced eddy currents in a target by a pair of opposing pulsed magnetic fields. A figure-eight coil was positioned outside the median of the back so that time varying magnetic fields pass through the body in opposite directions around the target. Magnetic stimulation of the spinal roots of human and a rabbit was carried out. It was found that each spine level can be stimulated selectively, producing electromyographic waves related to both the H-reflex and M-wave. The results indicate that the M-wave can be produced by currents flowing either in the rostral or caudal direction, whereas the H-reflex is only generated by currents flowing in the caudal direction. The H-reflex elicited by magnetic stimulation of nerves in the vicinity of the spine becomes a new tool in diagnosis of neuromuscular system diseases.

  5. A new genus of soft coral of the family Alcyoniidae (Cnidaria, Octocorallia) with re-description of a new combination and description of a new species

    PubMed Central

    Benayahu, Yehuda; McFadden, Catherine S.

    2011-01-01

    Abstract A new genus, Aldersladum (family Alcyoniidae), is established to accommodate a previously described species, Efflatounaria sodwanae Benayahu, 1993 (family Xeniidae) from Sodwana Bay, South Africa that was wrongly assigned to the latter genus. This species is redescribed and a second new species, Aldersladum jengi from Penghu Is., Taiwan, is described. The diagnostic features of the new genus include the presence of only figure-eight shaped platelets in all parts of the colony, thus differentiating it from all known genera of the Alcyoniidae. Based on examination of additional material from other localities, the zoogeographical distribution of the genus is confirmed to include the coral reefs of South Africa, Kenya, Gulf of Oman, Taiwan and Japan. Phylogenetic analyses of two mitochondrial genes strongly support its placement in the family Alcyoniidae. PMID:21594162

  6. High-performance, vibration-immune, fiber-laser frequency comb.

    PubMed

    Baumann, Esther; Giorgetta, Fabrizio R; Nicholson, Jeffrey W; Swann, William C; Coddington, Ian; Newbury, Nathan R

    2009-03-01

    We demonstrate an environmentally robust optical frequency comb based on a polarization-maintaining, all-fiber, figure-eight laser. The comb is phase locked to a cavity-stabilized cw laser by use of an intracavity electro-optic phase modulator yielding 1.6 MHz feedback bandwidth. This high bandwidth provides close to shot-noise-limited residual phase noise between the comb and cw reference laser of -94 dBc/Hz from 20 Hz to 200 kHz and an integrated in-loop phase noise of 32 mrad from 1 Hz to 1 MHz. Moreover, the comb remains phase locked under significant mechanical vibrations of over 1 g. This level of environmental robustness is an important step toward a fieldable fiber frequency comb. PMID:19252577

  7. Nuclear-magnetic-resonance quantum calculations of the Jones polynomial

    SciTech Connect

    Marx, Raimund; Spoerl, Andreas; Pomplun, Nikolas; Schulte-Herbrueggen, Thomas; Glaser, Steffen J.; Fahmy, Amr; Kauffman, Louis; Lomonaco, Samuel; Myers, John M.

    2010-03-15

    The repertoire of problems theoretically solvable by a quantum computer recently expanded to include the approximate evaluation of knot invariants, specifically the Jones polynomial. The experimental implementation of this evaluation, however, involves many known experimental challenges. Here we present experimental results for a small-scale approximate evaluation of the Jones polynomial by nuclear magnetic resonance (NMR); in addition, we show how to escape from the limitations of NMR approaches that employ pseudopure states. Specifically, we use two spin-1/2 nuclei of natural abundance chloroform and apply a sequence of unitary transforms representing the trefoil knot, the figure-eight knot, and the Borromean rings. After measuring the nuclear spin state of the molecule in each case, we are able to estimate the value of the Jones polynomial for each of the knots.

  8. Hysteresis effects in suspended sediment concentration of an allogenic river channel in a very arid environment

    NASA Astrophysics Data System (ADS)

    Yu, Guo-An; Disse, Markus; Yu, Yang

    2016-04-01

    Suspended sediment dynamics of the Tarim River, an allogenic and perennial river flowing in a very arid environment in China, are analyzed to examine the hysteresis effects based on data of flow discharge (Q) and suspended sediment concentration (SSC) from two hydrologic gauging stations in the river in the last five decades (1960-2011). Strong hysteresis effects existed in the sediment rating curves of the Tarim River. Under similar flow conditions, the first flood event in a year quite often causes higher suspended sediment concentration (SSC value), and form a rating curve visibly different from later flood processes. The successive flood events often form rating curves gradually from left to right progressively with time on the SSC-Q plot, indicating that higher flow intensity is needed for later flood events to reach the same SSC value of the earlier flood events. Three hysteresis loop forms, i.e., clockwise, anti-clockwise and Figure-eight existed with occurrence frequency of 57%, 27.3% and 15.6% respectively, showing that clockwise loop is the major hysteresis form and sediment load is generally derived from the channel bed. The very weak banks due to composition of quite homogeneous noncohesive particles (fine sand, silt and almost no clay content) often induce bank failure, which complicates suspended sediment dynamics and causes to shape different hysteresis loops. Somehow random but occurrence of bank collapse with higher possibility near the peak and at the falling limb of a flood hydrograph is probably the major reason causing anti-clockwise and figure-eight hysteresis loops.

  9. FBG-based reconfigurable bidirectional OXC for 8×10 Gb/s DWDM transmission

    NASA Astrophysics Data System (ADS)

    Liaw, Shien-Kuei; Tsai, Pei-Shih; Wang, Hsiang; Le Minh, Hoa; Ghassemlooy, Zabih

    2016-01-01

    The paper presents a bidirectional high-speed, power-compensated, 3×3 reconfigurable and multiwavelength optical cross-connect (RMB-OXC) for all-optical networks. RMB-OXC characteristics and its performance are experimentally verified in a bidirectional 8-channel×10 Gb/s capacity system. The optical signal to noise ratio (OSNR) is achieved of 18.4 dB corresponds to a BER of 5×10-10. The channel cross-connect function was demonstrated by incorporating RMB-OXC in an 50 km lightwave system. We have observed only ~0.5 dB power penalty in the bidirectional transmission in comparison to the unidirectional transmission. The proposed RMB-OXC has vast potential and it can be utilized in many applications in high-speed wavelength division multiplexed (WDM) networks.

  10. MEMS for optical communication: present and future

    NASA Astrophysics Data System (ADS)

    Pu, Chuan; Lee, Shi-sheng; Park, Sangtae; Chu, Patrick B.; Brener, Igal

    2002-07-01

    The current fiber optical communication system has evolved into a complicated multi-wavelength system with the deployment of Wavelength Division Multiplexing (WDM) networks. Many innovative technologies are desired to materialize its vast capacities and promises. MEMS technology has recently emerged as a competitive candidate to solve many technical challenges encountered in current WDM networks. Its applications have spanned from large scale optical switch fabrics such as optical cross-connects, optical add/drop multiplexers, to a large variety of active and passive optical components for transmission networks, such as tunable lasers and filters, dispersion compensation devices, amplifier gain equalizers, polarization controllers, and many others. In this paper we will discuss the current development status, promises and challenges, and the future prospects of MEMS technologies for optical communication, with a primary focus on MEMS-based optical cross-connects.

  11. Novel cryogen-free actively shielded superconducting magnets for maglev vehicles. Final report, August 1991-June 1992

    SciTech Connect

    Vermilyea, M.E.

    1992-06-01

    The report presents the results of a research effort into the design of a shielded superconducting magnet system for a maglev vehicle. The magnet design is based on a novel cryogen-free technology which allows operation without the use of any cryogenic fluids. This is accomplished by the use of a two-stage Gifford-McMahon (G-M) cryogenic refrigerator to provide cooling of the coil and a single cryostat thermal radiation shield by conduction. The design operating temperature of the magnet is 7.5 K, and that of the shield is 43 K. The magnet is wound with a tape form of niobium tin superconductor which allows operation at a module current density of 8100 A/sq cm at a flux density of 3.4 T at the 7.5 K temperature with a margin of 4.5 K to critical temperature. The magnet design is coupled with a linear synchronous motor and null-flux sidewall levitation system to provide a workable maglev system design. Costs for several components of the design, including coils and cryostat, shielding, and power conditioning apparatus are estimated.

  12. Digital-data receiver synchronization method and apparatus

    DOEpatents

    Smith, Stephen F.; Turner, Gary W.

    2005-12-06

    Digital-data receiver synchronization is provided with composite phase-frequency detectors, mutually cross-connected comparison feedback or both to provide robust reception of digital data signals. A single master clock may be used to provide frequency signals. Advantages can include fast lock-up time in moderately to severely noisy conditions, greater tolerance to noise and jitter when locked, and improved tolerance to clock asymmetries.

  13. Digital-data receiver synchronization

    DOEpatents

    Smith, Stephen F.; Turner, Gary W.

    2005-08-02

    Digital-data receiver synchronization is provided with composite phase-frequency detectors, mutually cross-connected comparison feedback or both to provide robust reception of digital data signals. A single master clock can be used to provide frequency signals. Advantages can include fast lock-up time in moderately to severely noisy conditions, greater tolerance to noise and jitter when locked, and improved tolerance to clock asymmetries.

  14. Improving Data Mobility & Management for International Cosmology

    SciTech Connect

    Borrill, Julian; Dart, Eli; Gore, Brooklin; Habib, Salman; Myers, Steven T.; Nugent, Peter; Petravick, Don; Thomas, Rollin

    2015-10-02

    In February 2015 the third workshop in the CrossConnects series, with a focus on Improving Data Mobility & Management for International Cosmology, was held at Lawrence Berkeley National Laboratory. Scientists from fields including astrophysics, cosmology, and astronomy collaborated with experts in computing and networking to outline strategic opportunities for enhancing scientific productivity and effectively managing the ever-increasing scale of scientific data.

  15. Learning new tricks from an old dog: MalT of the Escherichia coli maltose system is part of a complex regulatory network.

    PubMed

    Boos, W; Böhm, A

    2000-09-01

    The regulation of the maltose system in Escherichia coli has traditionally been viewed as a simple positive feedback loop. Today, we know that there are cross connections to several, seemingly unrelated, metabolic pathways. MalT, the central activator of the mal genes, is the key element in this complex regulatory network and integrates the different signals to give an appropriate transcriptional response. PMID:10973069

  16. Crosstalk accumulation performance comparison among different OXC architecture

    NASA Astrophysics Data System (ADS)

    Guan, Ai-hong; Liu, Ji-cheng; Fu, Hong-liang

    2007-11-01

    Optical crosstalk imposes a major limit to the practical implementation of optical cross-connects (OXCs). Inraband crosstalk contributions in three types of OXCs topologies based on the dilated Benes (DB) and generally modified dilated Benes (GMDB) networks are investigated and compared. Numerical simulation and experimental results confirm that OXCs based on GMDB networks can eliminate intraband crosstalk influence effectively compared with OXCs based on DB networks.

  17. Digital-data receiver synchronization method and apparatus

    DOEpatents

    Smith, Stephen F [Loudon, TN; Turner, Gary W [Clinton, TN

    2009-09-08

    Digital data receiver synchronization is provided with composite phase-frequency detectors, mutually cross-connected comparison feedback or both to provide robust reception of digital data signals. A single master clock can be used to provide frequency signals. Advantages can include fast lock-up time in moderately to severely noisy conditions, greater tolerance to noise and jitter when locked, and improved tolerance to clock asymmetries.

  18. Optical transposition transform interconnects using a free-space and fiber hybrid module

    NASA Astrophysics Data System (ADS)

    Popelek, Jan; Li, Yao

    1999-04-01

    Cross-connect switch is a popular switching architecture for telecom and datacom applications. Using various switching components and a k-shuffle interconnect, a cross-connect switch can be configured for general-purpose, blocking as well as non-blocking networking applications. We show that a 1D k-shuffle interconnect pattern is topologically equivalent to a 2D transposition transform pattern. Based on this observation and using space-invariant optical components, the transposition transform interconnect is experimentally implemented. To achieve a sensible packing, we propose to incorporate fiber arrays into the implementation so that the interconnect offers connectorized plug-and-play capability with its switching arrays. Experimental results of implementing a 256 X 256 connectorized free-space and fiber hybrid transposition transform interconnect for cross-connect switching are presented. Key parameters, such as insertion loss, cross- talk, and bit-error-rate of the hybrid interconnect module are measured. Video data are used to demonstrate interconnect quality of various link channels. Scalability to larger interconnects are speculated.

  19. Comparative human health risk analysis of coastal community water and waste service options.

    PubMed

    Schoen, Mary E; Xue, Xiaobo; Hawkins, Troy R; Ashbolt, Nicholas J

    2014-08-19

    As a pilot approach to describe adverse human health effects from alternative decentralized community water systems compared to conventional centralized services (business-as-usual [BAU]), selected chemical and microbial hazards were assessed using disability adjusted life years (DALYs) as the common metric. The alternatives included: (1) composting toilets with septic system, (2) urine-diverting toilets with septic system, (3) low flush toilets with blackwater pressure sewer and on-site greywater collection and treatment for nonpotable reuse, and (4) alternative 3 with on-site rainwater treatment and use. Various pathogens (viral, bacterial, and protozoan) and chemicals (disinfection byproducts [DBPs]) were used as reference hazards. The exposure pathways for BAU included accidental ingestion of contaminated recreational water, ingestion of cross-connected sewage to drinking water, and shower exposures to DBPs. The alternative systems included ingestion of treated greywater from garden irrigation, toilet flushing, and crop consumption; and ingestion of treated rainwater while showering. The pathways with the highest health impact included the ingestion of cross-connected drinking water and ingestion of recreational water contaminated by septic seepage. These were also among the most uncertain when characterizing input parameters, particularly the scale of the cross-connection event, and the removal of pathogens during groundwater transport of septic seepage. A comparison of the health burdens indicated potential health benefits by switching from BAU to decentralized water and wastewater systems. PMID:24988142

  20. Spatial Light Modulators as Optical Crossbar Switches

    NASA Technical Reports Server (NTRS)

    Juday, Richard

    2003-01-01

    A proposed method of implementing cross connections in an optical communication network is based on the use of a spatial light modulator (SLM) to form controlled diffraction patterns that connect inputs (light sources) and outputs (light sinks). Sources would typically include optical fibers and/or light-emitting diodes; sinks would typically include optical fibers and/or photodetectors. The sources and/or sinks could be distributed in two dimensions; that is, on planes. Alternatively or in addition, sources and/or sinks could be distributed in three dimensions -- for example, on curved surfaces or in more complex (including random) three-dimensional patterns.

  1. Wireless power transmission for biomedical implants: The role of near-zero threshold CMOS rectifiers.

    PubMed

    Mohammadi, Ali; Redoute, Jean-Michel; Yuce, Mehmet R

    2015-01-01

    Biomedical implants require an electronic power conditioning circuitry to provide a stable electrical power supply. The efficiency of wireless power transmission is strongly dependent on the power conditioning circuitry specifically the rectifier. A cross-connected CMOS bridge rectifier is implemented to demonstrate the impact of thresholds of rectifiers on wireless power transfer. The performance of the proposed rectifier is experimentally compared with a conventional Schottky diode full wave rectifier over 9 cm distance of air and tissue medium between the transmitter and receiver. The output voltage generated by the CMOS rectifier across a 1 KΩ resistive load is around twice as much as the Schottky rectifier. PMID:26737525

  2. Lamar repowering project's creative modeling of old and new wins Marmaduke award

    SciTech Connect

    Peltier, R.

    2008-08-15

    Lamar Light and Power is a municipal utility that has been generating the south eastern Colorado city's electricity since 1920. Rising natural gas and oil costs pushed LL & P to retire its steam plant five years ago and begin hunting for more economic power sources. The answer: repower the existing plant with a state-of-the-art coal-fired circulating fluidized-bed combustor and cross-connect old and new steam turbines. The 120 million dollar project will stabilize the region's electricity rates for many years to come. 10 figs. 1 tab.

  3. A parameter map of synthetic jet regimes based on the Reynolds and Stokes numbers: Commentary on the article by Rimasauskiene et al.

    NASA Astrophysics Data System (ADS)

    Broučková, Z.; Šafařík, P.; Trávníček, Z.

    2016-02-01

    Recently, Rimasauskiene et al. ([1] Mech. Syst. Signal Process. (2015) 50-51) presented an experimental study focusing on synthetic jets. Their paper presented a parameter map based on the Reynolds number. However, the map was shown without an adequate explanation, without definition of the horizontal axis, and without cross-connections with previous literature. This commentary attempts (A) to elucidate the unnecessary misunderstanding for readers and (B) to reveal that the parameter map, based on the Reynolds and Stokes numbers, can be a useful tool in the study of synthetic jets.

  4. Differences in gaze anticipation for locomotion with and without vision.

    PubMed

    Authié, Colas N; Hilt, Pauline M; N'Guyen, Steve; Berthoz, Alain; Bennequin, Daniel

    2015-01-01

    Previous experimental studies have shown a spontaneous anticipation of locomotor trajectory by the head and gaze direction during human locomotion. This anticipatory behavior could serve several functions: an optimal selection of visual information, for instance through landmarks and optic flow, as well as trajectory planning and motor control. This would imply that anticipation remains in darkness but with different characteristics. We asked 10 participants to walk along two predefined complex trajectories (limaçon and figure eight) without any cue on the trajectory to follow. Two visual conditions were used: (i) in light and (ii) in complete darkness with eyes open. The whole body kinematics were recorded by motion capture, along with the participant's right eye movements. We showed that in darkness and in light, horizontal gaze anticipates the orientation of the head which itself anticipates the trajectory direction. However, the horizontal angular anticipation decreases by a half in darkness for both gaze and head. In both visual conditions we observed an eye nystagmus with similar properties (frequency and amplitude). The main difference comes from the fact that in light, there is a shift of the orientations of the eye nystagmus and the head in the direction of the trajectory. These results suggest that a fundamental function of gaze is to represent self motion, stabilize the perception of space during locomotion, and to simulate the future trajectory, regardless of the vision condition. PMID:26106313

  5. [Electrovectorcardiographic manifestations of supraventricular ectopic rhythms (an interpretive hypothesis)].

    PubMed

    de Micheli, A; Medrano, G A

    1989-01-01

    When a low right atrial rhythm is present, P waves are negative in the low leads, they are variable in a VR and positive in a VL and LI. The figure eighth PF loop is located in the first quadrant, the PH loop has a counterclockwise rotation, and the PS can rotate in either direction. In the presence of upper left atrial rhythms, P waves are positive in the low leads and negative in a VL and a VR. The PF and PH loops can be found in the third quadrant of both planes with a clockwise rotation. If the rhythm originates in low left atrial regions, negative P waves are recorded in left precordial leads and positive ones in a VR and a VL. The PF loop has counterclockwise rotation or its branches superimposed and is situated in the second quadrant; PH with clockwise rotation is registered in the third quadrant; PS with either counterclockwise or clockwise rotation develops above and slightly ahead of the E point. When a nodal rhythm exists, P waves are negative in the low leads. The P loops show a counterclockwise rotation or a figure eight morphology. In the absence of atrial enlargements, the PF loop can be recorded in the first quadrant and the PH in the first or the fourth quadrant. PMID:2696444

  6. Mode-locked fiber laser using the Sagnac interferometer and the nonlinear polarization rotation

    NASA Astrophysics Data System (ADS)

    Ibarra-Escamilla, Baldeamr; Kuzin, Evgueni A.; Haus, Joseph W.; Pottiez, Olivier; Gomez-Garcia, Dario E.; Gutierrez-Zainos, Francisco; Mendoza-Vazquez, Sergio; Grajales-Coutico, Ruben

    2003-07-01

    In figure-eight lasers (F8L) mode locking is achieved through a nonlinear fiber amplifier loop mirror (NALM) or an asymmetrical nonlinear optical loop mirror (NOLM). Recently, we have theoretically shown that the symmetrical NOLM with a twisted fiber is useful for passive mode locking of fiber lasers. In this work we experimentally demonstrate the operation of a F8L based on the symmetrical NOLM with a twisted low-birefringence fiber in the loop. The modelocking operation is achieved by nonlinear polarization rotation. We found that the counter-propagating beams accumulate a differential nonlinear phase shift when they have different As (where As is the Stokes parameter). At the input NOLM, we used a polarizer controller to adjust the clockwise beam to be circularly polarized, As=1. In the loop of the NOLM, we used a quarter-wave retarder to transform the counter-clockwise beam to linear polarization, As=0. The quarter-wave retarder was the only element that we adjust to achieve modelocking. The pulse repetition frequency was 0.8 MHz. The FWHM of the autocorrelation function was 0.7 ps. We used a pump power of 80 mW to get the modelocking operation. The modelocked laser ran in stable operation for hours. Even in this first experiments the laser shown several advantages. The adjustment procedure was straightforward. The laser shows stable operation and exhibits high pulse energy. We achieved stable generation of subpicosecond pulses with milliwatts of average output power.

  7. Dynamic multi-channel TMS with reconfigurable coil.

    PubMed

    Jiang, Ruoli; Jansen, Ben H; Sheth, Bhavin R; Chen, Ji

    2013-05-01

    Investigations of the causal involvement of particular brain areas and interconnections in behavior require an external stimulation system with reasonable spatio-temporal resolution. Current transcranial magnetic stimulation (TMS) technology is limited to stimulating a single brain area once in a given trial. Here, we present a feasibility study for a novel TMS system based on multi-channel reconfigurable coils. With this hardware, researchers will be able to stimulate multiple brain sites in any temporal order in a trial. The system employs a wire-mesh coil, constructed using x- and y-directional wires. By varying the current direction and/or strength on each wire, we can configure the proposed mesh-wire coil into a standard loop coil and figure-eight coil of varying size. This provides maximum flexibility to the experimenter in that the location and extent of stimulation on the brain surface can be modified depending on experimental requirement. Moreover, one can dynamically and automatically modify the site(s) of stimulation several times within the span of seconds. By pre-storing various sequences of excitation patterns inside a control unit, one can explore the effect of dynamic TMS on behavior, in associative learning, and as rehabilitative therapy. Here, we present a computer simulation and bench experiments that show the feasibility of the dynamically-reconfigurable coil. PMID:23193321

  8. Three-body choreographies in given curves

    NASA Astrophysics Data System (ADS)

    Ozaki, Hiroshi; Fukuda, Hiroshi; Fujiwara, Toshiaki

    2009-10-01

    As shown by Johannes Kepler in 1609, in the two-body problem, the shape of the orbit, a given ellipse, and a given non-vanishing constant angular momentum determine the motion of the planet completely. Even in the three-body problem, in some cases, the shape of the orbit, conservation of the center of mass and a constant of motion (the angular momentum or the total energy) determine the motion of the three bodies. We show, by a geometrical method, that choreographic motions, in which equal mass three bodies chase each other around the same curve, will be uniquely determined for the following two cases. (i) Convex curves that have point symmetry and non-vanishing angular momentum are given. (ii) Eight-shaped curves which are similar to the curve for the figure-eight solution and the energy constant are given. The reality of the motion should be tested whether the motion satisfies an equation of motion or not. Extensions of the method for generic curves are shown. The extended methods are applicable to generic curves which do not have point symmetry. Each body may have its own curve and its own non-vanishing masses.

  9. VIV of a Flexible Cylinder: Three-dimensional Response Reconstruction from Limited Localized Measurement Points

    NASA Astrophysics Data System (ADS)

    Seyed-Aghazadeh, Banafsheh; Modarres-Sadeghi, Yahya

    2015-11-01

    Vortex-induced vibration (VIV) of a low mass ratio flexible cylinder (m*<1), is studied experimentally. The flexible tension-dominated cylinder was held fixed at both ends and was immersed in the uniform incoming flow. Dynamic response of the system was studied in the reduced velocity range of U* = 2.9 - 14.5 and the Reynolds number range of Re = 315 - 1580. Continuous response of the cylinder was reconstructed from limited number of measurement points based on modal expansion theorem modified using Modal Assurance Criterion (MAC). This reconstruction technique made it possible to properly reconstruct a continuous response along the length of the cylinder, even when the measurement points were localized in a small region of the cylinder. Mono- and multi-frequency excitation responses as well as transition from low mode numbers to higher ones were studied. Also, flow forces acting on the cylinder were calculated and they showed a consistent relation between the regions where the cylinder was being excited by the flow (CLv>0) and the counterclockwise figure-eight trajectories of oscillations in which the phase difference between the inline and crossflow directions were in the range of φxy =[ 0 π].

  10. Dynamical analysis of a cubic Liénard system with global parameters (II)

    NASA Astrophysics Data System (ADS)

    Chen, Hebai; Chen, Xingwu

    2016-06-01

    In this paper, we continue to study the global dynamics of a cubic Liénard system for global parameters in the case of three equilibria to follow (2015 Nonlinearity 28 3535–62), which deals with the case of two equilibria. We first analyse qualitative properties of all equilibria and judge the existences of limit cycles and homoclinic loops and their numbers. Then we obtain the bifurcation diagram and all phase portraits as our main results. Based on these results, in the case of three equilibria a positive answer to conjecture 3.2 of (1998 Nonlinearity 11 1505–19), which is about the existence of some function whose graph is exactly the surface of double limit cycles, is obtained. Moreover, a parameter region for the nonexistence of figure-eight loops is given theoretically to compensate for previous numerical results and is illustrated numerically. Supported by NSFC 11471228, 11572263, the Fundamental Research Funds for the Central Universities and Cultivation Foundation of Excellent Doctoral Dissertation of Southwest Jiaotong University (2015).

  11. Tightening the knot in phytochrome by single-molecule atomic force microscopy.

    PubMed

    Bornschlögl, Thomas; Anstrom, David M; Mey, Elisabeth; Dzubiella, Joachim; Rief, Matthias; Forest, Katrina T

    2009-02-18

    A growing number of proteins have been shown to adopt knotted folds. Yet the biological roles and biophysical properties of these knots remain poorly understood. We used protein engineering and atomic force microscopy to explore the single-molecule mechanics of the figure-eight knot in the chromophore-binding domain of the red/far-red photoreceptor, phytochrome. Under load, apo phytochrome unfolds at forces of approximately 47 pN, whereas phytochrome carrying its covalently bound tetrapyrrole chromophore unfolds at approximately 73 pN. These forces are not unusual in mechanical protein unfolding, and thus the presence of the knot does not automatically indicate a superstable protein. Our experiments reveal a stable intermediate along the mechanical unfolding pathway, reflecting the sequential unfolding of two distinct subdomains in phytochrome, potentially the GAF and PAS domains. For the first time (to the best of our knowledge), our experiments allow a direct determination of knot size under load. In the unfolded chain, the tightened knot is reduced to 17 amino acids, resulting in apparent shortening of the polypeptide chain by 6.2 nm. Steered molecular-dynamics simulations corroborate this number. Finally, we find that covalent phytochrome dimers created for these experiments retain characteristic photoreversibility, unexpectedly arguing against a dramatic rearrangement of the native GAF dimer interface upon photoconversion. PMID:19217867

  12. Material Properties of Hagfish Skin, with Insights into Knotting Behaviors.

    PubMed

    Clark, Andrew J; Crawford, Callie H; King, Brooke D; Demas, Andrew M; Uyeno, Theodore A

    2016-06-01

    Hagfishes (Myxinidae) often integrate whole-body knotting movements with jawless biting motions when reducing large marine carcasses to ingestible items. Adaptations for these behaviors include complex arrangements of axial muscles and flexible, elongate bodies without vertebrae. Between the axial muscles and the hagfish skin is a large, blood-filled subcutaneous sinus devoid of the intricate, myoseptal tendon networks characteristic of the taut skins of other fishes. We propose that the loose-fitting skin of the hagfish facilitates the formation and manipulation of body knots, even if it is of little functional significance to steady swimming. Hagfish skin is a relatively thick, anisotropic, multilayered composite material comprising a superficial, thin, and slimy epidermis, a middle dermal layer densely packed with fibrous tissues, and a deep subdermal layer comprised of adipose tissue. Hagfish skin is stiffer when pulled longitudinally than circumferentially. Stress-strain data from uniaxial tensile tests show that hagfish skins are comparable in tensile strength and stiffness to the taut skins of elongate fishes that do not engage in knotting behaviors (e.g., sea lamprey and penpoint gunnel). Sheath-core-constructed ropes, which serve as more accurate models for hagfish bodies, demonstrate that loose skin (extra sheathing) enhances flexibility of the body (rope). Along with a loose-fitting skin, the morphologies of hagfish skin parallel those of moray eels, which are also known for generating and manipulating figure-eight-style body knots when struggling with prey. PMID:27365419

  13. Imaging the early stages of phospholipase C/sphingomyelinase activity on vesicles containing coexisting ordered-disordered and gel-fluid domains[S

    PubMed Central

    Ibarguren, Maitane; López, David J.; Montes, L.-Ruth; Sot, Jesús; Vasil, Adriana I.; Vasil, Michael L.; Goñi, Félix M.; Alonso, Alicia

    2011-01-01

    The binding and early stages of activity of a phospholipase C/sphingomyelinase from Pseudomonas aeruginosa on giant unilamellar vesicles (GUV) have been monitored using fluorescence confocal microscopy. Both the lipids and the enzyme were labeled with specific fluorescent markers. GUV consisted of a mixture of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, and cholesterol in equimolar ratios, to which 5–10 mol% of the enzyme end-product ceramide and/or diacylglycerol were occasionally added. Morphological examination of the GUV in the presence of enzyme reveals that, although the enzyme diffuses rapidly throughout the observation chamber, detectable enzyme binding appears to be a slow, random process, with new bound-enzyme-containing vesicles appearing for several minutes. Enzyme binding to the vesicles appears to be a cooperative process. After the initial cluster of bound enzyme is detected, further binding and catalytic activity follow rapidly. After the activity has started, the enzyme is not released by repeated washing, suggesting a “scooting” mechanism for the hydrolytic activity. The enzyme preferentially binds the more disordered domains, and, in most cases, the catalytic activity causes the disordering of the other domains. Simultaneously, peanut- or figure-eight-shaped vesicles containing two separate lipid domains become spherical. At a further stage of lipid hydrolysis, lipid aggregates are formed and vesicles disintegrate. PMID:21252263

  14. Bulk mixed ion electron conduction in amorphous gallium oxide causes memristive behaviour.

    PubMed

    Aoki, Yoshitaka; Wiemann, Carsten; Feyer, Vitaliy; Kim, Hong-Seok; Schneider, Claus Michael; Ill-Yoo, Han; Martin, Manfred

    2014-01-01

    In thin films of mixed ionic electronic conductors sandwiched by two ion-blocking electrodes, the homogeneous migration of ions and their polarization will modify the electronic carrier distribution across the conductor, thereby enabling homogeneous resistive switching. Here we report non-filamentary memristive switching based on the bulk oxide ion conductivity of amorphous GaOx (x~1.1) thin films. We directly observe reversible enrichment and depletion of oxygen ions at the blocking electrodes responding to the bias polarity by using photoemission and transmission electron microscopies, thus proving that oxygen ion mobility at room temperature causes memristive behaviour. The shape of the hysteresis I-V curves is tunable by the bias history, ranging from narrow counter figure-eight loops to wide hysteresis, triangle loops as found in the mathematically derived memristor model. This dynamical behaviour can be attributed to the coupled ion drift and diffusion motion and the oxygen concentration profile acting as a state function of the memristor. PMID:24632885

  15. Vortex-induced vibrations of a flexible cylinder at large inclination angle.

    PubMed

    Bourguet, Rémi; Triantafyllou, Michael S

    2015-01-28

    The free vibrations of a flexible circular cylinder inclined at 80° within a uniform current are investigated by means of direct numerical simulation, at Reynolds number 500 based on the body diameter and inflow velocity. In spite of the large inclination angle, the cylinder exhibits regular in-line and cross-flow vibrations excited by the flow through the lock-in mechanism, i.e. synchronization of body motion and vortex formation. A profound reconfiguration of the wake is observed compared with the stationary body case. The vortex-induced vibrations are found to occur under parallel, but also oblique vortex shedding where the spanwise wavenumbers of the wake and structural response coincide. The shedding angle and frequency increase with the spanwise wavenumber. The cylinder vibrations and fluid forces present a persistent spanwise asymmetry which relates to the asymmetry of the local current relative to the body axis, owing to its in-line bending. In particular, the asymmetrical trend of flow-body energy transfer results in a monotonic orientation of the structural waves. Clockwise and counter-clockwise figure eight orbits of the body alternate along the span, but the latter are found to be more favourable to structure excitation. Additional simulations at normal incidence highlight a dramatic deviation from the independence principle, which states that the system behaviour is essentially driven by the normal component of the inflow velocity. PMID:25512586

  16. Trajectories of Listeria-type motility in two dimensions

    NASA Astrophysics Data System (ADS)

    Wen, Fu-Lai; Leung, Kwan-tai; Chen, Hsuan-Yi

    2012-12-01

    Force generated by actin polymerization is essential in cell motility and the locomotion of organelles or bacteria such as Listeria monocytogenes. Both in vivo and in vitro experiments on actin-based motility have observed geometrical trajectories including straight lines, circles, S-shaped curves, and translating figure eights. This paper reports a phenomenological model of an actin-propelled disk in two dimensions that generates geometrical trajectories. Our model shows that when the evolutions of actin density and force per filament on the disk are strongly coupled to the disk self-rotation, it is possible for a straight trajectory to lose its stability. When the instability is due to a pitchfork bifurcation, the resulting trajectory is a circle; a straight trajectory can also lose stability through a Hopf bifurcation, and the resulting trajectory is an S-shaped curve. We also show that a half-coated disk, which mimics the distribution of functionalized proteins in Listeria, also undergoes similar symmetry-breaking bifurcations when the straight trajectory loses stability. For both a fully coated disk and a half-coated disk, when the trajectory is an S-shaped curve, the angular frequency of the disk self-rotation is different from that of the disk trajectory. However, for circular trajectories, these angular frequencies are different for a fully coated disk but the same for a half-coated disk.

  17. Complex dynamics of a fiber laser in non-stationary pulsed operation.

    PubMed

    Garcia-Sanchez, E; Pottiez, O; Bracamontes-Rodriguez, Y; Lauterio-Cruz, J P; Ibarra-Villalon, H E; Hernandez-Garcia, J C; Bello-Jimenez, M; Kuzin, E A

    2016-08-22

    Conventional mode locking is characterized by the generation of a stable train of optical pulses. Even in the noise-like pulsing regime of fiber lasers, sometimes described as partial mode locking, a periodic train of waveforms is still generated. In this work we study the dynamics of a figure-eight fiber laser away from the stable noise-like pulsing regime. By analyzing sequences of time-domain measurements performed with ns resolution, we reveal a wide range of puzzling dynamics, in which sub-structures emerge and drift away from the main bunch, decay or grow in a step-like manner, before vanishing abruptly. In some cases, sub-packets also concentrate in the central part of the period, forming one or multiple wide clouds that merge or split over time scales of seconds or minutes. Spontaneous transitions between these multiple states occur in a non-periodic manner, so that no quasi-stationary behavior is found over long time scales. These results provide a dramatic illustration of the extremely rich dynamics taking place in fiber lasers at the frontier of mode locking. PMID:27557173

  18. Compensation Techniques in Accelerator Physics

    SciTech Connect

    Sayed, Hisham Kamal

    2011-05-01

    Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

  19. Comparison of current distributions in electroconvulsive therapy and transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Sekino, Masaki; Ueno, Shoogo

    2002-05-01

    We compared current density distributions in electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) by numerical calculations. The model consisted of an air region and three types of tissues with different conductivities representing the brain, the skull, and the scalp. In the ECT model, electric currents were applied through electrodes with a voltage of 100 V. In the TMS model, a figure-eight coil (6 cm diameter per coil) was placed on the vertex of the head model. An alternating current with a peak intensity of 3.0 kA and a frequency of 4.2 kHz was applied to the coil. The maximum current densities inside the brain in ECT (bilateral electrode position) and TMS were 234 and 322 A/m2, respectively. The results indicate that magnetic stimulators can generate comparable current densities to ECT. While the skull significantly affected current distributions in ECT, TMS efficiently induced eddy currents in the brain. In addition, TMS is more beneficial than ECT because the localized current distribution reduces the risk of adverse side effects.

  20. Preliminary observations on the response of Chironex fleckeri (Cnidaria: Cubozoa: Chirodropida) to different colors of light.

    PubMed

    Gershwin, Lisa-Ann; Dawes, Peter

    2008-08-01

    Cubozoans are well known for their attraction to light and light-colored objects. Two highly venomous types are a public safety concern in Australian waters and elsewhere: Chironex fleckeri, long considered the world's deadliest animal and colloquially called the box jellyfish; and the irukandjis, a group of at least 10 species that cause various degrees of debilitating illness. We were asked by the tourism industry whether there might be a color of light that box jellyfish and irukandjis are not attracted to, such that nighttime diving activities might pose less risk of being stung. Our preliminary trials with Chironex fleckeri indicated a marked positive response to lights of white, red, yellow, green, orange, and blue. All colors elicited a strong and directed attraction to light; however, medusae slowed down their pulsation rate, streamed out their tentacles, and performed a series of figure-eight patterns back and forth through the lighted area when exposed to blue light, which we interpreted as feeding behavior. This compares curiously with a report subsequent to our testing, in which the small, mangrove-inhabiting cubomedusa Tripedalia cystophora and the beach-dwelling Chiropsella bronzie demonstrate a peak sensitivity to blue-green light in the region of 500 nm, and that the former is behaviorally attracted to blue and green light, but ignores red. This leaves open the possibility that Irukandji species, which are more closely related to Tripedalia than to Chironex, may be blind to red. PMID:18723637

  1. Optimal propulsive flapping in Stokes flows.

    PubMed

    Was, Loïc; Lauga, Eric

    2014-03-01

    Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds numbers, we compute in this paper the optimal flapping kinematics of a rigid spheroid in a Stokes flow. The hydrodynamics for the force generation and energetics of the flapping motion is solved exactly. We then compute analytically the gradient of a flapping efficiency in the space of all flapping gaits and employ it to derive numerically the optimal flapping kinematics as a function of the shape of the flapper and the amplitude of the motion. The kinematics of optimal flapping are observed to depend weakly on the flapper shape and are very similar to the figure-eight motion observed in the motion of insect wings. Our results suggest that flapping could be a exploited experimentally as a propulsion mechanism valid across the whole range of Reynolds numbers. PMID:24343130

  2. Vortex-induced vibrations of a flexible cylinder at large inclination angle

    PubMed Central

    Bourguet, Rémi; Triantafyllou, Michael S.

    2015-01-01

    The free vibrations of a flexible circular cylinder inclined at 80° within a uniform current are investigated by means of direct numerical simulation, at Reynolds number 500 based on the body diameter and inflow velocity. In spite of the large inclination angle, the cylinder exhibits regular in-line and cross-flow vibrations excited by the flow through the lock-in mechanism, i.e. synchronization of body motion and vortex formation. A profound reconfiguration of the wake is observed compared with the stationary body case. The vortex-induced vibrations are found to occur under parallel, but also oblique vortex shedding where the spanwise wavenumbers of the wake and structural response coincide. The shedding angle and frequency increase with the spanwise wavenumber. The cylinder vibrations and fluid forces present a persistent spanwise asymmetry which relates to the asymmetry of the local current relative to the body axis, owing to its in-line bending. In particular, the asymmetrical trend of flow–body energy transfer results in a monotonic orientation of the structural waves. Clockwise and counter-clockwise figure eight orbits of the body alternate along the span, but the latter are found to be more favourable to structure excitation. Additional simulations at normal incidence highlight a dramatic deviation from the independence principle, which states that the system behaviour is essentially driven by the normal component of the inflow velocity. PMID:25512586

  3. Relative effectiveness of central, peripheral, and abrupt-onset cues in visual attention.

    PubMed

    Koshino, H; Warner, C B; Juola, J F

    1992-11-01

    The relative effectiveness of central arrow, peripheral arrow, and abrupt-onset cues was assessed in a character recognition task. On each trial, either a central or a peripheral arrow cue was presented 0, 100, or 200 msec before the appearance of a three-digit display. Two of the digits were "uncamouflaged" from previous figure-eight masks, whereas the third digit appeared abruptly in a previously empty space. Four different groups of subjects were run in factorial combinations of high or low expected validities for arrow and onset cues. In Experiment 1, arrow cues were located centrally, near the fixation point. Abrupt onsets showed larger cost-plus benefits than central arrows, except when subjects expected the central cues to have higher validity than the onsets. In Experiment 2, arrow cues were located peripherally, near the display digits, and abrupt onsets were again more effective in capturing attention except when peripheral cues had higher validity and led the onsets by 100 msec or more. In both experiments, the relative effectiveness of abrupt onsets decreased with arrow SOA. The results were consistent with a model in which automatic and voluntary processes interact in their control of attentional resources. PMID:1484975

  4. Neural network training by integration of adjoint systems of equations forward in time

    NASA Technical Reports Server (NTRS)

    Toomarian, Nikzad (Inventor); Barhen, Jacob (Inventor)

    1992-01-01

    A method and apparatus for supervised neural learning of time dependent trajectories exploits the concepts of adjoint operators to enable computation of the gradient of an objective functional with respect to the various parameters of the network architecture in a highly efficient manner. Specifically, it combines the advantage of dramatic reductions in computational complexity inherent in adjoint methods with the ability to solve two adjoint systems of equations together forward in time. Not only is a large amount of computation and storage saved, but the handling of real-time applications becomes also possible. The invention has been applied it to two examples of representative complexity which have recently been analyzed in the open literature and demonstrated that a circular trajectory can be learned in approximately 200 iterations compared to the 12000 reported in the literature. A figure eight trajectory was achieved in under 500 iterations compared to 20000 previously required. The trajectories computed using our new method are much closer to the target trajectories than was reported in previous studies.

  5. Neural Network Training by Integration of Adjoint Systems of Equations Forward in Time

    NASA Technical Reports Server (NTRS)

    Toomarian, Nikzad (Inventor); Barhen, Jacob (Inventor)

    1999-01-01

    A method and apparatus for supervised neural learning of time dependent trajectories exploits the concepts of adjoint operators to enable computation of the gradient of an objective functional with respect to the various parameters of the network architecture in a highly efficient manner. Specifically. it combines the advantage of dramatic reductions in computational complexity inherent in adjoint methods with the ability to solve two adjoint systems of equations together forward in time. Not only is a large amount of computation and storage saved. but the handling of real-time applications becomes also possible. The invention has been applied it to two examples of representative complexity which have recently been analyzed in the open literature and demonstrated that a circular trajectory can be learned in approximately 200 iterations compared to the 12000 reported in the literature. A figure eight trajectory was achieved in under 500 iterations compared to 20000 previously required. Tbc trajectories computed using our new method are much closer to the target trajectories than was reported in previous studies.

  6. Migratory shearwaters integrate oceanic resources across the Pacific Ocean in an endless summer

    PubMed Central

    Shaffer, Scott A.; Tremblay, Yann; Weimerskirch, Henri; Scott, Darren; Thompson, David R.; Sagar, Paul M.; Moller, Henrik; Taylor, Graeme A.; Foley, David G.; Block, Barbara A.; Costa, Daniel P.

    2006-01-01

    Electronic tracking tags have revolutionized our understanding of broad-scale movements and habitat use of highly mobile marine animals, but a large gap in our knowledge still remains for a wide range of small species. Here, we report the extraordinary transequatorial postbreeding migrations of a small seabird, the sooty shearwater, obtained with miniature archival tags that log data for estimating position, dive depth, and ambient temperature. Tracks (262 ± 23 days) reveal that shearwaters fly across the entire Pacific Ocean in a figure-eight pattern while traveling 64,037 ± 9,779 km roundtrip, the longest animal migration ever recorded electronically. Each shearwater made a prolonged stopover in one of three discrete regions off Japan, Alaska, or California before returning to New Zealand through a relatively narrow corridor in the central Pacific Ocean. Transit rates as high as 910 ± 186 km·day−1 were recorded, and shearwaters accessed prey resources in both the Northern and Southern Hemisphere’s most productive waters from the surface to 68.2 m depth. Our results indicate that sooty shearwaters integrate oceanic resources throughout the Pacific Basin on a yearly scale. Sooty shearwater populations today are declining, and because they operate on a global scale, they may serve as an important indicator of climate change and ocean health. PMID:16908846

  7. Disturbance of visual search by stimulating to posterior parietal cortex in the brain using transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Iramina, Keiji; Ge, Sheng; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo

    2009-04-01

    In this study, we applied a transcranial magnetic stimulation (TMS) to investigate the temporal aspect for the functional processing of visual attention. Although it has been known that right posterior parietal cortex (PPC) in the brain has a role in certain visual search tasks, there is little knowledge about the temporal aspect of this area. Three visual search tasks that have different difficulties of task execution individually were carried out. These three visual search tasks are the "easy feature task," the "hard feature task," and the "conjunction task." To investigate the temporal aspect of the PPC involved in the visual search, we applied various stimulus onset asynchronies (SOAs) and measured the reaction time of the visual search. The magnetic stimulation was applied on the right PPC or the left PPC by the figure-eight coil. The results show that the reaction times of the hard feature task are longer than those of the easy feature task. When SOA=150 ms, compared with no-TMS condition, there was a significant increase in target-present reaction time when TMS pulses were applied. We considered that the right PPC was involved in the visual search at about SOA=150 ms after visual stimulus presentation. The magnetic stimulation to the right PPC disturbed the processing of the visual search. However, the magnetic stimulation to the left PPC gives no effect on the processing of the visual search.

  8. The vertical disk structure of the edge-on spiral galaxy NGC 3079

    NASA Technical Reports Server (NTRS)

    Veilleux, S.; Bland-Hawthorn, Jonathan; Cecil, G.; Tully, R. B.

    1993-01-01

    NGC 3079 is an edge-on SB(s)c galaxy at a redshift of 1225 km/s relative to the Local Group. Earlier researchers found a spectacular 'figure-eight' radio structure aligned along the minor axis of the galaxy, centered on the nucleus, and extending 3 kpc above and below the plane. The geometry of this structure and the evidence of unusually high nuclear gas velocities suggest that a wind-type outflow from the nucleus is taking place. The disk of NGC 3079 is also remarkable: it is extremely rich in H 2 regions and is the only unambiguous example of a galaxy outside M31 and our own Galaxy to exhibit 'Heiles-like' shells. Other researchers have also identified a nebulosity with a ragged X-shaped morphology formed by a system of lumpy filaments with individual lengths of 3 - 5 kpc. They suggest that this material is ambient halo gas entrained into the boundary layers of the nuclear outflow. The complex structure of the line emission in NGC 3079 makes this object an ideal target for an imaging spectroscopic study. The present paper reports the preliminary results of such a study.

  9. Bulk mixed ion electron conduction in amorphous gallium oxide causes memristive behaviour

    NASA Astrophysics Data System (ADS)

    Aoki, Yoshitaka; Wiemann, Carsten; Feyer, Vitaliy; Kim, Hong-Seok; Schneider, Claus Michael; Ill-Yoo, Han; Martin, Manfred

    2014-03-01

    In thin films of mixed ionic electronic conductors sandwiched by two ion-blocking electrodes, the homogeneous migration of ions and their polarization will modify the electronic carrier distribution across the conductor, thereby enabling homogeneous resistive switching. Here we report non-filamentary memristive switching based on the bulk oxide ion conductivity of amorphous GaOx (x~1.1) thin films. We directly observe reversible enrichment and depletion of oxygen ions at the blocking electrodes responding to the bias polarity by using photoemission and transmission electron microscopies, thus proving that oxygen ion mobility at room temperature causes memristive behaviour. The shape of the hysteresis I-V curves is tunable by the bias history, ranging from narrow counter figure-eight loops to wide hysteresis, triangle loops as found in the mathematically derived memristor model. This dynamical behaviour can be attributed to the coupled ion drift and diffusion motion and the oxygen concentration profile acting as a state function of the memristor.

  10. Pixel structure for asymmetry removal in ToF 3D camera

    NASA Astrophysics Data System (ADS)

    Kang, Byongmin; Shin, Jungsoon; Choi, Jaehyuk; Kim, James D. K.

    2014-03-01

    Most of time-of-flight (ToF) cameras have a 2-tap pixel structure for demodulating a reflected near infrared (NIR) from objects. In order to eliminate the asymmetry between two taps in the pixel, a ToF camera needs another measurement, which collects photo-generated electrons from reflected NIR by inverting the phase of clock signals to transfer gates. This asymmetry removal needs additional frame memories and suppresses the frame rate due to the additional timing budget. In this paper, we propose novel asymmetry removal scheme without timing and area overheads by employing 2×2 shared 2-tap pixels with cross-connected transfer gates. The 2-tap pixel is shared with neighbor pixels and transfer gates in the pixel are cross-connected between upper and lower pixels. In order to verify the proposed pixel architecture, an electron charge generated in floating diffusion is simulated. And then we try to calculate a depth from camera to objects using simulated electron charge and measure a linearity of depth. In simulation result, proposed pixel architecture has more linear graph than conventional pixel structure along the real distance of objects.

  11. Full vector spherical harmonic analysis of the Holocene geomagnetic field

    NASA Astrophysics Data System (ADS)

    Richardson, Marcia

    many of the expected characteristics of the field over time (high-latitude flux lobes, South Atlantic reverse flux patch, north pole reverse or null flux region).

  12. [Vectorcardiographic manifestations of atrial enlargements].

    PubMed

    de Micheli, A; Medrano, G A

    1990-01-01

    Rational interpretation of changes of the P loop due to atrial enlargements must to rely on the magnitude and spatial orientation of main resultant vectors of the activation sequence of the atria. Under normal conditions, these vectors give rise to a mean vector oriented to the left downward and discretely forward with respect to their point of origin. In the presence of right atrial enlargement, the manifestation of the first vector of atrial depolarization, oriented downward and forward, is increased. This one moves in the same direction as the mean vector of atrial depolarization, originating an elongated P loop of more than 100 mcv in the three planes. Nevertheless, in the horizontal plane, increase of the P loop voltage predominates when hypertrophy exists, while augmentation of its area predominates when dilatation exists. In left atrial enlargement, the manifestation of the second vector of atrial depolarization, oriented to the left and backward, is augmented, and it moves in the same direction as the mean vector of atrial depolarization. For this, the PF loop acquires a characteristic aspect of a boxing glove, an the PH loop becomes diphasic, with its posterior area more or less prominent, or with a typical figure-eight conformation. If a biatrial enlargement is present, the manifestation of both the main resultant vectors of atrial depolarization is accentuated. Therefore the voltage of the diphasic P loop increases. Moreover the Ps loop has a triangular configuration, with its base of 30 msc or more, located below its point of origin. Generally disturbances of interatrial and intraatrial conduction coexist owing to myocardial damage. PMID:2146934

  13. Functional Assessment of Corticospinal System Excitability in Karate Athletes

    PubMed Central

    Moscatelli, Fiorenzo; Messina, Giovanni; Valenzano, Anna; Monda, Vincenzo; Viggiano, Andrea; Messina, Antonietta; Petito, Annamaria; Triggiani, Antonio Ivano; Ciliberti, Michela Anna Pia; Monda, Marcellino; Capranica, Laura; Cibelli, Giuseppe

    2016-01-01

    Objectives To investigate the involvement of the primary motor cortex (M1) in the coordination performance of karate athletes through transcranial magnetic stimulation (TMS). Methods Thirteen right-handed male karate athletes (25.0±5.0 years) and 13 matched non-athlete controls (26.7±6.2 years) were enrolled. A single-pulse TMS was applied using a figure-eight coil stimulator. Resting motor threshold (rMT) was determined. Surface electromyography was recorded from the first dorsal interosseous muscle. Motor evoked potential (MEP) latencies and amplitudes at rMT, 110%, and 120% of rMT were considered. Functional assessment of the coordination performance was assessed by in-phase (IP) and anti-phase (AP) homolateral hand and foot coordination tasks performed at 80, 120, and 180 bpm. Results Compared to controls, athletes showed lower rMT (p<0.01), shorter MEP latency (p<0.01) and higher MEP amplitude (p<0.01), with a significant correlation (r = 0.50, p<0.01) between rMT and MEP latency. Coordination decreased with increasing velocity, and better IP performances emerged compared to AP ones (p<0.001). In general, a high correlation between rMT and coordination tasks was found for both IP and AP conditions. Conclusion With respect to controls, karate athletes present a higher corticospinal excitability indicating the presence of an activity-dependent alteration in the balance and interactions between inhibitory and facilitatory circuits determining the final output from the M1. Furthermore, the high correlation between corticospinal excitability and coordination performance could support sport-specific neurophysiological arrangements. PMID:27218465

  14. A hypomorphic mutation of the gamma-1 adaptin gene (Ap1g1) causes inner ear, retina, thyroid, and testes abnormalities in mice.

    PubMed

    Johnson, Kenneth R; Gagnon, Leona H; Chang, Bo

    2016-06-01

    Adaptor protein (AP) complexes function in the intracellular sorting and vesicular transport of membrane proteins. The clathrin-associated AP-1 complex functions at the trans-Golgi network and endosomes, and some forms of this complex are thought to mediate the sorting of proteins in plasma membranes of polarized epithelial cells. A null mutation of the mouse Ap1g1 gene, which encodes the gamma-1 subunit of the AP-1 complex, causes embryonic lethality when homozygous, indicating its critical importance in early development but precluding studies of its possible roles during later stages. Here, we describe our analyses of a new spontaneous mutation of Ap1g1 named "figure eight" (symbol fgt) and show that it is an in-frame deletion of 6 bp, which results in the elimination of two amino acids of the encoded protein. In contrast to Ap1g1 (-/-) null mice, mice homozygous for the recessive fgt mutation are viable with adult survival similar to controls. Although Ap1g1 is ubiquitously expressed, the phenotype of Ap1g1 (fgt) mutant mice is primarily restricted to abnormalities in sensory epithelial cells of the inner ear, pigmented epithelial cells of the retina, follicular epithelial cells of the thyroid gland, and the germinal epithelium of the testis, suggesting that impaired AP-1 sorting and targeting of membrane proteins in these polarized cells may underlie the observed pathologies. Ap1g1 (fgt) mutant mice provide a new animal model to study the in vivo roles of gamma-1 adaptin and the AP-1 complex throughout development and to investigate factors that underlie its associated phenotypic abnormalities. PMID:27090238

  15. Discharge and suspended sediment patterns in a small mountainous watershed with widely distributed rock fragments

    NASA Astrophysics Data System (ADS)

    Fang, N. F.; Shi, Z. H.; Chen, F. X.; Zhang, H. Y.; Wang, Y. X.

    2015-09-01

    Understanding and quantifying sediment loads is important in watersheds with highly erodible materials, which will eventually cause environmental and ecological problems. Within this context, suspended sediment (SS) transport and its temporal dynamics were studied in a small mountainous watershed with sloping lands containing rock fragments in subtropical China. Soils containing rock fragments with many macro-pores have a high permeability rate. Over a 7-year period, the mean runoff coefficient of this watershed was 0.65. Overall, 30 flood events were monitored and accounted for 95.5%, 27.3%, 17.1% of the total SS load, precipitation and total discharge, respectively, over a 5-year period. The presence of rock fragments in soils can affect soil loss. When comparing the soil loss in the studied watershed with that of other watersheds under similar climatic conditions, rock fragments negatively affect soil loss. However, an extreme event occurred on 14 August 1990, and the sediment load exhibited a phenomenon called "small deposits towards lump withdrawal", which resulted in a soil loss of 20,499 t (4.6 times the mean yearly soil loss). This event exhausted most of the SSs stored by the rock fragments on the slope and channel. Following this event, the mean SS concentration (SSC) of the 11 events was 1.05 kg m-3, and the mean SSC of the 18 previous events was 1.75 kg m-3. Twelve variables were separated using the classical hydrograph separation method. Partial least-squares regression (PLSR) was used to determine the highly co-related variables of the discharge. The results indicated that PLSR could explain runoff well. The relationship between discharge and SSC was highly scattered. During 24 flood events, three types of hysteresis loops were observed: clockwise (17 events), figure-eight (3 events), and complex (4 events).

  16. Basic study on the influence of inhibition induced by the magnetic stimulation on the peripheral nerve

    NASA Astrophysics Data System (ADS)

    Sato, Aya; Torii, Tetsuya; Iwahashi, Masakuni; Iramina, Keiji

    2015-05-01

    The purpose of this study is to analyze the inhibition mechanism of magnetic stimulation on motor function. A magnetic stimulator with a flat figure-eight coil was used to stimulate the peripheral nerve of the antebrachium. The intensity of magnetic stimulation was 0.8 T, and the stimulation frequency was 1 Hz. The amplitudes of the motor-evoked potentials (MEPs) at the abductor pollicis brevis muscle and first dorsal interosseous muscle were used to evaluate the effects of magnetic stimulation. The effects of magnetic stimulation were evaluated by analyzing the MEP amplitude before and after magnetic stimulation to the primary motor cortex. The results showed that MEP amplitude after magnetic stimulation compared with before magnetic stimulation decreased. Because there were individual differences in MEP amplitude induced by magnetic stimulation, the MEP amplitude after stimulation was normalized by the amplitude of each participant before stimulation. The MEP amplitude after stimulation decreased by approximately 58% (p < 0.01) on average compared with before stimulation. Previous studies suggested that magnetic stimulation to the primary motor cortex induced an increase or a decrease in MEP amplitude. Furthermore, previous studies have shown that the alteration in MEP amplitude was induced by cortical excitability based on magnetic stimulation. The results of this study showed that MEP amplitude decreased following magnetic stimulation to the peripheral nerve. We suggest that the decrease in MEP amplitude found in this study was obtained via the feedback from a peripheral nerve through an afferent nerve to the brain. This study suggests that peripheral excitement by magnetic stimulation of the peripheral nerve may control the central nervous system via afferent feedback.

  17. Effects of low-frequency repetitive transcranial magnetic stimulation on event-related potential P300

    NASA Astrophysics Data System (ADS)

    Torii, Tetsuya; Sato, Aya; Iwahashi, Masakuni; Iramina, Keiji

    2012-04-01

    The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effects of low-frequency and short-term rTMS by stimulating the supramarginal gyrus (SMG), which is considered to be the related area of P300 origin. In addition, the prolonged stimulation effects on P300 latency were analyzed after applying rTMS. A figure-eight coil was used to stimulate left-right SMG, and intensity of magnetic stimulation was 80% of motor threshold. A total of 100 magnetic pulses were applied for rTMS. The effects of stimulus frequency at 0.5 or 1 Hz were determined. Following rTMS, an odd-ball task was performed and P300 latency of ERP was measured. The odd-ball task was performed at 5, 10, and 15 min post-rTMS. ERP was measured prior to magnetic stimulation as a control. Electroencephalograph (EEG) was measured at Fz, Cz, and Pz that were indicated by the international 10-20 electrode system. Results demonstrated that different effects on P300 latency occurred between 0.5-1 Hz rTMS. With 1 Hz low-frequency magnetic stimulation to the left SMG, P300 latency decreased. Compared to the control, the latency time difference was approximately 15 ms at Cz. This decrease continued for approximately 10 min post-rTMS. In contrast, 0.5 Hz rTMS resulted in delayed P300 latency. Compared to the control, the latency time difference was approximately 20 ms at Fz, and this delayed effect continued for approximately 15 min post-rTMS. Results demonstrated that P300 latency varied according to rTMS frequency. Furthermore, the duration of the effect was not similar for stimulus frequency of low-frequency rTMS.

  18. Segmentation of endpoint trajectories does not imply segmented control.

    PubMed

    Sternad, D; Schaal, S

    1999-01-01

    While it is generally assumed that complex movements consist of a sequence of simpler units, the quest to define these units of action, or movement primitives, remains an open question. In this context, two hypotheses of movement segmentation of endpoint trajectories in three-dimensional human drawing movements are reexamined: (1) the stroke-based segmentation hypothesis based on the results that the proportionality coefficient of the two-thirds power law changes discontinuously with each new "stroke," and (2) the segmentation hypothesis inferred from the observation of piecewise planar endpoint trajectories of three-dimensional drawing movements. In two experiments human subjects performed a set of elliptical and figure eight patterns of different sizes and orientations using their whole arm in three dimensions. The kinematic characteristics of the endpoint trajectories and the seven joint angles of the arm were analyzed. While the endpoint trajectories produced similar segmentation features to those reported in the literature, analyses of the joint angles show no obvious segmentation but rather continuous oscillatory patterns. By approximating the joint angle data of human subjects with sinusoidal trajectories, and by implementing this model on a 7-degree-of-freedom (DOF) anthropomorphic robot arm, it is shown that such a continuous movement strategy can produce exactly the same features as observed by the above segmentation hypotheses. The origin of this apparent segmentation of endpoint trajectories is traced back to the nonlinear transformations of the forward kinematics of human arms. The presented results demonstrate that principles of discrete movement generation may not be reconciled with those of rhythmic movement as easily as has been previously suggested, while the generalization of nonlinear pattern generators to arm movements can offer an interesting alternative to approach the question of units of action. PMID:9928796

  19. NASA advanced-aeronautics design solar-powered remotely piloted vehicle

    SciTech Connect

    Elario, D.S.; Guillmette, N.H.; Lind, G.S.; Webster, J.D.; Ferreira, M.J.; Konstantakis, G.C.; Marshall, D.L.; Windt, C.L.

    1991-04-01

    Environmental problems such as the depletion of the ozone layer and air pollution demand a change in traditional means of propulsion that is sensitive to the ecology. Solar powered propulsion is a favorable alternative that is both ecologically harmless as well as cost effective. Integration of solar energy into designs ranging from futuristic vehicles to heating is beneficial to society. The design and construction of a Multi-Purpose Remotely Piloted Vehicle (MPRPV) seeks to verify the feasibility of utilizing solar propulsion as a primary fuel source. This task has been a year long effort by a group of ten students, divided into five teams, each dealing with different aspects of the design. The aircraft was designed to take-off, climb to the design altitude, fly in a sustained figure-eight flight path, and cruise for approximately one hour. This mission requires flight at Reynolds numbers between 150,000 and 200,000 and demands special considerations in the aerodynamic design in order to achieve flight in this regime. Optimal performance requires a light weight configuration with both structural integrity and maximum power availability. The structure design and choice of solar cells for the propulsion was governed by the weight, efficiency, and cost considerations. The final design is a MPRPV weighting 35 N which cruises 7 m/s at the design altitude of 50 m. The configuration includes a wing composed of balsa and foam NACA 6409 airfoil sections and carbon fiber spars, a tail of similar construction, and a truss structure fuselage. The propulsion system consists of 98 10 percent efficient solar cells donated by Mobil Solar, a NiCad battery for energy storage, and a folding propeller regulated by a lightweight and efficient control system. The airfoils and propeller chosen for the design were research and tested during the design process.

  20. Integrating research on ecohydrology and land use change with land use management

    NASA Astrophysics Data System (ADS)

    Bass, Brad; Byers, Ralph E.; Lister, Nina-Marie

    1998-10-01

    One objective of the International Geosphere-Biosphere Programme is to provide a scientific basis for sustainable development policies. Land use change and ecohydrology are important components of this scientific basis, but predicting change is difficult because of the scale and complexity of the interactions between non-linear ecohydrological and socio-economic processes at different spatial and temporal scales. A systems framework, the Ecosystem Approach, has been developed to conceptualize these interactions for the purpose of providing information for sustainable development policy. The Ecosystem Approach combines the dynamics of the Holling figure-eight model - a conceptual model of dynamics that stresses discontinuous change and destruction as an internal property of the system - and the properties of self-organizing systems with the socio political aspects of decision making.The Ecosystem Approach highlights the problems of managing change in complex systems when that change may involve unpredictable shifts to a different attractor. Although there are methods available to detect the occurrence of such shifts, both detection and modelling are complicated by the presence of semi-stable attractors. When a model or an ecosystem is on a semi-stable attractor, it may appear to remain stable for an extended period prior to changing as a consequence of inherent instabilities. When the shift to a new attractor occurs, it is quite sudden and unpredictable. A technical discussion on prediction under conditions of semi-stability and chaos is included because it enhances our understanding of the role of surprise in ecosystems, as well as the utility of simulation models.The principles of the Ecosystem Approach are derived from the theoretical discussion and an example of a land use policy in the Huron Natural Area in south-western Ontario. These principles provide a clear role for scientific research, and particularly simulation modelling, within the larger context of

  1. Physiological modules for generating discrete and rhythmic movements: action identification by a dynamic recurrent neural network

    PubMed Central

    Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana M.; Dan, Bernard; McIntyre, Joseph; Cheron, Guy

    2014-01-01

    In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles. We trained different instances of the same network on a single movement direction, on all four movement directions in a single movement plane, or on all eight possible movement patterns and looked at the ability of the DRNN to generalize and predict movements for trials that were not included in the training set. Within a single movement plane, a DRNN trained on one movement direction was not able to predict movements of the hand for trials in the other three directions, but a DRNN trained simultaneously on all four movement directions could generalize across movement directions within the same plane. Similarly, the DRNN was able to reproduce the kinematics of the hand for both movement planes, but only if it was trained on examples performed in each one. As we will discuss, these results indicate that there are important dynamical constraints on the mapping of EMG to hand movement that depend on both the time sequence of the movement and on the anatomical constraints of the musculoskeletal system. In a second step, we injected EMG signals constructed from different synergies derived by the PCA in order to identify the mechanical significance of each of these components. From these results, one can surmise that discrete-rhythmic movements may be constructed from three different fundamental modules, one regulating the co-activation of all muscles over the time span of the movement and two others elliciting patterns of reciprocal activation operating in orthogonal directions

  2. Understanding the molecular switching properties of octaphyrins.

    PubMed

    Woller, T; Contreras-García, J; Geerlings, P; De Proft, Frank; Alonso, M

    2016-04-28

    Several expanded porphyrins switch between Hückel, Möbius and twisted-Hückel topologies, encoding different aromaticity and NLO properties. Since the topological switch can be induced by different external stimuli, expanded porphyrins represent a promising platform to develop molecular switches for molecular electronic devices. In order to determine the optimum conditions for efficient molecular switches from octaphyrins, we have carried out a comprehensive quantum chemical study focusing on the conformational preferences and aromaticity of [36]octaphyrins. Different external stimuli for triggering the topological switch have been considered in our work, such as protonation and redox reactions. Importantly, the structure-property relationships between the molecular conformation, the number of π-electrons and aromaticity in octaphyrins have been established by using energetic, magnetic, structural and reactivity descriptors. Remarkably, we found that the aromaticity of octaphyrins is highly dependent on the π-conjugation topology and the number of π-electrons and it can be modulated by protonation and redox reactions. A non-aromatic figure-eight conformation is strongly preferred by neutral [36]octaphyrins that switches to a Möbius aromatic conformation upon protonation. Such a change of topology involves an aromaticity switch in a single molecule and is accompanied by a drastic change in the NLO properties. In contrast, the twisted-Hückel topology remains the most stable one in the oxidized and reduced species, but the aromaticity is totally reversed upon redox reactions. Aromaticity is shown to be a key concept in expanded porphyrins, determining the electronic, magnetic and NLO properties of these macrocycles. PMID:26924378

  3. Solar powered multipurpose remotely powered aircraft

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Environmental problems such as the depletion of the ozone layer and air pollution demand a change in traditional means of propulsion that is sensitive to the ecology. Solar-powered propulsion is a favorable alternative that is both ecologically harmless as well as cost effective. Integration of solar energy into designs ranging from futuristic vehicles to heating is, therefore, beneficial to society. The design and construction of a Multipurpose Remotely Piloted Vehicle (MPRPV) seeks to verify the feasibility of using solar propulsion as a primary fuel source. This task has been a year-long effort by a group of eight students, divided into four teams, each dealing with different aspects of the design. The aircraft was designed to take off, climb to the design altitude, fly in a sustained figure-eight flight path, and cruise for approximately one hour. This mission requires flight at Reynolds numbers between 150,000 and 200,000 and demands special considerations in the aerodynamic design to achieve flight in this regime. Optimal performance requires a lightweight configuration with both structural integrity and maximum power availability. The structural design and choice of solar cells for the propulsion were governed by weight, efficiency, and cost considerations. The final design is an MPRPV weighing 35 N that cruises at 7 m/s at the design altitude of 50 m. The configuration includes a wing composed of balsa and foam NACA 6409 airfoil sections and carbon fiber spars, a tail of similar construction, and a truss structure fuselage. The propulsion system consists of 98 12.5 percent-efficient solar cells donated by Mobil Solar, a NiCad battery for energy storage, and a folding propeller regulated by a lightweight and efficient control system. The airfoils and propeller chosen for the design were researched and tested during the design process.

  4. Movement strategies for maintaining standing balance during arm tracking in people with multiple sclerosis

    PubMed Central

    Chua, Matthew C.; Hyngstrom, Allison S.; Ng, Alexander V.

    2014-01-01

    The purpose of this study was to quantify hip and ankle movement strategies during a standing arm tracking task in people with multiple sclerosis (MS). Full-body kinematics and kinetics were assessed with motion analysis cameras and force plates in nine MS and nine age-matched control subjects. While standing, participants used their dominant hand to track a target moving around a large horizontal or vertical figure eight on a screen in front of them. The target moved at constant speed, or linearly increasing speeds, with a frequency between 0.05 Hz and 0.35 Hz. Hip and ankle moments and angles during tracking were calculated from kinematic and kinetic measurements. Ratios of peak-to-peak (PP) hip/ankle moments (kinetics) and angles (kinematics) were calculated to determine the strategies of the hips and ankles used to maintain balance during arm movements. Center of mass (CoM) root mean square (RMS) acceleration was calculated as a measure of overall balance performance. The MS group produced larger PP hip/ankle moments at all speeds compared with the control group (P < 0.05). The CoM RMS acceleration increased with tracking speed for both groups but was not significantly different between groups. Additionally, the ratios of hip to ankle moments were highly correlated with the Berg Balance Scale during horizontal steady-speed tracking in MS. These results suggest that people with MS increase the use of the hip during standing arm tracking compared with age-matched control subjects. This adapted strategy might allow people with MS to achieve balance performance similar to control subjects, possibly increasing the importance of the hip in maintaining balance during voluntary movements. PMID:24966303

  5. NASA advanced aeronautics design solar powered remotely piloted vehicle

    NASA Technical Reports Server (NTRS)

    Elario, David S.; Guillmette, Neal H.; Lind, Gregory S.; Webster, Jonathan D.; Ferreira, Michael J.; Konstantakis, George C.; Marshall, David L.; Windt, Cari L.

    1991-01-01

    Environmental problems such as the depletion of the ozone layer and air pollution demand a change in traditional means of propulsion that is sensitive to the ecology. Solar powered propulsion is a favorable alternative that is both ecologically harmless as well as cost effective. Integration of solar energy into designs ranging from futuristic vehicles to heating is beneficial to society. The design and construction of a Multi-Purpose Remotely Piloted Vehicle (MPRPV) seeks to verify the feasibility of utilizing solar propulsion as a primary fuel source. This task has been a year long effort by a group of ten students, divided into five teams, each dealing with different aspects of the design. The aircraft was designed to take-off, climb to the design altitude, fly in a sustained figure-eight flight path, and cruise for approximately one hour. This mission requires flight at Reynolds numbers between 150,000 and 200,000 and demands special considerations in the aerodynamic design in order to achieve flight in this regime. Optimal performance requires a light weight configuration with both structural integrity and maximum power availability. The structure design and choice of solar cells for the propulsion was governed by the weight, efficiency, and cost considerations. The final design is a MPRPV weighting 35 N which cruises 7 m/s at the design altitude of 50 m. The configuration includes a wing composed of balsa and foam NACA 6409 airfoil sections and carbon fiber spars, a tail of similar construction, and a truss structure fuselage. The propulsion system consists of 98 10 percent efficient solar cells donated by Mobil Solar, a NiCad battery for energy storage, and a folding propeller regulated by a lightweight and efficient control system. The airfoils and propeller chosen for the design were research and tested during the design process.

  6. Dual-wavelength operation of continuous-wave and mode-locked erbium-doped fiber lasers

    NASA Astrophysics Data System (ADS)

    Pottiez, O.; Martinez-Rios, A.; Monzon-Hernandez, D.; Ibarra-Escamilla, B.; Kuzin, E. A.; Hernandez-Garcia, J. C.

    2012-06-01

    We study numerically and experimentally multiple-wavelength operation of an erbium-doped figure-eight fiber laser including a multiple-bandpass optical filter formed by two concatenated fiber tapers. Both continuous-wave and pulsed operations are considered. In the continuous-wave regime, stable long-term operation at multiple closely spaced wavelengths is only obtained if fine adjustments of the cavity losses are performed. Under these conditions, simultaneous lasing at up to four wavelengths separated by 1.5 nm was observed experimentally. Tunable single-wavelength operation over more than 20 nm is also observed in the continuous-wave regime. In the passive mode locking regime, numerical simulations indicate that mechanisms involving the filter losses and the nonlinear transmission characteristic of the NOLM contribute in principle to stabilize dual-wavelength operation, allowing less demanding cavity loss adjustments. In this regime, the problem of synchronization between the pulse trains generated at each wavelength adds an additional dimension to the problem. In presence of cavity dispersion, the pulses at each wavelength tend to be asynchronous if the wavelength separation is large, however they can be synchronous in the case of closely spaced wavelengths, if cross-phase modulation is able to compensate for the dispersion-induced walkoff. Experimentally, fundamental and 2nd-order harmonic mode locking was observed, characterized by the generation of noise-like pulses. Finally, a regime of multi-wavelength passive Q-switching was also observed. We believe that this work will be helpful to guide the design of multiple-wavelength fiber laser sources, which are attractive for a wide range of applications including Wavelength Division Multiplexing transmissions, signal processing and sensing.

  7. Polarization converters on double hetero structures containing strained quantum wells

    NASA Astrophysics Data System (ADS)

    Khalique, U.; van der Tol, J. J. G. M.; Nötzel, R.; Smit, M. K.

    2009-02-01

    The importance of polarization manipulation is increased as optical fiber systems evolve to higher data rates. Photonic integrated circuits should be insensitive to the state of polarization of the light emanating from fibers if they are to be used as detectors, add-drop mutiplexers or cross connects. Either all the integrated components have to be polarization independent or only one polarization direction should be used. For either method, a compact polarization converter is useful. A model is developed for the mode propagation in the waveguide of the slanted side polarization converter based on double hetero structures. The model is extended to include polarization dependent absorption and mismatch. Polarization converters on different double heterostructures (with and without quantum wells) have been designed and are realized by contact optical lithography. The performance of the realized converters is well described with the model.

  8. Using WWW to Improve Software Development and Maintenance: Application of the Light System to Aleph Programs

    NASA Astrophysics Data System (ADS)

    Aimar, A.; Aimar, M.; Khodabandeh, A.; Palazzi, P.; Rousseau, B.; Ruggier, M.; Cattaneo, M.; Comas Illas, P.

    Programmers who develop, use, maintain, modify software are faced with the problem of scanning and understanding large amounts of documents, ranging from source code to requirements, analysis and design diagrams, user and reference manuals, etc. This task is non trivial and time consuming, because of the number and size of documents, and the many implicit cross-references that they contain. In large distributed development teams, where software and related documents are produced at various sites, the problem can be even more severe. LIGHT, Life cycle Global HyperText, is an attempt to solve the problem using WWW technology. The basic idea is to make all the software documents, including code, available and cross-connected on the WWW. The first application of this concept to go in production is JULIA/LIGHT, a system to convert and publish on WWW the software documentation of the JULIA reconstruction program of the ALEPH experiment at CERN, European Organisation for Particle Physics, Geneva.

  9. Architecture Design and Experimental Platform Demonstration of Optical Network based on OpenFlow Protocol

    NASA Astrophysics Data System (ADS)

    Xing, Fangyuan; Wang, Honghuan; Yin, Hongxi; Li, Ming; Luo, Shenzi; Wu, Chenguang

    2016-02-01

    With the extensive application of cloud computing and data centres, as well as the constantly emerging services, the big data with the burst characteristic has brought huge challenges to optical networks. Consequently, the software defined optical network (SDON) that combines optical networks with software defined network (SDN), has attracted much attention. In this paper, an OpenFlow-enabled optical node employed in optical cross-connect (OXC) and reconfigurable optical add/drop multiplexer (ROADM), is proposed. An open source OpenFlow controller is extended on routing strategies. In addition, the experiment platform based on OpenFlow protocol for software defined optical network, is designed. The feasibility and availability of the OpenFlow-enabled optical nodes and the extended OpenFlow controller are validated by the connectivity test, protection switching and load balancing experiments in this test platform.

  10. Electrothermally actuated tip-tilt-piston micromirror with integrated varifocal capability.

    PubMed

    Morrison, Jessica; Imboden, Matthias; Little, Thomas D C; Bishop, D J

    2015-04-01

    MEMS micromirrors have proven to be very important optical devices with applications ranging from steerable mirrors for switches and cross-connects to spatial light modulators for correcting optical distortions. Usually beam steering and focusing are done with different MEMS devices and tilt angles in excess of 10 degrees are seldom obtained. Here we describe a single MEMS device that combines tip/tilt, piston mode and varifocal capability into a single, low cost device with very large tilt angles. Our device consists of a 400 micron diameter mirror driven with thermal bimorphs. We have demonstrated deflection angles of ± 40 degrees along both axes, a tunable focal length which varies between -0.48 mm to + 20.5 mm and a piston mode range of 300 microns - four separately controllable degrees of freedom in a single device. Potential applications range from smart lighting to optical switches and devices for telecom systems. PMID:25968784

  11. A novel optical path routing network that combines coarse granularity optical multicast with fine granularity add/drop and block

    NASA Astrophysics Data System (ADS)

    Soares, Mauro M.; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi

    2015-01-01

    We propose a novel optical path routing mechanism that combines coarse-granularity optical multicast with fine-granularity add/drop and block. We implement the proposal in an optical cross-connect node with broadcast-and-select functionality that offers high cost-effectiveness since no addition equipment from conventional ROADMs is needed. The proposed method, called branching, enhances the routing capabilities over the original grouped routing networks by enabling wavelength paths to be established through different GRE pipes. We also present a novel path/GRE routing and wavelength/GRE index assignment algorithm that supports the new routing function. Numerical experiments using real network topologies verify the improved routing performance and the superior efficiency of the proposed control algorithm over original GRE-based networks.

  12. Neuroanatomy of Cornudescoides kulkarnii n. sp., a gill parasite of Mystus vittatus in Meerut (UP), India.

    PubMed

    Rastogi, Pragati; Mishra, Deepmala; Singh, Jyoti; Rani, Kavita

    2012-04-01

    Chemical named 5-bromo indoxyl acetate has been used to describe the nervous system of a viviparous monogenean Cornudescoides Kulkarni (1969), a gill parasite of Mystus vittatus. Central nervous system consists of paired cerebral ganglia from which anterior and posterior neuronal pathways arise. These neuronal pathways are interlinked by cross connectives and commissures. Paired dorsal, ventral and lateral nerve cords emanate from the cerebral ganglia, connected at intervals by transverse connectives. Huge arrangement of dorsal, ventral and lateral nerve cords and their innervations have been examined. Peripheral nervous system (PNS) includes innervations of the alimentary tract, reproductive organs and attachment organs (anterior adhesive areas and haptor). Both the CNS and PNS are bilaterally symmetrical, and better developed ventrally than laterally and dorsally. PMID:23542825

  13. The Transductive Nature of Intra-Urban Networks and Implications for Urban Hydrology

    NASA Astrophysics Data System (ADS)

    Bain, D.

    2015-12-01

    As urban populations continue to grow, the resulting stresses on natural systems will persistently challenge urban residents and managers. Management tools incorporating both human and natural processes are a fundamental part of forging sustainable solutions to these challenges. While cities are in some ways complex, they also are constructed following relatively consistent methods and norms, particularly in the post-WWII period of rapid urban growth. This regularity can provide insights into the function of urban systems. Using Pittsburgh, PA, the influence of the road network on sewer network characteristics and resulting sewer hydrology is demonstrated. As sewers generally follow road right of ways to simplify access, urban drainage networks inherit extremely dense and rectilinear forms, distinct from most drainage networks. These forms focus flows and dictate patterns of cross-connections between human and hydrologic systems. With improved understanding of resulting patterns, designs for more sustainable, next-generation infrastructure can be more effectively implemented.

  14. Investigation of improved designs for rotational micromirrors using multiuser MEMS processes

    NASA Astrophysics Data System (ADS)

    Lin, Julianna E.; Michael, Feras S. J.; Kirk, Andrew G.

    2001-04-01

    In recent years, the design of rotational micromirrors for use in optical cross connects has received much attention. Although several companies have already produced and marketed a number of torsional mirror devices, more work is still needed to determine how these mirrors can be integrated into optical systems to form compact optical switches. However, recently several commercial MEMS foundry services have become available. Thus, due to the low cost of these prototyping services, new devices can be fabricated in short amounts of time and the designs adapted to meet the needs of different applications. The purpose of this work is to investigate the fabrication of new micromirror designs using the Multi-User MEMS Processes (MUMPs) foundry service available from Cronos Integrated Microsystems, located in North Carolina, USA). Several sets of mirror designs were submitted for fabrication and the resulting structures characterized using a phase-shifting Mirau interferometer. The results of these devices are presented.

  15. Comparison of large guided-wave interconnection networks for optical computation systems

    NASA Astrophysics Data System (ADS)

    Schneider, Eric G.; Michalson, William R.

    1993-07-01

    Seven common interconnection architectures are evaluated for use as guided-wave interconnection networks. Comparisons are based on characteristics such as the number of switching elements, number of stages or path length, number of layers, number of waveguide crossings, connectivity and routing algorithms. Investigation of the active splitter/active combiner, passive splitter/active combiner, crossbar, n-stage, buddy type multistage interconnection network (MIN), duobanyan and Benes architectures reveals a trade space which is both complicated and previously not well explored. Even among the topologically equivalent MINs such as the baseline, reverse baseline, regular SW banyan with S equals F equals 2, indirect binary n-cube, modified data manipulator, omega or flip networks, the number of waveguide crossings varies while other properties remain constant. Analysis of this larger set of factors reveals more complex trade offs, and presents these architectures in a new perspective.

  16. A channel for 3D environmental shape in anterior inferotemporal cortex

    PubMed Central

    Vaziri, Siavash; Carlson, Eric T.; Wang, Zhihong; Connor, Charles E.

    2014-01-01

    SUMMARY Inferotemporal cortex (IT) has long been studied as a single pathway dedicated to object vision, but connectivity analysis reveals anatomically distinct channels, through ventral superior temporal sulcus (STSv) and dorsal/ventral inferotemporal gyrus (TEd, TEv). Here, we report a major functional distinction between channels. We studied individual IT neurons in monkeys viewing stereoscopic 3D images projected on a large screen. We used adaptive stimuli to explore neural tuning for 3D abstract shapes ranging in scale and topology from small, closed, bounded objects to large, open, unbounded environments (landscape-like surfaces and cave-like interiors). In STSv, most neurons were more responsive to objects, as expected. In TEd, surprisingly, most neurons were more responsive to 3D environmental shape. Previous studies have localized environmental information to posterior cortical modules. Our results show it is also channeled through anterior IT, where extensive cross-connections between STSv and TEd could integrate object and environmental shape information. PMID:25242216

  17. [Study on the design and detection method of a novel blood pressure measurement system].

    PubMed

    Feng, Xueji; Deng, Qinkai; Guo, Jinsong; Liang, Feixue

    2013-05-01

    A novel blood pressure measurement system was designed which based on auscultatory method. And the electret sensor that embedded into the internal instrument can detect the Korotkoff-sound signal directly which is coupled by the cuff and transmitted in the cross connection. The BP values identification algorithm is based on combined detection of Korotkoff-sound and pulse signal, and the products of amplitudes and energies are calculated as the characteristic values of Korotkoff-sound, and the Korotkoff-sound phases are classified and detected by means of clustering of characteristic values, and then BP parameters are determined. The contrast test and statistical analysis showed good consistency and accuracy between the new BP detection method and conventional mercury sphygmomanometer. PMID:24015608

  18. Simple optical neighbor discovery (SOND): architecture, applications, and experimental verification

    NASA Astrophysics Data System (ADS)

    Larsson, Stefan N.; Hubendick, Sten; Nedelchef, Robert

    2003-10-01

    The architecture, applications, and experimental verification of a simple neighbor discovery method are presented. The method follows the recent International Telecommunication Union - Telecommunication Standardization Sector (ITU-T) and Internet Engineering Task Force (IETF) standardization, automatically switched optical network (ASON)/generalized multiprotocol label switching (GMPLS), on automatically switched optical networks. The method needs no specific hardware components but claims to be so simple that virtually any equipment with common optical ports can support it. It eliminates the need for costly and complex synchronous optical network/synchronous digital hierarchy/optical transport network (SONET/SDH/OTN) overhead read-write functionality in optical elements such as optical cross connects (OXCs). The method thus offers a fast track to automated optical networks.

  19. Global seamless network demonstrator: carrier grade automatic switched transport network implementation in realistic telecom field environment

    NASA Astrophysics Data System (ADS)

    Foisel, Hans-Martin; Hanik, Norbert; Braun, Ralf-Peter; Lehr, Georg; Gladisch, Andreas

    2004-04-01

    The Global Seamless Network (GSN) Demonstrator is presented, a joint effort of system vendors and Deutsche Telekom Group R&D to demonstrate network functions and management integration and enable, for the first time, experiences with a carrier grade Automatically Switched Transport Network (ASTN) implementation and the envisaged main ASTN clients, IP and Ethernet. For end-to-end monitoring capability, integrating the view on the ASTN and Ethernet-MAN configuration, an UMS (Upper Monitoring System) is being developed. Furthermore broadband application were implemented to visualise the network functions. The ASTN backbone consists of four cross connects and an ULH-WDM system with 3x 10Gbit/s channels (OCh) between Berlin and Darmstadt, whereby each OCh is treated as a virtual fibre.

  20. High-Throughput Synthesis of Diverse Compound Collections for Lead Discovery and Optimization.

    PubMed

    Rademacher, C; Seeberger, P H

    2016-01-01

    Small-molecule intervention of protein function is one central dogma of drug discovery. The generation of small-molecule libraries fuels the discovery pipeline at many stages and thereby resembles a key aspect of this endeavor. High-throughput synthesis is a major source for compound libraries utilized in academia and industry, seeking new chemical modulators of pharmacological targets. Here, we discuss the crucial factors of library design strategies from the perspective of synthetic chemistry, giving a brief historic background and a summary of current approaches. Simple measures of success of a high-throughput synthesis such as quantity or diversity have long been discarded and replaced by more integrated measures. Case studies are presented and put into context to highlight the cross-connectivity of the various stages of the drug discovery process. PMID:26330259

  1. Genome Integrity in Aging: Human Syndromes, Mouse Models, and Therapeutic Options.

    PubMed

    Vermeij, Wilbert P; Hoeijmakers, Jan H J; Pothof, Joris

    2016-01-01

    Human syndromes and mouse mutants that exhibit accelerated but bona fide aging in multiple organs and tissues have been invaluable for the identification of nine denominators of aging: telomere attrition, genome instability, epigenetic alterations, mitochondrial dysfunction, deregulated nutrient sensing, altered intercellular communication, loss of proteostasis, cellular senescence and adult stem cell exhaustion. However, whether and how these instigators of aging interrelate or whether they have one root cause is currently largely unknown. Rare human progeroid syndromes and corresponding mouse mutants with resolved genetic defects highlight the dominant importance of genome maintenance for aging. A second class of aging-related disorders reveals a cross connection with metabolism. As genome maintenance and metabolism are closely interconnected, they may constitute the main underlying biology of aging. This review focuses on the role of genome stability in aging, its crosstalk with metabolism, and options for nutritional and/or pharmaceutical interventions that delay age-related pathology. PMID:26514200

  2. Connection error in the delivery of medical gases to a surgical unit.

    PubMed

    Dangoisse, M J; Lalot, M; Lechat, J P

    2010-01-01

    Whilst anesthetic incidents due to problems with the delivery of medical gases to a surgical unit are exceptional, their consequences are potentially drastic. With the growing of modern hospitals, every anesthetist may one day find himself confronted with such events, which are new to him, partly because they are infrequent, but mainly because they are due to causes outside his immediate environment. A simple mistake in the labelling and identification of medical gas lines resulted in a cross-connection of the oxygen and air, causing perioperative hypoxemia following the administration of a mixture poor in oxygen. The questions of training, responsibility and procedures in regard to these types of incidents are discussed below. PMID:20593642

  3. The E3 ubiquitin ligase WVIP2 highlights the versatility of protein ubiquitination

    PubMed Central

    Guerra, Davide; Cattivelli, Luigi; Mazzucotelli, Elisabetta

    2012-01-01

    Plant cells regulate many cellular processes controlling the half-life of critical proteins through ubiquitination. Previously, we characterized two interacting RING-type E3 ubiquitin ligases of Triticum durum, TdRF1 and WVIP2. We revealed their role in tolerance to dehydration, and existing knowledge about their partners also indicated their involvement in the regulation of some aspects of plant development. Here we located WVIP2 in the regulation of the ABA signaling, based on sequence similarities. Further we acquired general evidence about the versatility of ubiquitination in plant cells. A protein can be target of different E3 ligases for a perfect tuning of its abundance as well as the same E3 ligase can ubiquitinate different and unrelated proteins, thus representing a cross-connections between different signaling pathways for a global coordination of cellular processes. PMID:22899050

  4. Multi-objective optimization of two-dimensional phoxonic crystals with multi-level substructure scheme

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Yin, J.; Zhang, H. W.; Chen, B. S.

    2016-03-01

    Phoxonic crystal (PXC) is a promising artificial periodic material for optomechanical systems and acousto-optical devices. The multi-objective topology optimization of dual phononic and photonic max relative bandgaps in a kind of two-dimensional (2D) PXC is investigated to find the regular pattern of topological configurations. In order to improve the efficiency, a multi-level substructure scheme is proposed to analyze phononic and photonic band structures, which is stable, efficient and less memory-consuming. The efficient and reliable numerical algorithm provides a powerful tool to optimize and design crystal devices. The results show that with the reduction of the relative phononic bandgap (PTBG), the central dielectric scatterer becomes smaller and the dielectric veins of cross-connections between different dielectric scatterers turn into the horizontal and vertical shape gradually. These characteristics can be of great value to the design and synthesis of new materials with different topological configurations for applications of the PXC.

  5. Fbis report. Science and technology: China, October 18, 1995

    SciTech Connect

    1995-10-18

    ;Partial Contents: Nanomaterials Fabrication, Applications Research Advances Noted; CAST Announces World`s First Space-Grown Large-Diameter GaAs Monocrystal; Assay of Antiviral Activity of Antisense Phosphorothioate Oligodeoxynucleotide Against Dengue Virus; Expression and Antigenicity of Chimeric Proteins of Cholera Toxin B Subunit With Hepatitis C Virus; CNCOFIEC Signs Agreement With IBM for New Intelligent Building; Latest Reports on Optical Computing, Memory; BIDC To Introduce S3 Company`s Multimedia Accelerator Chipset; Virtual Private PCN Ring Network Based on ATM VP Cross-Connection; Beijing Gets Nation`s First Frame Relay Network; Situation of Power Industry Development and International Cooperation; Diagrams of China`s Nuclear Waste Containment Vessels; Chinese-Developed Containment Vessel Material Reaches World Standards; Second Fuel Elements for Qinshan Plant Passes Inspection; and Geothermal Deep-Well Electric Pump Technology Developed.

  6. Waste Isolation Pilot Plant Biennial Environmental Compliance Report

    SciTech Connect

    Westinghouse TRU Solutions

    2000-12-01

    This Biennial Environmental Compliance Report (BECR) documents environmental regulatory compliance at the Waste Isolation Pilot Plant (WIPP), a facility designed for the safe disposal of transuranic (TRU) radioactive waste, for the reporting period of April 1, 1998, to March 31, 2000. As required by the WIPP Land Withdrawal Act (LWA)(Public Law [Pub. L.] 102-579, and amended by Pub. L. 104-201), the BECR documents U.S. Department of Energy (DOE) Carlsbad Area Office's (hereinafter the ''CAO'') compliance with applicable environmental protection laws and regulations implemented by agencies of the federal government and the state of New Mexico. An issue was identified in the 1998 BECR relating to a potential cross-connection between the fire-water systems and the site domestic water system. While the CAO and its managing and operating contractor (hereinafter the ''MOC'') believe the site was always in compliance with cross-connection control requirements, hardware and procedural upgrades w ere implemented in March 1999 to strengthen its compliance posture. Further discussion of this issue is presented in section 30.2.2 herein. During this reporting period WIPP received two letters and a compliance order alleging violation of certain requirements outlined in section 9(a)(1) of the LWA. With the exception of one item, pending a final decision by the New Mexico Environment Department (NMED), all alleged violations have been resolved without the assessment of fines or penalties. Non-mixed TRU waste shipments began on March 26, 1999. Shipments continued through November 26, 1999, the effective date of the Waste Isolation Pilot Plant Hazardous Waste Facility Permit (NM4890139088-TSDF). No shipments regulated under the Hazardous Waste Facility Permit were received at WIPP during this BECR reporting period.

  7. Optical phase transmultiplexing to support traffic grooming in transparent optical networks

    NASA Astrophysics Data System (ADS)

    Lu, Guo-Wei

    2009-08-01

    Advanced phase modulation formats, such as differential binary phase-shift keying (DPSK), differential quadrature phase-shift keying (DQPSK), and differential eight-ary phase-shift keying (D8PSK), and so on, have attracted considerable research attention as promising candidates for future optical communication systems. To accommodate different requirements such as nonlinear and dispersion tolerance, implementation complexity or spectral efficiency in different regions of networks, several different modulation formats are expected to coexist in the future optical network. For example, low-speed binary modulation formats may be deployed in the edge networks such as metro or access networks, whereas high-speed or multi-level modulation formats are preferred to be employed at the core networks to support high-speed long-haul transmission. To support the transparent cross-connection among various networks, and the traffic grooming from low-speed edge networks to high-speed core networks, optical phase transmultiplexing technology is highly desirable. In this paper, we report an all-optical phase interleaving technology to phase-multiplex 3x10-Gb/s differential phase-shift keying (DPSK) wavelength-division multiplexing (WDM) signals to a single 30-Gb/s DPSK, and an optical phase-modulated format conversion scheme to convert 2x10-Gb/s DPSK WDM to a single quadrature 20-Gb/s differential quadrature phase-shift keying (DQPSK). The proposed schemes are based on four-wave mixing effect in highly-nonlinear fiber. Different from conventional optical signal processing schemes, the proposed schemes are achieved in optical phase domain directly. Experiments were performed to verify the feasibility of the proposed schemes. Both of them could be applied in transparent optical networks to act as an optical phase transmultiplexer enabling traffic grooming and cross-connection among different networks.

  8. Testbed for ROADM and WXC Based Metro WDM Networks

    NASA Astrophysics Data System (ADS)

    Zong, Lei; Ji, Philip; Xu, Lei; Wang, Ting; Matsuda, Osamu; Cvijetic, Milorad

    2005-11-01

    A testbed for metro wavelength division multiplexing (WDM) network is realized and tested. The testbed contains a reconfigurable optical add/drop multiplexer (ROADM) node, a 2x2 wavelength cross-connect (WXC) node, and two interconnected two-fiber bidirectional path protected switching ring networks (TF-BPSR). Both the ROADM and WXC node are bidirectional nodes, so they can select channels from the working and the protection ring networks simultaneously, and they support both protected and unprotected services. The ROADM node uses a flexible band tunable filter (FBTF) to drop a waveband from the input WDM signals and send the express channels directly to the output port. As a result, the physical impairment accumulated on the express channels can be minimized. It also has a modular structure, so additional modules can be cascaded to expand the capacity and functionality of the node without any interruption to current services. The WXC node is realized with interconnected ROADM modules that are comprised of wavelength selective switches (WSSes). Arbitrary wavelength or wavelength sets can be either dropped in the node or cross-connected in a non-blocking manner. Multiple services, such as OC-48 and OC-192 SONET signals, gigabit Ethernet streams carrying interactive movie signals, and live video broadcasting services, are carried in the network, dropped in the ROADM and WXC node, and switched between the two ring networks. The testbed is controlled by a websever based network management system that facilitates remote control and monitoring. Experiments demonstrate that the performance of the nodes and the testbed meets the requirement of the services.

  9. Hybrid centralized pre-computing/local distributed optimization of shared disjoint-backup path approach to GMPLS optical mesh network intelligent restoration

    NASA Astrophysics Data System (ADS)

    Gong, Qian; Xu, Rong; Lin, Jintong

    2004-04-01

    Wavelength Division Multiplexed (WDM) networks that route optical connections using intelligent optical cross-connects (OXCs) is firmly established as the core constituent of next generation networks. Rapid failure recovery is fundamental to building reliable transport networks. Mesh restoration promises cost effective failure recovery compared with legacy ring networks, and is now seeing large-scale deployment. Many carriers are migrating away from SONET ring restoration for their core transport networks and replacing it with mesh restoration through "intelligent" O-E-O cross-connects (XC). The mesh restoration is typically provided via two fiber-disjoint paths: a service path and a restoration path. this scheme can restore any single link failure or node failure. And by used shared mesh restoration, although every service route is assigned a restoration route, no dedicated capacity needs to be reserved for the restoration route, resulting in capacity savings. The restoration approach we propose is Centralized Pre-computing, Local Distributed Optimization, and Shared Disjoint-backup Path. This approach combines the merits of centralized and distributed solutions. It avoids the scalability issues of centralized solutions by using a distributed control plane for disjoint service path computation and restoration path provisioning. Moreover, if the service routes of two demands are disjoint, no single failure will affect both demands simultaneously. This means that the restoration routes of these two demands can share link capacities, because these two routes will not be activated at the same time. So we can say, this restoration capacity sharing approach achieves low restoration capacity and fast restoration speed, while requiring few control plane changes.

  10. Quantification of Natural Gradient Flow Using Active Fiber Optic DTS in Sealed Boreholes

    NASA Astrophysics Data System (ADS)

    Coleman, T. I.; Parker, B. L.; Munn, J. D.; Chalari, A.; Mondanos, M.

    2014-12-01

    Temperature has been used for many years to characterize flow in fractured rock systems. Fiber-optic distributed temperature sensing (DTS) was adopted by the oil/gas industry over two decades ago for monitoring processes in deep fractured rock environments. Improvements in DTS system resolutions, methodology advancements, and improved data processing techniques have caused recent popularity for shallow fractured rock hydrogeologic applications. A powerful advance in DTS methodology is the use of response data collected during active cable heating. When applied to borehole applications active heating creates a thermal disequilibrium in the aquifer system that enhances the detection of groundwater flow. Active DTS has been applied to open borehole environments; however, characterization methods based on open borehole measurements are limited in that only the effects of unnatural flow (i.e. vertical cross-connection and redistribution of flow creating local, induced flows) can be observed. To characterize natural gradient flow processes borehole effects need to be minimized.The literature shows borehole sealing using flexible impervious fabric liners creates a static water column in the well that eliminates the negative effects of cross-connection. Measurements in this sealed environment have been shown by others to be representative of natural gradient flow conditions, rather than the conditions created by the borehole short circuiting units or fractures with varying hydraulic head. A new method for flow system characterization using active DTS in sealed boreholes has been developed with excellent prospects for quantitation of natural gradient groundwater fluxes and related hydraulic properties. This project demonstrates the utility of using an analytical solution for calculating apparent thermal conductivities and natural gradient groundwater fluxes at depth-discrete intervals observed continuously along a borehole using active DTS. Groundwater flux data can then be

  11. Modulation of amplitude and latency of motor evoked potential by direction of transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Sato, Aya; Torii, Tetsuya; Iwahashi, Masakuni; Itoh, Yuji; Iramina, Keiji

    2014-05-01

    The present study analyzed the effects of monophasic magnetic stimulation to the motor cortex. The effects of magnetic stimulation were evaluated by analyzing the motor evoked potentials (MEPs). The amplitude and latency of MEPs on the abductor pollicis brevis muscle were used to evaluate the effects of repetitive magnetic stimulation. A figure eight-shaped flat coil was used to stimulate the region over the primary motor cortex. The intensity of magnetic stimulation was 120% of the resting motor threshold, and the frequency of magnetic stimulation was 0.1 Hz. In addition, the direction of the current in the brain was posterior-anterior (PA) or anterior-posterior (AP). The latency of MEP was compared with PA and AP on initial magnetic stimulation. The results demonstrated that a stimulus in the AP direction increased the latency of the MEP by approximately 2.5 ms. MEP amplitude was also compared with PA and AP during 60 magnetic stimulations. The results showed that a stimulus in the PA direction gradually increased the amplitude of the MEP. However, a stimulus in the AP direction did not modulate the MEP amplitude. The average MEP amplitude induced from every 10 magnetic pulses was normalized by the average amplitude of the first 10 stimuli. These results demonstrated that the normalized MEP amplitude increased up to approximately 150%. In terms of pyramidal neuron indirect waves (I waves), magnetic stimulation inducing current flowing backward to the anterior preferentially elicited an I1 wave, and current flowing forward to the posterior elicited an I3 wave. It has been reported that the latency of the I3 wave is approximately 2.5 ms longer than the I1 wave elicitation, so the resulting difference in latency may be caused by this phenomenon. It has also been reported that there is no alteration of MEP amplitude at a frequency of 0.1 Hz. However, this study suggested that the modulation of MEP amplitude depends on stimulation strength and stimulation direction.

  12. Adaptive Morphological Feature-Based Object Classifier for a Color Imaging System

    NASA Technical Reports Server (NTRS)

    McDowell, Mark; Gray, Elizabeth

    2009-01-01

    Utilizing a Compact Color Microscope Imaging System (CCMIS), a unique algorithm has been developed that combines human intelligence along with machine vision techniques to produce an autonomous microscope tool for biomedical, industrial, and space applications. This technique is based on an adaptive, morphological, feature-based mapping function comprising 24 mutually inclusive feature metrics that are used to determine the metrics for complex cell/objects derived from color image analysis. Some of the features include: Area (total numbers of non-background pixels inside and including the perimeter), Bounding Box (smallest rectangle that bounds and object), centerX (x-coordinate of intensity-weighted, center-of-mass of an entire object or multi-object blob), centerY (y-coordinate of intensity-weighted, center-of-mass, of an entire object or multi-object blob), Circumference (a measure of circumference that takes into account whether neighboring pixels are diagonal, which is a longer distance than horizontally or vertically joined pixels), . Elongation (measure of particle elongation given as a number between 0 and 1. If equal to 1, the particle bounding box is square. As the elongation decreases from 1, the particle becomes more elongated), . Ext_vector (extremal vector), . Major Axis (the length of a major axis of a smallest ellipse encompassing an object), . Minor Axis (the length of a minor axis of a smallest ellipse encompassing an object), . Partial (indicates if the particle extends beyond the field of view), . Perimeter Points (points that make up a particle perimeter), . Roundness [(4(pi) x area)/perimeter(squared)) the result is a measure of object roundness, or compactness, given as a value between 0 and 1. The greater the ratio, the rounder the object.], . Thin in center (determines if an object becomes thin in the center, (figure-eight-shaped), . Theta (orientation of the major axis), . Smoothness and color metrics for each component (red, green, blue

  13. Enhanced detection of hydraulically active fractures by temperature profiling in lined heated bedrock boreholes

    NASA Astrophysics Data System (ADS)

    Pehme, P. E.; Parker, B. L.; Cherry, J. A.; Molson, J. W.; Greenhouse, J. P.

    2013-03-01

    SummaryThe effectiveness of borehole profiling using a temperature probe for identifying hydraulically active fractures in rock has improved due to the combination of two advances: improved temperature sensors, with resolution on the order of 0.001 °C, and temperature profiling within water inflated flexible impermeable liners used to temporarily seal boreholes from hydraulic cross-connection. The open-hole cross-connection effects dissipate after inflation, so that both the groundwater flow regime and the temperature distribution return to the ambient (background) condition. This paper introduces a third advancement: the use of an electrical heating cable that quickly increases the temperature of the entire static water column within the lined hole and thus places the entire borehole and its immediate vicinity into thermal disequilibrium with the broader rock mass. After heating for 4-6 h, profiling is conducted several times over a 24 h period as the temperature returns to background conditions. This procedure, referred to as the Active Line Source (ALS) method, offers two key improvements over prior methods. First, there is no depth limit for detection of fractures with flow. Second, both identification and qualitative comparison of evidence for ambient groundwater flow in fractures is improved throughout the entire test interval. The benefits of the ALS method are demonstrated by comparing results from two boreholes tested to depths of 90 and 120 m in a dolostone aquifer used for municipal water supply and in which most groundwater flow occurs in fractures. Temperature logging in the lined holes shows many fractures in the heterothermic zone both with and without heating, but only the ALS method shows many hydraulically active fractures in the deeper homothermic portion of the hole. The identification of discrete groundwater flow at many depths is supported by additional evidence concerning fracture occurrence, including continuous core visual inspection

  14. Telecommunications administration standard

    SciTech Connect

    Gustwiller, K.D.

    1996-05-01

    The administration of telecommunications is critical to proper maintenance and operation. The intent is to be able to properly support telecommunications for the distribution of all information within a building/campus. This standard will provide a uniform administration scheme that is independent of applications, and will establish guidelines for owners, installers, designers and contractors. This standard will accommodate existing building wiring, new building wiring and outside plant wiring. Existing buildings may not readily adapt to all applications of this standard, but the requirement for telecommunications administration is applicable to all buildings. Administration of the telecommunications infrastructure includes documentation (labels, records, drawings, reports, and work orders) of cables, termination hardware, patching and cross-connect facilities, telecommunications rooms, and other telecommunications spaces (conduits, grounding, and cable pathways are documented by Facilities Engineering). The investment in properly documenting telecommunications is a worthwhile effort. It is necessary to adhere to these standards to ensure quality and efficiency for the operation and maintenance of the telecommunications infrastructure for Sandia National Laboratories.

  15. Improved resolution of ambient flow through fractured rock with temperature logs.

    PubMed

    Pehme, P E; Parker, B L; Cherry, J A; Greenhouse, J P

    2010-01-01

    In contaminant hydrogeology, investigations at fractured rock sites are typically undertaken to improve understanding of the fracture networks and associated groundwater flow that govern past and/or future contaminant transport. Conventional hydrogeologic, geophysical, and hydrophysical techniques used to develop a conceptual model are often implemented in open boreholes under conditions of cross-connected flow. A new approach using high-resolution temperature (+/-0.001 degrees C) profiles measured within static water columns of boreholes sealed using continuous, water-inflated, flexible liners (FLUTe) identifies hydraulically active fractures under ambient (natural) groundwater flow conditions. The value of this approach is assessed by comparisons of temperature profiles from holes (100 to 200 m deep) with and without liners at four contaminated sites with distinctly different hydrogeologic conditions. The results from the lined holes consistently show many more hydraulically active fractures than the open-hole profiles, in which the influence of vertical flow through the borehole between a few fractures masks important intermediary flow zones. Temperature measurements in temporarily sealed boreholes not only improve the sensitivity and accuracy of identifying hydraulically active fractures under ambient conditions but also offer new insights regarding previously unresolvable flow distributions in fractured rock systems, while leaving the borehole available for other forms of testing and monitoring device installation. PMID:19840124

  16. Manufacturing microcomponents for optical information technology using the LIGA technique

    NASA Astrophysics Data System (ADS)

    Bauer, Hans-Dieter; Ehrfeld, Wolfgang; Hossfeld, Jens; Paatzsch, Thomas

    1999-09-01

    Recently, splices and connectors for fibers ribbons, optical cross connects and especially planar waveguide devices have been fabricated via LIGA in combination with precision engineering techniques. LIGA combines high precision and mass production capability, necessary for products designed for applications in the telecom and datacom market. In this presentation the fabrication of three-level molding and embossing tools is presented, which have been used for the manufacturing of waveguide prestructures consisting of waveguide channels and bier-to-waveguide coupling grooves. The precision of the tools is better than 1 micrometers in all directions, which allows for simple passive pigtailing. A first product, a precision of the tool is better than 1 micrometers in all directions, which allows for simple passive pigtailing. A first product, sixfold array of 4 X 4 multimode star couplers has been realized. The molding behavior of PMMA and COC material has been tested and compared. Production and assembly was tested by fabricating a series of 300 star couplers. The average insertion los has been found better than 9dB, the uniformity better than 3dB, both measured at 830nm. THe device is designed for application in optical backplanes for high-speed computers.

  17. Design of an All-Optical Network Based on LCoS Technologies

    NASA Astrophysics Data System (ADS)

    Cheng, Yuh-Jiuh; Shiau, Yhi

    2016-06-01

    In this paper, an all-optical network composed of the ROADMs (reconfigurable optical add-drop multiplexer), L2/L3 optical packet switches, and the fiber optical cross-connection for fiber scheduling and measurement based on LCoS (liquid crystal on silicon) technologies is proposed. The L2/L3 optical packet switches are designed with optical output buffers. Only the header of optical packets is converted to electronic signals to control the wavelength of input ports and the packet payloads can be transparently destined to their output ports. An optical output buffer is designed to queue the packets when more than one incoming packet should reach to the same destination output port. For preserving service-packet sequencing and fairness of routing sequence, a priority scheme and a round-robin algorithm are adopted at the optical output buffer. The wavelength of input ports is designed for routing incoming packets using LCoS technologies. Finally, the proposed OFS (optical flow switch) with input buffers can quickly transfer the big data to the output ports and the main purpose of the OFS is to reduce the number of wavelength reflections. The all-optical content delivery network is comprised of the OFSs for a large amount of audio and video data transmissions in the future.

  18. Geochemical heterogeneity in a small, stratigraphically complex moraine aquifer system (Ontario, Canada): Interpretation of flow and recharge using multiple geochemical parameters

    USGS Publications Warehouse

    Stotler, R.L.; Frape, S.K.; El Mugammar, H.T.; Johnston, C.; Judd-Henrey, I.; Harvey, F.E.; Drimmie, R.; Jones, J.P.

    2011-01-01

    The Waterloo Moraine is a stratigraphically complex system and is the major water supply to the cities of Kitchener and Waterloo in Ontario, Canada. Despite over 30 years of investigation, no attempt has been made to unify existing geochemical data into a single database. A composite view of the moraine geochemistry has been created using the available geochemical information, and a framework created for geochemical data synthesis of other similar flow systems. Regionally, fluid chemistry is highly heterogeneous, with large variations in both water type and total dissolved solids content. Locally, upper aquifer units are affected by nitrate and chloride from fertilizer and road salt. Typical upper-aquifer fluid chemistry is dominated by calcium, magnesium, and bicarbonate, a result of calcite and dolomite dissolution. Evidence also suggests that ion exchange and diffusion from tills and bedrock units accounts for some elevated sodium concentrations. Locally, hydraulic "windows" cross connect upper and lower aquifer units, which are typically separated by a clay till. Lower aquifer units are also affected by dedolomitization, mixing with bedrock water, and locally, upward diffusion of solutes from the bedrock aquifers. A map of areas where aquifer units are geochemically similar was constructed to highlight areas with potential hydraulic windows. ?? 2010 Springer-Verlag.

  19. Human enteric viruses in groundwater from a confined bedrock aquifer

    USGS Publications Warehouse

    Borchardt, M. A.; Bradbury, K.R.; Gotkowitz, M.B.; Cherry, J.A.; Parker, B.L.

    2007-01-01

    Confined aquifers are overlain by low-permeability aquitards that are commonly assumed to protect underlying aquifers from microbial contaminants. However, empirical data on microbial contamination beneath aquitards is limited. This study determined the occurrence of human pathogenic viruses in well water from a deep sandstone aquifer confined by a regionally extensive shale aquitard. Three public water-supply wells were each sampled 10 times over 15 months. Samples were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) for several virus groups and by cell culture for infectious enteroviruses. Seven of 30 samples were positive by RT-PCR for enteroviruses; one of these was positive for infectious echovirus 18. The virus-positive samples were collected from two wells cased through the aquitard, indicating the viruses were present in the confined aquifer. Samples from the same wells showed atmospheric tritium, indicating water recharged within the past few decades. Hydrogeologic conditions support rapid porous media transport of viruses through the upper sandstone aquifer to the top of the aquitard 61 m below ground surface. Natural fractures in the shale aquitard are one possible virus transport pathway through the aquitard; however, windows, cross-connecting well bores, or imperfect grout seals along well casings also may be involved. Deep confined aquifers can be more vulnerable to contamination by human viruses than commonly believed. ?? 2007 American Chemical Society.

  20. Microbial health risks associated with exposure to stormwater in a water plaza.

    PubMed

    Sales-Ortells, Helena; Medema, Gertjan

    2015-05-01

    Climate change scenarios predict an increase of intense rainfall events in summer in Western Europe. Current urban drainage systems cannot cope with such intense precipitation events. Cities are constructing stormwater storage facilities to prevent pluvial flooding. Combining storage with other functions, such as recreation, may lead to exposure to contaminants. This study assessed the microbial quality of rainwater collected in a water plaza and the health risks associated with recreational exposure. The water plaza collects street run-off, diverges first flush to the sewer system and stores the rest of the run-off in the plaza as open water. Campylobacter, Cryptosporidium and Legionella pneumophila were the pathogens investigated. Microbial source tracking tools were used to determine the origin (human, animal) of the intestinal pathogens. Cryptosporidium was not found in any sample. Campylobacter was found in all samples, with higher concentrations in samples containing human Bacteroides than in samples with zoonotic contamination (15 vs 3.7 gc (genomic copies)/100 mL). In both cases, the estimated disease risk associated with Campylobacter and recreational exposure was higher than the Dutch national incidence. This indicates that the health risk associated with recreational exposure to the water plaza is significant. L. pneumophila was found only in two out of ten pond samples. Legionnaire's disease risks were lower than the Dutch national incidence. Presence of human Bacteroides indicates possible cross-connections with the CSS that should be identified and removed. PMID:25706222

  1. An Experiment of GMPLS-Based Dispersion Compensation Control over In-Field Fibers

    NASA Astrophysics Data System (ADS)

    Seno, Shoichiro; Horiuchi, Eiichi; Yoshida, Sota; Sugihara, Takashi; Onohara, Kiyoshi; Kamei, Misato; Baba, Yoshimasa; Kubo, Kazuo; Mizuochi, Takashi

    As ROADMs (Reconfigurable Optical Add/Drop Multiplexers) are becoming widely used in metro/core networks, distributed control of wavelength paths by extended GMPLS (Generalized MultiProtocol Label Switching) protocols has attracted much attention. For the automatic establishment of an arbitrary wavelength path satisfying dynamic traffic demands over a ROADM or WXC (Wavelength Cross Connect)-based network, precise determination of chromatic dispersion over the path and optimized assignment of dispersion compensation capabilities at related nodes are essential. This paper reports an experiment over in-field fibers where GMPLS-based control was applied for the automatic discovery of chromatic dispersion, path computation, and wavelength path establishment with dynamic adjustment of variable dispersion compensation. The GMPLS-based control scheme, which the authors called GMPLS-Plus, extended GMPLS's distributed control architecture with attributes for automatic discovery, advertisement, and signaling of chromatic dispersion. In this experiment, wavelength paths with distances of 24km and 360km were successfully established and error-free data transmission was verified. The experiment also confirmed path restoration with dynamic compensation adjustment upon fiber failure.

  2. Smart repeater system for communications interoperability during multi-agency law enforcement operations

    SciTech Connect

    Crutcher, R.I.; Jones, R.W.; Moore, M.R.; Smith, S.F.; Tolley, A.L.; Rochelle, R.W.

    1996-12-31

    A prototype smart repeater that provides interoperability capabilities for radio communication systems in multi-agency and multi-user scenarios is being developed by the Oak Ridge National Laboratory. The smart repeater functions as a deployable communications platform that can be dynamically reconfigured to cross-link the radios of participating federal, state, and local government agencies. This interconnection capability improves the coordination and execution of multi-agency operations, including coordinated law enforcement activities and general emergency or disaster response scenarios. The repeater provides multiple channels of operation in the 30--50, 118--136, 138--174, and 403--512 MHz land mobile communications and aircraft bands while providing the ability to cross-connect among multiple frequencies, bands, modulation types, and encryption formats. Additionally, two telephone interconnects provide links to the fixed and cellular telephone networks. The 800- and 900-MHz bands are not supported by the prototype, but the modular design of the system accommodates future retrofits to extend frequency capabilities with minimal impact to the system. Configuration of the repeater is through a portable personal computer with a Windows-based graphical interface control screen that provides dynamic reconfiguration of network interconnections and formats.

  3. The 650-nm variable optical attenuator based on polymer/silica hybrid waveguide

    NASA Astrophysics Data System (ADS)

    Yue-Yang, Yu; Xiao-Qiang, Sun; Lan-Ting, Ji; Guo-Bing, He; Xi-Bin, Wang; Yun-Ji, Yi; Chang-Ming, Chen; Fei, Wang; Da-Ming, Zhang

    2016-05-01

    Visible light variable optical attenuators (VOA) are essential devices in the application of channel power regulation and equalization in wavelength-division multiplexing cross-connect nodes in plastic optical fiber (POF) transmission systems. In this paper, a polymer/silica hybrid waveguide thermo–optic attenuator based on multimode interference (MMI) coupler is designed and fabricated to operate at 650 nm. The single-mode transmission condition, MMI coupler, and transition taper dimensions are optimized through the beam propagation method. Thermal analysis based on material properties provides the optimized heater placement angle. The fabricated VOA presents an attenuation of 26.5 dB with a 21-mW electrical input power at 650 nm. The rise time and fall time are 51.99 and 192 μs, respectively. The time–stability measurement results prove its working reliability. Project supported by the National Natural Science Foundation of China (Grant Nos. 61205032, 61475061, 61405070, 61177027, 61275033, and 61261130586) and the Science and Technology Development Plan of Jilin Province, China (Grant No. 20140519006JH).

  4. Structure of the nidogen binding LE module of the laminin gamma1 chain in solution.

    PubMed

    Baumgartner, R; Czisch, M; Mayer, U; Pöschl, E; Huber, R; Timpl, R; Holak, T A

    1996-04-01

    The structure of the single LE module between residues 791 and 848 of the laminin gamma1 chain, which contains the high affinity binding site for nidogen, has been probed using NMR methods. The module folds into an autonomous domain which has a stable and unique three-dimensional (3D) structure in solution. The 3D structure was determined on the basis of 362 interproton distance constraints derived from nuclear Overhauser enhancement measurements and 39 phi angles, supplemented by 5 psi and 22 chi1 angles. The main features of the NMR structures are two-stranded antiparallel beta-sheets which are separated by loops and cross-connected by four disulfide bridges. The N-terminal segment which contains the first three disulfide bridges is similar to epidermal growth factor. The C-terminal segment has an S-like backbone profile with a crossover at the last disulfide bridge and comprises two three-residue long beta-strands that form an antiparallel beta-sheet. The LE module possesses an exposed nidogen binding loop that projects away from the main body of the protein. The side-chains of three amino acids which are crucial for binding (Asp, Asn, Val) are all exposed at the domain surface. An inactivating Asn-Ser mutation in this region showed the same 3D structure indicating that these three residues, and possibly an additional Tyr in an adjacent loop, provide direct contacts in the interaction with nidogen. PMID:8648631

  5. Design and Implementation of a RF Powering Circuit for RFID Tags or Other Batteryless Embedded Devices

    PubMed Central

    Liu, Dongsheng; Wang, Rencai; Yao, Ke; Zou, Xuecheng; Guo, Liang

    2014-01-01

    A RF powering circuit used in radio-frequency identification (RFID) tags and other batteryless embedded devices is presented in this paper. The RF powering circuit harvests energy from electromagnetic waves and converts the RF energy to a stable voltage source. Analysis of a NMOS gate-cross connected bridge rectifier is conducted to demonstrate relationship between device sizes and power conversion efficiency (PCE) of the rectifier. A rectifier with 38.54% PCE under normal working conditions is designed. Moreover, a stable voltage regulator with a temperature and voltage optimizing strategy including adoption of a combination resistor is developed, which is able to accommodate a large input range of 4 V to 12 V and be immune to temperature variations. Latch-up prevention and noise isolation methods in layout design are also presented. Designed with the HJTC 0.25 μm process, this regulator achieves 0.04 mV/°C temperature rejection ratio (TRR) and 2.5 mV/V voltage rejection ratio (VRR). The RF powering circuit is also fabricated in the HJTC 0.25 μm process. The area of the RF powering circuit is 0.23 × 0.24 mm2. The RF powering circuit is successfully integrated with ISO/IEC 15693-compatible and ISO/IEC 14443-compatible RFID tag chips. PMID:25123466

  6. Metro-oriented multiservice transport platform

    NASA Astrophysics Data System (ADS)

    Li, Guangcheng

    2004-04-01

    As the link and gateway between backbone network and access network, metro-network becomes next infrastructure hotpot for both telecom and datacom carriers. In the transport plane of metro network, there are many solution choices to meet the various needs of carriers and operators. One of these practical solutions is with the help of metro-oriented Multi-services Transport Platform (MSTP). Inheriting from SDH transmission system, MSTP can process packaged data traffics like Ethernet on L1/L2 layers and ATM cells as well as TDM voice traffic. There has been a trend that packet data service will be the dominate in a metro-network near future. More reliable and efficient packet processing function such as RPR and LCAS will be needed in MSTP equipment. With the development of ASON/ASTN technology, more intelligent functions originated from ASON/ASTN will be added to MSTP and ASON/ASTN will be the development direction of MSTP. With the transition process of metro-network bandwidth limit from electrical domain to optical domain, some WDM and electrical/optical hybrid cross-connection functions will be merged into MSTP as optional modules. Metro-oriented MSTP will act as major node equipment in metro-transport network.

  7. Broadband local service offerings using free-space optical links: a network business perspective

    NASA Astrophysics Data System (ADS)

    Britz, David M.; Dodley, J. P.; Barnickel, D. J.

    2001-02-01

    12 This paper describes a promising optical wireless broadband technology that will provide low cost broadband services to the local access `last mile' market. This paper examines the application, advantages and limitations of utilizing Free Space Optical Communications (FSOC) systems for broadband access markets. The service markets that would fully utilize FSOC technologies include metropolitan areas, BLECs (multi- tenant dwellings/business apartments), campuses, industrial parks and `pole-to-hole' neighborhood deployments. This paper will identify weather dependent link availability as being the primary consideration in defining and selecting suitable locations for FSOC-based systems. Link availability in turn determines link range, type of service, and the need for transmission diversity. This paper will describe the implications of telecom `five nines' last-mile access availability and its effect on the transparent integration of FSOC technologies into the existing fiber optic networks. This paper will also describe propagation losses and link budget requirements for broadband FSOC-based local service. During adverse weather conditions, stand-alone, FSOC-based optical wireless links typically offer path lengths of less than 200 meters while still meeting the `five nines' availability criteria. This paper will also consider `availability limited' services. These services may prove to be attractive to customers who are willing to accept broadband service on an `as available basis'. The use of availability-enhancing transmission diversity and the use of intelligent `roof-top' routing and optical wireless cross connects between buildings will also be discussed.

  8. An extensive gastroenteritis outbreak after drinking-water contamination by sewage effluent, Finland.

    PubMed

    Laine, J; Huovinen, E; Virtanen, M J; Snellman, M; Lumio, J; Ruutu, P; Kujansuu, E; Vuento, R; Pitkänen, T; Miettinen, I; Herrala, J; Lepistö, O; Antonen, J; Helenius, J; Hänninen, M-L; Maunula, L; Mustonen, J; Kuusi, M

    2011-07-01

    An inappropriate cross-connection between sewage- and drinking-water pipelines contaminated tap water in a Finnish town, resulting in an extensive waterborne gastroenteritis outbreak in this developed country. According to a database and a line-list, altogether 1222 subjects sought medical care as a result of this exposure. Seven pathogens were found in patient samples of those who sought treatment. To establish the true disease burden from this exposure, we undertook a population-based questionnaire investigation with a control population, infrequently used to study waterborne outbreaks. The study covered three areas, contaminated and uncontaminated parts of the town and a control town. An estimated 8453 residents fell ill during the outbreak, the excess number of illnesses being 6501. Attack rates were 53% [95% confidence interval (CI) 49.5-56.4] in the contaminated area, 15.6% (95% CI 13.1-18.5) in the uncontaminated area and 6.5% (95% CI 4.8-8.8) in the control population. Using a control population allowed us to differentiate baseline morbidity from the observed morbidity caused by the water contamination, thus enabling a more accurate estimate of the disease burden of this outbreak. PMID:20843387

  9. Design and implementation of a RF powering circuit for RFID tags or other batteryless embedded devices.

    PubMed

    Liu, Dongsheng; Wang, Rencai; Yao, Ke; Zou, Xuecheng; Guo, Liang

    2014-01-01

    A RF powering circuit used in radio-frequency identification (RFID) tags and other batteryless embedded devices is presented in this paper. The RF powering circuit harvests energy from electromagnetic waves and converts the RF energy to a stable voltage source. Analysis of a NMOS gate-cross connected bridge rectifier is conducted to demonstrate relationship between device sizes and power conversion efficiency (PCE) of the rectifier. A rectifier with 38.54% PCE under normal working conditions is designed. Moreover, a stable voltage regulator with a temperature and voltage optimizing strategy including adoption of a combination resistor is developed, which is able to accommodate a large input range of 4 V to 12 V and be immune to temperature variations. Latch-up prevention and noise isolation methods in layout design are also presented. Designed with the HJTC 0.25 μm process, this regulator achieves 0.04 mV/°C temperature rejection ratio (TRR) and 2.5 mV/V voltage rejection ratio (VRR). The RF powering circuit is also fabricated in the HJTC 0.25 μm process. The area of the RF powering circuit is 0.23 × 0.24 mm². The RF powering circuit is successfully integrated with ISO/IEC 15693-compatible and ISO/IEC 14443-compatible RFID tag chips. PMID:25123466

  10. Influence of the observation window size on the performance of multilayer traffic engineering

    NASA Astrophysics Data System (ADS)

    Yan, Qiang; De Maesschalck, Sophie; Colle, Didier; Puype, Bart; Lievens, Ilse; Pickavet, Mario; Demeester, Piet

    2003-08-01

    Although the Optical Transport Network, based on technologies such as Wavelength Division Multiplexing and Optical Cross-Connects, offers tremendous transportation capacity, its management requires frequent manual intervention. However, as the traffic pattern offered to today's transport networks is subject to continuous changes due to the Internet traffic dominance, an optical transport network with a smart, automatic and real-time control system, denoted as Intelligent Optical Network (ION) or Automatic Switched Optical Network (ASON), is desired by network operators. Duly and correctly retrieving the changing traffic load information is a very important factor for the successful deployment of an ION. In this paper, we discuss the influence of the observation window size used for collecting the traffic load information, on the performance of an ION. By comparing the performance of an ION using different traffic observation window sizes, we show that a smaller observation window harms the network stability; while a too large observation window worsens the network reliability. We demonstrate that a suitable traffic observation window size improves the offered Quality of Service (QoS) by reconfiguring the logical layer network at the right time and in the right way.

  11. Transparent optical network design for standard single-mode infrastructure

    NASA Astrophysics Data System (ADS)

    Breuer, Dirk; Hanik, Norbert

    2001-10-01

    Design, control and management of all-optical transparent islands based on fibers, optical amplifiers and transparent Optical Cross Connects (OXC) have to deal with a vast number of issues such as network topology, routing, protection, and restoration schemes. However, since in such a transparent network light-paths generally have to transit through several fiber sections, amplifiers, and OXCs, all of which add noise and degrade the signal performance, optical layer network protocols have to be aware of the end-to-end signal quality for each specific light-path. This information should be obtained without burdening these protocols with details of the physical layer. In this paper we propose a simplified network design approach based on normalized optical transmission sections where the physical links are built from a cascade of identical basic blocks. For an upper layer protocol only the number of traversed blocks has to be monitored for estimating signal quality. Using numerical simulations the maximum number of cascaded building blocks for 10 Gbit/s RZ modulation format for different basic building block-configurations is investigated and compared with the performance of NRZ based systems under similar conditions. It is shown that robust transparent islands of about 1600 km maximum link length without 3R regeneration are feasible for both modulation formats using the concept of normalized sections.

  12. Energy efficiency in WDM fiber-optical links considering OADM/OXC nodes

    NASA Astrophysics Data System (ADS)

    Udalcovs, Aleksejs; Bobrovs, Vjaceslavs

    2016-01-01

    In this paper, authors discuss the energy consumption for 1 bit transmission as a function of spectral efficiency (SE, bps/Hz), aggregated traffic amount (C, bps), and overall transmission distance (LP2P, km) in wavelength division multiplexing (WDM) systems with optical add-drop multiplexer/ optical cross-connect (OADM/OXC) nodes. The choice of bitrate and modulation formats was limited to three options: 10G non-return-to-zero on-off keying (NRZ-OOK), 40G NRZ differential phase-shift keying (NRZ-DPSK) and 100 dual polarization quadrature phase-shift keying (DP-QPSK). The reasons for that is the legacy in transmission networks and high energy efficiency of 3R (re-amplification, re-timing, re-shaping) regenerators and transponders, respectively. In addition, these formats are commonly used for 10-40-100G mixed-line rate solutions in core networks. It is found out that 100G DP-QPSK is the best solutions among two other considered in terms of both energy consumption per bit and spectral efficiency. Finally and foremost, it is estimated that for the WDM channels added at the OADM/OXC node, energy consumption per 1 transmitted bit could growth more than two times as compared to wavelengths transmitted over point-to-point fiber-optical links and then dropped at the receiving node.

  13. ProPepper: a curated database for identification and analysis of peptide and immune-responsive epitope composition of cereal grain protein families

    PubMed Central

    Juhász, Angéla; Haraszi, Réka; Maulis, Csaba

    2015-01-01

    ProPepper is a database that contains prolamin proteins identified from true grasses (Poaceae), their peptides obtained with single- and multi-enzyme in silico digestions as well as linear T- and B-cell-specific epitopes that are responsible for wheat-related food disorders. The integrated database and analysis platform contains datasets that are collected from multiple public databases (UniprotKB, IEDB, NCBI GenBank), manually curated and annotated, and interpreted in three main data tables: Protein-, Peptide- and Epitope list views that are cross-connected by unique identifications. Altogether 21 genera and 80 different species are represented. Currently, the database contains 2146 unique and complete protein sequences related to 2618 GenBank entries and 35 657 unique peptide sequences that are a result of 575 110 unique digestion events obtained by in silico digestion methods involving six proteolytic enzymes and their combinations. The interface allows advanced global and parametric search functions along with a download option, with direct connections to the relevant public databases. Database URL: https://propepper.net PMID:26450949

  14. A unified view on heterogeneous and homogeneous catalysts through a combination of spectroscopy and quantum chemistry.

    PubMed

    Maganas, Dimitrios; Trunschke, Annette; Schlögl, Robert; Neese, Frank

    2016-07-01

    Identifying catalytically active structures or intermediates in homogeneous and heterogeneous catalysis is a formidable challenge. However, obtaining experimentally verified insight into the active species in heterogeneous catalysis is a tremendously challenging problem. Many highly advanced spectroscopic and microscopic methods have been developed to probe surfaces. In this discussion we employ a combination of spectroscopic methods to study two closely related systems from the heterogeneous (the silica-supported vanadium oxide VOx/SBA-15) and homogeneous (the complex K[VO(O2)Hheida]) domains. Spectroscopic measurements were conducted strictly in parallel for both systems and consisted of oxygen K-edge and vanadium L-edge X-ray absorption measurements in conjunction with resonance Raman spectroscopy. It is shown that the full information content of the spectra can be developed through advanced quantum chemical calculations that directly address the sought after structure-spectra relationships. To this end we employ the recently developed restricted open shell configuration interaction theory together with the time-dependent theory of electronic spectroscopy to calculate XAS and rR spectra respectively. The results of the study demonstrate that: (a) a combination of several spectroscopic techniques is of paramount importance in identifying signature structural motifs and (b) quantum chemistry is an extremely powerful guide in cross connecting theory and experiment as well as the homogeneous and heterogeneous catalysis fields. It is emphasized that the calculation of spectroscopic observables provides an excellent way for the critical experimental validation of theoretical results. PMID:27062973

  15. Silicon Photonics Research in Hong Kong: Microresonator Devices and Optical Nonlinearities

    NASA Astrophysics Data System (ADS)

    Poon, Andrew W.; Zhou, Linjie; Xu, Fang; Li, Chao; Chen, Hui; Liang, Tak-Keung; Liu, Yang; Tsang, Hon K.

    In this review paper we showcase recent activities on silicon photonics science and technology research in Hong Kong regarding two important topical areas-microresonator devices and optical nonlinearities. Our work on silicon microresonator filters, switches and modulators have shown promise for the nascent development of on-chip optoelectronic signal processing systems, while our studies on optical nonlinearities have contributed to basic understanding of silicon-based optically-pumped light sources and helium-implanted detectors. Here, we review our various passive and electro-optic active microresonator devices including (i) cascaded microring resonator cross-connect filters, (ii) NRZ-to-PRZ data format converters using a microring resonator notch filter, (iii) GHz-speed carrier-injection-based microring resonator modulators and 0.5-GHz-speed carrier-injection-based microdisk resonator modulators, and (iv) electrically reconfigurable microring resonator add-drop filters and electro-optic logic switches using interferometric resonance control. On the nonlinear waveguide front, we review the main nonlinear optical effects in silicon, and show that even at fairly modest average powers two-photon absorption and the accompanied free-carrier linear absorption could lead to optical limiting and a dramatic reduction in the effective lengths of nonlinear devices.

  16. Proxy-agent management platform for OXC managed objects

    NASA Astrophysics Data System (ADS)

    Pahk, Soomyung; Joo, Seong-Soon; Nam, Hyun-Soon; Lee, Sang-Wha; Kim, Hae G.

    2001-10-01

    In this paper, we present a Proxy-Agent Management Platform, which supports the managed objects of the Optical Cross-Connects (OXC). OXC is a sophisticated WDM network element (NE) that makes the WDM networks reconfigurable. It consists of several sub-NEs, such as 3R modules, Mux/Demux modules, transponder modules, optical switch fabric modules, and operation administration and maintenance processing modules. The OXC network element manager requests and gathers the managed information, alarms, and events from those sub-NEs in the OXC network element, and updates the Management Information Base (MIB) of the OXC managed object existed in the local or remote OXC network element management system. We propose an OXC network element manager with proxy-agent functions which could configure, control, and manage the sub-NEs via an unified access interface on the Common Object Request Broker Architecture (CORBA). The proxy-agent in the OXC network element management system offers its own MIB information to SNMP and/or CMIP manager. The proposed platform achieves high code reusability, provides unified access interfaces between sub-NEs and proxy-agent via ORB, and offers authentication and authorization. The proposed platform is verified on simulated testbed, and shows that managed objects can be added or droped easily to develop an intelligent OXC system.

  17. Groundwater flow characterization in a fractured bedrock aquifer using active DTS tests in sealed boreholes

    NASA Astrophysics Data System (ADS)

    Coleman, Thomas I.; Parker, Beth L.; Maldaner, Carlos H.; Mondanos, Michael J.

    2015-09-01

    In recent years, wireline temperature profiling methods have evolved to offer new insight into fractured rock hydrogeology. Important advances in wireline temperature logging in boreholes make use of active line source heating alone and then in combination with temporary borehole sealing with flexible impervious fabric liners to eliminate the effects of borehole cross-connection and recreate natural flow conditions. Here, a characterization technique was developed based on combining fiber optic distributed temperature sensing (DTS) with active heating within boreholes sealed with flexible borehole liners. DTS systems provide a temperature profiling method that offers significantly enhanced temporal resolution when compared with conventional wireline trolling-based techniques that obtain a temperature-depth profile every few hours. The ability to rapidly and continuously collect temperature profiles can better our understanding of transient processes, allowing for improved identification of hydraulically active fractures and determination of relative rates of groundwater flow. The advantage of a sealed borehole environment for DTS-based investigations is demonstrated through a comparison of DTS data from open and lined conditions for the same borehole. Evidence for many depth-discrete active groundwater flow features under natural gradient conditions using active DTS heat pulse testing is presented along with high resolution geologic and geophysical logging and hydraulic datasets. Implications for field implementation are discussed.

  18. Death and Transfiguration in Static Staphylococcus epidermidis Cultures

    PubMed Central

    Schaudinn, Christoph; Stoodley, Paul; Hall-Stoodley, Luanne; Gorur, Amita; Remis, Jonathan; Wu, Siva; Auer, Manfred; Hertwig, Stefan; Guerrero-Given, Debbie; Hu, Fen Ze; Ehrlich, Garth D.; Costerton, John William; Robinson, Douglas H.; Webster, Paul

    2014-01-01

    The overwhelming majority of bacteria live in slime embedded microbial communities termed biofilms, which are typically adherent to a surface. However, when several Staphylococcus epidermidis strains were cultivated in static liquid cultures, macroscopic aggregates were seen floating within the broth and also sedimented at the test tube bottom. Light- and electron microscopy revealed that early-stage aggregates consisted of bacteria and extracellular matrix, organized in sheet-like structures. Perpendicular under the sheets hung a network of periodically arranged, bacteria-associated strands. During the extended cultivation, the strands of a subpopulation of aggregates developed into cross-connected wall-like structures, in which aligned bacteria formed the walls. The resulting architecture had a compartmentalized appearance. In late-stage cultures, the wall-associated bacteria disintegrated so that, henceforth, the walls were made of the coalescing remnants of lysed bacteria, while the compartment-like organization remained intact. At the same time, the majority of strand-containing aggregates with associated culturable bacteria continued to exist. These observations indicate that some strains of Staphylococcus epidermidis are able to build highly sophisticated structures, in which a subpopulation undergoes cell lysis, presumably to provide continued access to nutrients in a nutrient-limited environment, whilst maintaining structural integrity. PMID:24964210

  19. AOSC multichannel electronic variable optical attenuator

    NASA Astrophysics Data System (ADS)

    Vonsovici, Adrian P.; Day, Ian E.; House, Andrew A.; Asghari, Mehdi

    2001-05-01

    Optical networks are becoming a reality as the physical layer of high-performance telecommunication networks. The deployment of wavelength-division multiplexing (WDM) technology allows the extended exploitation of installed fibers now facing an increasing traffic capacity demand. Performances of such systems can be degraded by wide variations of the optical channel power following propagation in the network. Therefore a tilt control of optical amplifiers in WDM networks and dynamic channel power regulation and equalisation in cross-connected nodes is necessary. An important tool for the system designer is the variable optical attenuator (VOA). We present the design and the realization of newly developed VOAs using the ASOC technology. This technology refers to the fabrication of integrated optics components in silicon-on-insulator (SOI) material. The device is based on the light absorption by the free-carriers that are injected in the core of a rib waveguide from a p-i-n diode. The devices incorporate horizontally and vertically tapered waveguides for minimum fiber coupling loss. The p-i-n diode for carrier injection into the active region of the rib waveguide was optimised in order to enhance the attenuation. One major advantage of the ASOC technology is the possibility of monolithic integration of many integrated optics devices on one chip. In the light of this the paper illustrates the result of characterisation of multichannel VOAs.

  20. Free-space optical technology and distribution architecture for broadband metro and local services

    NASA Astrophysics Data System (ADS)

    Dodley, J. P.; Britz, David M.; Bowen, D. J.; Lundgren, Carl W.

    2001-02-01

    12 This paper addresses the hardware and operational requirements for broadband metro and local services using line of sight wireless Free Space Optical Communication (FSOC) optical links. The primary considerations for successful optical wireless service provisions include link availability, type of service and integration into existing fiber optic networks. A comprehensive link analysis for broadband access services is presented. This paper addresses FSOC critical atmospheric transmission impairments and describes one possible FSOC/network fiber optic interface and routing scenario. This paper will also detail methods to restor FSOC service links that have failed due to atmospheric impairments. This paper will detail the use of secondary radio (mm wave or ISM band radio) link architectures to provide critical transmission back-up for data, emergency and voice call services. An FSOC back-up link for existing millimeter-wave radio local services is also discussed. A co-operative network of FSOC links is discussed for achieving availability requirements for metro and local distribution services. This paper also describes one possible rooftop routing scenario using optical cross- connect architectures located at each node of the local FSOC access network. Rooftop routing will utilize the technology flexibility and system redundancy described above to provide high `five nines' metro service availability. This paper will also describe a proposed FSOC test installation to study link architectures, performance of such links, and vendor product interface and evaluation.

  1. Toxicologic Pathology Analysis for Translational Neuroscience: Improving Human Risk Assessment Using Optimized Animal Data.

    PubMed

    Sharma, Alok K; Morrison, James P; Rao, Deepa B; Pardo, Ingrid D; Garman, Robert H; Bolon, Brad

    2016-07-01

    A half-day American College of Toxicology continuing education course presented key issues often confronted by translational neuroscientists when predicting human risk from animal-derived toxicologic pathology data. Two talks correlated discrete structures with major functions in brains of rodents and nonrodents. The third lecture provided practical advice to obtain highly homologous rodent brain sections for quantitative morphometry in developmental neurotoxicity testing. The last presentation discussed demographic influences (eg, species, strain, sex, age), physiological attributes (eg, body composition, brain vascularity, pharmacokinetic/pharmacodynamic patterns, etc), and husbandry parameters (eg, group housing) recognized to impact the actions of neuroactive chemicals. Speakers described common cases of real-world challenges to animal data interpretation encountered when designing studies or extrapolating biological responses across species. The efficiency of translational neuroscience efforts will likely be enhanced as new methods (eg, high-resolution non-invasive imaging) improve our capability to cross-connect subtle anatomic and/or biochemical lesions with functional changes over time. PMID:27012643

  2. IC design of low power, wide tuning range VCO in 90 nm CMOS technology

    NASA Astrophysics Data System (ADS)

    Zhu, Li; Zhigong, Wang; Zhiqun, Li; Qin, Li; Faen, Liu

    2014-12-01

    A low power VCO with a wide tuning range and low phase noise has been designed and realized in a standard 90 nm CMOS technology. A newly proposed current-reuse cross-connected pair is utilized as a negative conductance generator to compensate the energy loss of the resonator. The supply current is reduced by half compared to that of the conventional LC-VCO. An improved inversion-mode MOSFET (IMOS) varactor is introduced to extend the capacitance tuning range from 32.8% to 66%. A detailed analysis of the proposed varactor is provided. The VCO achieves a tuning range of 27-32.5 GHz, exhibiting a frequency tuning range (FTR) of 18.4% and a phase noise of -101.38 dBc/Hz at 1 MHz offset from a 30 GHz carrier, and shows an excellent FOM of -185 dBc/Hz. With the voltage supply of 1.5 V, the core circuit of VCO draws only 2.1 mA DC current.

  3. Low Voltage Low Power Quadrature LC Oscillator Based on Back-gate Superharmonic Capacitive Coupling

    NASA Astrophysics Data System (ADS)

    Ma, Minglin; Li, Zhijun

    2013-09-01

    This work introduces a new low voltage low power superharmonic capacitive coupling quadrature LC oscillator (QLCO) made by coupling two identical cross-connected LC oscillators without tail transistor. In each of the core oscillators, the back-gate nodes of the cross-coupled NMOS pair and PMOS pair, acting as common mode nodes, have been connected directly. Then the core oscillators are coupled together via capacitive coupling of the PMOS common mode node in one of the core oscillators to the NMOS common mode node in the other core oscillator, and vice versa. Only capacitors are used for coupling of the two core oscillators and therefore no extra noise sources are imposed on the circuit. Operation of the proposed QLCO was investigated with simulation using a commercial 0.18 µm RF CMOS technology: it shows a power dissipation of 5.2 mW from a 0.6 V supply voltage. Since the proposed core oscillator has Complementary NMOS and PMOS cross coupled pairs, and capacitive coupling method will not introduce extra phase noise, so this circuit can operate with a low phase noise as low as -126.8 dBc/Hz at 1 MHz offset from center oscillation frequency of 2.4 GHz, as confirmed with simulation.

  4. Effect of ingress buffering on self-similarity of optical burst traffic

    NASA Astrophysics Data System (ADS)

    Huang, Rui; Zaruba, Gergely V.

    2003-10-01

    Recently, optical burst switching and aggregated optical packet switching have gained significant exposure as possible future mechanisms for routing aggregated IP traffic over all-optical core networks. However, the limited buffering capacity in all-optical networks presents a major challenge, as current IP traffic displays strong self-similar properties. Reducing the burst loss rate of such long-range dependent traffic can be costly requiring a significant increase in either the network bandwidth or the buffer size of optical cross connects. In this paper, we revisit the possibility of using buffers to reduce self-similarity before the traffic is routed onto the all-optical core. The aim of this paper is to increase the understanding of the effect of packet/burst aggregation on the self-similarity measure of the traffic. In particular, we implement a simple burst assembly mechanism with two parameters, the maximum burst length L and the maximum burst delay d, so that incoming traffic is smoothed with a guaranteed delay bound. Unlike previous works, we simulate the burst assembler using more realistic input traffic sources, and analyze the results using both R/S plot and discrete wavelet analysis methods. Our detailed results show that buffering indeed reduces traffic self-similarity (an area of research controversy) when parameters L and d are set appropriately.

  5. Polymeric methylenebis(diphenylphosphine oxide) hydrogen triiodide.

    PubMed

    Boraei, Ahmed A; du Mont, Wolf W; Ruthe, Frank; Jones, Peter G

    2002-06-01

    The conformation of the cationic part of the title compound, [[(C(6)H(5))(2)POH(0.5)](2)CH(2)]I(3) or dppmO(2)H(+) x I(3)(-) (dppm is diphenylphosphinomethane), is determined by hydrogen bonds between cations of monoprotonated [(C(6)H(5))(2)P([double bond]O)](2)CH(2) (dppmO(2)). Symmetric P[double bond]O...H...O[bond]P bridging, with H atoms lying on centres of inversion, leads to chain-like polymeric cations, (dppmO(2)H(+))(x), made up of H...OP(C(6)H(5))(2)[bond]CH(2)[bond](C(6)H(5))(2)PO... moieties. These are, in turn, cross-connected by non-classical C[bond]H...I contacts between the (dppmO(2)H(+))(x) methylene-group H atoms and the terminal I atoms of the triiodide anions, which display crystallographic inversion symmetry. PMID:12050427

  6. “Stop Ne(c)king around”: How interactomics contributes to functionally characterize Nek family kinases

    PubMed Central

    Meirelles, Gabriela Vaz; Perez, Arina Marina; de Souza, Edmárcia Elisa; Basei, Fernanda Luisa; Papa, Priscila Ferreira; Melo Hanchuk, Talita Diniz; Cardoso, Vanessa Bomfim; Kobarg, Jörg

    2014-01-01

    Aside from Polo and Aurora, a third but less studied kinase family involved in mitosis regulation is the never in mitosis-gene A (NIMA)-related kinases (Neks). The founding member of this family is the sole member NIMA of Aspergillus nidulans, which is crucial for the initiation of mitosis in that organism. All 11 human Neks have been functionally assigned to one of the three core functions established for this family in mammals: (1) centrioles/mitosis; (2) primary ciliary function/ciliopathies; and (3) DNA damage response (DDR). Recent findings, especially on Nek 1 and 8, showed however, that several Neks participate in parallel in at least two of these contexts: primary ciliary function and DDR. In the core section of this in-depth review, we report the current detailed functional knowledge on each of the 11 Neks. In the discussion, we return to the cross-connections among Neks and point out how our and other groups’ functional and interactomics studies revealed that most Neks interact with protein partners associated with two if not all three of the functional contexts. We then raise the hypothesis that Neks may be the connecting regulatory elements that allow the cell to fine tune and synchronize the cellular events associated with these three core functions. The new and exciting findings on the Nek family open new perspectives and should allow the Neks to finally claim the attention they deserve in the field of kinases and cell cycle biology. PMID:24921005

  7. Demonstration of 1×32 LCOS-based wavelength selective switch

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Chen, Xiao; Gao, Yunshu; Tian, Miao; Chen, Ran; Wang, Shan; Chen, Genxiang; Wang, Yiquan

    2015-08-01

    In recent years, reconfigurable optical add drop multiplexers (ROADM) and multiple-dimensions optical cross-connection (OXC), as the essential devices of next-generation dynamic optical networks, have been attracted great interests by research institutions and relevant industry. 1×N Wavelength selective switches (WSSs) are one of the key components in current and next generation ROADM. Currently, WSS primarily rely on micro-electromechanical systems (MEMS) and liquid crystal on silicon spatial light modulators (LCOS-SLM) switches. LCOS-based WSSs have several advantages, including flexible spectrum coverage, adaptive alignment, and robustness. Based on a novel 2-f optical structure, we therefore propose 1×32 WSS system including a 1×32 fiber-coupling lenslet arrays, a collimating lens, a transmission grating, a cylindrical lens and a LCOS-SLM. By uploading the optimized phased holograms on the LCOS, we have successfully switched input signal with arbitrary wavelength in C-band into any output port. The output channel spacing can be adjusted flexibly and each port switches independently. Experimental results demonstrate the insertion loss is around 5~10dB and the switch crosstalk at 1550nm is -35dB. The 3dB-bandwidth of signal@100G is 40G.The research has established the theory and experiment foundation for the development of M×N WSS in future.

  8. Detailed measurement of the magnitude and orientation of thermal gradients in lined boreholes for characterizing groundwater flow in fractured rock

    NASA Astrophysics Data System (ADS)

    Pehme, Peeter; Parker, Beth L.; Cherry, John A.; Blohm, Detlef

    2014-05-01

    Recent developments have led to revitalization of the use of temperature logging for characterizing flow through fractured rock. The sealing of boreholes using water-filled, flexible impermeable liners prevents vertical cross connection between fractures intersecting the hole and establishes a static water column with a temperature stratification that mimics that in the surrounding formation. Measurement of the temperature profile of the lined-hole, water column (using a high sensitivity single-point probe achieving resolution on the order of 0.001 °C) has identified fractures with active flow under ambient groundwater conditions (without cross connecting flow along the borehole). Detection of flow in fractures was further improved with the use of a heater to create thermal disequilibrium in the active line source (ALS) technique and eliminate normal depth limitations in the process. This paper presents another advancement; detailed measurement of the magnitude and direction of the thermal gradient to characterize flow through fractured rock. The temperature within the water column is measured along the length of the lined hole using a temperature vector probe (TVP): four high sensitivity sensors arranged in a tetrahedral pattern oriented using three directional magnetometers. Based on these data, the horizontal and vertical components of the thermal field, as well as the direction of temperature gradient are determined, typically at depth intervals of less than 0.01 m. This probe was assessed and refined by trials in over 30 lined boreholes; the results from two holes through a fractured dolostone aquifer in Guelph, Ontario are used as exampled. Since no other device exists for measuring flow magnitude and direction under the ambient flow condition created by lined holes, the performance of the TVP is assessed by examining the reproducibility of the temperature measurements through an ALS test, and by the consistency of the results relative to other types of

  9. Effect of Emergency Argon on FCF Operational Incidents

    SciTech Connect

    Charles Solbrig

    2011-12-01

    The following report presents analyses of operational incidents which are considered in the safety analysis of the FCF argon cell and the effect that the operability of the emergency argon system has on the course of these incidents. The purpose of this study is to determine if the emergency argon system makes a significant difference in ameliorating the course of these incidents. Six incidents were considered. The following three incidents were analyzed. These are: 1. Cooling failing on 2. Vacuum Pump Failing on 3. Argon Supplies Failing on. In the remaining three incidents, the emergency argon supply would have no effect on the course of these transients since it would not come on during these incidents. The transients are 1. Loss of Cooling 2. Loss of power (Differs from above by startup delay till the Diesel Generators come on.) 3. Cell rupture due to an earthquake or other cause. The analyses of the first three incidents are reported on in the next three sections. This report is issued realizing the control parameters used may not be optimum, and additional modeling must be done to model the inertia of refrigeration system, but the major conclusion concerning the need for the emergency argon system is still valid. The timing of some events may change with a more accurate model but the differences between the transients with and without emergency argon will remain the same. Some of the parameters assumed in the analyses are Makeup argon supply, 18 cfm, initiates when pressure is = -6 iwg., shuts off when pressure is = -3.1 iwg. 170,000 ft3 supply. Min 1/7th always available, can be cross connected to HFEF argon supply dewar. Emergency argon supply, 900 cfm, initiates when pressure is = -8 iwg. shuts off when pressure is =-4 iwg. reservoir 220 ft3, refilled when tank farm pressure reduces to 1050 psi which is about 110 ft3.

  10. A complete design flow for silicon photonics

    NASA Astrophysics Data System (ADS)

    Pond, James; Cone, Chris; Chrostowski, Lukas; Klein, Jackson; Flueckiger, Jonas; Liu, Amy; McGuire, Dylan; Wang, Xu

    2014-05-01

    Broad adoption of silicon photonics technology for photonic integrated circuits requires standardized design flows that are similar to what is available for analog and mixed signal electrical circuit design. We have developed a design flow that combines mature electronic design automation (EDA) software with optical simulation software. An essential component of any design flow, whether electrical or photonic, is the ability to accurately simulate largescale circuits. This is particularly important when the behavior of the circuit is not trivially related to the individual component performance. While this is clearly the case for electronic circuits consisting of hundreds to billions of transistors, it is already becoming important in photonic circuits such as WDM transmitters, where signal cross talk needs to be considered, as well as optical cross-connect switches. In addition, optical routing to connect different components requires the introduction of additional waveguide sections, waveguide bends, and waveguide crossings, which affect the overall circuit performance. Manufacturing variability can also have dramatic circuit-level consequences that need to be simulated. Circuit simulations must rely on compact models that can accurately represent the behavior of each component, and the compact model parameters must be extracted from physical level simulation and experimental results. We show how large scale circuits can be simulated in both the time and frequency domains, including the effects of bidirectional and, where appropriate, multimode and multichannel photonic waveguides. We also show how active, passive and nonlinear individual components such as grating couplers, waveguides, splitters, filters, electro-optical modulators and detectors can be simulated using a combination of electrical and optical algorithms, and good agreement with experimental results can be obtained. We then show how parameters, with inclusion of fabrication process variations, can

  11. New method for continuous transmissivity profiling in fractured rock.

    PubMed

    Keller, Carl E; Cherry, John A; Parker, Beth L

    2014-01-01

    A new method is presented to search for hydraulically transmissive features in open boreholes in bedrock. A flexible borehole liner made of a watertight, nylon fabric is filled with water to create a constant driving head to evert (reverse of invert) the liner down the hole so that the liner pushes the borehole water out into transmissive fractures or other permeable features. The descent rate is governed by the bulk transmissivity of the remaining permeable features below the liner. Initially, the liner descent rate or velocity is a measure of transmissivity (T) of the entire hole. As the everting liner passes and seals each permeable feature, changes in the liner velocity indicate the position of each feature and an estimate of T using the Thiem equation for steady radial flow. This method has been performed in boreholes with diameters ranging from 96 to 330 mm. Profiling commonly takes a few hours in holes 200- to 300-m long. After arrival of the liner at the bottom of the hole, the liner acts as a seal preventing borehole cross connection between transmissive features at different depths. Liner removal allows the hole to be used for other purposes. The T values determined using this method in a dolostone aquifer were found to be similar to the values from injection tests using conventional straddle packers. This method is not a replacement for straddle-packer hydraulic testing of specific zones where greater accuracy is desired; however, it is effective and efficient for scanning entire holes for transmissive features. PMID:23692626

  12. Cross-Coupled Eye Movement Supports Neural Origin of Pattern Strabismus

    PubMed Central

    Ghasia, Fatema F.; Shaikh, Aasef G.; Jacobs, Jonathan; Walker, Mark F.

    2015-01-01

    Purpose. Pattern strabismus describes vertically incomitant horizontal strabismus. Conventional theories emphasized the role of orbital etiologies, such as abnormal fundus torsion and misaligned orbital pulleys as a cause of the pattern strabismus. Experiments in animal models, however, suggested the role of abnormal cross-connections between the neural circuits. We quantitatively assessed eye movements in patients with pattern strabismus with a goal to delineate the role of neural circuits versus orbital etiologies. Methods. We measured saccadic eye movements with high-precision video-oculography in 14 subjects with pattern strabismus, 5 with comitant strabismus, and 15 healthy controls. We assessed change in eye position in the direction orthogonal to that of the desired eye movement (cross-coupled responses). We used fundus photography to quantify the fundus torsion. Results. We found cross-coupling of saccades in all patients with pattern strabismus. The cross-coupled responses were in the same direction in both eyes, but larger in the nonviewing eye. All patients had clinically apparent inferior oblique overaction with abnormal excylotorsion. There was no correlation between the amount of the fundus torsion or the grade of oblique overaction and the severity of cross-coupling. The disconjugacy in the saccade direction and amplitude in pattern strabismics did not have characteristics predicted by clinically apparent inferior oblique overaction. Conclusions. Our results validated primate models of pattern strabismus in human patients. We found no correlation between ocular torsion or oblique overaction and cross-coupling. Therefore, we could not ascribe cross-coupling exclusively to the orbital etiology. Patients with pattern strabismus could have abnormalities in the saccade generators. PMID:26024072

  13. Miniaturized fiber optical switches with nonmoving polymeric mirrors for tele- and data-communication networks fabricated using the LIGA technology

    NASA Astrophysics Data System (ADS)

    Neumeier, Michel; Ehrfeld, Wolfgang; Jaeger, Jutta; Picard, Antoni; Schulze, Jens

    1998-03-01

    Fiber optical switches for telecom and datacom purposes become more and more important with the growth of fiber- based networks. This paper proposes a new principle for manipulating optical light paths through switchable, but non-moving polymeric mirrors in free-space optical interconnects. To achieve this a polymeric body and a thin liquid film are moved within a cavity. By moving the body up and down perpendicular to the light path the cavity wall can be switched from total reflective to transmissive state while the liquid film remains between body and wall due to capillary forces. The body can be moved with integrated electro-magnetic actuators and so the whole concept allows the realization of very compact switching elements. The coupling of single mode optical fibers requires a lateral and angular alignment precision in the micron and millirad range for both direct coupling and expanded beam coupling concepts. To meet these requirements, the LIGA technology provides a promising approach with respect to the high precision and also low-cost fabrication by mass replication processes. The combination of LIGA technology with other precision machining technologies allows the fabrication of miniaturized systems with both micro-optic and micromechanic components which fulfill the required tolerances for optical coupling. First demonstrators of 1 X 2 and 2 X 2 switches with bistable electro-magnetic actuators have been fabricated to show the feasibility of the proposed principle. The measured insertion loss is less than 2 dB at 1300 nm with -40 dB crosstalk. The switching time was measured 100 ms. The capabilities of the proposed non-moving mirror principle can be applied to 1 X 2 repair switches for the access area as well as to FDDI-switching-nodes up to compact N X M cross-connect switches for reconfiguration purposes or parallel interconnects to optical backplanes for the office area.

  14. Regeneration in synchronous optical network/WDM rings

    NASA Astrophysics Data System (ADS)

    Sevian, Armen R.

    2003-06-01

    In today's WDM all-optical networks, a majority of existing virtual topology design algorithms have ignored link-performance limiting factors such as dispersion, amplified spontaneous emission (ASE), cross talk resulting from signal leakage in optical cross connects (OXCs), and fiber nonlinearities. All these factors result in bit-error-rate (BER) degradation at the receiving end. To maintain a BER below a certain level, some lightpaths in the network will require regeneration at the intermediate nodes, thus, setting up a lightpath in a multihop manner. In synchronous optical network (SONET) ring networks, the terminal equipment cost associated with electronic multiplexing is predominantly high. Wavelength add-drop multiplexers reduce the amount of SONET terminal equipment at each node by allowing certain wavelengths or bands to bypass the node optically without being electronically terminated. Most of the previous research in this area has focused on the virtual topology design and wavelength-routing algorithms to address the cost savings. Here we consider both unidirectional path-switched and bidirectional line-switched rings (UPSR, BLSR/2) with optical bypass. We analytically derive a relationship for the number of regenerators to support both single-hub and all-to-all situations for uniform and nonuniform traffic cases with an arbitrary internodal length distribution. We obtain lower and upper bounds for regeneration cost on a ring when nodes are randomly placed. Equivalency is established between UPSR and BLSR/2 networks in terms of regeneration cost for cases of single link failure. Regeneration cost advantage is shown for nonzero dispersion-shifted fiber (NZDSF) over standard single-mode fiber in dispersion-limited regimes.

  15. The structure of the cuticular plate, an in vivo actin gel.

    PubMed

    DeRosier, D J; Tilney, L G

    1989-12-01

    The cuticular plate is a network of actin filaments found in hair cells of the cochlea. In the alligator lizard, it consists of rootlets, emanating from the stereocilia, and of cross-connecting actin filaments that anchor these rootlets. In thin sections, this network displays striking patches of 650 +/- 110-A striae. By quantitative analyses of the images, the mystery of the striae can be explained. They are due in part to the rootlets which are sets of flat ribbons of actin filaments. The ribbons in each set are separated by approximately 650 A. Numerous whiskers 30 A in diameter extend from each ribbon's face, interconnecting adjacent ribbons. The nonrootlet filaments, except at the margins of the cell, occur primarily as single filaments. Like the ribbons, they are bristling with whiskers. The patches of striae are explained by ribbons and filaments held at a 650-A separation by the whiskers that project from them. A simple model for regions of bewhiskered filaments is a box crammed full of randomly oriented test-tube brushes. A thin slice through the box will show regions of dark lines or striae due to the wire backbones of the brushes separated from one another by the bristle length. Using the computer instead of test-tube brushes, we have been able to model quantitatively the filament distribution and pattern of striae seen in the cuticular plate of the lizard. The organization of actin filaments we have deduced from our simulations differs from that found in macrophages or in the terminal web of intestinal epithelial cells. PMID:2592408

  16. A review of outbreaks of waterborne disease associated with ships: evidence for risk management.

    PubMed Central

    Rooney, Roisin M.; Bartram, Jamie K.; Cramer, Elaine H.; Mantha, Stacey; Nichols, Gordon; Suraj, Rohini; Todd, Ewen C. D.

    2004-01-01

    OBJECTIVE: The organization of water supply to and on ships differs considerably from that of water supply on land. Risks of contamination can arise from source water at the port or during loading, storage, or distribution on the ship. The purpose of this article is to review documented outbreaks of waterborne diseases associated with passenger, cargo, fishing, and naval ships to identify contributing factors so that similar outbreaks can be prevented in the future. METHODS: The authors reviewed 21 reported outbreaks of waterborne diseases associated with ships. For each outbreak, data on pathogens/toxins, type of ship, factors contributing to outbreaks, mortality and morbidity, and remedial action are presented. RESULTS: The findings of this review show that the majority of reported outbreaks were associated with passenger ships and that more than 6,400 people were affected. Waterborne outbreaks due to Enterotoxigenic Escherichia coli, noroviruses, Salmonella spp, Shigella sp, Cryptosporidium sp, and Giardia lamblia occurred on ships. Enterotoxigenic E. coli was the pathogen most frequently associated with outbreaks. One outbreak of chemical water poisoning also occurred on a ship. Risk factors included contaminated port water, inadequate treatment, improper loading techniques, poor design and maintenance of storage tanks, ingress of contamination during repair and maintenance, cross-connections, back siphonage, and insufficient residual disinfectant. CONCLUSIONS: Waterborne disease outbreaks on ships can be prevented. The factors contributing to outbreaks emphasize the need for hygienic handling of water along the supply chain from source to consumption. A comprehensive approach to water safety on ships is essential. This may be achieved by the adoption of Water Safety Plans that cover design, construction, operation, and routine inspection and maintenance. PMID:15219801

  17. Routing and wavelength assignment based on normalized resource and constraints for all-optical network

    NASA Astrophysics Data System (ADS)

    Joo, Seong-Soon; Nam, Hyun-Soon; Lim, Chang-Kyu

    2003-08-01

    With the rapid growth of the Optical Internet, high capacity pipes is finally destined to support end-to-end IP on the WDM optical network. Newly launched 2D MEMS optical switching module in the market supports that expectations of upcoming a transparent optical cross-connect in the network have encouraged the field applicable research on establishing real all-optical transparent network. To open up a customer-driven bandwidth services, design of the optical transport network becomes more challenging task in terms of optimal network resource usage. This paper presents a practical approach to finding a route and wavelength assignment for wavelength routed all-optical network, which has λ-plane OXC switches and wavelength converters, and supports that optical paths are randomly set up and released by dynamic wavelength provisioning to create bandwidth between end users with timescales on the order of seconds or milliseconds. We suggest three constraints to make the RWA problem become more practical one on deployment for wavelength routed all-optical network in network view: limitation on maximum hop of a route within bearable optical network impairments, limitation on minimum hops to travel before converting a wavelength, and limitation on calculation time to find all routes for connections requested at once. We design the NRCD (Normalized Resource and Constraints for All-Optical Network RWA Design) algorithm for the Tera OXC: network resource for a route is calculated by the number of internal switching paths established in each OXC nodes on the route, and is normalized by ratio of number of paths established and number of paths equipped in a node. We show that it fits for the RWA algorithm of the wavelength routed all-optical network through real experiments on the distributed objects platform.

  18. The covalent structure of the elastase inhibitor from Anemonia sulcata--a "non-classical" Kazal-type protein.

    PubMed

    Tschesche, H; Kolkenbrock, H; Bode, W

    1987-10-01

    The amino-acid sequence of the proteinase inhibitor specific for elastases from the sea anemone Anemonia sulcata was determined from performic-acid oxidized inhibitor and from three cyanogen bromide fragments of reduced and carboxymethylated inhibitor. The molecule consists of a single polypeptide chain formed from 48 amino-acid residues and is stabilized by three intramolecular disulfide bridges. After cyanogen bromide cleavage of the native protein at methionines 10 and 28 followed by chymotryptic cleavage two fragments each containing a single disulfide bridge were isolated. These indicated the location of three intramolecular disulfide linkages between Cys4 and Cys34 (part of A-loop), Cys8 and Cys27 (B-loop) and Cys16 and Cys48 (C-loop). The sequential homology and the disulfide pattern identified the elastase inhibitor as a Kazal-type inhibitor in which, however, not only the CysI-CysII segment is rather short but interestingly the Cys4-Cys34 disulfide anchoring point (i.e. CysI-CysV) in the C-loop is shifted by one turn in the alpha-helical segment towards the C-terminus. Thus, the elastase inhibitor is a non-classical Kazal-type inhibitor with respect to the positioning of the half-cystines. The inhibitor molecule was modelled based on the known three-dimensional structure of the silver pheasant ovomucoid third domain. The shortened amino-terminal segment was arranged in such a manner to allow disulfide bridge formation between the first cysteine Cys4 and the replaced Cys34 under maintenance of a suitable binding loop conformation. The characteristic ovomucoid scaffold consisting of a central alpha-helix, an adjacent three-stranded beta-sheet and the proteinase-binding loop cross-connected through disulfide bridges CysI-CysV and CysIII-CysVI was conserved. PMID:2892502

  19. Multiscale fracture network characterization and impact on flow: A case study on the Latemar carbonate platform

    NASA Astrophysics Data System (ADS)

    Hardebol, N. J.; Maier, C.; Nick, H.; Geiger, S.; Bertotti, G.; Boro, H.

    2015-12-01

    A fracture network arrangement is quantified across an isolated carbonate platform from outcrop and aerial imagery to address its impact on fluid flow. The network is described in terms of fracture density, orientation, and length distribution parameters. Of particular interest is the role of fracture cross connections and abutments on the effective permeability. Hence, the flow simulations explicitly account for network topology by adopting Discrete-Fracture-and-Matrix description. The interior of the Latemar carbonate platform (Dolomites, Italy) is taken as outcrop analogue for subsurface reservoirs of isolated carbonate build-ups that exhibit a fracture-dominated permeability. New is our dual strategy to describe the fracture network both as deterministic- and stochastic-based inputs for flow simulations. The fracture geometries are captured explicitly and form a multiscale data set by integration of interpretations from outcrops, airborne imagery, and lidar. The deterministic network descriptions form the basis for descriptive rules that are diagnostic of the complex natural fracture arrangement. The fracture networks exhibit a variable degree of multitier hierarchies with smaller-sized fractures abutting against larger fractures under both right and oblique angles. The influence of network topology on connectivity is quantified using Discrete-Fracture-Single phase fluid flow simulations. The simulation results show that the effective permeability for the fracture and matrix ensemble can be 50 to 400 times higher than the matrix permeability of 1.0 · 10-14 m2. The permeability enhancement is strongly controlled by the connectivity of the fracture network. Therefore, the degree of intersecting and abutting fractures should be captured from outcrops with accuracy to be of value as analogue.

  20. Quantifying Urban Water Subsidies with Hydrological Tracers of Domestic Water

    NASA Astrophysics Data System (ADS)

    Bain, D. J.; Sikora, M. T.; Wozniak, E.; Fisher, K. R.; Carr, J.; Elliott, E. M.

    2011-12-01

    Connections between urban hydrological systems and human water infrastructure are well established. Interactions between these systems occur at a wide range of scales, from large inter-basin transfers to individual leaking pipes. However, much of the interest in these connections arises from practical considerations, for example, substantially altered in-stream flow or the presence/absence of sewage in surface water systems. Less recognized is that in smaller urban catchments, daily water flux through human water distribution systems is often much larger than low flow surface water flux from the catchment. As infrastructure ages and cross-connections grow, transfers from the substantial human fluxes to the catchment will increasingly subsidize urban water budgets. Tools for quantifying the contribution of this subsidy to urban hydrological systems can clarify both practical questions for urban managers and our understanding of flow generation in catchments. Stream water chemistry from a multi-year sampling campaign in Nine Mile Run (Pittsburgh, PA) is used to examine potential hydrological tracers of human domestic water. In particular, we examine the use of fluoride added in precise quantities as a dental health supplement as a tracer of human domestic water (e.g., drinking and waste water). While fluoride is not necessarily a conservative tracer, equilibrium reactions governing fluoride solubility generally require substantially higher cationic concentrations than those observed in surface water chemistry. Further, during periods where human subsidies dominate (e.g., water line breaks or hydrant flushes discharging to the stream) fluoride concentrations generally approach the concentration added to domestic water. We use multiple modeling approaches to demonstrate the appropriateness of fluoride as a tracer, infer contributions of human domestic water to the hydrologic budget, and explore fluoride dynamics in the Nine Mile Run basin. A fluoride tracer is

  1. Analysis of elemental concentration using ICP-AES and pathogen indicator in drinking water of Qasim Abad, District Rawalpindi, Pakistan.

    PubMed

    Sehar, Shama; Naz, Iffat; Ali, Naeem; Ahmed, Safia

    2013-02-01

    The present study was conducted to investigate drinking water quality (groundwater) from water samples taken from Qasim Abad, a locality of approximately 5,000 population, situated between twin cities Rawalpindi and Islamabad in Pakistan. The main sources of drinking water in this area are water bores which are dug upto the depth of 250-280 ft in almost every house. The study consists of the determination of physico-chemical properties, trace metals, heavy metals, rare earth elements and microbiological quality of drinking water. The data showed the variation of the investigated parameters in samples as follows: pH 6.75 to 8.70, electrical conductivity 540 to 855 μS/cm, total dissolved solids 325.46 to 515.23 ppm and dissolved oxygen 1.50 to 5.64 mg/L which are within the WHO guidelines for drinking water quality. The water samples were analysed for 30 elements (aluminium, iron, magnesium, manganese, silicon, zinc, molybdenum, titanium, chromium, nickel, tungsten, silver, arsenic, boron, barium, beryllium, cadmium, cobalt, copper, gallium, mercury, lanthanum, niobium, neodymium, lead, selenium, samarium, tin, vanadium and zirconium) by using inductively coupled plasma atomic emission spectroscopy. The organic contamination was detected in terms of most probable number (MPN) of faecal coliforms. Overall, elemental levels were lower than the recommended values but three water bores (B-1, B-6, B-7) had higher values of iron (1.6, 2.206, 0.65 ppm), two water bores (B-1, B-6) had higher values of aluminium (0.95, 1.92 ppm), respectively, and molybdenum was higher by 0.01 ppm only in one water bore (B-11). The total number of coliforms present in water samples was found to be within the prescribed limit of the WHO except for 5 out of 11 bore water samples (B-2, B-3, B-4, B-8, B-11), which were found in the range 5-35 MPN/100 mL, a consequence of infiltration of contaminated water (sewage) through cross connection, leakage points and back siphoning. PMID:22544071

  2. James Clerk Maxwell Prize for Plasma Physics: The Physics of Magnetic Reconnection and Associated Particle Acceleration

    NASA Astrophysics Data System (ADS)

    Drake, James

    2010-11-01

    Solar and stellar flares, substorms in the Earth's magnetosphere, and disruptions in laboratory fusion experiments are driven by the explosive release of magnetic energy through the process of magnetic reconnection. During reconnection oppositely directed magnetic fields break and cross-connect. The resulting magnetic slingshots convert magnetic energy into high velocity flows, thermal energy and energetic particles. A major scientific challenge has been the multi-scale nature of the problem: a narrow boundary layer, ``the dissipation region,'' breaks field lines and controls the release of energy in a macroscale system. Significant progress has been made on fundamental questions such as how magnetic energy is released so quickly and why the release occurs as an explosion. At the small spatial scales of the dissipation region the motion of electrons and ions decouples, the MHD description breaks down and whistler and kinetic Alfven dynamics drives reconnection. The dispersive property of these waves leads to fast reconnection, insensitive to system size and weakly dependent on dissipation, consistent with observations. The evidence for these waves during reconnection in the magnetosphere and the laboratory is compelling. The role of turbulence within the dissipation region in the form of ``secondary islands'' or as a source of anomalous resistivity continues to be explored. A large fraction of the magnetic energy released during reconnection appears in the form of energetic electrons and protons -- up to 50% or more during solar flares. The mechanism for energetic particle production during magnetic reconnection has remained a mystery. Models based on reconnection at a single large x-line are incapable of producing the large numbers of energetic electrons seen in observations. Scenarios based on particle acceleration in a multi-x-line environment are more promising. In such models a link between the energy gain of electrons and the magnetic energy released, a

  3. Integrated conceptual modelling of faecal contamination in an urban estuary catchment.

    PubMed

    Jovanovic, Dusan; Henry, Rebekah; Coleman, Rhys; Deletic, Ana; McCarthy, David

    2015-01-01

    Urban stormwater is regarded as a key input of faecal contamination in receiving water bodies and therefore, a major concern for health risks associated with aquatic recreation. Wastewater leakages, cross connections and overflows, together with faeces washed from surfaces during rainfall events, are possible origins of faecal contamination which enter these water bodies through stormwater drains. This paper applies conceptual models to a case study of the Yarra River estuary to understand the relative importance of fluxes derived from an urban creek and the 219 urban stormwater pipes which drain directly to the estuary as compared with other inputs, such as the Yarra River itself. Existing hydrologic-microorganism models were used for the estimation of the inputs from riverine and urban stormwater fluxes. These predictions were applied as boundary conditions for a new, highly simplified, model which accounts for the transport and survival of faecal microorganisms in the estuary. All models were calibrated using a rich dataset, containing over 2,000 measured Escherichia coli concentrations. Mass balances from the riverine and stormwater models indicate the limited influence of urban stormwater drains on the estuary during dry weather; less than 0.05% to 10% (5th and 95th percentile; median 0.5%) of the total daily E. coli load entering the estuary was derived from urban stormwater drains. While wet weather contributions from stormwater drains could be more significant (2% to 50%; 5th and 95th percentile), the average contribution remained marginal (median 10%). Sensitivity testing of the estuarine microorganism model by switching off stormwater boundary conditions resulted in minimal model efficiency reduction; this may reflect the low average daily contribution from urban stormwater drains. While these results confirm previous studies which show that E. coli loads derived from stormwater drains are dwarfed by other inputs, it is essential to note that these

  4. Assessing the Role of Sewers and Atmospheric Deposition as Nitrate Contamination Sources to Urban Surface Waters using Stable Nitrate Isotopes

    NASA Astrophysics Data System (ADS)

    Sikora, M. T.; Elliott, E. M.

    2009-12-01

    Excess nitrate (NO3-) contributes to the overall degraded quality of streams in many urban areas. These systems are often dominated by impervious surfaces and storm sewers that can route atmospherically deposited nitrogen, from both wet and dry deposition, to waterways. Moreover, in densely populated watersheds there is the potential for interaction between urban waterways and sewer systems. The affects of accumulated nitrate in riverine and estuary systems include low dissolved oxygen, loss of species diversity, increased mortality of aquatic species, and general eutrophication of the waterbody. However, the dynamics of nitrate pollution from each source and it’s affect on urban waterways is poorly constrained. The isotopes of nitrogen and oxygen in nitrate have been proven effective in helping to distinguish contamination sources to ground and surface waters. In order to improve our understanding of urban nitrate pollution sources and dynamics, we examined nitrate isotopes (δ15N and δ18O) in base- and stormflow samples collected over a two-year period from a restored urban stream in Pittsburgh, Pennsylvania (USA). Nine Mile Run drains a 1,600 hectare urban watershed characterized by 38% impervious surface cover. Prior work has documented high nitrate export from the watershed (~19 kg NO3- ha-1 yr-1). Potential nitrate sources to the watershed include observed sewer overflows draining directly to the stream, as well as atmospheric deposition (~23 kg NO3- ha-1 yr-1). In this and other urban systems with high percentages of impervious surfaces, there is likely minimal input from nitrate derived from soil or fertilizer. In this presentation, we examine spatial and temporal patterns in nitrate isotopic composition collected at five locations along Nine Mile Run characterized by both sanitary and combined-sewer cross-connections. Preliminary isotopic analysis of low-flow winter streamwater samples suggest nitrate export from Nine Mile Run is primarily influenced by

  5. "I CAMMINI DELLA REGINA" - Open Source based tools for preserving and culturally exploring historical traffic routes.

    NASA Astrophysics Data System (ADS)

    Cannata, Massimiliano; Colombo, Massimo; Antonovic, Milan; Cardoso, Mirko; Delucchi, Andrea; Gianocca, Giancarlo; Brovelli, Maria Antonia

    2015-04-01

    "I CAMMINI DELLA REGINA" (The Via Regina Paths) is an Interreg project funded within the transnational cooperation program between Italy and Switzerland 2007-2013. The aim of this project is the preservation and valorization of the cultural heritage linked to the walking historically paths crossing, connecting and serving the local territories. With the approach of leveraging the already existing tools, which generally consist of technical descriptions of the paths, the project uses the open source geospatial technologies to deploy innovative solutions which can fill some of the gaps in historical-cultural tourism offers. The Swiss part, and particularly the IST-SUPSI team, has been focusing its activities in the realization of two innovative solutions: a mobile application for the survey of historical paths and a storytelling system for immersive cultural exploration of the historical paths. The former, based on Android, allows to apply in a revised manner a consolidated and already successfully used methodology of survey focused on the conservation of the historical paths (Inventory of historical traffic routes in Switzerland). Up to now operators could rely only on hand work based on a combination of notes, pictures and GPS devices synthesized in manually drawn maps; this procedure is error prone and shows many problems both in data updating and extracting for elaborations. Thus it has been created an easy to use interface which allows to map, according to a newly developed spatially enabled data model, paths, morphological elements, and multimedia notes. When connected to the internet the application can send the data to a web service which, after applying linear referencing and further elaborating the data, makes them available using open standards. The storytelling system has been designed to provide users with cultural insights embedded in a multimedial and immersive geospatial portal. Whether the tourist is exploring physically or virtually the desired

  6. BOOK REVIEW: Equations of Motion in General Relativity Equations of Motion in General Relativity

    NASA Astrophysics Data System (ADS)

    Schäfer, Gerhard

    2012-03-01

    -like signals in gravitational fields of binary systems is treated, which is important for a precise interpretation of pulsar observation measurements. Based on original research by the authors, a detailed presentation is given of a mathematical scheme which makes feasible the treatment of small black holes in background space-times. Using that approach, the equations of motion of small charged black holes are derived in vacuum Einstein-Maxwell space-times without encountering infinities, showing up electromagnetic radiation reaction, background field, and tail forces. At this stage, the book defines various issues to be tackled in future research within the given formalism, such as a physical understanding of the very structure of the tail contribution or a more detailed calculation of the motion of a small Schwarzschild black hole in an external vacuum gravitational field. A unique chapter is devoted to the choreographic three-body solution of the 1PNA dynamics, also mentioning the 2PNA dynamics, in the form of figure-eight configurations. The emitted gravitational waves are shown, and a discussion of their observability in future gravitational wave astronomy is given. Four appendices support and complement the main part of the book. Here, the far zone non-contribution to the equations of motion at 3PNA is carefully investigated, forces resulting from the extendedness of objects are presented in analytic form, null geodesic congruences with their optical scalars are discussed, and the perturbed vacuum Einstein-Maxwell field equations are given. The book delivers a very readable account of the problem of motion in general relativity. It covers the state of the art up to the years 2006/8 and presents a plethora of interesting and important topics and results. Whenever appropriate, connection with observation is made. A reader with good post-introductory knowledge of the theory of general relativity should find easy access to the book, and will surely benefit from the

  7. Polarization-insensitive all-optical dual pump-phase transmultiplexing from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK using cross-phase modulation in a passive nonlinear birefringent photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Mahmood, Tanvir

    Considering the network size, bit rate, spectral and channel capacity limitations, different modulation formats may be selectively used in future optical networks. Although the traditional metropolitan area networks (MANs) still uses the non-return-to-zero on-off keying (NRZ-OOK) modulation format due to its technical simplicity and therefore low cost, QPSK format is more advantageous in spectrally efficient long-haul fiber optic transmission systems because of its constant power envelope, and robustness to various transmission impairments. Consequently, an important problem may arise, in particular how to route the OOK-data streams from MANs to long-haul backbone networks when the state of polarization (SOP) of the remotely generated OOK is unpredictable. Hence, the focus of this dissertation was to investigate a polarization insensitive (PI) all-optical nonlinear optical signal processing (NOSP) method that can be implemented at the network cross-connect (X-connect) to transfer data from a remotely and a locally generated OOK data simultaneously to more effectual QPSK format for long-haul transmission. By utilizing cross-phase modulation (XPM) and inherent birefringence of the device, the work demonstrated, for the first time, PI all-optical data transfer utilizing dual pump-phase transmultiplexing (DPTM) from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK in a passive nonlinear birefringent photonic crystal fiber (PCF). Polarization insensitivity was achieved by scrambling the SOP of the remotely generated OOK pump and launching the locally generated OOK pump and the probe off-axis. To mitigate polarization induced power fluctuations and detrimental effects due to nearby partially degenerate and non-degenerate four wave mixings, an optimum pump-probe detuning was also utilized. The PI DPTM RZ-QPSK demonstrated a pre-amplified receiver sensitivity penalty < 5.5 dB at 10--9 bit-error-rate (BER), relative to relative to the FPGA-precoded RZ-DQPSK baseline in ASE

  8. Microbial Health Risks Associated with Exposure to Stormwater in a Water Plaza

    NASA Astrophysics Data System (ADS)

    Sales-Ortells, Helena; Medema, Gertjan

    2015-04-01

    . was found in all samples, with higher concentrations in samples that contained human Bacteroides than in samples with contamination from birds and dogs (15 vs 3.7 gc (genomic copies)/100mL). In both cases, the estimated disease risk associated with Campylobacter and recreational exposure to the water plaza were higher than the Dutch national incidence. This indicates that the health risk associated with recreational exposure to the water plaza is significant. L. pneumophila was found only in two out of ten pond samples. Legionnaire's disease risks were lower than the Dutch national incidence. However,higher health risks are expected in the future because of increased frequency of rain events. Presence of human Bacteroides indicates possible cross-connections with the combined sewer system that should be identified and removed to reduce the gastrointestinal disease risks. Other measures include cleaning/disinfection of the water plaza after extreme precipitation; increasing the capacity of the first flush pump; regular cleaning of the catchment area and gutters; informing the neighbours of the importance of keeping the streets clean of pets depositions; and informing the public about the health risks derived from recreational uses of the water plaza after rain events. Finally, monitoring the water quality during real rain events is recommended to better characterize the health risks.

  9. Detection of Human Sewage in Urban Stormwater Using DNA Based Methods and Stable Isotope Analysis

    NASA Astrophysics Data System (ADS)

    McLellan, S. L.; Malet, N.; Sauer, E.; Mueller-Spitz, S.; Borchardt, M.

    2008-12-01

    Urban stormwater is a major source of fecal indicator bacteria in the Milwaukee River Basin, a major watershed draining to Lake Michigan. Much of the watershed is in highly urbanized areas and Escherichia coli (E. coli) levels have been found to be 20,000 CFU per 100 ml in the estuary leading to Lake Michigan. Aging infrastructure and illicit cross connections may allow sewage to infiltrate the stormwater system and could contribute both fecal indicator bacteria and human pathogens to these waters. We conducted extensive sampling of stormwater outfalls in the lower reaches of three major tributaries. Three outfalls along the heavily urbanized Kinnickinnick (KK) were found to have geometric mean E. coli and enterococci levels of 16,200 and 28,700 CFU/100 ml, respectively. Four outfalls along the Menomonee River, draining both suburban and urban areas, had geometric mean E. coli and enterococci levels of 14,700 and 12,800 CFU/100 ml, respectively. These seven outfalls had more than 60% of the samples positive for human specific Bacteroides genetic marker (n=46), suggesting the presence of human sources. In addition, two outfalls on Lincoln Creek, a smaller tributary of the Milwaukee River, had geometric mean E. coli and enterococci levels of 16,700 and 14,900 CFU per 100 ml, respectively. The human specific Bacteroides marker was positive in nearly 90% of the samples (n=24). Subsequent virus testing at one of these outfalls confirmed human pathogens were present with adenovirus detected at 1.3 x 10E3 genomic equivalents (ge)/L, enterovirus at 1.9 x 10E4 ge/L and G1 norovirus at 1.5 x 10E3 ge/L; these values are similar to concentrations found in sewage. Stable isotope studies were conducted in the three tributaries to investigate the relationship between delta C and delta N isotopic composition and microbiological quality of this urban freshwater system. This work is based on the premise that the organic matter of the stormwater will have a stable isotopic signature

  10. Simulation of external contamination into water distribution systems through defects in pipes

    NASA Astrophysics Data System (ADS)

    López, P. A.; Mora, J. J.; García, F. J.; López, G.

    2009-04-01

    Water quality can be defined as a set of properties (physical, biological and chemical) that determine its suitability for human use or for its role in the biosphere. In this contribution we focus on the possible impact on water distribution systems quality of external contaminant fluids entering through defects in pipes. The physical integrity of the distribution system is a primary barrier against the entry of external contaminants and the loss in quality of the treated drinking water, but this integrity can be broken. Deficiencies in physical and hydraulic integrity can lead into water losses, but also into the influx of contaminants through pipes walls, either through breaks coming from external subsoil waters, or via cross connections coming from sewerage or other facilities. These external contamination events (the so called pathogen intrusion phenomenon) can act as a source of income by introducing nutrients and sediments as well as decreasing disinfectant concentrations within the distribution system, thus resulting in a degradation of the distribution water quality. The objective of this contribution is to represent this pathogen intrusion phenomenon. The combination of presence of defects in the infrastructures (equipment failure), suppression and back-siphonage and lack of disinfection is the cause of propagation of contamination in the clean current of water. Intrusion of pathogenic microorganisms has been studied and registered even in well maintained services. Therefore, this situation can happen when negative pressure conditions are achieved in the systems combined with the presence of defects in pipes nearby the suppression. A simulation of the process by which the external fluids can come inside pipes across their defects in a steady-state situation will be considered, by using different techniques to get such a successful modeling, combining numerical and experimental simulations. The proposed modeling process is based on experimental and

  11. A Multiple-Tracer Approach for Identifying Sewage Sources to an Urban Stream System

    USGS Publications Warehouse

    Hyer, Kenneth Edward

    2007-01-01

    The presence of human-derived fecal coliform bacteria (sewage) in streams and rivers is recognized as a human health hazard. The source of these human-derived bacteria, however, is often difficult to identify and eliminate, because sewage can be delivered to streams through a variety of mechanisms, such as leaking sanitary sewers or private lateral lines, cross-connected pipes, straight pipes, sewer-line overflows, illicit dumping of septic waste, and vagrancy. A multiple-tracer study was conducted to identify site-specific sources of sewage in Accotink Creek, an urban stream in Fairfax County, Virginia, that is listed on the Commonwealth's priority list of impaired streams for violations of the fecal coliform bacteria standard. Beyond developing this multiple-tracer approach for locating sources of sewage inputs to Accotink Creek, the second objective of the study was to demonstrate how the multiple-tracer approach can be applied to other streams affected by sewage sources. The tracers used in this study were separated into indicator tracers, which are relatively simple and inexpensive to apply, and confirmatory tracers, which are relatively difficult and expensive to analyze. Indicator tracers include fecal coliform bacteria, surfactants, boron, chloride, chloride/bromide ratio, specific conductance, dissolved oxygen, turbidity, and water temperature. Confirmatory tracers include 13 organic compounds that are associated with human waste, including caffeine, cotinine, triclosan, a number of detergent metabolites, several fragrances, and several plasticizers. To identify sources of sewage to Accotink Creek, a detailed investigation of the Accotink Creek main channel, tributaries, and flowing storm drains was undertaken from 2001 to 2004. Sampling was conducted in a series of eight synoptic sampling events, each of which began at the most downstream site and extended upstream through the watershed and into the headwaters of each tributary. Using the synoptic

  12. Simulation of external contamination into water distribution systems through defects in pipes

    NASA Astrophysics Data System (ADS)

    López, P. A.; Mora, J. J.; García, F. J.; López, G.

    2009-04-01

    Water quality can be defined as a set of properties (physical, biological and chemical) that determine its suitability for human use or for its role in the biosphere. In this contribution we focus on the possible impact on water distribution systems quality of external contaminant fluids entering through defects in pipes. The physical integrity of the distribution system is a primary barrier against the entry of external contaminants and the loss in quality of the treated drinking water, but this integrity can be broken. Deficiencies in physical and hydraulic integrity can lead into water losses, but also into the influx of contaminants through pipes walls, either through breaks coming from external subsoil waters, or via cross connections coming from sewerage or other facilities. These external contamination events (the so called pathogen intrusion phenomenon) can act as a source of income by introducing nutrients and sediments as well as decreasing disinfectant concentrations within the distribution system, thus resulting in a degradation of the distribution water quality. The objective of this contribution is to represent this pathogen intrusion phenomenon. The combination of presence of defects in the infrastructures (equipment failure), suppression and back-siphonage and lack of disinfection is the cause of propagation of contamination in the clean current of water. Intrusion of pathogenic microorganisms has been studied and registered even in well maintained services. Therefore, this situation can happen when negative pressure conditions are achieved in the systems combined with the presence of defects in pipes nearby the suppression. A simulation of the process by which the external fluids can come inside pipes across their defects in a steady-state situation will be considered, by using different techniques to get such a successful modeling, combining numerical and experimental simulations. The proposed modeling process is based on experimental and

  13. A simplified soil extraction sequence to monitor the main and trace element speciation in soil after compost and mineral fertilizer additions upon the composition of wheat grains

    NASA Astrophysics Data System (ADS)

    Sager, Manfred; Erhart, Eva

    2016-04-01

    High quality biological waste treatment aims at producing compost in order to maintain a clean environment and to sustain soil organic carbon levels. Fertilization with compost as a source of organic carbon, nutrients, and accessory elements, as well as fertilization with mineral N- and PK fertilizer have been tested in a field experiment on a calcaric Fluvisol in the Danube wetlands, at 4 levels each. Yields of wheat were recorded, and grains and soils were sampled from each treatment, and analyzed for main and trace element composition. The corresponding soils were characterized by mobile phases, obtained by leaching with 0,16M acetic acid to cover exchangeables plus carbonates, and subsequently by 0,1M oxalate buffer pH 3 to dissolve the pedogenic oxides. Total amounts were obtained from digests with perchloric- nitric-hydrofluoric acid. For quasi-total amounts, aqua regia was replaced by pressure decomposition with KClO3 in dilute nitric acid. The proposed extraction sequence permits to analyze and interpret soil for main elements, trace elements, nutrients and anions simultaneously. Factor analyses of soil extracts obtained from dilute acetic acid revealed Ba-Be-Cd-Cu-Li-S (traces), Ca-Mg-Mn (main carbonates), Al-Fe-B, Y, and P-K (nutrients) as chemically feasible principal components. Subsequent soil extracts from oxalate contained Al-B-Co-K-Na-Pb-Si-V-S (maybe acid silicate weathering), Cr-Li-Ni-Sr-Ti (maybe basic silicate weathering), Be-Cu-Fe-P, Co-Mg-Mn-Zn (Mn-oxides) and Ba-Sc as principal components. Factor analyses of total element data distinguished the principal components Ce-La-Li-Sc-Y-P (rare earths), Al-Ca-Fe-K-Mg-Na-P (main elements), Cd-Co-Cr-Cu-Ni-Zn (trace elements), As-Pb (contaminants), Ba-Mn-Sr, and Ti, which looks chemically feasible also. Factor analyses of those soil fractions which presumably form the main fractions of exchangeables, carbonates, pedogenic oxides and silicates, showed no cross connections, except for P. Oxalate