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Sample records for brillouin zones

  1. What is the Brillouin Zone of an Anisotropic Photonic Crystal?

    CERN Document Server

    Sivarajah, P; Ofori-Okai, B K; Nelson, K A

    2015-01-01

    The concept of the Brillouin zone (BZ) in relation to a photonic crystal fabricated in an optically anisotropic material is explored both experimentally and theoretically. In experiment, we used femtosecond laser pulses to excite THz polaritons and image their propagation in lithium niobate and lithium tantalate photonic crystal (PhC) slabs. We directly measured the dispersion relation inside PhCs and observed that the lowest bandgap expected to form at the BZ boundary forms inside the BZ in the anisotropic lithium niobate PhC. Our analysis shows that in an anisotropic material the BZ - defined as the Wigner-Seitz cell in the reciprocal lattice - is no longer bounded by Bragg planes and thus does not conform to the original definition of the BZ by Brillouin. We construct an alternative Brillouin zone defined by Bragg planes and show its utility in identifying features of the dispersion bands. We show that for an anisotropic 2D PhC without dispersion, the Bragg plane BZ can be constructed by applying the Wigne...

  2. Quantum Rabi model in the Brillouin zone with ultracold atoms

    Science.gov (United States)

    Felicetti, Simone; Rico, Enrique; Sabin, Carlos; Ockenfels, Till; Koch, Johannes; Leder, Martin; Grossert, Christopher; Weitz, Martin; Solano, Enrique

    2017-01-01

    The quantum Rabi model describes the interaction between a two-level quantum system and a single bosonic mode. We propose a method to perform a quantum simulation of the quantum Rabi model, introducing an implementation of the two-level system provided by the occupation of Bloch bands in the first Brillouin zone by ultracold atoms in tailored optical lattices. The effective qubit interacts with a quantum harmonic oscillator implemented in an optical dipole trap. Our realistic proposal allows one to experimentally investigate the quantum Rabi model for extreme parameter regimes, which are not achievable with natural light-matter interactions. When the simulated wave function exceeds the validity region of the simulation, we identify a generalized version of the quantum Rabi model in a periodic phase space.

  3. Dynamical Chern-Simons Theory in the Brillouin Zone

    CERN Document Server

    Lian, Biao; Vafa, Farzan; Zhang, Shou-Cheng

    2016-01-01

    Berry connection is conventionally defined as a static gauge field in the Brillouin zone. Here we show that for three-dimensional (3d) time-reversal invariant superconductors, a generalized Berry gauge field behaves as a dynamical fluctuating field of a Chern-Simons gauge theory. The gapless nodal lines in the momentum space play the role of Wilson loop observables, while their linking and knot invariants modify the gravitational theta angle. This angle induces a topological gravitomagnetoelectric effect where a temperature gradient induces a rotational energy flow. We also show how topological strings may be realized in the 6 dimensional phase space, where the physical space defects play the role of topological D-branes.

  4. Simulation of guided wave propagation near numerical Brillouin zones

    Science.gov (United States)

    Kijanka, Piotr; Staszewski, Wieslaw J.; Packo, Pawel

    2016-04-01

    Attractive properties of guided waves provides very unique potential for characterization of incipient damage, particularly in plate-like structures. Among other properties, guided waves can propagate over long distances and can be used to monitor hidden structural features and components. On the other hand, guided propagation brings substantial challenges for data analysis. Signal processing techniques are frequently supported by numerical simulations in order to facilitate problem solution. When employing numerical models additional sources of errors are introduced. These can play significant role for design and development of a wave-based monitoring strategy. Hence, the paper presents an investigation of numerical models for guided waves generation, propagation and sensing. Numerical dispersion analysis, for guided waves in plates, based on the LISA approach is presented and discussed in the paper. Both dispersion and modal amplitudes characteristics are analysed. It is shown that wave propagation in a numerical model resembles propagation in a periodic medium. Consequently, Lamb wave propagation close to numerical Brillouin zone is investigated and characterized.

  5. Exploiting the locality of periodic subsystem density-functional theory: efficient sampling of the Brillouin zone

    Science.gov (United States)

    Genova, Alessandro; Pavanello, Michele

    2015-12-01

    In order to approximately satisfy the Bloch theorem, simulations of complex materials involving periodic systems are made {{n}\\text{k}} times more complex by the need to sample the first Brillouin zone at {{n}\\text{k}} points. By combining ideas from Kohn-Sham density-functional theory (DFT) and orbital-free DFT, for which no sampling is needed due to the absence of waves, subsystem DFT offers an interesting middle ground capable of sizable theoretical speedups against Kohn-Sham DFT. By splitting the supersystem into interacting subsystems, and mapping their quantum problem onto separate auxiliary Kohn-Sham systems, subsystem DFT allows an optimal topical sampling of the Brillouin zone. We elucidate this concept with two proof of principle simulations: a water bilayer on Pt[1 1 1]; and a complex system relevant to catalysis—a thiophene molecule physisorbed on a molybdenum sulfide monolayer deposited on top of an α-alumina support. For the latter system, a speedup of 300% is achieved against the subsystem DTF reference by using an optimized Brillouin zone sampling (600% against KS-DFT).

  6. Existence of Dirac cones in the Brillouin zone of diperiodic atomic crystals according to group theory.

    Science.gov (United States)

    Damljanović, V; Gajić, R

    2016-03-02

    We have considered non-magnetic materials with weak spin-orbit coupling, that are periodic in two non-collinear directions, and finite in the third, orthogonal direction. In some cases, the combined time-reversal and crystal symmetry of such systems, allows the existence of Dirac cones at certain points in the reciprocal space. We have investigated in a systematic way, all points of the Brillouin zone of all 80 diperiodic groups and have found sufficient conditions for the existence of s  =  1/2 Dirac fermions, with symmetry-provided band touching at the vertex of the Dirac cones. Conversely, complete linear dispersion is forbidden for orbital wave functions belonging to two-dimensional (2D) irreducible representations (irreps) of little groups that do not satisfy certain group theoretical conditions given in this paper. Our results are illustrated by a tight-binding example.

  7. Existence of Dirac cones in the Brillouin zone of diperiodic atomic crystals according to group theory

    Science.gov (United States)

    Damljanović, V.; Gajić, R.

    2016-03-01

    We have considered non-magnetic materials with weak spin-orbit coupling, that are periodic in two non-collinear directions, and finite in the third, orthogonal direction. In some cases, the combined time-reversal and crystal symmetry of such systems, allows the existence of Dirac cones at certain points in the reciprocal space. We have investigated in a systematic way, all points of the Brillouin zone of all 80 diperiodic groups and have found sufficient conditions for the existence of s  =  1/2 Dirac fermions, with symmetry-provided band touching at the vertex of the Dirac cones. Conversely, complete linear dispersion is forbidden for orbital wave functions belonging to two-dimensional (2D) irreducible representations (irreps) of little groups that do not satisfy certain group theoretical conditions given in this paper. Our results are illustrated by a tight-binding example.

  8. Chern-Simons theory and Wilson loops in the Brillouin zone

    Science.gov (United States)

    Lian, Biao; Vafa, Cumrun; Vafa, Farzan; Zhang, Shou-Cheng

    2017-03-01

    Berry connection is conventionally defined as a static gauge field in the Brillouin zone. Here we show that for three-dimensional (3D) time-reversal invariant superconductors, a generalized Berry gauge field behaves as a fluctuating field of a Chern-Simons gauge theory. The gapless nodal lines in the momentum space play the role of Wilson loop observables, while their linking and knot invariants modify the gravitational theta angle. This angle induces a topological gravitomagnetoelectric effect where a temperature gradient induces a rotational energy flow. We also show how topological strings may be realized in the six-dimensional phase space, where the physical space defects play the role of topological D-branes.

  9. Nonuniform sampling schemes of the Brillouin zone for many-electron perturbation-theory calculations in reduced dimensionality

    Science.gov (United States)

    da Jornada, Felipe H.; Qiu, Diana Y.; Louie, Steven G.

    2017-01-01

    First-principles calculations based on many-electron perturbation theory methods, such as the ab initio G W and G W plus Bethe-Salpeter equation (G W -BSE) approach, are reliable ways to predict quasiparticle and optical properties of materials, respectively. However, these methods involve more care in treating the electron-electron interaction and are considerably more computationally demanding when applied to systems with reduced dimensionality, since the electronic confinement leads to a slower convergence of sums over the Brillouin zone due to a much more complicated screening environment that manifests in the "head" and "neck" elements of the dielectric matrix. Here we present two schemes to sample the Brillouin zone for G W and G W -BSE calculations: the nonuniform neck subsampling method and the clustered sampling interpolation method, which can respectively be used for a family of single-particle problems, such as G W calculations, and for problems involving the scattering of two-particle states, such as when solving the BSE. We tested these methods on several few-layer semiconductors and graphene and show that they perform a much more efficient sampling of the Brillouin zone and yield two to three orders of magnitude reduction in the computer time. These two methods can be readily incorporated into several ab initio packages that compute electronic and optical properties through the G W and G W -BSE approaches.

  10. Method to map one-dimensional electronic wave function by using multiple Brillouin zone angle resolved photoemission

    Directory of Open Access Journals (Sweden)

    Dong-Wook Lee

    2010-10-01

    Full Text Available Angle resolved photoemission spectroscopy (ARPES is a powerful tool to investigate electronic structures in solids and has been widely used in studying various materials. The electronic structure information by ARPES is obtained in the momentum space. However, in the case of one-dimensional system, we here show that we extract the real space information from ARPES data taken over multiple Brillouin zones (BZs. Intensities in the multiple BZs are proportional to the photoemission matrix element which contains information on the coefficient of the Bloch wave function. It is shown that the Bloch wave function coefficients can be extracted from ARPES data, which allows us to construct the real space wave function. As a test, we use ARPES data from proto-typical one-dimensional system SrCuO2 and construct the real space wave function.

  11. Physical and mathematical justification of the numerical Brillouin zone integration of the Boltzmann rate equation by Gaussian smearing

    Science.gov (United States)

    Illg, Christian; Haag, Michael; Teeny, Nicolas; Wirth, Jens; Fähnle, Manfred

    2016-03-01

    Scatterings of electrons at quasiparticles or photons are very important for many topics in solid-state physics, e.g., spintronics, magnonics or photonics, and therefore a correct numerical treatment of these scatterings is very important. For a quantum-mechanical description of these scatterings, Fermi's golden rule is used to calculate the transition rate from an initial state to a final state in a first-order time-dependent perturbation theory. One can calculate the total transition rate from all initial states to all final states with Boltzmann rate equations involving Brillouin zone integrations. The numerical treatment of these integrations on a finite grid is often done via a replacement of the Dirac delta distribution by a Gaussian. The Dirac delta distribution appears in Fermi's golden rule where it describes the energy conservation among the interacting particles. Since the Dirac delta distribution is a not a function it is not clear from a mathematical point of view that this procedure is justified. We show with physical and mathematical arguments that this numerical procedure is in general correct, and we comment on critical points.

  12. Electronic structure in a one-Fe Brillouin zone of the iron pnictide superconductors CsFe2As2 and RbFe2As2

    Science.gov (United States)

    Kong, S.; Liu, D. Y.; Cui, S. T.; Ju, S. L.; Wang, A. F.; Luo, X. G.; Zou, L. J.; Chen, X. H.; Zhang, G. B.; Sun, Z.

    2015-11-01

    Using angle-resolved photoemission spectroscopy, we studied the electronic structures of CsFe2As2 and RbFe2As2 . Contrary to other iron-based superconductors where the band structures are usually depicted in the two-Fe Brillouin zone (BZ), we found that the distribution of electronic spectral weight in CsFe2As2 and RbFe2As2 follows the one-Fe BZ, and that the emerging band structure is qualitatively consistent with theoretical band calculations of the one-Fe BZ except for some shadow band effect. Our data suggest that the interlayer separation is an important tuning factor for the physics of FeAs layers, the increase of which can reduce the coupling between Fe and As and lead to the emergence of the electronic structure in accord with the one-Fe symmetry of the Fe square lattice. Our finding puts strong constraints on the theoretical models constructed on the basis of the one-Fe BZ.

  13. Hume-Rothery stabilisation mechanism and d-states-mediated Fermi surface-Brillouin zone interactions in structurally complex metallic alloys

    Science.gov (United States)

    Mizutani, U.; Inukai, M.; Sato, H.

    2011-07-01

    The stability of Co2Zn11 and Al8V5 gamma-brasses, both of which are composed of a transition metal element and polyvalent elements Zn or Al, can be discussed in terms of d-states-mediated Fermi surface-Brillouin zone (FsBz) interactions in the context of first-principles full-potential linearised augmented plane wave (FLAPW) band calculations. A FsBz-induced pseudogap is revealed in the FLAPW-Fourier spectrum, though it is hidden behind a much larger d-band in the total density of states. The stability range of three families of complex metallic alloys (CMAs) that include gamma-brasses, RT-, MI- and Tsai-type 1/1-1/1-1/1 approximants and 2/1-2/1-2/1 approximant, each of which is characterised by ? = 18, 50 and 125, respectively, can be well scaled in terms of the number of electrons per unit cell (e/uc) given by the product of the number of atoms per unit cell and the e/a value determined by the Hume-Rothery plot on the basis of the FLAPW-Fourier method. This is taken as the evidence for the justification of the Hume-Rothery stabilisation mechanism for all these CMAs having a pseudogap at the Fermi level.

  14. Fermi surface-Brillouin-zone-induced pseudogap in {gamma}-Mg{sub 17}Al{sub 12} and a possible stabilization mechanism of {beta}-Al{sub 3}Mg{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mizutani, U [Nagoya Industrial Science Research Institute, JST Plaza-Tokai, Ahara-cho, Minami-ku, Nagoya 457-0063 (Japan); Kondo, Y; Nishino, Y [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Inukai, M [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Kouto, Sayo, Hyogo 679-5198 (Japan); Feuerbacher, M [Institut fuer Mikrostrukturforschung, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany); Sato, H, E-mail: uichiro@sky.sannet.ne.j [Department of Physics, Aichi University of Education, Kariya-shi, Aichi 448-8542 (Japan)

    2010-12-08

    The electronic structure of {gamma} phase in the system Mg{sub 17}Al{sub 12} containing 58 atoms per unit cell with space group I 4-bar 3m has been calculated by using the WIEN2k-FLAPW program package. A pseudogap is found across the Fermi level. The FLAPW-Fourier spectra at the symmetry points N and {Gamma} of the bcc Brillouin zone revealed that electronic states across the Fermi level at these symmetry points are dominated by |G|{sup 2} = 26 and 24 states corresponding to centers of {l_brace}510{r_brace} + {l_brace}431{r_brace} and {l_brace}422{r_brace} zone planes, respectively. The 1253-wave nearly-free-electron (NFE) band calculations identified that a combination of the two Fermi surface-Brillouin-zone (FsBz) interactions associated with |G|{sup 2} = 26 and 24 account well for the observed DOS pseudogap in {gamma}-Mg{sub 17}Al{sub 12}, most likely leading to the stabilization of this complex metallic compound. The {beta}-Al{sub 3}Mg{sub 2} containing 1178 atoms per cubic unit cell is suggested to be stabilized by satisfying the Hume-Rothery matching condition expressed in terms of e/uc, the number of electrons per unit cell, versus critical |G|{sup 2}. A critical |G|{sup 2} is predicted to be 200 in {beta}-Al{sub 3}Mg{sub 2}, which results in 84 Brillouin zone planes interacting almost simultaneously with a more or less spherical Fermi surface.

  15. Quasi-two-dimensional Fermi surfaces in the flat antiferromagnetic Brillouin zone of NpRhGa{sub 5} studied by dHvA experiments and energy band calculations

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Dai [Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Yamagami, Hiroshi [Department of Physics, Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555 (Japan); Homma, Yoshiya [Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Shiokawa, Yoshinobu [Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Yamamoto, Etsuji [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan); Nakamura, Akio [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan); Haga, Yoshinori [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan); Settai, Rikio [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Onuki, Yoshichika [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan)

    2005-05-04

    We succeeded in growing a high-quality single crystal of NpRhGa{sub 5} by the Ga-flux method and observed the de Haas-van Alphen oscillation in the antiferromagnetic state. Four kinds of nearly cylindrical Fermi surfaces, which correspond to main Fermi surfaces, were clearly detected. These quasi-two-dimensional Fermi surfaces are formed in the flat antiferromagnetic Brillouin zone and are well explained on the basis of spin- and orbital-polarized LAPW energy band calculations. The cyclotron masses are moderately enhanced, ranging from 8.1 to 11.7 m{sub 0}, which are approximately four times larger than the corresponding band masses. This is the first case where the 5f-itinerant band model is applicable to a neptunium magnetic compound. (letter to the editor)

  16. Stimulated Brillouin Scattering Microscopic Imaging.

    Science.gov (United States)

    Ballmann, Charles W; Thompson, Jonathan V; Traverso, Andrew J; Meng, Zhaokai; Scully, Marlan O; Yakovlev, Vladislav V

    2015-01-01

    Two-dimensional stimulated Brillouin scattering microscopy is demonstrated for the first time using low power continuous-wave lasers tunable around 780 nm. Spontaneous Brillouin spectroscopy has much potential for probing viscoelastic properties remotely and non-invasively on a microscopic scale. Nonlinear Brillouin scattering spectroscopy and microscopy may provide a way to tremendously accelerate the data aquisition and improve spatial resolution. This general imaging setup can be easily adapted for specific applications in biology and material science. The low power and optical wavelengths in the water transparency window used in this setup provide a powerful bioimaging technique for probing the mechanical properties of hard and soft tissue.

  17. Stimulated Brillouin Scattering Microscopic Imaging

    Science.gov (United States)

    Ballmann, Charles W.; Thompson, Jonathan V.; Traverso, Andrew J.; Meng, Zhaokai; Scully, Marlan O.; Yakovlev, Vladislav V.

    2015-12-01

    Two-dimensional stimulated Brillouin scattering microscopy is demonstrated for the first time using low power continuous-wave lasers tunable around 780 nm. Spontaneous Brillouin spectroscopy has much potential for probing viscoelastic properties remotely and non-invasively on a microscopic scale. Nonlinear Brillouin scattering spectroscopy and microscopy may provide a way to tremendously accelerate the data aquisition and improve spatial resolution. This general imaging setup can be easily adapted for specific applications in biology and material science. The low power and optical wavelengths in the water transparency window used in this setup provide a powerful bioimaging technique for probing the mechanical properties of hard and soft tissue.

  18. Collective stimulated Brillouin backscatter

    CERN Document Server

    Lushnikov, Pavel M

    2007-01-01

    We develop the statistical theory of the stimulated Brillouin backscatter (BSBS) instability of a spatially and temporally partially incoherent laser beam for laser fusion relevant plasma. We find a new regime of BSBS which has a much larger threshold than the classical threshold of a coherent beam in long-scale-length laser fusion plasma. Instability is collective because it does not depend on the dynamics of isolated speckles of laser intensity, but rather depends on averaged beam intensity. We identify convective and absolute instability regimes. Well above the incoherent threshold the coherent instability growth rate is recovered. The threshold of convective instability is inside the typical parameter region of National Ignition Facility (NIF) designs although current NIF bandwidth is not large enough to insure dominance of collective instability and suggests lower instability threshold due to speckle contribution. In contrast, we estimate that the bandwidth of KrF-laser-based fusion systems would be larg...

  19. Collective stimulated Brillouin scatter

    CERN Document Server

    Korotkevich, Alexander O; Rose, Harvey A

    2011-01-01

    We develop a statistical theory of stimulated Brillouin backscatter (BSBS) of a spatially and temporally partially incoherent laser beam for laser fusion relevant plasma. We find a new collective regime of BSBS which has a much larger threshold than the classical threshold of a coherent beam in long-scale-length laser fusion plasma. We identify two contributions to BSBS convective instability increment. The first is collective with intensity threshold independent of the laser correlation time and controlled by diffraction. The second is independent of diffraction, it grows with increase of the correlation time and does not have an intensity threshold. The instability threshold is inside the typical parameter region of National Ignition Facility (NIF). We also find that the bandwidth of KrF-laser-based fusion systems would be large enough to allow additional suppression of BSBS.

  20. Perspectives on stimulated Brillouin scattering

    Science.gov (United States)

    Garmire, Elsa

    2017-01-01

    This collection of papers describes research that goes into detail on some of the more important issues in the physics of stimulated Brillouin scattering. This perspective describes the earliest years of the physics of stimulated Brillouin scattering, along with key developments that have led to this technically and physically rich field of today’s nonlinear optics. Stimulated Brillouin has a profound effect in optical fiber communications, initially discovered by its limit on the transmitted power. By controlling SBS in fibers and making use of its phase conjugation properties in both fibers and bulk media, a wide range of applications have been enabled. Today ring Brillouin lasers in fibers, whispering gallery modes and in photonic integrated circuits provide optical delay lines and switches, pulse shapers and components for increasingly complex and important optical systems.

  1. SELECTION OF BRILLOUIN SHIFT DISCRIMINATOR FOR BRILLOUIN LIDAR

    Institute of Scientific and Technical Information of China (English)

    吴东; 刘智深

    2002-01-01

    For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high-resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selec ted as the frequency shift discriminator and several kinds of absorption gases were tri ed. It was found that the strong line (#1095) of 127I2 at 18783.3297 cm-1 and two absorption lines of 129I2 located at the two sides of the #1095 line of 127 I2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency s hift. This selection is the best one within the range from 532.0131 nm to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.

  2. SELECTION OF BRILLOUIN SHIFT DISCRIMINATOR FOR BRILLOUIN LIDAR

    Institute of Scientific and Technical Information of China (English)

    吴东; 刘智深

    2002-01-01

    For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high-resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selected as the frequency shift discriminator and several kinds of absorption gases were tried. It was found that the strong line ( # 1095) of 127 I2 at 18783. 3297 cm-1 and two absorption lines of 129 I2 located at the two sides of the # 1095 line of 127 I2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency shift. This selection is the best one within the range from 532.0131 run to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.

  3. Conventional and Stuffed Bergman-Type Phases in the Na-Au-T (T = Ga, Ge, Sn) Systems: Syntheses, Structures, Coloring of Cluster Centers, and Fermi Sphere–Brillouin Zone Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Qisheng; Smetana, Volodymyr; Miller, Gordon J.; Corbett, John D.

    2012-08-20

    Bergman-type phases in the Na-Au-T (T = Ga, Ge, and Sn) systems were synthesized by solid-state means and structurally characterized by single-crystal X-ray diffraction studies. Two structurally related (1:1) Bergman phases were found in the Na-Au-Ga system: (a) a conventional Bergman-type (CB) structure, Na26AuxGa54-x, which features empty innermost icosahedra, as refined with x = 18.1 (3), Im$\\overline{3}$ a = 14.512(2) Å, and Z = 2; (b) a stuffed Bergman-type (SB) structure, Na26AuyGa55-y, which contains Gacentered innermost icosahedra, as refined with y = 36.0 (1), Im$\\overline{3}$, a = 14.597(2) Å, and Z = 2. Although these two subtypes have considerable phase widths along with respective tie lines at Na ≈ 32.5 and 32.1 atom %, they do not merge into a continuous solid solution. Rather, a quasicrystalline phase close to the Au-poor CB phase and an orthorhombic derivative near the Au-rich SB phase lie between them. In contrast, only Au-rich SB phases exist in the Ge and Sn systems, in which the innermost icosahedra are centered by Au rather than Ge or Sn. These were refined for Na26Au40.93(5)Ge14.07(5) (Im$\\overline{3}$, a = 14.581(2) Å, and Z = 2) and Na26Au39.83(6)Sn15.17(6) (Im$\\overline{3}$, a = 15.009(2) Å, and Z = 2), respectively. Occupations of the centers of Bergman clusters are rare. Such centering and coloring correlate with the sizes of the neighboring icosahedra, the size ratios between electropositive and electronegative components, and the values of the average valence electron count per atom (e/a). Theoretical calculations revealed that all of these phases are Hume-Rothery phases, with evident pseudogaps in the density of states curves that arise from the interactions between Fermi surface and Brillouin zone boundaries corresponding to a strong diffraction intensity.

  4. Brillouin precursors in Debye media

    CERN Document Server

    Macke, Bruno

    2015-01-01

    We theoretically study the formation of Brillouin precursors in Debye media. We point out that the precursors are only visible at propagation distances such that the impulse response of the medium is essentially determined by the frequency-dependence of its absorption and is practically Gaussian. By simple convolution, we then obtain explicit analytical expressions of the transmitted waves generated by reference incident waves, distinguishing precursor and main signal by physical arguments. These expressions are in good agreement with the signals obtained in numerical or real experiments performed on water and explain some features of these signals that remained mysterious or unnoticed. In addition, we show quite generally that the shape of the Brillouin precursor appearing alone at large enough propagation distance and the law giving its amplitude as a function of this distance do not depend on the precise form of the incident wave but only on its integral properties. The incidence of a static conductivity o...

  5. Brillouin scattering self-cancellation

    Science.gov (United States)

    Florez, O.; Jarschel, P. F.; Espinel, Y. A. V.; Cordeiro, C. M. B.; Mayer Alegre, T. P.; Wiederhecker, G. S.; Dainese, P.

    2016-06-01

    The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin scattering arising from Rayleigh acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it.

  6. Brillouin Scattering Self-Cancellation

    CERN Document Server

    Florez, Omar; Espinel, Yovanny A V; Cordeiro, Cristiano M B; Alegre, Thiago P Mayer; Wiederhecker, Gustavo S; Dainese, Paulo

    2016-01-01

    The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result proper material and structure engineering allows one to control each contribution individually. In this paper, we experimentally demonstrate the perfect cancellation of Brillouin scattering by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancin...

  7. Bursting behaviours in cascaded stimulated Brillouin scattering

    Institute of Scientific and Technical Information of China (English)

    Liu Zhan-Jun; He Xian-Tu; Zheng Chun-Yang; Wang Yu-Gang

    2012-01-01

    Stimulated Brillouin scattering is studied by numerically solving the Vlasov-Maxwell system.A cascade of stimulated Brillouin scattering can occur when a linearly polarized laser pulse propagates in a plasma.It is found that a stimulated Brillouin scattering cascade can reduce the scattering and increase the transmission of light,as well as introduce a bursting behaviour in the evolution of the laser-plasma interaction.The bursting time in the reflectivity is found to be less than half the ion acoustic period.The ion temperature can affect the stimulated Brillouin scattering cascade,which can repeat several times at low ion temperatures and can be completely eliminated at high ion temperatures.For stimulated Brillouin scattering saturation,higher-harmonic generation and wave-wave interaction of the excited ion acoustic waves can restrict the amplitude of the latter.In addition,stimulated Brillouin scattering cascade can restrict the amplitude of the scattered light.

  8. Zonas de Brillouin del grafito

    OpenAIRE

    A. Velázquez-Arriaga; P. Rosendo-Francisco; J. López-Lemus

    2009-01-01

    La celda unitaria de un cristal de grafito se analiza usando el principio básico de oscilador armónico. Para este propósito, consideramos a los átomos que conforman la celda unitaria hexagonal unidos por pequeños resortes. Se establece la ecuación de movimiento de dicha celda para obtener la frecuencia normal de vibración del sistema (w) en términos del vector de onda (k) y la distancia interatómica. Con estos datos se generan las zonas de Brillouin y se determinan los puntos silla en los con...

  9. Stimulated Brillouin scattering in metamaterials

    Science.gov (United States)

    Smith, M. J. A.; Wolff, C.; Martijn de Sterke, C.; Lapine, M.; Kuhlmey, B. T.; Poulton, C. G.

    2016-10-01

    We compute the SBS gain for a metamaterial comprising a cubic lattice of dielectric spheres suspended in a background dielectric material. Theoretical methods are presented to calculate the optical, acoustic, and opto-acoustic parameters that describe the SBS properties of the material at long wavelengths. Using the electromagnetic and strain energy densities we accurately characterise the optical and acoustic properties of the metamaterial. From a combination of energy density methods and perturbation theory, we recover the appropriate terms of the photoelastic tensor for the metamaterial. We demonstrate that electrostriction is not necessarily the dominant mechanism in the enhancement and suppression of the SBS gain coefficient in a metamaterial, and that other parameters, such as the Brillouin linewidth, can dominate instead. Examples are presented that exhibit an order of magnitude enhancement in the SBS gain as well as perfect suppression.

  10. Stimulated Brillouin scattering in metamaterials

    CERN Document Server

    Smith, M J A; de Sterke, C Martijn; Wolff, C; Lapine, M; Poulton, C G

    2016-01-01

    We compute the SBS gain for a metamaterial comprising a cubic lattice of dielectric spheres suspended in a background dielectric material. Theoretical methods are presented to calculate the optical, acoustic, and opto-acoustic parameters that describe the SBS properties of the material at long wavelengths. Using the electromagnetic and strain energy densities we accurately characterise the optical and acoustic properties of the metamaterial. From a combination of energy density methods and perturbation theory, we recover the appropriate terms of the photoelastic tensor for the metamaterial. We demonstrate that electrostriction is not necessarily the dominant mechanism in the enhancement and suppression of the SBS gain coefficient in a metamaterial, and that other parameters, such as the Brillouin linewidth, can dominate instead. Examples are presented that exhibit an order of magnitude enhancement in the SBS gain as well as perfect suppression.

  11. Brillouin Cooling in a Linear Waveguide

    CERN Document Server

    Chen, Yin-Chung; Bahl, Gaurav

    2016-01-01

    Brillouin scattering is rarely considered as a mechanism that can cause cooling of a material due to the thermodynamic dominance of Stokes scattering in most practical systems. However, it has been shown in experiments on resonators that net phonon annihilation through anti-Stokes Brillouin scattering can be enabled by means of a suitable set of optical and acoustic states. The cooling of traveling phonons in a linear waveguide, on the other hand, could lead to the exciting future prospect of manipulating unidirectional heat fluxes and even the nonreciprocal transport of quantum information via phonons. In this work, we present the first analysis of the conditions under which Brillouin cooling may be achieved in a linear waveguide. We analyze the three-wave mixing interaction between the optical and acoustic modes that participate in forward Brillouin scattering, and reveal the key regimes of operation for the process. Our calculations indicate that measurable cooling may occur in state-of-the-art systems whe...

  12. Guided-wave Brillouin scattering in air

    CERN Document Server

    Renninger, William H; Rakich, Peter T

    2016-01-01

    Here we identify a new form of optomechanical coupling in gas-filled hollow-core fibers. Stimulated forward Brillouin scattering is observed in air in the core of a photonic bandgap fiber. A single resonance is observed at 35 MHz, which corresponds to the first excited axial-radial acoustic mode in the air-filled core. The linewidth and coupling strengths are determined by the acoustic loss and electrostrictive coupling in air, respectively. A simple analytical model, refined by numerical simulations, is developed that accurately predicts the Brillouin coupling strength and frequency from the gas and fiber parameters. Since this form of Brillouin coupling depends strongly on both the acoustic and dispersive optical properties of the gas within the fiber, this new type of optomechanical interaction is highly tailorable. These results allow for forward Brillouin spectroscopy in dilute gases, could be useful for sensing and will present a power and noise limitation for certain applications.

  13. High quality tunable Brillouin optoelectronic oscillator

    Science.gov (United States)

    Mousa, Mohamed; Ahmed, Mahmoud H.; Hassan, Kamel M. M.; Abouelatta, Mohamed; Afifi, Abdelrahman E.

    2016-09-01

    An optical scheme to improve the quality of an RF signal is proposed. The 6 dB linewidth is reduced to sub hertz and the low frequency noise below 1 KHz is reduced about 10 dB. The scheme utilizes a Brillouin-semiconductor optical amplifier (SOA) ring laser fitted with an RF intensity modulator and an APD detector. The experimental results show cavity modes with FSR of 30.57 KHz due to Brillouin fiber length of 6.6 km and 6 dB bandwidth of 780 mHz typical of Brillouin lasers. The gain of the SOA balances out most of the losses in the ring mainly that due to the RF modulator. The modulated optical signal beats at the APD. The optical loop acts as a cavity filter to the RF signal. A jitter in the cavity resonances due to temperature variations is completely eliminated from the output beat signal. There is a 10 dB increase in the phase noise at the FSR frequency and its harmonics. The setup is tested with signals generated by different sources and to frequencies up to 10 GHz, the limit of the APD. Sources with RF linewidth less than the optical FSR produces one output mode with sub-hertz line width. For larger line width signals more than one RF frequency is produced, separated by the FSR, each showing the Brillouin linewidth.

  14. Neutron Brillouin scattering in dense fluids

    Energy Technology Data Exchange (ETDEWEB)

    Verkerk, P. [Technische Univ. Delft (Netherlands); FINGO Collaboration

    1997-04-01

    Thermal neutron scattering is a typical microscopic probe for investigating dynamics and structure in condensed matter. In contrast, light (Brillouin) scattering with its three orders of magnitude larger wavelength is a typical macroscopic probe. In a series of experiments using the improved small-angle facility of IN5 a significant step forward is made towards reducing the gap between the two. For the first time the transition from the conventional single line in the neutron spectrum scattered by a fluid to the Rayleigh-Brillouin triplet known from light-scattering experiments is clearly and unambiguously observed in the raw neutron data without applying any corrections. Results of these experiments are presented. (author).

  15. Brillouin Optomechanics in Coupled Silicon Microcavities

    CERN Document Server

    Espinel, Yovanny A V; Luiz, Gustavo O; Alegre, Thiago P M; Wiederhecker, Gustavo S

    2016-01-01

    The simultaneous control of optical and mechanical waves has enabled a range of fundamental and technological breakthroughs, from the demonstration of ultra-stable frequency reference devices to the exploration of the quantum-classical boundaries in laser-cooling experiments. More recently, such an opto-mechanical interaction has been observed in integrated nano-waveguides and microcavities in the Brillouin regime, where short-wavelength mechanical modes scatters light at several GHz. Here we engineer coupled optical microcavities spectra to enable a low threshold excitation of mechanical travelling-wave modes through backward stimulated Brillouin scattering. Exploring the backward scattering we propose microcavity designs supporting super high frequency modes ($\\sim25$ GHz) an large optomechanical coupling rates ($g_0/2\\pi \\sim 50$ kHz).

  16. Electron Gyro-Harmonic Effects on Ionospheric Stimulated Brillouin Scatter

    Science.gov (United States)

    2014-08-21

    identification of metallic ions of meteoric origin in the E layer, because the composi- tion of the lower ionosphere can be altered by meteorite ablation ...SECURITY CLASSIFICATION OF: Stimulated Brillouin scattering (SBS) and resonant phenomena are well known in the context of laser fusion, fiber optics...stimulated Brillouin scatter Report Title Stimulated Brillouin scattering (SBS) and resonant phenomena are well known in the context of laser fusion

  17. Acoustic profilometry within polymers as performed by Brillouin microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sanctuary, R [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (LERUSL) at the Centre Universitaire de Luxembourg, Departement des Sciences, Laboratoire 1.19, 162a avenue de la Faiencerie, L-1511 Luxembourg (Luxembourg); Bactavatchalou, Ravi [Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Mueller, Ulrich [Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Possart, W [Universitaet des Saarlandes, Fakultaet fuer Chemie, Pharmazie und Werkstoffwissenschaften 8.15, Gebaeude 22, D-66041 Saarbruecken (Germany); Alnot, P [Laboratoire de Physique des Milieux Ionises et Applications (LPMIA), UMR 7040-C.N.R.S, Universite de Nancy I, Bd des Aiguillettes, B.P. 239 F-54506 Vandoeuvre les Nancy (France); Krueger, J K [Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany)

    2003-11-07

    Using high performance Brillouin spectroscopy we present a new technique, which enables us to perform acoustic microscopy with a spatial resolution of about 1 {mu}m. This technique, called Brillouin microscopy, is tested on several bulk- and film-like polymer samples.

  18. Short-Pulse Amplification by Strongly-Coupled Brillouin Scattering

    CERN Document Server

    Edwards, Matthew R; Mikhailova, Julia M; Fisch, Nathaniel J

    2016-01-01

    We examine the feasibility of strongly-coupled stimulated Brillouin scattering as a mechanism for the plasma-based amplification of sub-picosecond pulses. In particular, we use fluid theory and particle-in-cell simulations to compare the relative advantages of Raman and Brillouin amplification over a broad range of achievable parameters.

  19. Tailorable Stimulated Brillouin Scattering in Nanoscale Silicon Waveguides

    CERN Document Server

    Shin, Heedeuk; Jarecki, Robert; Cox, Jonathan A; Olsson, Roy H; Starbuck, Andrew; Wang, Zheng; Rakich, Peter T

    2013-01-01

    While nanoscale modal confinement radically enhances a variety of nonlinear light-matter interactions within silicon waveguides, traveling-wave stimulated Brillouin scattering nonlinearities have never been observed in silicon nanophotonics. Through a new class of hybrid photonic-phononic waveguides, we demonstrate tailorable traveling-wave forward stimulated Brillouin scattering in nanophotonic silicon waveguides for the first time, yielding 3000 times stronger forward SBS responses than any previous waveguide system. Simulations reveal that a coherent combination of electrostrictive forces and radiation pressures are responsible for greatly enhanced photon-phonon coupling at nano-scales. Highly tailorable Brillouin nonlinearities are produced by engineering the structure of a membrane-suspended waveguide to yield Brillouin resonances from 1 to 18 GHz through high quality-factor (>1000) phonon modes. Such wideband and tailorable stimulated Brillouin scattering in silicon photonics could enable practical real...

  20. Quantification of plaque stiffness by Brillouin microscopy (Conference Presentation)

    Science.gov (United States)

    Antonacci, Giuseppe; Pedrigi, Ryan; Krams, Rob; Török, Peter

    2016-03-01

    Spontaneous Brillouin scattering is an inelastic scattering process arising from inherent thermal density fluctuations, or acoustic phonons, propagating in a medium. Over the last few years, Brillouin spectroscopy has shown great potential to become a reliable non-invasive diagnostic tool due to its unique capability of retrieving viscoelastic properties of materials such as strain and stiffness. The detection of the weak scattered light, in addition to the resolution of the Brillouin peaks (typically shifted by few GHz from the central peak) represent one of the greatest challenges in Brillouin. The recent development of high sensitivity CCD cameras has brought Brillouin spectroscopy from a point sampling technique to a new imaging modality. Furthermore, the application of Virtually Imaged Phased Array (VIPA) etalons has dramatically reduced insertion loss simultaneously allowing fast (myocardial infarction yet it is not currently possible to credibly assess its stiffness due to lack of suitable methods.

  1. Dynamics of ultra-long Brillouin fiber laser

    Science.gov (United States)

    Fotiadi, Andrei A.; Lobach, Ivan; Mégret, Patrice

    2013-02-01

    We report on experimental studies of random lasing realized in optical fibers with the use of Brillouin amplification and Rayleigh backscattering employed as a distributed feedback instead of a cavity mirror. In our experiment 25-km-long high quality standard telecom single-mode fiber was employed for Rayleigh reflection uniformly distributed over all fiber length. We have observed a clear competition between a classical Brillouin scattering and Brillouin lasing. Presence of extended fluctuation-free fragments in the recorded oscilloscope traces highlights Stokes power statistics typical for laser radiation rather than for Brillouin process. The results of the experiments are in a perfect agreement with the model of Brillouin - Rayleigh cooperative process in long fibers.

  2. Narrow linewidth Brillouin laser based on chalcogenide photonic chip

    CERN Document Server

    Kabakova, Irina V; Choi, Duk-Yong; Debbarma, Sukhanta; Luther-Davies, Barry; Madden, Stephen J; Eggleton, Benjamin J

    2013-01-01

    We present the first demonstration of a narrow linewidth, waveguide-based Brillouin laser which is enabled by large Brillouin gain of a chalcogenide chip. The waveguides are equipped with vertical tapers for low loss coupling. Due to optical feedback for the Stokes wave, the lasing threshold is reduced to 360 mW, which is 5 times lower than the calculated single-pass Brillouin threshold for the same waveguide. The slope efficiency of the laser is found to be 30% and the linewidth of 100 kHz is measured using a self-heterodyne method.

  3. Cascaded forward Brillouin scattering to all Stokes orders

    CERN Document Server

    Wolff, Christian; Eggleton, Benjamin J; Steel, Michael J; Poulton, Christopher G

    2016-01-01

    Inelastic scattering processes such as Brillouin scattering can often function in cascaded regimes and this is likely to occur in certain integrated opto-acoustic devices. We develop a Hamiltonian formalism for cascaded Brillouin scattering valid for both quantum and classical regimes. By regarding Brillouin scattering as the interaction of a single acoustic envelope and a single optical envelope that covers all Stokes and anti-Stokes orders, we obtain a compact model that is well suited for numerical implementation, extension to include other optical nonlinearities or short pulses, and application in the quantum-optics domain. We then theoretically analyze intra-mode forward Brillouin scattering (FBS) for arbitrary waveguides with and without optical dispersion. In the absence of optical dispersion, we find an exact analytical solution. With a perturbative approach, we furthermore solve the case of weak optical dispersion. Our work leads to several key results on intra-mode FBS. For negligible dispersion, we...

  4. Simple asymptotic forms for Sommerfeld and Brillouin precursors

    CERN Document Server

    Macke, Bruno

    2012-01-01

    We examine from a physical viewpoint the classical problem of the propagation of a causal optical field in a dense Lorentz-medium when the propagation distance is such that the medium is opaque in a broad spectral region including the frequency of the optical carrier. The transmitted signal is then reduced to the celebrated precursors of Sommerfeld and Brillouin, well separated in time. In these conditions, we obtain explicit analytical expressions of the first (Sommerfeld) precursor, which only depend on the nature and the importance of the initial discontinuity of the incident field, and we show that the second (Brillouin) precursor has a Gaussian or Gaussian-derivative shape, depending whether the time-integral (algebraic area) of the incident field differs or not from zero. We demonstrate that the Brillouin precursor that has been actually observed in a Debye medium at decimetric wavelengths is also Gaussian. We complete these results by establishing a more general expression of the Brillouin precursor in...

  5. Ultralow-threshold cascaded Brillouin microlaser for tunable microwave generation.

    Science.gov (United States)

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

    2015-11-01

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

  6. On-chip Inter-modal Brillouin Scattering

    CERN Document Server

    Kittlaus, Eric A; Rakich, Peter T

    2016-01-01

    Stimulated Brillouin interactions mediate nonlinear coupling between photons and acoustic phonons through an optomechanical three-wave interaction. Though these nonlinearities were previously very weak in silicon photonic systems, the recent emergence of new optomechanical waveguide structures have transformed Brillouin processes into one of the strongest and most tailorable on-chip nonlinear interactions. New technologies based on Brillouin couplings have formed a basis for amplification, filtering, and nonreciprocal signal processing techniques. In this paper, we demonstrate strong guided-wave Brillouin scattering between light fields guided in distinct spatial modes of a silicon waveguide for the first time. This inter-modal coupling creates dispersive symmetry breaking between Stokes and anti-Stokes processes, permitting single-sideband amplification and wave dynamics that permit near-unity power conversion. Combining these physics with integrated mode-multiplexers enables novel device topologies and elim...

  7. Broadband Brillouin Scatter from CO2-Laser-Target Interactions

    Science.gov (United States)

    Mitchel, G. R.; Grek, B.; Johnston, T. W.; Pépin, H.; Church, P.; Lavigne, P.; Martin, F.; Décoste, R.

    1982-05-01

    Light scattered near the incident wavelength from CO2 laser-solid target interactions in oblique incidence shows the spectral signature of Brillouin scattering both in the backward and in the near specular directions. This instability is apparently seeded by broadband scatter from the critical density surface and then amplified in the underdense plasma. 60% of the incident light is scattered, and the Brillouin contribution to total scatter may be large if the source is also large.

  8. Sources of noise in Brillouin optical time-domain analyzers

    OpenAIRE

    Urricelqui Polvorinos, Javier; Soto, Marcelo A.; Thévenaz, Luc

    2015-01-01

    This paper presents a thorough study of the different sources of noise affecting Brillouin optical time-domain analyzers (BOTDA), providing a deep insight into the understanding of the fundamental limitations of this kind of sensors. Analytical and experimental results indicate that the noise source ultimately fixing the sensor performance depends basically on the fiber length and the input pump-probe powers. Thus, while the phase-to-intensity noise conversion induced by stimulated Brillouin ...

  9. Cascaded Brillouin lasing in monolithic barium fluoride whispering gallery mode resonators

    CERN Document Server

    Lin, Guoping; Saleh, Khaldoun; Martinenghi, Romain; Beugnot, Jean-Charles; Sylvestre, Thibaut; Chembo, Yanne K

    2015-01-01

    We report the observation of stimulated Brillouin scattering and lasing at 1550~nm in barium fluoride (BaF$_2$) crystal. Brillouin lasing was achieved with ultra-high quality ($Q$) factor monolithic whispering gallery mode (WGM) mm-size disk resonators. Overmoded resonators were specifically used to provide cavity resonances for both the pump and all Brillouin Stokes waves. Single and multiple Brillouin Stokes radiations with frequency shift ranging from $8.2$ GHz up to $49$ GHz have been generated through cascaded Brillouin lasing. BaF$_2$ resonator-based Brillouin lasing can find potential applications for high-coherence lasers and microwave photonics.

  10. Photonic-phononic orbital angular momentum in Brillouin parametric conversion

    CERN Document Server

    Zhu, Zhihan; Mu, Chunyuan; Li, Hongwei

    2014-01-01

    Orbital angular momentum (OAM) is a fundamental photonic degree of freedom, showed by Allen and co-workers. Its most attractive feature is an inherently infinite dimensionality, which in recent years has obtained several ground-breaking demonstrations for high information-density communication and processing, both in classical and quantum. Here, by seeking the reason for photonic OAM non-conservation in stimulated Brillouin amplification, we report the first demonstration of the evolution law for OAM in Brillouin process. The parameter of OAM can conveniently transfer between the phonons and different polarized photons due to the photonic spin angular momentum conservation. Our results have revealed a parametric conversion mechanism of Brillouin process for Photonic-phononic OAM, demonstrated the role of phononic OAM and the vortex acoustic wave in this process, and suggested this mechanism may find important applications in OAM-based information communication and processing.

  11. Phase-locking in cascaded stimulated Brillouin scattering

    CERN Document Server

    Büttner, Thomas F S; Steel, M J; Hudson, Darren D; Eggleton, Benjamin J

    2015-01-01

    Cascaded stimulated Brillouin scattering (SBS) is a complex nonlinear optical process that results in the generation of several optical waves that are frequency shifted by an acoustic resonance frequency. Four-wave mixing (FWM) between these Brillouin shifted optical waves can create an equally spaced optical frequency comb with a stable spectral phase, i.e. a Brillouin frequency comb (BFC). Here, we investigate phase-locking of the spectral components of BFCs, considering FWM interactions arising from the Kerr-nonlinearity as well as from coupling by the acoustic field. Deriving for the first time the coupled-mode equations that include all relevant nonlinear interactions, we examine the contribution of the various nonlinear processes to phase-locking, and show that different regimes can be obtained that depend on the length scale on which the field amplitudes vary.

  12. Phase-locking in cascaded stimulated Brillouin scattering

    Science.gov (United States)

    Büttner, Thomas F. S.; Poulton, Christopher G.; Steel, M. J.; Hudson, Darren D.; Eggleton, Benjamin J.

    2016-02-01

    Cascaded stimulated Brillouin scattering is a complex nonlinear optical process that results in the generation of several optical waves that are frequency shifted by an acoustic resonance frequency. Four-wave mixing (FWM) between these Brillouin shifted optical waves can create an equally spaced optical frequency comb with a stable spectral phase, i.e. a Brillouin frequency comb (BFC). Here, we investigate phase-locking of the spectral components of BFCs, considering FWM interactions arising from the Kerr-nonlinearity as well as from coupling by the acoustic field. Deriving for the first time the coupled-mode equations that include all relevant nonlinear interactions, we examine the contribution of the various nonlinear processes to phase-locking, and show that different regimes can be obtained that depend on the length scale on which the field amplitudes vary.

  13. Temperature sensing based on a Brillouin fiber microwave generator

    Science.gov (United States)

    Yang, X. P.; Gan, J. L.; Xu, S. H.; Yang, Z. M.

    2013-04-01

    We propose and demonstrate a novel dual-frequency Brillouin fiber laser used for microwave generation. Based on this configuration, temperature sensing has been realized. The dual-frequency Brillouin lasing is generated independently from two pieces of fiber cascaded within one ring resonator. Microwave generation is acquired as the beat signal of the dual-frequency Brillouin fiber laser, with the beat frequency being linearly proportional to the temperature difference of the two fiber sections. In the experiment, the temperature coefficient of frequency shift is 1.015 ± 0.001 MHz °C-1. The temperature can be precisely measured by acquiring the frequency of the microwave generator, and this new configuration provides a promising application for temperature sensing.

  14. Brillouin spectroscopy of clotting dynamics in a model system

    Science.gov (United States)

    Bustamante-Lopez, Sandra C.; Traverso, Andrew J.; Yakovlev, Vladislav V.; Meissner, Kenith E.

    2016-02-01

    Keys to successful treatment of disease include early diagnosis and timely treatment. It is hypothesized that early clotting events may contribute to a pro-thrombotic state that exacerbates atherothrombotic vascular disease. Brillouin spectroscopy involves inelastic coupling of light with phonons and enables viscoelastic characterization of samples at the microscale. In this work, we apply Brillouin spectroscopy to a model fibrinogen-thrombin clotting system with the goal of measuring clotting dynamics at the microscale and providing characterization that is not possible with standard rheometric techniques. Here, the clotting dynamics of the model clotting system are measured at various fibrinogen and thrombin concentrations.

  15. High-pressure Brillouin scattering in a simple molecular system

    CERN Document Server

    Shimizu, H

    2002-01-01

    Recent developments in high-pressure in situ Brillouin spectroscopy of a simple molecular system are reviewed by demonstrating experimental and analytical methods for the study of acoustic velocities in any direction, adiabatic elastic constants, and elastic anisotropy. Detailed applications to solid argon (Ar) are presented, at pressures up to 70 GPa in a diamond anvil cell, using recently developed approaches that combine the method of in situ Brillouin spectroscopy, for a single crystal of Ar up to 4 GPa, and the envelope method applied to both longitudinal acoustic and transverse acoustic modes, for recrystallized Ar between 4 and 70 GPa.

  16. High-speed stimulated Brillouin scattering spectroscopy at 780 nm

    Directory of Open Access Journals (Sweden)

    Itay Remer

    2016-09-01

    Full Text Available We demonstrate a high-speed stimulated Brillouin scattering (SBS spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (∼25 dB in water samples and ∼15 dB in tissue phantoms. These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

  17. Cascaded forward Brillouin scattering to all Stokes orders

    Science.gov (United States)

    Wolff, C.; Stiller, B.; Eggleton, B. J.; Steel, M. J.; Poulton, C. G.

    2017-02-01

    Inelastic scattering processes such as Brillouin scattering can often function in cascaded regimes and this is likely to occur in certain integrated opto-acoustic devices. We develop a Hamiltonian formalism for cascaded Brillouin scattering valid for both quantum and classical regimes. By regarding Brillouin scattering as the interaction of a single acoustic envelope and a single optical envelope that covers all Stokes and anti-Stokes orders, we obtain a compact model that is well suited for numerical implementation, extension to include other optical nonlinearities or short pulses, and application in the quantum-optics domain. We then theoretically analyze intra-mode forward Brillouin scattering (FBS) for arbitrary waveguides with and without optical dispersion. In the absence of optical dispersion, we find an exact analytical solution. With a perturbative approach, we furthermore solve the case of weak optical dispersion. Our work leads to several key results on intra-mode FBS. For negligible dispersion, we show that cascaded intra-mode FBS results in a pure phase modulation and discuss how this necessitates specific experimental methods for the observation of fiber-based and integrated FBS. Further, we discuss how the descriptions that have been established in these two classes of waveguides connect to each other and to the broader context of cavity opto-mechanics and Raman scattering. Finally, we draw an unexpected striking similarity between FBS and discrete diffraction phenomena in waveguide arrays, which makes FBS an interesting candidate for future research in quantum-optics.

  18. Optical coherent detection Brillouin distributed optical fiber sensor based on orthogonal polarization diversity reception

    Institute of Scientific and Technical Information of China (English)

    Muping Song; Bin Zhao; Xianmin Zhang

    2005-01-01

    In Brillouin distributed optical fiber sensor, using optical coherent detection to detect Brillouin scattering optical signal is a good method, but there exists the polarization correlated detection problem. A novel detecting scheme is presented and demonstrated experimentally, which adopts orthogonal polarization diversity reception to resolve the polarization correlated detection problem. A laser is used as pump and reference light sources, a microwave electric-optical modulator (EOM) is adopted to produce frequency shift reference light, a polarization controller is used to control the polarization of the reference light which is changed into two orthogonal polarization for two adjacent acquisition periods. The Brillouin scattering light is coherently detected with the reference light, and the Brillouin scattering optical signal is taken out based on Brillouin frequency shift. After electronic processing, better Brillouin distributed sensing signal is obtained. A 25-km Brillouin distributed optical fiber sensor is achieved.

  19. Extreme temperature sensing using brillouin scattering in optical fibers

    CERN Document Server

    Fellay, Alexandre

    Stimulated Brillouin scattering in silica-based optical fibers may be considered from two different and complementary standpoints. For a physicist, this interaction of light and pressure wave in a material, or equivalently in quantum theory terms between photons and phonons, gives some glimpses of the atomic structure of the solid and of its vibration modes. For an applied engineer, the same phenomenon may be put to good use as a sensing mechanism for distributed measurements, thanks to the dependence of the scattered light on external parameters such as the temperature, the pressure or the strain applied to the fiber. As far as temperature measurements are concerned, Brillouin-based distributed sensors have progressively gained wide recognition as efficient systems, even if their rather high cost still restricts the number of their applications. Yet they are generally used in a relatively narrow temperature range around the usual ambient temperature; in this domain, the frequency of the scattered light incre...

  20. Stability of Brillouin Flow in Slow-Wave Structures

    Science.gov (United States)

    Simon, David; Lau, Y. Y.; Greening, Geoffrey; Wong, Patrick; Gilgenbach, Ronald; Hoff, Brad

    2016-10-01

    For the first time, we include a slow-wave structure (SWS) to study the stability of Brillouin flow in the conventional, planar, and inverted magnetron geometry. The resonant interaction of the SWS circuit mode and the corresponding smooth-bore diocotron-like mode is found to be the dominant cause for instability, overwhelming the intrinsic negative (positive) mass property of electrons in the inverted (conventional) magnetron geometry. It severely restricts the wavenumber for instability to the narrow range in which the cold tube frequency of the SWS is within a few percent of the corresponding smooth bore diocotron-like mode in the Brillouin flow. This resonant interaction is absent in a smooth bore magnetron. Work supported by ONR N00014-13-1-0566 and N00014-16-1-2353, AFOSR FA9550-15-1-0097, and L-3 Communications Electron Device Division.

  1. A high-efficiency Brillouin fiber ring laser

    Institute of Scientific and Technical Information of China (English)

    Pingping Zhang; Shuling Hu; Shuying Chen; Yuanhong Yang; Chunxi Zhang

    2009-01-01

    A high-efficiency Brillouin fiber ring laser is demonstrated using the standard single-mode fiber.The laser exhibits a 3.6-mW threshold.The output power is 22 mW with 40-nlW pump power,and the maximum optical-to-optical efficiency is 55%. The output is single wavelength with a 3-dB linewidth of 5 MHz,and the interval of center frequency between the laser and the pump light is 11 GHz (0.088 nm).It is shown that the stimulated Brillouin scattering threshold of ring resonator is lower and the energy transfer efficiency is higher than those in fiber.

  2. A Rayleigh-Brillouin scattering spectrometer for ultraviolet wavelengths

    CERN Document Server

    Gu, Ziyu; van Duijn, Eric-Jan; Ubachs, Wim; 10.1063/1.4721272

    2012-01-01

    A spectrometer for the measurement of spontaneous Rayleigh-Brillouin scattering line profiles at ultraviolet wavelengths from gas phase molecules has been developed, employing a high-power frequency-stabilized UV laser with narrow bandwidth (2 MHz). The UV light from a frequency-doubled titanium:sapphire laser is further amplified in an enhancement cavity, delivering a 5 Watt UV-beam propagating through the interaction region inside a scattering cell. The design of the RB-scattering cell allows for measurements at gas pressures in the range 0-4 bar and at stably controlled temperatures from -30 to 70 degree Celsius. A scannable Fabry-Perot analyzer with instrument resolution of 232 MHz probes the Rayleigh-Brillouin profiles. Measurements on N2 and SF6 gases demonstrate the high signal-to-noise ratio achievable with the instrument, at the 1% level at the peak amplitude of the scattering profile.

  3. Brillouin microspectroscopy of nanostructured biomaterials: photonics assisted tailoring mechanical properties

    Science.gov (United States)

    Meng, Zhaokai; Jaiswal, Manish K.; Chitrakar, Chandani; Thakur, Teena; Gaharwar, Akhilesh K.; Yakovlev, Vladislav V.

    2016-03-01

    Developing new biomaterials is essential for the next-generation of materials for bioenergy, bioelectronics, basic biology, medical diagnostics, cancer research, and regenerative medicine. Specifically, recent progress in nanotechnology has stimulated the development of multifunctional biomaterials for tissue engineering applications. The physical properties of nanocomposite biomaterials, including elasticity and viscosity, play key roles in controlling cell fate, which underlines therapeutic success. Conventional mechanical tests, including uniaxial compression and tension, dynamic mechanical analysis and shear rheology, require mechanical forces to be directly exerted onto the sample and therefore may not be suitable for in situ measurements or continuous monitoring of mechanical stiffness. In this study, we employ spontaneous Brillouin spectroscopy as a viscoelasticity-specific probing technique. We utilized a Brillouin spectrometer to characterize biomaterial's microscopic elasticity and correlated those with conventional mechanical tests (e.g., rheology).

  4. Brillouin-Wigner perturbation theory in open electromagnetic systems

    CERN Document Server

    Muljarov, E A; Zimmermann, R; 10.1209/0295-5075/92/50010

    2012-01-01

    A Brillouin-Wigner perturbation theory is developed for open electromagnetic systems which are characterised by discrete resonant states with complex eigenenergies. Since these states are exponentially growing at large distances, a modified normalisation is introduced that allows a simple spectral representation of the Green's function. The perturbed modes are found by solving a linear eigenvalue problem in matrix form. The method is illustrated on exactly solvable one- and three-dimensional examples being, respectively, a dielectric slab and a microsphere.

  5. Reduced Brillouin backscatter in CO2 laser-target interaction

    Science.gov (United States)

    Ng, A.; Offenberger, A. A.; Karttunen, S. J.

    1981-02-01

    A substantially reduced Brillouin reflection has been found for CO2 laser-irradiated high-density gas targets. In contrast to the high reflectivity (60%) previously observed for underdense hydrogen plasma, total backscatter (stimulated plus specular) is found to peak at 30% for incident intensity 5 times 10 to the twelfth W per square centimeter and decrease thereafter to 18% at 10 to the thirteenth W per square centimeter. The ponderomotive effects are postulated to account for these observations.

  6. Self-pulsation threshold of Raman amplified Brillouin fiber cavities.

    Science.gov (United States)

    Ott, J R; Pedersen, M E V; Rottwitt, K

    2009-08-31

    An implicit equation for the oscillation threshold of stimulated Brillouin scattering from Raman amplified signals in fibers with external feedback is derived under the assumption of no depletion. This is compared to numerical investigations of Raman amplification schemes showing good agreement for high reflectivities. For low reflectivities and high attenuation or long fibers, the assumption of no depletion is shown not to be valid. In these cases the effects of the depletion on the self-pulsation is examined.

  7. Self-pulsation threshold of Raman amplified Brillouin fiber cavities

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Pedersen, Martin Erland Vestergaard; Rottwitt, Karsten

    2009-01-01

    An implicit equation for the oscillation threshold of stimulated Brillouin scattering from Raman amplified signals in fibers with external feedback is derived under the assumption of no depletion. This is compared to numerical investigations of Raman amplification schemes showing good agreement...... for high reflectivities. For low reflectivities and high attenuation or long fibers, the assumption of no depletion is shown not to be valid. In these cases the effects of the depletion on the self-pulsation is examined....

  8. All-optical signal processing using dynamic Brillouin gratings

    Science.gov (United States)

    Santagiustina, Marco; Chin, Sanghoon; Primerov, Nicolay; Ursini, Leonora; Thévenaz, Luc

    2013-01-01

    The manipulation of dynamic Brillouin gratings in optical fibers is demonstrated to be an extremely flexible technique to achieve, with a single experimental setup, several all-optical signal processing functions. In particular, all-optical time differentiation, time integration and true time reversal are theoretically predicted, and then numerically and experimentally demonstrated. The technique can be exploited to process both photonic and ultra-wide band microwave signals, so enabling many applications in photonics and in radio science. PMID:23549159

  9. Brillouin optical time-domain analysis for geotechnical monitoring

    Institute of Scientific and Technical Information of China (English)

    L. Zeni; L. Picarelli; B. Avolio; A. Coscetta; R. Papa; G. Zeni; C. Di Maio; R. Vassallo; A. Minardo

    2015-01-01

    In this paper, we show some recent experimental applications of Brillouin optical time-domain analysis (BOTDA) based sensors for geotechnical monitoring. In particular, how these sensors can be applied to detecting early movements of soil slopes by the direct embedding of suitable fiber cables in the ground is presented. Furthermore, the same technology can be used to realize innovative inclinometers, as well as smart foundation anchors.

  10. Polarization-dependent phase locking in stimulated Brillouin scattering systems.

    Science.gov (United States)

    Hua, X; Falk, J

    1993-10-20

    Measurements of the mutual coherence of the output beams from a seeded, two-pump-beam, stimulated Brillouin scattering system are reported. Mutual coherence depends on the relative polarizations of the pump beams and the seed beam. A seed beam can phase-lock the Stokes outputs even if the pump beams are orthogonally polarized. Four-wave mixing is responsible for this phase locking.

  11. Transformation optics simulation method for stimulated Brillouin scattering

    CERN Document Server

    Zecca, Roberto; Smith, David R; Larouche, Stéphane

    2016-01-01

    We develop a novel approach to enable the full-wave simulation of stimulated Brillouin scattering and related phenomena in a frequency-domain, finite-element environment. The method uses transformation optics techniques to implement a time-harmonic coordinate transform that reconciles the different frames of reference used by electromagnetic and mechanical finite-element solvers. We show how this strategy can be successfully applied to bulk and guided systems, comparing the results with the predictions of established theory.

  12. High-extinction VIPA-based Brillouin spectroscopy of turbid biological media

    CERN Document Server

    Fiore, Antonio; Shao, Peng; Yun, Seok Hyun; Scarcelli, Giuliano

    2016-01-01

    Brillouin microscopy has recently emerged as powerful technique to characterize the mechanical properties of biological tissue, cell and biomaterials. However, the potential of Brillouin microscopy is currently limited to transparent samples, because Brillouin spectrometers do not have sufficient spectral extinction to reject the predominant non-Brillouin scattered light of turbid media. To overcome this issue, we developed a spectrometer composed of a two VIPA stages and a multi-pass Fabry-Perot interferometer. The Fabry-Perot etalon acts as an ultra-narrow band-pass filter for Brillouin light with high spectral extinction and low loss. We report background-free Brillouin spectra from Intralipid solutions and up to 100 microns deep within chicken muscle tissue.

  13. Signal Processing for Fibre-optic Distributed Sensing Techniques Employing Brillouin Scattering

    Institute of Scientific and Technical Information of China (English)

    XIAO Shang-hui; LI Li

    2009-01-01

    As fibre optic distributed scattering sensing systems are providing innovative solutions for the monitoring of large structures, Brillouin-based distributed scattering sensing techniques represent a new physical approach for structures health monitoring, which seems extremely promising and is receiving most attentions. This paper comprehensively presents some methods of signal interrogation for fibre optic Brillouin-based distributed scattering sensing technology, especially establishes an accurate Pseudo-Voigt model of Brillouin gain spectrum and gives some results on spectrum analysis and data processing.

  14. Biomechanics of subcellular structures by non-invasive Brillouin microscopy

    Science.gov (United States)

    Antonacci, Giuseppe; Braakman, Sietse

    2016-11-01

    Cellular biomechanics play a pivotal role in the pathophysiology of several diseases. Unfortunately, current methods to measure biomechanical properties are invasive and mostly limited to the surface of a cell. As a result, the mechanical behaviour of subcellular structures and organelles remains poorly characterised. Here, we show three-dimensional biomechanical images of single cells obtained with non-invasive, non-destructive Brillouin microscopy with an unprecedented spatial resolution. Our results quantify the longitudinal elastic modulus of subcellular structures. In particular, we found the nucleoli to be stiffer than both the nuclear envelope (p biomechanics and its role in pathophysiology.

  15. Rayleigh-Brillouin spectrum in special relativistic hydrodynamics.

    Science.gov (United States)

    Garcia-Perciante, A L; Garcia-Colin, L S; Sandoval-Villalbazo, A

    2009-06-01

    In this paper we calculate the Rayleigh-Brillouin spectrum for a relativistic simple fluid according to three different versions available for a relativistic approach to nonequilibrium thermodynamics. An outcome of these calculations is that Eckart's version predicts that such spectrum does not exist. This provides an argument to question its validity. The remaining two results, which differ one from another, do provide a finite form for such spectrum. This raises the rather intriguing question as to which of the two theories is a better candidate to be taken as a possible version of relativistic nonequilibrium thermodynamics. The answer will clearly require deeper examination of this problem.

  16. The Rayleigh-Brillouin Spectrum in Special Relativistic Hydrodynamics

    CERN Document Server

    García-Perciante, A L; Sandoval-Villalbazo, A

    2009-01-01

    In this paper we calculate the Rayleigh-Brillouin spectrum for a relativistic simple fluid according to three different versions available for a relativistic approach to non-equilibrium thermodynamics. An outcome of these calculations is that Eckart's version predicts that such spectrum does not exist. This provides an argument to question its validity. The remaining two results, which differ one from another, do provide a finite form for such spectrum. This raises the rather intriguing question as to which of the two theories is a better candidate to be taken as a possible version of relativistic non-equilibrium thermodynamics. The answer will clearly require deeper examination of this problem.

  17. Stimulated Brillouin scattering enhancement in silicon inverse opal waveguides

    CERN Document Server

    Smith, M J A; de Sterke, C Martijn; Lapine, M; Kuhlmey, B T; Poulton, C G

    2016-01-01

    Silicon is an ideal material for on-chip applications, however its poor acoustic properties limit its performance for important optoacoustic applications, particularly for Stimulated Brillouin Scattering (SBS). We theoretically show that silicon inverse opals exhibit a strongly improved acoustic performance that enhances the bulk SBS gain coefficient by more than two orders of magnitude. We also design a waveguide that incorporates silicon inverse opals and which has SBS gain values that are comparable with chalcogenide glass waveguides. This research opens new directions for opto-acoustic applications in on-chip material systems.

  18. Rayleigh-Brillouin Scattering in Binary Gas Mixtures

    CERN Document Server

    Gu, Ziyu; van de Water, Willem; Marques, Wilson

    2015-01-01

    Precise measurements are performed on spectral lineshapes of spontaneous Rayleigh-Brillouin scattering in mixtures of the noble gases Ar and Kr, with He. Admixture of a light He atomic fraction results in marked changes of the spectra, although in all experiments He is merely a spectator atom: it affects the relaxation of density fluctuations of the heavy constituent, but its contribution to the scattered light intensity is negligibly small. The results are compared to a theory for the spectral lineshape without adjustable parameters, yielding excellent agreement for the case of binary mono-atomic gases, signifying a step towards modeling and understanding of light scattering in more complex molecular media.

  19. Zonas de Brillouin de los grupos de capa

    OpenAIRE

    García Santos, Laura

    2016-01-01

    La base de datos de las zonas de Brillouin de los grupos de capa del Bilbao Crystallographic Server incluye tablas de vectores de onda y figuras que forman la base para la clasificación de las representaciones de los grupos de capa. Las propiedades de simetría de los vectores de onda se determinan por los llamados grupos del espacio recíproco y esta clasificación se compara con la que recoge el libro “Character Tables and Compatibility Relations of The Eighty Layer Groups and Seventeen Plane ...

  20. Brillouin Lasing with a CaF_2 Whispering Gallery Mode Resonator

    CERN Document Server

    Grudinin, Ivan S; Maleki, Lute

    2008-01-01

    Stimulated Brillouin scattering with both pump and Stokes beams in resonance with whispering gallery modes of an ultra high Q CaF_2 resonator is demonstrated for the first time. The resonator is pumped with 1064 nm light and has a Brillouin lasing threshold of 3.5 microwatt. Potential applications include optical generation of microwaves and sensitive gyros.

  1. Single Brillouin frequency shifted S-band multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier in ring cavity

    Science.gov (United States)

    Reshak, A. H.; Hambali, N. A. M. Ahmad; Shahimin, M. M.; Wahid, M. H. A.; Anwar, Nur Elina; Alahmed, Zeyad A.; Chyský, J.

    2016-10-01

    This paper is focusing on simulation and analyzing of S-band multi-wavelength Brillouin-Raman fiber laser performance utilizing fiber Bragg grating and Raman amplifier in ring cavity. Raman amplifier-average power model is employed for signal amplification. This laser system is operates in S-band wavelength region due to vast demanding on transmitting the information. Multi-wavelength fiber lasers based on hybrid Brillouin-Raman gain configuration supported by Raman scattering effect have attracted significant research interest due to its ability to produced multi-wavelength signals from a single light source. In multi-wavelength Brillouin-Raman fiber, single mode fiber is utilized as the nonlinear gain medium. From output results, 90% output coupling ratio has ability to provide the maximum average output power of 43 dBm at Brillouin pump power of 20 dBm and Raman pump power of 14 dBm. Furthermore, multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier is capable of generated 7 Brillouin Stokes signals at 1480 nm, 1510 nm and 1530 nm.

  2. Elasticity of Pyrope at High Pressures and Temperatures by Brillouin Scattering and X-ray Diffraction

    Science.gov (United States)

    Lu, C.; Mao, Z.; Lin, J.; Prakapenka, V.

    2011-12-01

    Iron-containing pyrope ((Fe,Mg)3Al2Si3O12)) is believed to be an abundant rock-forming mineral in the Earth's interior, ranging from the crust to the top of the lower mantle. Based on the pyrolite mineralogical model, pyrope accounts for 13% by volume in the upper mantle and 10% in the transition zone. Therefore, laboratory measurements on the elasticity of pyrope at relevant pressure and temperature conditions are critical in understanding the seismic images and in constraining the chemistry and mineralogy of the region. The elasticity of single-crystal pyrope has been studied up to 20 GPa at 300 K and up to 1100 K at 1 bar, yet it has never been investigated at simultaneous high pressure-temperature conditions. Thus, much of our knowledge of the upper mantle and transition zone seismic profiles largely relies on extrapolated experimental results or theoretical calculations. Here we have measured the single-crystal elasticity of garnet, ((Mg2.04Ca0.16Fe0.74)Al2.02(SiO4)3) up to 20 GPa and 750 K using combined Brillouin scattering and synchrontron X-ray diffraction in an externally-heated diamond anvil cell at GSECARS of the Advanced Photon Source, Argonne National Laboratory. We have derived full elastic constants (Cij) of the sample as a function of pressure and temperature at relevant conditions of the deep mantle. The temperature derivatives of the Cijs are similar to that at ambient pressure, indicating a minimal pressure effect. Together with the elasticity of other major mantle minerals, we have used a thermoelastic model to reconstruct the seismic velocity profile of the upper mantle and the transition zone and to reference the mineralogy of the regions.

  3. Distributed hot-wire anemometry based on Brillouin optical time-domain analysis.

    Science.gov (United States)

    Wylie, Michael T V; Brown, Anthony W; Colpitts, Bruce G

    2012-07-02

    A distributed hot-wire anemometer based on Brillouin optical time-domain analysis is presented. The anemometer is created by passing a current through a stainless steel tube fibre bundle and monitoring Brillouin frequency changes in the presence of airflow. A wind tunnel is used to provide laminar airflow while the device response is calibrated against theoretical models. The sensitivity equation for this anemometer is derived and discussed. Airspeeds from 0 m/s to 10 m/s are examined, and the results show that a Brillouin scattering based distributed hot-wire anemometer is feasible.

  4. A new approach to measure the ocean temperature using Brillouin lidar

    Institute of Scientific and Technical Information of China (English)

    Wei Gao; Zhiwei Lü; Yongkang Dong; Weiming He

    2006-01-01

    @@ An approach of lidar measurements of ocean temperature through measuring the spectral linewidth of the backscattered Brillouin lines is presented. An empirical equation for the temperature as a function of Brillouin linewidth and salinity is derived. Theoretical results are in good agreement with the experimental data. The equation also reveals the dependence of the temperature on the salinity and Brillouin linewidth.It is shown that the uncertainty of the salinity has very little impact on the temperature measurement.The uncertainty of this temperature measurement methodology is approximately 0.02 ℃.

  5. ESTIMATION OF SOUNDING ABILITY OF A BRILLOUIN LIDAR IN THE EAST CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Vertical profiles of sound speed in the sea can be measured by using laser excited Brillouin scattering. In this paper the dependence of the accuracy of sound speed measurement on the accuracy of the Brillouin shift measurement is analyzed. We calculated the maximum detecting depths of sound speed to an accuracy of 1 m/s by lidar with different laser pulse energy, platform altitude, telescope aperture and lidar effective attenuation coefficient. The estimation of sounding ability in the East China Sea is made in some stations. These data can be used in the design of Brillouin Lidar for the China Sea.

  6. Brillouin scattering studies of isotopic effects in solid ammonia

    Science.gov (United States)

    Kiefte, H.; Penney, R.; Breckon, S. W.; Clouter, M. J.

    1987-01-01

    The technique of high resolution Brillouin spectroscopy has been used to determine the adiabatic elastic constants and the elasto-optic coupling (Pockels) coefficient ratios of oriented single crystals of (solid I) ND3 at temperatures near the gas-liquid-solid triple point. The values of the elastic constants at 196.0 K are C11=83.3, C12=44.0, and C44=49.6 (in units of kbar) with an estimated absolute uncertainty of ±2%. The values of the elasto-optic coefficient ratios are P12/P11=0.90 and P44/P11=0.16 for ND3 and 0.89 and 0.16 for NH3, respectively. Other than that expected from the mass ratio, no significant isotopic differences are evident.

  7. Brillouin resonance broadening due to structural variations in nanoscale waveguides

    CERN Document Server

    Wolff, Christian; Steel, Michael J; Eggleton, Benjamin J; Poulton, Christopher G

    2015-01-01

    We study the impact of structural variations (that is slowly varying geometry aberrations and internal strain fields) on the resonance width and shape of stimulated Brillouin scattering (SBS) in nanoscale waveguides. We find that they lead to an inhomogeneous resonance broadening through two distinct mechanisms: firstly, the acoustic frequency is directly influenced via mechanical nonlinearities; secondly, the optical wave numbers are influenced via the opto-mechanical nonlinearity leading to an additional acoustic frequency shift via the phase-matching condition. We find that this second mechanism is proportional to the opto-mechanical coupling and, hence, related to the SBS-gain itself. It is absent in intra-mode forward SBS, while it plays a significant role in backward scattering. In backward SBS increasing the opto-acoustic overlap beyond a threshold defined by the fabrication tolerances will therefore no longer yield the expected quadratic increase in overall Stokes amplification. Our results can be tra...

  8. Bunching of temporal cavity solitons via forward Brillouin scattering

    CERN Document Server

    Erkintalo, Miro; Jang, Jae K; Coen, Stéphane; Murdoch, Stuart G

    2015-01-01

    We report on the experimental observation of bunching dynamics with temporal cavity solitons in a continuously-driven passive fibre resonator. Specifically, we excite a large number of ultrafast cavity solitons with random temporal separations, and observe in real time how the initially random sequence self-organizes into regularly-spaced aggregates. To explain our experimental observations, we develop a simple theoretical model that allows long-range acoustically-induced interactions between a large number of temporal cavity solitons to be simulated. Significantly, results from our simulations are in excellent agreement with our experimental observations, strongly suggesting that the soliton bunching dynamics arise from forward Brillouin scattering. In addition to confirming prior theoretical analyses and unveiling a new cavity soliton self-organization phenomenon, our findings elucidate the manner in which sound interacts with large ensembles of ultrafast pulses of light.

  9. Dual-microcavity narrow-linewidth Brillouin laser

    CERN Document Server

    Loh, William; Baynes, Frederick; Cole, Daniel; Quinlan, Franklyn; Lee, Hansuek; Vahala, Kerry; Papp, Scott; Diddams, Scott

    2014-01-01

    Ultralow noise, yet tunable lasers are a revolutionary tool in precision spectroscopy, displacement measurements at the standard quantum limit, and the development of advanced optical atomic clocks. Further applications include LIDAR, coherent communications, frequency synthesis, and precision sensors of strain, motion, and temperature. While all applications benefit from lower frequency noise, many also require a laser that is robust and compact. Here, we introduce a dual-microcavity laser that leverages one chip-integrable silica microresonator to generate tunable 1550 nm laser light via stimulated Brillouin scattering (SBS) and a second microresonator for frequency stabilization of the SBS light. This configuration reduces the fractional frequency noise to $7.8\\times10^{-14} 1/\\sqrt{Hz}$ at 10 Hz offset, which is a new regime of noise performance for a microresonator-based laser. Our system also features terahertz tunability and the potential for chip-level integration. We demonstrate the utility of our du...

  10. Coherent Rayleigh-Brillouin scattering as a flow diagnostic technique

    Energy Technology Data Exchange (ETDEWEB)

    Graul, J. S.; Lilly, T. C. [Department of Mechanical and Aerospace Engineering, University of Colorado Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918 (United States)

    2014-12-09

    Broadband coherent Rayleigh-Brillouin scattering (CRBS) was used to measure translational gas temperatures for nitrogen at the ambient pressure of 0.8 atm using a purpose-built Fabry-Perot etalon spectrometer. Temperatures derived from the CRBS spectral analysis were compared with experimentally-measured temperatures, and were found to be, on average, within 2% of the experimentally-measured value. Axial flow velocities from a double jet at a pressure ratio of 0.38 were also measured by looking at the Doppler shift of the CRBS line shape. With recent developments in chirped laser technology and the capacity of CRBS to simultaneously provide thermodynamic and bulk flow information, the CRBS line shape acquisition and analysis technique presented here may allow for future time-resolved, characterization of aerospace flows.

  11. DSMC simulation of Rayleigh-Brillouin scattering in binary mixtures

    Science.gov (United States)

    Bruno, Domenico; Frezzotti, Aldo; Ghiroldi, Gian Pietro

    2016-11-01

    Rayleigh-Brillouin scattering spectra (RBS) in dilute gas mixtures have been simulated by the Direct Simulation Monte Carlo method (DSMC). Different noble gas binary mixtures have been considered and the spectra have been simulated adopting the hard sphere collision model. It is suggested that DSMC simulations can be used in the interpretation of light scattering experiments in place of approximate kinetic models. Actually, the former have a firmer physical ground and can be readily extended to treat gas mixtures of arbitrary complexity. The results obtained confirm the capability of DSMC to predict experimental spectra and clears the way towards the simulation of polyatomic gas mixtures of interest for actual application (notably, air) where tractable kinetic model equations are still lacking.

  12. High Pressure Brillouin Scattering in the Fragile Glass Former Cumene

    Science.gov (United States)

    Ransom, Tim; Oliver, William

    2012-02-01

    In recent years full-spectrum analysis in light-scattering has been utilized to explore the liquid-glass transition at variable temperature and ambient pressure. In this study we present temperature- and pressure-dependent Brillouin scattering results for the fragile glass-former cumene. Both equal-angle forward scattering and depolarized backscattering geometries are used, and high pressures are attained by the use of a diamond anvil cell mounted in a custom temperature-controlled housing. Opening up the variable pressure regime to full-spectrum analysis will allow more stringent tests of mode-coupling theory as well as greater insight into the behavior of glass-forming systems.

  13. Brillouin light scattering studies of 2D magnonic crystals

    Science.gov (United States)

    Tacchi, S.; Gubbiotti, G.; Madami, M.; Carlotti, G.

    2017-02-01

    Magnonic crystals, materials with periodic modulation of their magnetic properties, represent the magnetic counterpart of photonic, phononic and plasmonic crystals, and have been largely investigated in recent years because of the possibility of using spin waves as a new means for carrying and processing information over a very large frequency bandwidth. Here, we review recent Brillouin light scattering studies of 2D magnonic crystals consisting of single- and bi-component arrays of interacting magnetic dots or antidot lattices. In particular, we discuss the principal properties of the magnonic band diagram of such systems, with emphasis given to its dependence on both magnetic and the geometrical parameters. Thanks to the possibility of tailoring their band structure by means of several degrees of freedom, planar magnonic crystals offer a good opportunity to design an innovative class of nanoscale microwave devices.

  14. Thermal Brillouin noise observed in silicon optomechanical waveguide

    CERN Document Server

    Van Laer, Raphaël; Baets, Roel; Van Thourhout, Dries; Safavi-Naeini, Amir H

    2016-01-01

    Stimulated Brillouin scattering was recently observed in nanoscale silicon waveguides. Surprisingly, thermally-driven photon-phonon conversion in these structures had not yet been reported. Here, we inject an optical probe in a suspended silicon waveguide and measure its phase fluctuations at the output. We observe mechanical resonances around 8 GHz with a scattering efficiency of $10^{-5} \\, \\text{m}^{-1}$ and a signal-to-noise ratio of 2. The observations are in agreement with a theory of noise in these waveguides as well as with stimulated measurements. Our scheme may simplify measurements of mechanical signatures in nanoscale waveguides and is a step towards a better grasp of thermal noise in these new continuum optomechanical systems.

  15. Enhanced multiwavelength generation in Brillouin fiber laser with pump noise suppression technique

    Science.gov (United States)

    Al-Alimi, A. W.; Cholan, N. A.; Yaacob, M. H.; Mahdi, M. A.

    2016-06-01

    A new multiwavelength Brillouin fiber laser (BFL) that provides a large number of Stokes lines with improved optical signal-to-noise ratio has been proposed and demonstrated. The BFL cavity is only formed by a nonlinear fiber loop mirror (NOLM) with 500 m long highly nonlinear fiber (HNLF). The BFL with improved performance is based on the suppression of the Brillouin pump noise floor utilizing a narrow tunable bandpass filter. The generation of Stokes lines covering up to a 33.67 nm wavelength range is achieved by setting the Brillouin pump signal within the HNLF’s zero dispersion wavelength and with power of 250 mW. This is owing to the combination of the stimulated Brillouin scattering and four-wave mixing effect in the NOLM structure.

  16. System optimization of a long-range Brillouin-loss-based distributed fiber sensor.

    Science.gov (United States)

    Dong, Yongkang; Chen, Liang; Bao, Xiaoyi

    2010-09-20

    We report a high-performance 25 km Brillouin-loss-based distributed fiber sensor through optimizing system parameters. First, the Brillouin spectrum distortion and measurement error induced by the excess amplification on probe pulse are investigated, and the results indicate that a low continuous-wave pump power is essential to decrease the measurement error. Then an optimal pulse pair is determined through the differential Brillouin gain evolution along the entire sensing fiber in a differential pulse-width pair Brillouin optical time domain analysis. Using dispersion-shifted fiber to allow a high-power probe pulse, we realize a 25 km sensing range with a spatial resolution of 30 cm and a strain accuracy of ±20 με, which we believe is the best performance in such a length, to the best of our knowledge.

  17. Brillouin spectroscopy as a new method of screening for increased CSF total protein during bacterial meningitis.

    Science.gov (United States)

    Steelman, Zachary; Meng, Zhaokai; Traverso, Andrew J; Yakovlev, Vladislav V

    2015-05-01

    Bacterial meningitis is a disease of pronounced clinical significance, especially in the developing world. Immediate treatment with antibiotics is essential, and no single test can provide a conclusive diagnosis. It is well established that elevated total protein in cerebrospinal fluid (CSF) is associated with bacterial meningitis. Brillouin spectroscopy is a widely used optical technique for noninvasive determination of the elastic moduli of materials. We found that elevated protein levels in CSF alter the fluid elasticity sufficiently to be measurable by Brillouin spectroscopy, with model healthy and diseased fluids distinguishable to marked significance (P = 0.014), which increases with sample concentration by dialysis. Typical raw output of a 2-stage VIPA Brillouin spectrometer: inelastically scattered Brillouin peaks (arrows) and elastically scattered incident radiation (center cross).

  18. Dual Raman-Brillouin Microscope for Chemical and Mechanical Characterization and Imaging.

    Science.gov (United States)

    Traverso, Andrew J; Thompson, Jonathan V; Steelman, Zachary A; Meng, Zhaokai; Scully, Marlan O; Yakovlev, Vladislav V

    2015-08-01

    We present a unique confocal microscope capable of measuring the Raman and Brillouin spectra simultaneously from a single spatial location. Raman and Brillouin scattering offer complementary information about a material's chemical and mechanical structure, respectively, and concurrent monitoring of both of these spectra would set a new standard for material characterization. We achieve this by applying recent innovations in Brillouin spectroscopy that reduce the necessary acquisition times to durations comparable to conventional Raman spectroscopy while attaining a high level of spectral accuracy. To demonstrate the potential of the system, we map the Raman and Brillouin spectra of a molded poly(ethylene glycol) diacrylate (PEGDA) hydrogel sample in cyclohexane to create two-dimensional images with high contrast at microscale resolutions. This powerful tool has the potential for very diverse analytical applications in basic science, industry, and medicine.

  19. Stimulated Brillouin scattering of laser in semiconductor plasma embedded with nano-sized grains

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Giriraj, E-mail: grsharma@gmail.com [SRJ Government Girls’ College, Neemuch (M P) (India); Dad, R. C. [Government P G College, Mandsaur (M P) (India); Ghosh, S. [School of Studies in Physics, Vikram University, Ujjain, (M P) (India)

    2015-07-31

    A high power laser propagating through semiconductor plasma undergoes Stimulated Brillouin scattering (SBS) from the electrostrictively generated acoustic perturbations. We have considered that nano-sized grains (NSGs) ions are embedded in semiconductor plasma by means of ion implantation. The NSGs are bombarded by the surrounding plasma particles and collect electrons. By considering a negative charge on the NSGs, we present an analytically study on the effects of NSGs on threshold field for the onset of SBS and Brillouin gain of generated Brillouin scattered mode. It is found that as the charge on the NSGs builds up, the Brillouin gain is significantly raised and the threshold pump field for the onset of SBS process is lowered.

  20. Stimulated Brillouin scattering of an electromagnetic wave in weakly magnetized plasma with variably charged dust particles

    Indian Academy of Sciences (India)

    Sourabh Bal; M Bose

    2009-10-01

    We have investigated analytically the stimulated Brillouin scattering (SBS) of an electromagnetic wave in non-dissipative weakly magnetized plasma in the presence of dust particles with variable charge.

  1. Brillouin suppression in a fiber optical parametric amplifier by combining temperature distribution and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2008-01-01

    We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation.......We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation....

  2. Broadband Brillouin scatter from CO/sub 2/-laser--target interactions

    Energy Technology Data Exchange (ETDEWEB)

    Mitchel, G.R.; Grek, B.; Johnston, T.W.; Pepin, H.; Church, P.; Lavigne, P.; Martin, F.; Decoste, R.

    1982-05-24

    Light scattered near the incident wavelength from CO/sub 2/ laser--solid target interactions in oblique incidence shows the spectral signature of Brillouin scattering both in the backward and in the near specular directions. This instability is apparently seeded by broadband scatter from the critical density surface and then amplified in the underdense plasma. 60% of the incident light is scattered, and the Brillouin contribution to total scatter may be large if the source is also large.

  3. First numerical experiences with overlap fermions based on the Brillouin kernel

    CERN Document Server

    Durr, Stephan

    2016-01-01

    Numerical experiences are reported with overlap fermions which employ the Brillouin action as a kernel. After discussing the dispersion relations of both the kernel and the resulting chiral action, some of the physics features are addressed on quenched backgrounds. We find that the overlap with Brillouin kernel is much better localized than the overlap with Wilson kernel. Also a preliminary account is given of the cost of the formulation, in terms of CPU time and memory.

  4. Investigation on the effect of EDFA location in ring cavity Brillouin-Erbium fiber laser.

    Science.gov (United States)

    Hambali, Nor Azura Malini A; Mahdi, Mohd Adzir; Al-Mansoori, Mohammed Hayder; Abas, Ahmad Fauzi; Saripan, M Iqbal

    2009-07-06

    We have investigated the characteristics of Brillouin-Erbium fiber laser (BEFL) with variation of Erbium-doped fiber amplifier (EDFA) locations in a ring cavity configuration. Three possible locations of the EDFA in the laser cavity have been studied. The experimental results show that the location of EDFA plays vital role in determining the output power and the tuning range. Besides the Erbium gain, Brillouin gain also contributes to the performance of the BEFL. By placing the EDFA next to the Brillouin gain medium (dispersion compensating fiber), the Brillouin pump signal is amplified thereby generating higher intensities of Brillouin Stokes line. This efficient process suppresses the free running self-lasing cavity modes from oscillating in cavity as a result of higher Stokes laser power and thus provide a wider tuning range. At the injected Brillouin pump power of 1.6 mW and the maximum 1480 nm pump power of 135 mW, the maximum Stokes laser power of 25.1 mW was measured and a tuning range of 50 nm without any self-lasing cavity modes was obtained.

  5. Widely tunable linear-cavity multiwavelength fiber laser with distributed Brillouin scattering

    Institute of Scientific and Technical Information of China (English)

    M. Ajiya; M. H. Al-Mansoori; M. A. Mahdi

    2011-01-01

    We demonstrate a multiple wavelength Brillouin/erbium fiber laser in a linear cavity configuration. The laser cavity is made up of a fiber loop mirror on one end of the resonator and a virtual mirror generated from the distributed stimulated Brillouin scattering effect on the other end. Due to the weak reflectivity provided by the virtual mirror, self-lasing cavity modes are completely suppressed from the laser cavity. At Brillouin pump and 1480-nm pump powers of 2 and 130 mW, respectively, 11 channels of the demonstrated laser with an average total power of 7.13 dBm can freely be tuned over a span of 37-nm wavelength from 1530 to 1567 nm.%@@ We demonstrate a multiple wavelength Brillouin/erbium fiber laser in a linear cavity configuration.The laser cavity is made up of a fiber loop mirror on one end of the resonator and a virtual mirror generated from the distributed stimulated Brillouin scattering effect on the other end.Due to the weak reflectivity provided by the virtual mirror, self-lasing cavity modes are completely suppressed from the laser cavity.At Brillouin pump and 1480-nm pump powers of 2 and 130 mW, respectively, 11 channels of the demonstrated laser with an average total power of 7.13 dBm can freely be tuned over a span of 37-nm wavelength from 1530 to 1567 nm.

  6. Performance of the distributed Brillouin sensor: Benefits and penalties due to pump depletion

    Science.gov (United States)

    Ravet, Fabien

    Disaster prevention in civil infrastructures requires the use of techniques that allow temperature and strain measurements in real time over lengths of a few meters to tens of kilometres. The distributed Brillouin sensor (DBS) technique has the advantage to combine all these characteristics. The sensing mechanism of the DBS involves the interaction of two counter-propagating lightwaves, the Stokes and the pump, in an optical fibre. Spatial information is obtained through time domain analysis. The sensing data are recorded from the measurement of the pump depletion. We explore the benefits and the drawbacks of this approach and show that there is a power range for which the sensing performances are optima. To achieve that goal, Brillouin fibre generator (BFG) and amplifier (BFA) were studied leading to the derivation of a threshold definition for the BFA, which is the configuration of the DBS. Within that context, numerical and analytical models describing the stimulated Brillouin scattering (SBS) interaction are introduced and validated experimentally. Even if pump depletion is carefully controlled, the Brillouin spectrum shape, and hence the sensor performance, still depend on the sensing parameters such as power, pulse and fibre characteristics. We use a signal processing method grounded in the physics of Brillouin scattering. An analytical approximation, valid for the optimum sensing region, reconstructs the Brillouin spectrum distribution from input sensing parameters and measured data. These data are obtained with a spectrum analysis methodology, based on three original tools: the Rayleigh equivalent criterion, the lengthstress diagram, and the spectrum form factors. This methodology has been successfully used on experimental spectra. The DBS and the signal processing approach were then used to monitor the structural changes in steel pipes and in a composite column, all subjected to heavy loads. The DBS measured the strain distribution of those structures

  7. Hemispherical Brillouin zone imaging of a diamond-type biological photonic crystal

    NARCIS (Netherlands)

    Wilts, Bodo D.; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G.

    2012-01-01

    The brilliant structural body colours of many animals are created by three-dimensional biological photonic crystals that act as wavelength-specific reflectors. Here, we report a study on the vividly coloured scales of the diamond weevil, Entimus imperialis. Electron microscopy identified the chitin

  8. Microresonator Brillouin Laser Stabilization Using a Microfabricated Rubidium Cell

    CERN Document Server

    Loh, William; Leopardi, Holly F; Fortier, Tara M; Quinlan, Frank; Kitching, John; Papp, Scott B; Diddams, Scott A

    2016-01-01

    We frequency stabilize the output of a miniature stimulated Brillouin scattering (SBS) laser to rubidium atoms in a microfabricated cell to realize a laser system with frequency stability at the $10^{-11}$ level over seven decades in averaging time. In addition, our system has the advantages of robustness, low cost and the potential for integration that would lead to still further miniaturization. The SBS laser operating at 1560 nm exhibits a spectral linewidth of 820 Hz, but its frequency drifts over a few MHz on the 1 hour timescale. By locking the second harmonic of the SBS laser to the Rb reference, we reduce this drift by a factor of $10^3$ to the level of a few kHz over the course of an hour. For our combined SBS and Rb laser system, we measure a frequency noise of $4\\times10^4$ $Hz^2/Hz$ at 10 Hz offset frequency which rapidly rolls off to a level of 0.2 $Hz^2/Hz$ at 100 kHz offset. The corresponding Allan deviation is $\\leq2\\times10^{-11}$ for averaging times spanning $10^{-4}$ to $10^3$ s. By optical...

  9. Small-scale self-focusing of 200 ps laser pulses in Brillouin amplification

    Science.gov (United States)

    Yuan, Hang; Wang, Yu-Lei; Lü, Zhi-Wei; Zheng, Zhen-Xing

    2015-09-01

    Brillouin amplification is a new method to obtain high power hundred-picosecond laser pulses for shock ignition. The laser pulse’s intensity can be amplified to 10 GW/cm2 through this method. In order to determine the near-field quality, the relationship between the Brillouin amplification gain and the B integral in the stimulated Brillouin scattering (SBS) energy transfer process was studied, and numerical simulations and calculations were carried out to explain the process. For achieving an output intensity of 10 GW/cm2 under the condition that the effect of small-scale self-focusing is insignificant in the Brillouin amplification, the influence of the configuration parameters on the Brillouin amplification and the B integral was investigated. The results showed that the 10 GW/cm2 high power output can be obtained by optimizing the intensities of the pump and Stokes light and choosing an appropriate SBS medium. Project supported by the National Natural Science Foundation of China (Grant Nos. 61378007 and 61138005) and the Fundamental Research Funds for the Central Universities, China (Grant No. HIT. IBRSEM. A. 201409).

  10. Brillouin scattering, piezobirefringence, and dispersion of photoelastic coefficients of CdS and ZnO

    DEFF Research Database (Denmark)

    Berkowicz, R.; Skettrup, Torben

    1975-01-01

    We have measured the dispersion of the Brillouin scattering from acoustoelectrical domains in CdS and ZnO. These spectra are compared with the birefringence spectra obtained by applying uniaxial stress. The resonant cancellation of the Brillouin scattering occurs at the spectral position of the i......We have measured the dispersion of the Brillouin scattering from acoustoelectrical domains in CdS and ZnO. These spectra are compared with the birefringence spectra obtained by applying uniaxial stress. The resonant cancellation of the Brillouin scattering occurs at the spectral position...... of the isotropic point of the stress-induced birefringence. From these spectra it is concluded that the Brillouin scattering in CdS and ZnO is determined by elasto-optic effects alone. The spectra of some of the photoelastic coefficients have been determined. A model dielectric constant is derived where both....... It is found that the exchange interaction between the excitons may change the values of the photoelastic coefficients in ZnO about 10%....

  11. Characterization of Brillouin fiber generator and amplifier for optimized working condition of distributed sensors

    Science.gov (United States)

    Ravet, Fabien; Bao, Xiaoyi; Snoddy, Jeff; Li, Yun; Chen, Liang

    2009-06-01

    The Brillouin fiber amplifier (BFA) has been used in Brillouin optical time and frequency domain analyzer based sensors. For BFA based distributed sensor the optimized working condition is to have the highest Brillouin gain, i.e., highest SNR, which avoids high pump depletion induced gain saturation. We have found that the optimum working condition for distributed sensor system is associated with the stimulated Brillouin scattering (SBS) threshold for BFA, which can be experimentally determined with Stokes power inflexion and/or Stokes spectrum linewidth minimum methods. This threshold depends on both pump and probe power instead of just the pump power as in Brillouin fiber generator (BFG), as well as on sensing length as confirmed by our experimental results and theoretical simulation. This was achieved by introducing the concept of absorption coefficient of the sensing medium defined as the ratio of the total output power to the total input power. We find that the medium absorption is minimized when input Stokes power is an order of magnitude lower than BFA threshold. This minimum is a signature of the balance between maximum Stokes gain and pump depletion which is also the reason why Stokes spectrum linewidth goes through a minimum.

  12. Stimulated Brillouin scattering-induced phase noise in an interferometric fiber sensing system

    Institute of Scientific and Technical Information of China (English)

    Chen Wei; Meng Zhou; Zhou Hui-Juan; Luo Hong

    2012-01-01

    Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. Thelocalized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber.The phase noise structure is analyzed for an interferometric fiber sensing system,and an unbalanced Michelson interferometer with an optical path difference of 1 m,as well as the phase-generated carrier technique,is used to measure the phase noise.It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold,increases dramatically at first and then gradually becomes fiat when the input power is above the threshold,which is similar to the variation in relative intensity noise.It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering,which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering.

  13. Seven-year-long crack detection monitoring by Brillouin-based fiber optic strain sensor

    Science.gov (United States)

    Imai, Michio

    2015-03-01

    As an optical fiber is able to act as a sensing medium, a Brillouin-based sensor provides continuous strain information along an optical fiber. The sensor has been used in a wide range of civil engineering applications because no other tool can satisfactorily detect discontinuity such as a crack. Cracking generates a local strain change on the embedded optical fiber, thus Brillouin optical correlation domain analysis (BOCDA), which offers a high spatial resolution by stimulated Brillouin scattering, is expected to detect a fine crack on concrete structures. The author installed the surface-mounted optical fiber on a concrete deck and periodically monitored strain distribution for seven years. This paper demonstrates how a BOCDA-based strain sensor can be employed to monitor cracks in a concrete surface. Additionally, focusing on another advantage of the sensor, the natural frequency of the deck is successfully measured by dynamic strain history.

  14. Characterization of red blood cells (RBCs) using dual Brillouin/Raman micro-spectroscopy

    Science.gov (United States)

    Meng, Zhaokai; Bustamante-Lopez, Sandra C.; Yakovlev, Vladislav V.; Meissner, Kenith E.

    2016-04-01

    Erythrocytes, or red blood cells, transport oxygen to and carbon dioxide from the body's tissues and organs. Red blood cell mechanical properties are altered in a number of diseases such as sickle cell anaemia and malaria. Additionally, mechanically modified red blood cell ghosts are being considered as a long-term, biocompatible carrier for drug delivery and for blood analyte sensing. Brillouin spectroscopy enables viscoelastic characterization of samples at the microscale. In this report, Brillouin spectroscopy is applied to characterize the mechanical properties of red blood cells and red blood cell ghosts.

  15. Brillouin-scattering measurements of the acoustic absorption coefficient in liquid CS2

    Science.gov (United States)

    Coakley, R. W.; Detenbeck, R. W.

    1975-01-01

    High-resolution Brillouin spectra were recorded for light scattered at small angles from liquid CS2. The use of a single-mode He-Ne laser, locked in frequency to a Fabry-Perot interferometer, permitted measurements of line widths of the order of 10 MHz for frequencies in the range 300-1000 MHz. These measurements extend previous Brillouin line-width measurements at higher frequencies into the region where relaxation effects are dominant and connect the optical measurements with lower-frequency acoustical data.

  16. Diagnostic techniques for photonic materials based on Raman and Brillouin spectroscopies

    Institute of Scientific and Technical Information of China (English)

    M. Mattarelli; M. Ferrari; Y. Jestin; G. Nunzi Conti; S. Pelli; G.C. Righini; S.Caponi; A. Chiappini; M. Montagna; E. Moser; F. Rossi; C.Tosello; C. Armellini; A. Chiasera

    2007-01-01

    The elastic and vibrational properties of a material, bulk or planar waveguide, are studied by Brillouin and Raman spectroscopy to follow the process of nanocrystals growth in glass-ceramics. The nanoparticles cause the appearance, in the low frequency Raman spectrum, of characteristic peaks, whose position depends on the size of the crystals. At the same time, sharp crystal peaks, due to optical phonons, appear in the Raman spectra, allowing the determination of the nucleated phase, and a frequency shift of the Brillouin peaks is observed.

  17. Essential criteria for efficient pulse amplification via Raman and Brillouin scattering

    CERN Document Server

    Trines, R M G M; Webb, E; Vieira, J; Fiuza, F; Fonseca, R A; Silva, L O; Sadler, J; Ratan, N; Ceurvorst, L; Kasim, M F; Tabak, M; Froula, D; Haberberger, D; Norreys, P A; Cairns, R A; Bingham, R

    2016-01-01

    Raman and Brillouin amplification are two schemes for amplifying and compressing short laser pulses in plasma. Analytical models have already been derived for both schemes, but the full consequences of these models are little known or used. Here, we present new criteria that govern the evolution of the attractor solution for the seed pulse in Raman and Brillouin amplification, and show how the initial laser pulses need to be shaped to control the properties of the final amplified seed and improve the amplification efficiency.

  18. Guided acoustic and optical waves in silicon-on-insulator for Brillouin scattering and optomechanics

    Science.gov (United States)

    Sarabalis, Christopher J.; Hill, Jeff T.; Safavi-Naeini, Amir H.

    2016-10-01

    We numerically study silicon waveguides on silica showing that it is possible to simultaneously guide optical and acoustic waves in the technologically important silicon on insulator (SOI) material system. Thin waveguides, or fins, exhibit geometrically softened mechanical modes at gigahertz frequencies with phase velocities below the Rayleigh velocity in glass, eliminating acoustic radiation losses. We propose slot waveguides on glass with telecom optical frequencies and strong radiation pressure forces resulting in Brillouin gains on the order of 500 and 50 000 W-1m-1 for backward and forward Brillouin scattering, respectively.

  19. Controllable optical delay line using a Brillouin optical fiber ring laser

    Institute of Scientific and Technical Information of China (English)

    Yongkang Dong; Zhiwei Lü; Qiang Li; Wei Gao

    2006-01-01

    A controllable optical delay line using a Brillouin optical fiber ring laser is demonstrated and a large timedelay is obtained by cascading two optical fiber segments. In experiment, a single-mode Brillouin opticalfiber ring laser is used to provide Stokes wave as probe wave. We achieve a maximum tunable time delayof 61 ns using two cascading optical fiber segments, about 1.5 times of the input probe pulse width of 40ns. In the meantime, a considerable pulse broadening is observed, which agrees well with the theoreticalprediction based on linear theory.

  20. Performance Analysis of Temperature and Strain Simultaneous Measurement System Based on Heterodyne Detection of Brillouin Scattering

    Institute of Scientific and Technical Information of China (English)

    Ji-Sheng Zhang; Yong-Qian Li; Shuo Zhang; Li-Juan Zhao

    2008-01-01

    Microwave heterodyne detection can be used to measure the temperature and strain distribution along a fiber with high accuracy in a Brillouin optical time domain reflectometry (BOTDR) system. This method involves simultaneous measurement of Brillouin scattering and Rayleigh scattering in fiber, and scanning of Briliouin spectrum to obtain the desired information. This paper presents a simultaneous measurement system of temperature and strain based on microwave detection and analyzed the system performances such as measurement accuracy, dynamic range, and spatial resolution theoretically. The analysis shows that the system can achieve a temperature resolution of 1℃ and a strain resolution of 100 με.

  1. Brillouin precursor waveforms pertaining to UWB noise radar signals propagating through dispersive media

    Science.gov (United States)

    Dawood, M.; Alejos, A. V.

    2011-06-01

    The electromagnetic (EM) waves propagating through causal, linear, and lossy dispersive media (soil, foliage, plasma, water, biological tissue, etc.), experience frequency-dependent attenuation and phase distortion. This has assumed significant importance for systems operating with ultrawideband (UWB) spectrum. This paper analyzes the dynamical evolution of UWB noise radar signals through dispersive media. The effects on the signal propagation due to the evolution of the Brillouin precursor through dispersive media are discussed. The evolving waveforms are then compared with the Brillouin precursor due to rectangular sine-modulated deterministic signals. The advantages of random noise waveforms through dispersive media are also discussed.

  2. ``Bloch wave'' modification of stimulated Raman by stimulated Brillouin scattering

    Science.gov (United States)

    Dodd, E. S.; Vu, H. X.; DuBois, D. F.; Bezzerides, B.

    2013-03-01

    Using the reduced-description particle-in-cell (RPIC) method, we study the coupling of backward stimulated Raman scattering (BSRS) and backward stimulated Brillouin scattering (BSBS) in regimes where the reflectivity involves the nonlinear behavior of particles trapped in the daughter plasma waves. The temporal envelope of a Langmuir wave (LW) obeys a Schrödinger equation where the potential is the periodic electron density fluctuation resulting from an ion-acoustic wave (IAW). The BSRS-driven LWs in this case have a Bloch wave structure and a modified dispersion due to the BSBS-driven spatially periodic IAW, which includes frequency band gaps at kLW˜kIAW/2˜k0 (kLW, kIAW, and k0 are the wave number of the LW, IAW, and incident pump electromagnetic wave, respectively). This band structure and the associated Bloch wave harmonic components are distinctly observed in RPIC calculations of the electron density fluctuation spectra and this structure may be observable in Thomson scatter. Bloch wave components grow up in the LW spectrum, and are not the result of isolated BSRS. Self-Thomson scattered light from these Bloch wave components can have forward scattering components. The distortion of the LW dispersion curve implies that the usual relationship connecting the frequency shift of the BSRS-scattered light and the density of origin of this light may become inaccurate. The modified LW frequency results in a time-dependent frequency shift that increases as the IAW grows, detunes the BSRS frequency matching condition, and reduces BSRS growth. A dependence of the BSRS reflectivity on the IAW Landau damping results because this damping determines the levels of IAWs. The time-dependent reflectivity in our simulations is characterized by bursts of sub-picosecond pulses of BSRS alternating with multi-ps pulses of BSBS, and BSRS is observed to decline precipitously as soon as SBS begins to grow from low levels. In strong BSBS regimes, the Bloch wave effects in BSRS are

  3. Determination of the elastic constants of portlandite by Brillouin spectroscopy

    KAUST Repository

    Speziale, S.

    2008-10-01

    The single crystal elastic constants Cij and the shear and adiabatic bulk modulus of a natural portlandite (Ca(OH)2) crystal were determined by Brillouin spectroscopy at ambient conditions. The elastic constants, expressed in GPa, are: C11 = 102.0(± 2.0), C12 = 32.1(± 1.0), C13 = 8.4(± 0.4), C14 = 4.5(± 0.2), C33 = 33.6(± 0.7), C44 = 12.0(± 0.3), C66 = (C11-C12)/2 = 35.0(± 1.1), where the numbers in parentheses are 1σ standard deviations. The Reuss bounds of the adiabatic bulk and shear moduli are K0S = 26.0(± 0.3) GPa and G0 = 17.5(± 0.4) GPa, respectively, while the Voigt bounds of these moduli are K0S = 37.3(± 0.4) GPa and G0 = 24.4(± 0.3) GPa. The Reuss and Voigt bounds for the aggregate Young\\'s modulus are 42.8(± 1.0) GPa and 60.0(± 0.8) GPa respectively, while the aggregate Poisson\\'s ratio is equal to 0.23(± 0.01). Portlandite exhibits both large compressional elastic anisotropy with C11/C33 = 3.03(± 0.09) equivalent to that of the isostructural hydroxide brucite (Mg(OH)2), and large shear anisotropy with C66/C44 = 2.92(± 0.12) which is 11% larger than brucite. The comparison between the bulk modulus of portlandite and that of lime (CaO) confirms a systematic linear relationship between the bulk moduli of brucite-type simple hydroxides and the corresponding NaCl-type oxides. © 2008 Elsevier Ltd. All rights reserved.

  4. All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

    NARCIS (Netherlands)

    Offerhaus, H.L.; Godfried, H.P.; Witteman, W.J.

    1996-01-01

    At the Nederlands Centrum voor Laser Research (NCLR) a 1 kHz diode-pumped Nd:YAG Master Oscillator Power Amplifier (MOPA) chain with a Stimulated Brillouin Scattering (SBS) Phase Conjugate mirror is designed and operated. A small Brewster angle Nd:YAG slab (2 by 2 by 20 mm) is side pumped with 200 μ

  5. An L-band multi-wavelength Brillouin-erbium fiber laser with switchable frequency spacing

    Science.gov (United States)

    Zhou, Xuefang; Hu, Kongwen; Wei, Yizhen; Bi, Meihua; Yang, Guowei

    2017-01-01

    In this paper, a novel L-band multi-wavelength Brillouin-erbium fiber laser consisting of two ring cavities is proposed and demonstrated. The frequency spacing can be switched, corresponding to the single and double Brillouin frequency shifts, by toggling the optical switch. Under a 980 nm pump power of 600 mw, and a Brillouin pump power of 4 mW and wavelength of 1599.4 nm, up to 16 Stokes signals with a frequency spacing of 0.089 nm and 5 Stokes signals with double spacing of 0.178 nm are generated. A wavelength tunability of 15 nm (1593 nm  -  1608 nm) is realized for both frequency spacings. The fluctuation of Stokes signals for both single and double Brillouin spacing regimes in the proposed setup is less than 1.5 dB throughout a 30 min time span.

  6. Nonlinear Evolutions of Stimulated Raman and Brillouin Scattering Processes in Partially Stripped-Ion Plasmas

    Institute of Scientific and Technical Information of China (English)

    胡业民; 胡希伟

    2001-01-01

    Numerical analyses for the nonlinear evolutions of stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) processes are given. Various effects of the second- and third-order nonlinear susceptibilities on the SRS and SBS processes are studied. The nonlinear evolutions of SRS and SBS processes are atfected more efficiently than their linear growth rates by the nonlinear susceptibility.

  7. The performance analysis of distributed Brillouin corrosion sensors for steel reinforced concrete structures.

    Science.gov (United States)

    Wei, Heming; Zhao, Xuefeng; Kong, Xianglong; Zhang, Pinglei; Cui, Yanjun; Sun, Changsen

    2013-12-27

    The Brillouin optical time-domain analysis (BOTDA)-based optical fiber method has been proposed to measure strain variations caused by corrosion expansion. Spatial resolutions of 1 m can be achieved with this kind of Brillouin sensor for detecting the distributed strain. However, when the sensing fiber is wound around the steel rebar in a number of circles in a range of several meters, this spatial resolution still has limitations for corrosion monitoring. Here, we employed a low-coherent fiber-optic strain sensor (LCFS) to survey the performance of Brillouin sensors based on the fact that the deformation measured by the LCFS equals the integral of the strains obtained from Brillouin sensors. An electrochemical accelerated corrosion experiment was carried out and the corrosion expansion was monitored by both BOTDA and the LCFS. Results demonstrated that the BOTDA can only measure the expansion strain of about 1,000 με, which was generated by the 18 mm steel rebar corrosion, but, the LCFS had high sensitivity from the beginning of corrosion to the destruction of the structure, and no obvious difference in expansion speed was observed during the acceleration stage of the corrosion developed in the reinforced concrete (RC) specimens. These results proved that the BOTDA method could only be employed to monitor the corrosion inside the structure in the early stage.

  8. KrF laser amplifier with phase-conjugate Brillouin retroreflectors.

    Science.gov (United States)

    Gower, M C

    1982-09-01

    We have demonstrated the use of phase-conjugate stimulated Brillouin scattering mirrors to produce high-quality, short-pulse KrF laser beams from angular multiplexed and regenerative amplifiers. The mirror was also shown to isolate systems optically from amplifier spontaneous emission. Automatic alignment of targets using this mirror as a retroreflector was also demonstrated.

  9. Dependence of Brillouin frequency shift on water absorption ratio in polymer optical fibers

    Science.gov (United States)

    Minakawa, Kazunari; Koike, Kotaro; Hayashi, Neisei; Koike, Yasuhiro; Mizuno, Yosuke; Nakamura, Kentaro

    2016-06-01

    We studied the dependence of the Brillouin frequency shift (BFS) on the water-absorption ratio in poly(methyl methacrylate)-based polymer optical fibers (POFs) to clarify the effect of the humidity on POF-based Brillouin sensors. The BFS, deduced indirectly using an ultrasonic pulse-echo technique, decreased monotonically as the water absorption ratio increased, mainly because of the decrease in the Young's modulus. For the same water absorption ratio, the BFS change was larger at a higher temperature. The maximal BFS changes (absolute values) at 40, 60, and 80 °C were 158, 285, and 510 MHz, respectively (corresponding to the temperature changes of ˜9 °C, ˜16 °C, and ˜30 °C). Thus, some countermeasure against the humidity is indispensable in implementing strain/temperature sensors based on Brillouin scattering in POFs, especially at a higher temperature. On the other hand, Brillouin-based distributed humidity sensors might be developed by exploiting the BFS dependence on water absorption in POFs.

  10. Brillouin scattering study of the ferroelectric phase transition in tris-sarcosine calcium chloride

    Science.gov (United States)

    Hikita, Tomoyuki; Schnackenberg, Paul; Schmidt, V. Hugo

    1985-01-01

    Brillouin spectra from longitudinal phonons in ferroelectric tris-sarcosine calcium chloride propagating along [100], [010], and [001] have been measured as functions of temperature. Large anomalies were found in the Brillouin shift and linewidth in the [100] and [001] phonons. These anomalies are interpreted as arising from the linear coupling of the polarization and the phonons. From the temperature where the linewidth is maximum, the relaxation time of the polarization fluctuations is estimated to be τ=3.1×10-12/(Tc-T) sec, where Tc is the ferroelectric transition temperature. We also observed anomalies in Brillouin shift and linewidth of the [010] phonons which propagate along the ferroelectric b axis. These anomalies are interpreted as coming from electro- strictive coupling. The energy-relaxation time was estimated to be τE=2.5×10-10/(T-Tc) sec in the paraelectric phase and τE=1.0×10-9/(Tc-T) sec in the ferroelectric phase, by comparing our Brillouin results with those of the ultrasonic measurements.

  11. High-resolution long-reach distributed Brillouin sensing based on combined time-domain and correlation-domain analysis.

    Science.gov (United States)

    Elooz, David; Antman, Yair; Levanon, Nadav; Zadok, Avi

    2014-03-24

    A new scheme for distributed Brillouin sensing of strain and temperature in optical fibers is proposed, analyzed and demonstrated experimentally. The technique combines between time-domain and correlation-domain analysis. Both Brillouin pump and signal waves are repeatedly co-modulated by a relatively short, high-rate phase sequence, which introduces Brillouin interactions in a large number of discrete correlation peaks. In addition, the pump wave is also modulated by a single amplitude pulse, which leads to a temporal separation between the generation of different peaks. The Brillouin amplification of the signal wave at individual peak locations is resolved in the time domain. The technique provides the high spatial resolution and long range of unambiguous measurement offered by correlation-domain Brillouin analysis, together with reduced acquisition time through the simultaneous interrogation of a large number of resolution points. In addition, perfect Golomb codes are used in the phase modulation of the two waves instead of random sequences, in order to reduce noise due to residual, off-peak Brillouin interactions. The principle of the method is supported by extensive numerical simulations. Using the proposed scheme, the Brillouin gain spectrum is mapped experimentally along a 400 m-long fiber under test with a spatial resolution of 2 cm, or 20,000 resolution points, with only 127 scans per choice of frequency offset between pump and signal. Compared with corresponding phase-coded, Brillouin correlation domain analysis schemes with equal range and resolution, the acquisition time is reduced by a factor of over 150. A 5 cm-long hot spot, located towards the output end of the pump wave, is properly identified in the measurements. The method represents a significant advance towards practical high-resolution and long range Brillouin sensing systems.

  12. Single-passband microwave photonic filter based on a self-seeded multiwavelength Brillouin-erbium fiber laser

    Science.gov (United States)

    Xu, Ronghui; Zhang, Xuping; Hu, Junhui; Xia, Lan

    2015-03-01

    In this paper, a single-passband microwave photonic filter based on a self-seeded multiwavelength Brillouin-erbium fiber laser is demonstrated experimentally. In the filter, the multiwavelength Brillouin comb generated from the laser is used as the filter taps. The Brillouin comb is with the feature of quasi-Gaussian continuous distribution, which can ensure the filter realizes single-passband characteristic. The baseband response is suppressed effectively with the help of phase modulation. The single-passband filter has an out-of-band rejection of 25 dB. By adjusting the Brillouin multiwavelengh, the 3-dB bandwidth and the center frequency of the filter can be changed.

  13. Distributed fiber Brillouin strain and temperature sensor with centimeter spatial resolution by coherent probe-pump technique

    Science.gov (United States)

    Zou, Lufan; Bao, Xiaoyi; Wan, Yidun; Ravet, Fabien; Chen, Liang

    2005-05-01

    We present a sensing principle of the distributed fiber Brillouin strain and temperature sensor by coherent probe-pump technique that offers a new method to achieve centimeter spatial resolution with high frequency resolution. A combination of continuous wave (cw) and pulse source as the probe (Stokes) beam and cw laser as the pump beam have resulted in stronger Brillouin interaction of Stokes and pump inside the pulse-length in the form of cw-pump and pulse-pump interactions. We find that the coherent portion inside the pulse-length of these two interactions due to the same phase has a very high Brillouin amplification. The Brillouin profile originating from the coherent interaction of pulse-pump with cw-pump results in high temperature and strain accuracy with centimeter resolution, which has been verified by successfully detecting 1.5 cm out-layer crack on an optical ground wire (OPGW) cable.

  14. Optimization of output coupling ratio on the performance of a ring-cavity Brillouin-erbium fiber laser.

    Science.gov (United States)

    Hambali, Nor Azura Malini A; Mahdi, Mohd Adzir; Al-Mansoori, Mohammed Hayder; Saripan, M Iqbal; Abas, Ahmad Fauzi

    2009-09-20

    The operation of a single-wavelength Brillouin-erbium fiber laser (BEFL) system with a Brillouin pump preamplified technique for different output coupling ratios in a ring cavity is experimentally demonstrated. The characteristics of Brillouin Stokes power and tunability were investigated in this research. The efficiency of the BEFL operation was obtained at an optimum output coupling ratio of 95%. By fixing the Brillouin pump wavelength at 1550 nm while its power was set at 1.6 mW and the 1480 pump power was set to its maximum value of 135 mW, the Brillioun Stokes power was found to be 28.7 mW. The Stokes signal can be tuned within a range of 60 nm from 1520 to 1580 nm without appearances of the self-lasing cavity modes in the laser system.

  15. Detrimental Effect Elimination of Laser Frequency Instability in Brillouin Optical Time Domain Reflectometer by Using Self-Heterodyne Detection

    Directory of Open Access Journals (Sweden)

    Yongqian Li

    2017-03-01

    Full Text Available A useful method for eliminating the detrimental effect of laser frequency instability on Brillouin signals by employing the self-heterodyne detection of Rayleigh and Brillouin scattering is presented. From the analysis of Brillouin scattering spectra from fibers with different lengths measured by heterodyne detection, the maximum usable pulse width immune to laser frequency instability is obtained to be about 4 µs in a self-heterodyne detection Brillouin optical time domain reflectometer (BOTDR system using a broad-band laser with low frequency stability. Applying the self-heterodyne detection of Rayleigh and Brillouin scattering in BOTDR system, we successfully demonstrate that the detrimental effect of laser frequency instability on Brillouin signals can be eliminated effectively. Employing the broad-band laser modulated by a 130-ns wide pulse driven electro-optic modulator, the observed maximum errors in temperatures measured by the local heterodyne and self-heterodyne detection BOTDR systems are 7.9 °C and 1.2 °C, respectively.

  16. Photonic crystal fiber-based multi-wavelength Brillouin fiber laser with dual-pass amplification configuration

    Institute of Scientific and Technical Information of China (English)

    R. Parvizi; S. W. Harun; N. M. Ali; N. S. Shahabuddin; H. Ahmad

    2011-01-01

    @@ A simple technique for achieving a stable, room temperature and multi-wavelength lasing with narrow linewidth is demonstrated using Brillouin fiber laser (BFL) with a 100-m-long photonic crystal fiber (PCF) in conjunction with a dual-pass configuration. A broadband fiber Bragg grating (FBG) operating in the C-band region is incorporated at the end side of the setup to allow a dual-pass operation. The proposed BFL can operate at any wavelength depending on the Brillouin pump wavelength and the FBG's reflection region used. With a Brillouin pump (BP) of 15.7 dBm, approximately 7 Stokes and 4 anti-Stokes lines are obtained with a line spacing of 0.08 nm.%A simple technique for achieving a stable, room temperature and multi-wavelength lasing with narrow linewidth is demonstrated using Brillouin fiber laser (BFL) with a 100-m-long photonic crystal fiber (PCF) in conjunction with a dual-pass configuration. A broadband fiber Bragg grating (FBG) operating in the C-band region is incorporated at the end side of the setup to allow a dual-pass operation. The proposed BFL can operate at any wavelength depending on the Brillouin pump wavelength and the FBG's reflection region used. With a Brillouin pump (BP) of 15.7 dBm, approximately 7 Stokes and 4 anti-Stokes lines are obtained with a line spacing of 0.08 nm.

  17. Phase-locking in Multi-Frequency Brillouin Oscillator via Four Wave Mixing

    CERN Document Server

    Buettner, Thomas F S; Hudson, Darren D; Pant, Ravi; Poulton, Christopher G; Judge, Alexander C; Eggleton, Benjamin J

    2014-01-01

    Stimulated Brillouin scattering (SBS) and Kerr-nonlinear four wave-mixing (FWM) are among the most important and widely studied nonlinear effects in optical fibres. At high powers SBS can be cascaded producing multiple Stokes waves spaced by the Brillouin frequency shift. Here, we investigate the complex nonlinear interaction of the cascade of Stokes waves, generated in a Fabry-Perot chalcogenide fibre resonator through the combined action of SBS and FWM. We demonstrate the existence of parameter regimes, in which pump and Stokes waves attain a phase-locked steady state. Real-time measurements of 40ps pulses with 8GHz repetition rate are presented, confirming short-and long-term stability. Numerical simulations qualitatively agree with experiments and show the significance of FWM in phase-locking of pump and Stokes waves. Our findings can be applied for the design of novel picosecond pulse sources with GHz repetition rate for optical communication systems.

  18. Production of petawatt laser pulses of picosecond duration via Brillouin amplification of nanosecond laser beams

    CERN Document Server

    Humphrey, Kathryn; Alves, Paulo; Fiuza, Frederico; Speirs, David; Bingham, Robert; Cairns, Alan; Fonseca, Ricardo; Silva, Luis; Norreys, Peter

    2013-01-01

    Previous studies have shown that Raman amplification in plasma is a potential route for the production of petawatt pulses of picosecond duration at 351 nm [Trines et al., Phys. Rev. Lett. 107, 105002 (2011)]. In this paper we show, through analytic theory and particle-in-cell simulations, that similar results can also be obtained through Brillouin amplification of a short seed laser beam off a long pump beam at moderate intensity. Scaling laws governing the optimal parameter space for pump beam, seed beam and plasma will be derived using a self-similar model for Brillouin scattering, and verified via simulations. A comparison with Raman scattering will be made, to determine which scheme is most suitable for a range of laser-plasma configurations.

  19. Unified approach to cascaded stimulated Brillouin scattering and frequency-comb generation

    Science.gov (United States)

    Dong, Mark; Winful, Herbert G.

    2016-04-01

    We present a unified approach to cascaded stimulated Brillouin scattering and frequency-comb generation in which the multitude of interacting pump, Stokes, and anti-Stokes optical fields is described by a single forward wave and a single backward wave at a single carrier frequency. The envelopes of these two waves are modulated through coupling to a single acoustic oscillation and through four-wave mixing. Starting from a single pump field, we observe the emergence of a comb of frequencies as the intensity is increased. The set of three differential equations derived here is sufficient to describe the generation of any number of Brillouin sidebands in oscillator systems that would have required hundreds of coupled equations in the standard approach. We test this approach on some published experiments and find excellent agreement with the results.

  20. High speed data encryption and decryption using stimulated Brillouin scattering effect in optical fiber

    Science.gov (United States)

    Yi, Lilin; Zhang, Tao; Hu, Weisheng

    2011-11-01

    A novel all-optical encryption/decryption method based on stimulated Brillouin scattering (SBS) effect in optical fiber is proposed for the first time. The operation principle is explained in detail and the encryption and decryption performance is experimentally evaluated. The encryption keys could be the SBS gain amplitude, bandwidth, central wavelength and spectral shape, which are configurable and flexibly controlled by the users. We experimentally demonstrate the SBS encryption/decryption process of a 10.86-Gb/s non-return-to-zero (NRZ) data by using both phase-modulated and current-dithered Brillouin pumps for proof-of-concept. Unlike the traditional optical encryption methods of chaotic communications and optical code-division-multiplexing access (OCDMA), the SBS based encryption/decryption technique can directly upgrade the current optical communication system to a secure communication system without changing the terminal transceivers, which is completely compatible with the current optical communication systems.

  1. Pressure and temperature dependences of the acoustic behaviors of biocompatible silk studied by using Brillouin spectroscopy

    Science.gov (United States)

    Lee, Byoung Wan; Ryeom, Junho; Ko, Jae-Hyeon; Kim, Dong Wook; Park, Chan Hum; Park, Jaehoon; Ko, Young Ho; Kim, Kwang Joo

    2016-07-01

    The elastic properties of a biocompatible silk film were investigated under temperature and pressure variations by using Brillouin spectroscopy. The Brillouin frequency shift decreased monotonically upon heating and showed a sudden change at the glass transition temperature. The existence of water molecules in the film increased the longitudinal modulus by approximately 10% and induced a relaxation peak in the hypersonic damping at ~60 ◦ C. The pressure dependences of the sound velocities of the longitudinal and the transverse acoustic modes and the refractive index were determined for the first time at pressures up to ~15.5 GPa. All these properties increased upon compression; these changes indicated that the free volume in the silk film collapsed at a pressure of about 3 GPa.

  2. Distributed Temperature and Strain Discrimination with Stimulated Brillouin Scattering and Rayleigh Backscatter in an Optical Fiber

    Directory of Open Access Journals (Sweden)

    Xiaoyi Bao

    2013-01-01

    Full Text Available A distributed optical fiber sensor with the capability of simultaneously measuring temperature and strain is proposed using a large effective area non-zero dispersion shifted fiber (LEAF with sub-meter spatial resolution. The Brillouin frequency shift is measured using Brillouin optical time-domain analysis (BOTDA with differential pulse-width pair technique, while the spectrum shift of the Rayleigh backscatter is measured using optical frequency-domain reflectometry (OFDR. These shifts are the functions of both temperature and strain, and can be used as two independent parameters for the discrimination of temperature and strain. A 92 m measurable range with the spatial resolution of 50 cm is demonstrated experimentally, and accuracies of ±1.2 °C in temperature and ±15 με in strain could be achieved.

  3. Photonic crystal fibre Brillouin laser based on Bragg grating Fabry-Perot cavity

    Institute of Scientific and Technical Information of China (English)

    Geng Dan; Yang Dong-Xiao; Shen Guo-Feng; Zhang Xian-Min

    2008-01-01

    A photonic crystal fibre Brillouin laser based on fibre Bragg grating Fabry-Perot cavity is presented. A highly nonlinear photonic crystal fibre 25 m in length is used as Brillouin gain medium and fibre Bragg grating Fabry-Perot cavity is chosen in order to enhance the laser conversion efficiency and suppress the higher-order Stokes waves. The laser reaches the threshold at input power of 35 mW, and the experimental laser conversion efficiency achieves 18% of the input power of 140 mW and does not show higher-order Stokes waves. A photonic crystal fibre BriUouin laser withshorter fibre length and lower threshold is experimentally realized.

  4. Modeling the effects of laser-beam smoothing on filamentation and stimulated Brillouin backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Berger, R.L.; Kaiser, T.B.; Lasinski, B.F. [and others

    1996-06-01

    Using the three-dimensional code (F3D), the authors compute the filamentation and backscattering of laser light. The results show that filamentation can be controlled and stimulated Brillouin backscattering (SBBS) can be reduced by using random phase plates (RPP) and small f-numbers or smoothing by spectral dispersion (SSD) with large bandwidth. An interesting result is that, for uniform plasmas, the SBBS amplification takes place over several laser axial coherence lengths (coherence length = speckle length).

  5. Reduction of Guided Acoustic Wave Brillouin Scattering in Photonic Crystal Fibers

    CERN Document Server

    Elser, D; Gloeckl, O; Korn, A; Leuchs, G; Lorenz, S; Marquardt, C; Marquardt, Ch.

    2005-01-01

    Guided Acoustic Wave Brillouin Scattering (GAWBS) generates phase and polarization noise of light propagating in glass fibers. This excess noise affects the performance of various experiments operating at the quantum noise limit. We experimentally demonstrate the reduction of GAWBS noise in a photonic crystal fiber in a broad frequency range using cavity sound dynamics. We compare the noise spectrum to the one of a standard fiber and observe a roughly 10-fold noise reduction in the frequency range up to 200 MHz.

  6. Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

    Science.gov (United States)

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  7. Stimulated Brillouin Scattering Suppression in Fiber Amplifiers via Chirped Diode Lasers

    Science.gov (United States)

    2011-09-01

    1.55-µm diode laser at 1014 Hz/s using a phase-locked loop and a fiber -optic Michelson interferometer (9). The chirp has now been extended to 5×1015...diode lasers. By incorporating a fiber interferometer , the technique has been extended to chirp a (single) laser diode at 1015 Hz/s in an extremely...Stimulated Brillouin Scattering Suppression in Fiber Amplifiers via Chirped Diode Lasers by Jeffrey O. White, George Rakuljic, and Carl E

  8. Local analysis of stimulated Brillouin interaction in installed fiber optics cables

    OpenAIRE

    Nikles, M.; Thévenaz, Luc; Salina, P.; Robert, P. A.

    1996-01-01

    Brillouin gain spectrum measurement along an optical fiber has recently gained a lot of interests owing to its potentiality for strain monitoring in installed telecom cables. The purpose of the paper is to show that this potentiality is now effective, since field measurements of installed fiber optics cables currently in operation are demonstrated. A portable instrument has been developed, based on an original experimental configuration developed in our Institute which is briefly described

  9. Remote-sensing gas measurements with coherent Rayleigh-Brillouin scattering

    Science.gov (United States)

    Gerakis, A.; Shneider, M. N.; Stratton, B. C.

    2016-07-01

    We measure the coherent Rayleigh-Brillouin scattering (CRBS) signal integral as a function of the recorded gas pressure in He, Co2, SF6, and air, and we confirm the already established quadratic dependence of the signal on the gas density. We propose the use of CRBS as an effective diagnostic for the remote measurement of gas' density (pressure) and temperature, as well as polarizability, for gases of known composition.

  10. Wentzel-Kramers-Brillouin Approximation for Dynamic Systems with Kinetic Coupling in Entangled State Representations

    Institute of Scientific and Technical Information of China (English)

    范洪义

    2002-01-01

    We study the Wentzel-Kramers-Brillouin (WKB) approximation for dynamic systems with kinetic couplings inentangled state representations. The result shows that the kinetic coupling will affect the position of classicalturning points where the condition of using the WKB approximation breaks down. The modified WKB approx-imation formula is derived in the entangled state representation, for example, the common eigenvector of therelative coordinate and the total momentum of two particles. The corresponding Bohr-Sommerfeld quantizationrule is also derived.

  11. Tunable narrowband microwave photonic filter created by stimulated Brillouin scattering from a Silicon nanowire

    CERN Document Server

    Casas-Bedoya, Alvaro; Pagani, Mattia; Marpaung, David; Eggleton, Benjamin J

    2015-01-01

    We demonstrate the first functional signal processing device based on stimulated Brillouin scattering in a silicon nanowire. We use only 1 dB of on-chip SBS gain to create an RF photonic notch filter with 48 dB of suppression, 98 MHz linewidth, and 6 GHz frequency tuning. This device has potential applications in on-chip microwave signal processing and establishes the foundation for the first CMOS-compatible high performance RF photonic filter.

  12. Temporal characterization of a multi-wavelength Brillouin-erbium fiber laser

    Science.gov (United States)

    Lambin Iezzi, Victor; Büttner, Thomas F. S.; Tehranchi, Amirhossein; Loranger, Sébastien; Kabakova, Irina V.; Eggleton, Benjamin J.; Kashyap, Raman

    2016-05-01

    This paper provides the first detailed temporal characterization of a multi-wavelength-Brillouin-erbium fiber laser (MWBEFL) by measuring the optical intensity of the individual frequency channels with high temporal resolution. It is found that the power in each channel is highly unstable due to the excitation of several cavity modes for typical conditions of operation. Also provided is the real-time measurements of the MWBEFL output power for two configurations that were previously reported to emit phase-locked picosecond pulse trains, concluded from their autocorrelation measurements. Real-time measurements reveal a high degree of instability without the formation of a stable pulse train. Finally, we model the MWBEFL using coupled wave equations describing the evolution of the Brillouin pump, Stokes and acoustic waves in the presence of stimulated Brillouin scattering, and the optical Kerr effect. A good qualitative consistency between the simulation and experimental results is evident, in which the interference signal at the output shows strong instability as well as the chaotic behavior due to the dynamics of participating pump and Stokes waves.

  13. Study on forward stimulated Brillouin scattering in a backward pumped fiber Raman amplifier

    Institute of Scientific and Technical Information of China (English)

    Zaixuan Zhang(张在宣); Dawei Fang(方达伟); Songlin Zhuang(庄松林); Laixiao Li(李来晓); Dan Geng(耿丹); Bizhi Dai(戴碧智); Yongxing Jin(金永兴); Honglin Liu(刘红林); Insoo S.Kim; Jianfeng Wang(王剑锋); Xiaobiao Wu(吴孝彪)

    2004-01-01

    Strong multi-order forward stimulated Brillouin scattering (SBS) has been observed in the backward pumped S-band distributed fiber Raman amplifier (FRA) with tunable narrow signal source (less than 100 MHz) when the pump power of FRA reached the SBS threshold. This does not obey the theory that only weak backward SBS lines exist according to the conservation of energy and momentum and the wave vector selected rule. This is because the sound waveguide characteristic weakens the wave vector rule, and the forward transmitted sound waveguide Brillouin scattering lines are generated and amplified in FRA.When the pump power is further increased, 11 orders of SBS lines and comb-like profile are observed. For the excited line, the frequency is 197.2296 THz and the power is 0 dBm. The even order SBS lines are stronger than odd order SBS lines, the power of the 2nd and 4th order SBS lines is 1.75 dBm, which is 16 dB higher than that of the 1st and 3rd order SBS lines. The odd order SBS lines are named BrillouinRayleigh scattering lines.

  14. Brillouin spectroscopy reveals changes in muscular viscoelasticity in Drosophila POMT mutants

    Science.gov (United States)

    Meng, Zhaokai; Baker, Ryan; Panin, Vladislav M.; Yakovlev, Vladislav V.

    2015-03-01

    Muscular dystrophy (MD) is a group of muscle diseases that induce weakness in skeletal muscle and cause progressive muscle degeneration. The muscular mechanical properties (i.e., viscoelasticity), however, have not been thoroughly examined before and after MD. On the other hand, Brillouin spectroscopy (BS) provides a non-invasive approach to probing the local sound speed within a small volume. Moreover, recent advances in background-free Brillouin spectroscopy enable investigators to imaging not only transparent samples, but also turbid ones. In this study, we investigated the mechanical properties of muscles while employing Drosophila model of dystroglycanopathies, human congenital muscular dystrophies resulting from abnormal glycosylation of alphadystroglycan. Specifically, we analyzed larval abdominal muscles of Drosophila with mutations in protein Omannosyltransferase (POMT) genes. As a comparison, we have also examined muscular tissues dissected from wildtype Drosophila. The Brillouin spectra were obtained by a background free VIPA (virtually imaged phased array) spectrometer described in the previous report. As a reference, the Raman spectra were also acquired for each test. Our current results indicated that POMT defects cause changes in muscle elasticity, which suggests that muscular dystrophy conditions may be also associated with abnormalities in muscle elastic properties.

  15. Single-crystal Brillouin spectroscopy with CO{sub 2} laser heating and variable q

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jin S.; Bass, Jay D. [Department of Geology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Zhu, Gaohua [Materials Research Department, Toyota Research Institute of North America, Ann Arbor, Michigan 48105 (United States)

    2015-06-15

    We describe a Brillouin spectroscopy system integrated with CO{sub 2} laser-heating and Raman spectroscopic capabilities. Temperature is determined by measurements of the grey-body thermal radiation emitted by the hot sample, with the system response calibrated relative to a standard tungsten ribbon lamp. High-pressure laser-heating Brillouin scattering measurements of acoustic velocities on liquid water and ice compressed in a diamond-anvil cell were performed at temperatures up to 2500 ± 150 K at high pressure. Single-crystal laser-heating Brillouin measurements were made on the (111) plane of San Carlos olivine at ∼13 GPa, 1300 ± 200 K. The pressure as measured by ruby fluorescence is shown to be within ±0.5 GPa of the pressure on the olivine sample during laser heating when KCl and KBr are used as pressure-transmitting media. In addition, the system is designed for continuously variable scattering angles from forward scattering (near 0° scattering angle) up to near back scattering (∼141°). This novel setup allows us to probe a wide range of wave vectors q for investigation of phonon dispersion on, for example, crystals with large unit cells (on the scale of hundreds of nm)

  16. Brillouin-scattering determination of the acoustic properties and their pressure dependence for three polymeric elastomers

    Science.gov (United States)

    Stevens, Lewis L.; Orler, E. Bruce; Dattelbaum, Dana M.; Ahart, Muhtar; Hemley, Russell J.

    2007-09-01

    The acoustic properties of three polymer elastomers, a cross-linked poly(dimethylsiloxane) (Sylgard® 184), a cross-linked terpolymer poly(ethylene-vinyl acetate-vinyl alcohol), and a segmented thermoplastic poly(ester urethane) copolymer (Estane® 5703), have been measured from ambient pressure to approximately 12GPa by using Brillouin scattering in high-pressure diamond anvil cells. The Brillouin-scattering technique is a powerful tool for aiding in the determination of equations of state for a variety of materials, but to date has not been applied to polymers at pressures exceeding a few kilobars. For the three elastomers, both transverse and longitudinal acoustic modes were observed, though the transverse modes were observed only at elevated pressures (>0.7GPa) in all cases. From the Brillouin frequency shifts, longitudinal and transverse sound speeds were calculated, as were the C11 and C12 elastic constants, bulk, shear, and Young's moduli, and Poisson's ratios, and their respective pressure dependencies. P-V isotherms were then constructed, and fit to several empirical/semiempirical equations of state to extract the isothermal bulk modulus and its pressure derivative for each material. Finally, the lack of shear waves observed for any polymer at ambient pressure, and the pressure dependency of their appearance is discussed with regard to instrumental and material considerations.

  17. [A Brillouin Scattering Spectrum Feature Extraction Based on Flies Optimization Algorithm with Adaptive Mutation and Generalized Regression Neural Network].

    Science.gov (United States)

    Zhang, Yan-jun; Liu, Wen-zhe; Fu, Xing-hu; Bi, Wei-hong

    2015-10-01

    According to the high precision extracting characteristics of scattering spectrum in Brillouin optical time domain reflection optical fiber sensing system, this paper proposes a new algorithm based on flies optimization algorithm with adaptive mutation and generalized regression neural network. The method takes advantages of the generalized regression neural network which has the ability of the approximation ability, learning speed and generalization of the model. Moreover, by using the strong search ability of flies optimization algorithm with adaptive mutation, it can enhance the learning ability of the neural network. Thus the fitting degree of Brillouin scattering spectrum and the extraction accuracy of frequency shift is improved. Model of actual Brillouin spectrum are constructed by Gaussian white noise on theoretical spectrum, whose center frequency is 11.213 GHz and the linewidths are 40-50, 30-60 and 20-70 MHz, respectively. Comparing the algorithm with the Levenberg-Marquardt fitting method based on finite element analysis, hybrid algorithm particle swarm optimization, Levenberg-Marquardt and the least square method, the maximum frequency shift error of the new algorithm is 0.4 MHz, the fitting degree is 0.991 2 and the root mean square error is 0.024 1. The simulation results show that the proposed algorithm has good fitting degree and minimum absolute error. Therefore, the algorithm can be used on distributed optical fiber sensing system based on Brillouin optical time domain reflection, which can improve the fitting of Brillouin scattering spectrum and the precision of frequency shift extraction effectively.

  18. Photonic methods of millimeter-wave generation based on Brillouin fiber laser

    Science.gov (United States)

    Al-Dabbagh, R. K.; Al-Raweshidy, H. S.

    2016-05-01

    In optical communication link, generation and delivering millimeter-wave (mm-waves) in radio over fiber (RoF) systems has limitation due to fiber non-linearity effects. To solve this problem, photonic methods of mm-wave generation based on characterizations of Brillouin fiber laser are proposed in this work for the first time. Three novel photonic approaches for mm-wave generation methods based on Brillouin fiber laser and phase modulator are proposed and demonstrated by simulation. According to our theoretical analysis and simulation, mm-waves with frequency up to 80 GHz and good signal to noise ratio (SNR) up to 90 dB are generated by new and cost effective methods of generation that make them suitable for applications of the fifth generation (5G) networks. The proposed configurations increase the stability and the quality of the mm-wave generation system by using a single laser source as a pump wave and the fiber non-linearity effects are reduced. A key advantage of this research is that proposed a number of very simple generation methods and cost effective which only use standard components of optical telecommunications. Stimulated Brillouin Scattering (SBS) effect that exists in the optical fiber is studied with the characterization of phase modulator. An all optically stable mm-wave carriers are achieved successfully in the three different methods with different frequencies from 20 GHz up to 80 GHz. Simulation results show that all these carriers have low phase noise, good SNR ranging between 60 and 90 dB and tuning capability in comparison with previous methods reported. This makes them suitable for mm-wave transmission in RoF systems to transmit data in the next generation networks.

  19. Reduced Brillouin scattering from multiline CO2 laser interaction with a plasma

    Science.gov (United States)

    Giles, R.; Fedosejevs, R.; Offenberger, A. A.

    1982-08-01

    Experimental verification of reduced stimulated Brillouin scattering (SBS) is reported for multiline CO2 laser radiation interacting with high-density plasma. For long-pulse (40-nsec) irradiation SBS was observed to decrease from 15% to a negligible level when the spectrum of the incident laser pulse was changed from 1 to 2 or more well-separated frequencies. Results for both long- and short-pulse multiline laser conditions are in general accord with the expected behavior for varying Δωγ0, where Δω is the frequency separation and γ0 is the homogeneous growth rate.

  20. Pressure dependence of acoustic anomalies of polydimethylsiloxane studied by Brillouin spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seonhyeop [Department of Physics, Hallym University, Chuncheon, Gangwondo 200-702, South Korea (Korea, Republic of); Ko, Jae-Hyeon, E-mail: hwangko@hallym.ac.kr [Department of Physics, Hallym University, Chuncheon, Gangwondo 200-702, South Korea (Korea, Republic of); Park, Jaehoon [Department of Electronic Engineering, Hallym University, Chuncheon, Gangwondo 200-702 (Korea, Republic of); Ko, Young Ho; Kim, Kwang Joo [4-2-2, Agency for Defense Development, P.O. Box 35, Yuseong, Daejeon 305-600 (Korea, Republic of)

    2015-06-15

    The acoustic properties of polydimethylsiloxane elastomer was investigated as a function of pressure by using a multi-pass Fabry–Perot interferometer and a diamond anvil cell. Pressure dependence of the sound velocity, the Brillouin linewidth, and the refractive index was determined up to ~8.7 GPa. Acoustic properties exhibited a crossover behavior at approximately 1 GPa, which was attributed to the complete collapse of the free volume content in this polymer. The refractive index increased from 1.46 at ambient condition to ~1.63 at 8.67 GPa, which reflected the corresponding increase in density.

  1. Analysis of stimulated Brillouin scattering in multi-mode fiber by numerical solution

    Institute of Scientific and Technical Information of China (English)

    周涛; 陈军

    2003-01-01

    Stimulated Brillouin scattering in optical fibers is described by a theoretical model and numerical analysis. The results showed that, for an optical fiber pumped by a laser beam with ns-order-pulse width and kW-order peak-power, SBS reflectivity tends to saturate when the fiber length exceeds a limit, named "effective fiber length". Using small core-diameter and long enough fiber, the SBS reflectivity level could be raised but is limited by optical damage of the entrance surface of the fiber. Therefore, just a small dynamic range can be obtained.

  2. A distributed fiber optic sensor system for dike monitoring using Brillouin optical frequency domain analysis

    Science.gov (United States)

    Nöther, Nils; Wosniok, Aleksander; Krebber, Katerina; Thiele, Elke

    2008-03-01

    We report on the development of a complete system for spatially resolved detection of critical soil displacement in river embankments. The system uses Brillouin frequency domain analysis (BOFDA) for distributed measurement of strain in silica optical fibers. Our development consists of the measurement unit, an adequate coating for the optical fibers and a technique to integrate the coated optical fibers into geotextiles as they are commonly used in dike construction. We present several laboratory and field tests that prove the capability of the system to detect areas of soil displacement as small as 2 meters. These are the first tests of truly distributed strain measurements on optical fibers embedded into geosynthetics.

  3. Distributed Strain Measurement along a Concrete Beam via Stimulated Brillouin Scattering in Optical Fibers

    Directory of Open Access Journals (Sweden)

    Romeo Bernini

    2011-01-01

    Full Text Available The structural strain measurement of tension and compression in a 4 m long concrete beam was demonstrated with a distributed fiber-optic sensor portable system based on Brillouin scattering. Strain measurements provided by the fiber-optic sensor permitted to detect the formation of a crack in the beam resulting from the external applied load. The sensor system is valuable for structural monitoring applications, enabling the long-term performance and health of structures to be efficiently monitored.

  4. Suppression of stimulated Brillouin scattering with phase modulator in soliton pulse compression

    Institute of Scientific and Technical Information of China (English)

    Bo Lü; Taorong Gong; Ming Chen; Muguang Wang; Tangjun Li; Genxiang Chen; Shuisheng Jian

    2009-01-01

    A phase modulator is employed in the scheme of soliton pulse compression with dispersion shifted fiber (DSF). Stimulated Brillouin scattering (SBS) effect, as a negative influence here, can be dramatically suppressed after optical phase modulation. The experimental result shows that the launched power required for high-order soliton pulse compression has been significantly increased by 11 dB under the condition of 100-MHz phase modulation. Accordingly, the experiment of picosecond pulse compression generated from electro-absorption sampling window (EASW) has also been implemented.

  5. Triple-resonant Brillouin light scattering in magneto-optical cavities

    CERN Document Server

    Haigh, J A; Ramsay, A J; Ferguson, A J

    2016-01-01

    An enhancement in Brillouin light scattering of optical photons with magnons is demonstrated in magneto-optical whispering gallery mode resonators tuned to a triple resonance point. This occurs when both the input and output optical modes are resonant with those of the whispering gallery resonator, with a separation given by the ferromagnetic resonance (FMR) frequency. The identification and excitation of specific optical modes allows us to gain a clear understanding of the mode-matching conditions. A selection rule due to wavevector matching leads to an intrinsic single-sideband excitation. Strong suppression of one sideband is essential for one-to-one frequency mapping in coherent optical-to-microwave conversion.

  6. High-pressure acoustic properties of glycerol studied by Brillouin spectroscopy

    Science.gov (United States)

    Jeong, Min-Seok; Ko, Jae-Hyeon; Ko, Young Ho; Kim, Kwang Joo

    2015-12-01

    Acoustic properties of glycerol was investigated in a wide pressure range from ambient pressure to 30.9 GPa by using a multi-pass Fabry-Perot interferometer and a diamond anvil cell. Pressure dependences of the sound velocity and the Brillouin linewidth showed substantial changes at low pressures below ~4 GPa. This was attributed to the coupling between the main structural relaxation process and the longitudinal acoustic waves. The pressure dependence of the refractive index and the density of glycerol could be obtained by using two scattering geometries and the Lorentz-Lorenz relation.

  7. High-pressure acoustic properties of glycerol studied by Brillouin spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Min-Seok [Department of Physics, Hallym University, Chuncheon, Gangwondo 200-702 (Korea, Republic of); Ko, Jae-Hyeon, E-mail: hwangko@hallym.ac.kr [Department of Physics, Hallym University, Chuncheon, Gangwondo 200-702 (Korea, Republic of); Ko, Young Ho; Kim, Kwang Joo [Agency for Defense Development, 4-2-2, P.O. Box 35, Yuseong, Daejeon 305-600 (Korea, Republic of)

    2015-12-01

    Acoustic properties of glycerol was investigated in a wide pressure range from ambient pressure to 30.9 GPa by using a multi-pass Fabry–Perot interferometer and a diamond anvil cell. Pressure dependences of the sound velocity and the Brillouin linewidth showed substantial changes at low pressures below ~4 GPa. This was attributed to the coupling between the main structural relaxation process and the longitudinal acoustic waves. The pressure dependence of the refractive index and the density of glycerol could be obtained by using two scattering geometries and the Lorentz–Lorenz relation.

  8. Elastic properties of aspirin in its crystalline and glassy phases studied by micro-Brillouin scattering

    Science.gov (United States)

    Ko, Jae-Hyeon; Lee, Kwang-Sei; Ike, Yuji; Kojima, Seiji

    2008-11-01

    The acoustic waves propagating along the direction perpendicular to the (1 0 0) cleavage plane of aspirin crystal were investigated using micro-Brillouin spectroscopy from which C11, C55 and C66 were obtained. The temperature dependence of the longitudinal acoustic waves could be explained by normal anharmonic lattice models, while the transverse acoustic waves showed an abnormal increase in the hypersonic attenuation at low temperatures indicating their coupling to local remnant dynamics. The sound velocity as well as the attenuation of the longitudinal acoustic waves of glassy aspirin showed a substantial change at ˜235 K confirming a transition from glassy to supercooled liquid state in vitreous aspirin.

  9. Assessing the effect of a high-fat diet on rodents' adipose tissue using Brillouin and Raman spectroscopy

    Science.gov (United States)

    Troyanova-Wood, Maria; Gobbell, Cassidy; Meng, Zhaokai; Yakovlev, Vladislav V.

    2016-03-01

    The purpose of this study is to evaluate the effect of a high-lipid diet on elasticity of adipose tissue. We employed dual Raman/Brillouin microspectroscopy to analyze brown and white adipose tissues obtained from adult rats. The rats were divided into two groups, one of which received a high-fat feed, while the other served as a control. We hypothesized that the changes in the elasticity of adipose tissues between the two groups can be successfully assessed using Brillouin spectroscopy. We found that the brown adipose tissue possessed a lesser Brillouin shift than the white adipose within each group and that the elastic modulus of both adipose tissues increases in the high-fat diet group. The Raman spectra provided supplementary chemical information and indicated an increase in the lipid-to-protein ratio in the brown adipose, but not in the white adipose.

  10. Multi-parameter sensor based on stimulated Brillouin scattering in inverse-parabolic graded-index fiber.

    Science.gov (United States)

    Xu, Yanping; Ren, Meiqi; Lu, Yang; Lu, Ping; Lu, Ping; Bao, Xiaoyi; Wang, Lixian; Messaddeq, Younès; LaRochelle, Sophie

    2016-03-15

    We propose a unique multi-parameter optical fiber sensor based on intramodal stimulated Brillouin scattering of higher-order acoustic modes in inverse-parabolic graded-index fiber (IPGIF) without a mode converter. Both optical modes and acoustic modes guided in the IPGIF are characterized and demonstrated theoretically and experimentally. Simulation analysis shows that the multi-peak feature in the Brillouin gain spectrum of the IPGIF is attributed to the couplings between the guided optical mode and the higher-order acoustic modes. Thanks to the distinct acoustic properties of the peaks induced by the sharp refractive index profile of the IPGIF, the different temperature and strain dependences of the first three Brillouin peaks enable the discrimination of the temperature and strain at an accuracy of 0.85°C and 17.4 με.

  11. Dual-frequency Brillouin fiber laser for optical generation of tunable low-noise radio frequency/microwave frequency.

    Science.gov (United States)

    Geng, Jihong; Staines, Sean; Jiang, Shibin

    2008-01-01

    We demonstrate a new approach, i.e., a cw dual-frequency Brillouin fiber laser pumped by two independent single-frequency Er-doped fiber lasers, for the generation of tunable low-noise rf/microwave optical signals. Its inherent features of both linewidth narrowing effect in a Brillouin fiber cavity and common mode noise cancellation between two laser modes sharing a common cavity allow us to achieve high frequency stability without using a supercavity. Beat frequency of the dual-frequency Brillouin fiber laser can be tuned from tens of megahertz up to 100 GHz by thermally tuning the wavelengths of the two pump lasers with tuning sensitivity of approximately 1.4 GHz/ degrees C. Allan variance measurements show the beat signals have the hertz-level frequency stability.

  12. Precise Determination of Brillouin Scattering Spectrum Using a Virtually Imaged Phase Array (VIPA) Spectrometer and Charge-Coupled Device (CCD) Camera.

    Science.gov (United States)

    Meng, Zhaokai; Yakovlev, Vladislav V

    2016-08-01

    Brillouin spectroscopy is an emerging tool for microscopic optical imaging as it allows noninvasive assessment of viscoelastic properties of materials. The use of atomic-molecular absorption cells as ultra-narrow notch filters allows acquisition of Brillouin spectra from turbid samples despite their strong elastic scattering. However, such systems alter the shapes of the Brillouin lines, making the precise determination of the Brillouin shift difficult. In this report, we propose a simple method for analyzing the Brillouin spectrum using a customized least-square fitting algorithm. The absorption spectrum induced by the atomic-molecular cell was taken into consideration. The capability of the method is confirmed by processing experimental spectroscopic data from the pure water at different temperatures. The accuracy of the measurements of ±1 MHz spectral line shift is experimentally demonstrated.

  13. Theoretical demonstration of Brillouin lasing effect in racetrack resonators based on germanium waveguides in the mid-infrared.

    Science.gov (United States)

    De Leonardis, Francesco; Troia, Benedetto; Soref, Richard A; Passaro, Vittorio M N

    2016-01-15

    In this Letter, we present a theoretical investigation of integrated racetrack Brillouin lasers based on germanium waveguides that are buried in silicon nitride and operate at a wavelength of 4 μm. General design equations in a steady-state regime have been carried out to determine the threshold power and the emitted Stokes power as a function of the resonance mismatch and coupling factor. The pulling effect as induced by the Brillouin gain dispersion and the pushing effects originated by SPM and XPM effects have been accurately investigated to predict the lasing frequency.

  14. Raman-assisted Brillouin optical time-domain analysis with sub-meter resolution over 100 km.

    Science.gov (United States)

    Angulo-Vinuesa, X; Martin-Lopez, S; Corredera, P; Gonzalez-Herraez, M

    2012-05-21

    Sub-meter resolution in long-distance Brillouin Optical Time Domain Analysis (BOTDA) cannot be trivially achieved due to several issues including: resolution-uncertainty trade-offs, self-phase modulation, fiber attenuation, depletion, etc. In this paper we show that combining Raman assistance, differential pulse-width pair (DPP) measurements and a novel numerical de-noising procedure, we could obtain sub-meter resolution Brillouin optical time-domain analysis over a range of 100 km. We successfully demonstrate the detection of a 0.5 meter hot-spot in the position of worst contrast along the fiber.

  15. Spatial structure and coherence properties of Brillouin scatter from CO2 laser-target interaction

    Science.gov (United States)

    Mitchel, G. R.; Grek, B.; Johnston, T. W.; Pépin, H.; Church, P.; Martin, F.

    1982-05-01

    The spatial structure and coherence properties of 10.6-μm light scattered from CO2 laser-target interactions in oblique incidence show many unexpected features. It is found that the Brillouin backscatter is neither a phase conjugate nor a ray retrace of the incident beam. Rather, it shows a preference for scattering directions other than those exactly antiparallel to the incident beam, apparently related to the angular distribution of the scattering source and also of the plasma corona that serves as the Brillouin amplifying medium. As well, the backscatter phasefront is strongly perturbed with respect to the incident phasefront. This is an indication of turbulence in the corona and/or memory of the structure in the source that is then amplified. Small-scale structures seen in the reimaged backscatter are due to phase perturbation and cannot be simply interpreted as geometric images of a (filamented) source. The phasefront of light that is scattered obliquely from the plasma is much more coherent.

  16. Bandwidth-tunable narrowband rectangular optical filter based on stimulated Brillouin scattering in optical fiber.

    Science.gov (United States)

    Wei, Wei; Yi, Lilin; Jaouën, Yves; Hu, Weisheng

    2014-09-22

    We propose a rectangular optical filter based on stimulated Brillouin scattering (SBS) in optical fiber with bandwidth tuning from 50 MHz to 4 GHz at less than 15-MHz resolution. The rectangular shape of the filter is precisely achieved utilizing digital feedback control of the comb-like pump spectral lines. The passband ripple is suppressed to ~1 dB by mitigating the nonlinearity influences of the comb-like pump lines generated in electrical and optical components and fibers. Moreover a fiber with a single Brillouin peak is employed to further reduce the in-band ripple and the out-of-band SBS gain at the same time. Finally, we analyze the noise performance of the filter at different bandwidth cases and demonstrate the system performance of the proposed filter with 2.1-GHz bandwidth and 19-dB gain by amplifying a 2-GHz orthogonal frequency-division-multiplexing (OFDM) signal with quadrature-phase-shift-keying (QPSK) and 16-quadrature-amplitude-modulation (16-QAM) on each subscriber.

  17. Stability of Brillouin flow in the presence of slow-wave structure

    Science.gov (United States)

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Hoff, B.; Gilgenbach, R. M.

    2016-09-01

    Including a slow-wave structure (SWS) on the anode in the conventional, planar, and inverted magnetron, we systematically study the linear stability of Brillouin flow, which is the prevalent flow in crossed-field devices. The analytic treatment is fully relativistic and fully electromagnetic, and it incorporates the equilibrium density profile, flow profile, and electric field and magnetic field profiles in the linear stability analysis. Using parameters similar to the University of Michigan's recirculating planar magnetron, the numerical data show that the resonant interaction of the vacuum circuit mode and the corresponding smooth-bore diocotron-like mode is the dominant cause for instability. This resonant interaction is far more important than the intrinsic negative (positive) mass property of electrons in the inverted (conventional) magnetron geometry. It is absent in either the smooth-bore magnetron or under the electrostatic assumption, one or both of which was almost always adopted in prior analytical formulation. This resonant interaction severely restricts the wavenumber for instability to the narrow range in which the cold tube frequency of the SWS is within a few percent of the corresponding smooth bore diocotron-like mode in the Brillouin flow.

  18. Attometer resolution spectral analysis based on polarization pulling assisted Brillouin scattering merged with heterodyne detection.

    Science.gov (United States)

    Preussler, Stefan; Schneider, Thomas

    2015-10-05

    Spectral analysis is essential for measuring and monitoring advanced optical communication systems and the characterization of active and passive devices like amplifiers, filters and especially frequency combs. Conventional devices have a limited resolution or tuning range. Therefore, the true spectral shape of the signal remains hidden. In this work, a small part of the signal under test is preselected with help of the polarization pulling effect of stimulated Brillouin scattering where all unwanted spectral components are suppressed. Subsequently, this part is analyzed more deeply through heterodyne detection. Thereby, the local oscillator is generated from a narrow linewidth fiber laser which acts also as pump wave for Brillouin scattering. By scanning the pump wave together with the local oscillator through the signal spectrum, the whole signal is measured. The method is tunable over a broad wavelength range, is not affected by unwanted mixing products and utilizes a conventional narrow bandwidth photo diode. First proof of concept experiments show the measurement of the power spectral density function with a resolution in the attometer or lower kilohertz range at 1550 nm.

  19. Phase-locking and Pulse Generation in Multi-Frequency Brillouin Oscillator via Four Wave Mixing

    Science.gov (United States)

    Büttner, Thomas F. S.; Kabakova, Irina V.; Hudson, Darren D.; Pant, Ravi; Poulton, Christopher G.; Judge, Alexander C.; Eggleton, Benjamin J.

    2014-05-01

    There is an increasing demand for pulsed all-fibre lasers with gigahertz repetition rates for applications in telecommunications and metrology. The repetition rate of conventional passively mode-locked fibre lasers is fundamentally linked to the laser cavity length and is therefore typically ~10-100 MHz, which is orders of magnitude lower than required. Cascading stimulated Brillouin scattering (SBS) in nonlinear resonators, however, enables the formation of Brillouin frequency combs (BFCs) with GHz line spacing, which is determined by the acoustic properties of the medium and is independent of the resonator length. Phase-locking of such combs therefore holds a promise to achieve gigahertz repetition rate lasers. The interplay of SBS and Kerr-nonlinear four-wave mixing (FWM) in nonlinear resonators has been previously investigated, yet the phase relationship of the waves has not been considered. Here, we present for the first time experimental and numerical results that demonstrate phase-locking of BFCs generated in a nonlinear waveguide cavity. Using real-time measurements we demonstrate stable 40 ps pulse trains with 8 GHz repetition rate based on a chalcogenide fibre cavity, without the aid of any additional phase-locking element. Detailed numerical modelling, which is in agreement with the experimental results, highlight the essential role of FWM in phase-locking of the BFC.

  20. A systematic study of Rayleigh-Brillouin scattering in air, N2 and O2 gases

    CERN Document Server

    Gu, Ziyu

    2014-01-01

    Spontaneous Rayleigh-Brillouin scattering experiments in air, N2 and O2 have been performed for a wide range of temperatures and pressures at a wavelength of 403 nm and at a 90 degrees scattering angle. Measurements of the Rayleigh-Brillouin spectral scattering profile were conducted at high signal-to-noise ratio for all three species, yielding high-quality spectra unambiguously showing the small differences between scattering in air, and its constituents N2 and O2. Comparison of the experimental spectra with calculations using the Tenti S6 model, developed in 1970s based on linearized kinetic equations for molecular gases, demonstrates that this model is valid to high accuracy. After previous measurements performed at 366 nm, the Tenti S6 model is here verified for a second wavelength of 403 nm. Values for the bulk viscosity for the gases are derived by optimizing the model to the measurements. It is verified that the bulk viscosity parameters obtained from previous experiments at 366 nm, are valid for wavel...

  1. Study on two-cell stimulated Brillouin scattering system with mixture medium

    Institute of Scientific and Technical Information of China (English)

    HASI Wuliji; L(U) ZhiWei; LI Qiang; BA DeXin; HE WeiMing

    2007-01-01

    In this paper, a method of choosing mixture medium in two-cell stimulated Brillouin scattering (SBS) system to improve the system performance is proposed. The Brillouin frequency shift (BFS) of mixture medium varies with the mixing ratio and thus the difference of the BFS between the two cells can be eliminated. The two-cell SBS system with acetone (C3H6O) in its generator cell and mixture liquid of CCl4/C2Cl4 in its amplifier cell is investigated. The C3H6O has a high optical break- down threshold and the mixture liquid of CCl4/C2Cl4 has a small absorption coefficient and the same BFS as that of C3H6O when the volume fraction of CCl4 is 4%. Compared with two-cell SBS system with the same liquid (C2Cl4) or different liquid (C3H6O and C2Cl4) in generator and amplifier cell, the SBS system with mixture liquid (CCl4/C2Cl4) in amplifier cell and C3H6O in generator cell improves the power-load, energy reflectivity (ER), phase conjugation (PC) fidelity and ER stability.

  2. A microrod-resonator Brillouin laser with 240 Hz absolute linewidth

    CERN Document Server

    Loh, William; Cole, Daniel C; Coillet, Aurelien; Baynes, Fred N; Papp, Scott B; Diddams, Scott A

    2015-01-01

    We demonstrate an ultralow-noise microrod-resonator based laser that oscillates on the gain supplied by the stimulated Brillouin scattering optical nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding frequency noise floor, which is limited by fundamental thermal fluctuations. Here, we show experimental evidence that thermal effects also dominate the close-to-carrier frequency fluctuations. The 6-mm diameter microrod resonator used in our experiments has a large optical mode area of ~100 {\\mu}m$^2$, and hence its 10 ms thermal time constant filters the close-to-carrier optical frequency noise. The result is an absolute laser linewidth of 240 Hz with a corresponding white-frequency noise floor of 0.1 Hz$^2$/Hz. We explain the steady-state performance of this laser by measurements of its operation state and of its mode detuning and lineshape. Our results highlight a mechanism for noise that is common to many microresonator devices due to the inherent coupling between intracavity power...

  3. Research on Structural Stress Optical Fiber Testing Technology Based on Brillouin Scattering

    Directory of Open Access Journals (Sweden)

    Wang Xian-Jin

    2016-01-01

    Full Text Available In this paper, the principle of distributed optical fiber measurement and measurement of axial stress is introduced by analyzing the principle of Brillouin scattering in an optical fiber with a certain power. Making the experimental device, measuring the individual strain model, analyzing the wave shape of the scattered wave, and preliminary understanding of the image characteristics of the stress in the optical fiber Brillouin scattering spectrum. The effect of stress on the different position of the fiber, and the difference between them and the scattering waveform obtained from the stress free action poetry are compared, and the effect of the light pulse on the optical fiber transmission is studied. The results show that the effect of the stress is different in the position of the action, and the effect of the propagation of the pulse light is mainly affected by the Stokes and anti Stokes light scattering. The research can provide reference for distributed optical fiber measurement, and it can promote the application of distributed optical fiber in measuring micro deformation. The innovative point of this study is to use the pulley method to solve the effect of the different position of the same stress in the distribution of optical fiber.

  4. Suppression of Brillouin scattering in fibre-optical parametric amplifier by applying temperature control and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2009-01-01

    An increased gain in a fibre-optical parametric amplifier through suppression of stimulated Brillouin scattering is demonstrated by applying a temperature distribution along the fibre for a fixed phase modulation of the pump. The temperature distribution slightly impacts the gain spectrum....

  5. Effect of the magnetic field on coexisting stimulated Raman and Brillouin backscattering of an extraordinary mode

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, Ashish, E-mail: ashishvyas.optics@gmail.com; Singh, Ram Kishor, E-mail: ram007kishor@gmail.com; Sharma, R. P., E-mail: rpsharma@ces.iitd.ernet.in [Centre for Energy Studies, IIT Delhi, Delhi 110016 (India)

    2016-01-15

    This paper presents a model to study the interplay between the stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in the presence of background magnetic field. This formalism is applicable to laser produced plasma as well as to heating mechanism in toroidal system by an extraordinary electromagnetic wave. In the former case, the magnetic field is self-generated, while in the latter case (toroidal plasmas) magnetic field is applied externally. The behavior of one scattering process is explicitly dependent on the coexisting scattering process as well as on the magnetic field. Explicit expressions for the back-reflectivity of scattered beams (SRS and SBS) are presented. It has been demonstrated that due to the magnetic field and coexistence of the scattering processes (SRS and SBS) the back-reflectivity gets modified significantly. Results are also compared with the three wave interaction case (isolated SRS or SBS case)

  6. Failure of relativistic codes in the non-relativistic limit: the role of Brillouin configurations

    CERN Document Server

    Indelicato, P J; Desclaux, J P

    2004-01-01

    In the present letter we solve a long standing problem with relativistic calculations done with the widely used Multi-Configuration Dirac-Fock Method. We show, using Relativistic Many-Body Perturbation Theory (RMBPT), how even for relatively high-$Z$, relaxation or correlation causes the non-relativistic limit of states of different total angular momentum but identical orbital angular momentum to have different energies. We identify the role of single excitations obeying to Brillouin's theorem in this problem. We show that with large scale calculations in which this problem is properly treated, we can reproduce very accurately recent high-precision measurements in F-like Ar, and turn then into precise test of QED

  7. Stimulated Brillouin scattering continuous wave phase conjugation in step-index fiber optics.

    Science.gov (United States)

    Massey, Steven M; Spring, Justin B; Russell, Timothy H

    2008-07-21

    Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber NA(2), but find that fidelity remains high over much longer fiber lengths than previous models calculated. Conditions for SBS beam cleanup in step-index fibers are discussed.

  8. Acoustic profilometry of interphases in epoxy due to segregation and diffusion using Brillouin microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, U; Bactavatchalou, R; Baller, J; Philipp, M; Sanctuary, R; Zielinski, B; Krueger, J K [Laboratoire de Physique des Materiaux, Universite du Luxembourg, 162A, Avenue de la Faiencerie, L-1115 Luxembourg (Luxembourg); Alnot, P; Possart, W [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (Germany)], E-mail: mail@tauron.de

    2008-02-15

    Reactive network forming polymer systems like epoxies are of huge technological interest because of their adhesive properties based on specific interactions with a large variety of materials. These specific interactions alter the morphology of the epoxy within areas determined by the correlation length of these interactions. The changed morphology leads to interphases with altered (mechanical) properties. Besides these surface-induced interphases, bulk interphases do occur due to segregation, crystallization, diffusion, etc. A new experimental technique to characterize such mechanical interphases is {mu}-Brillouin spectroscopy ({mu}-BS). With {mu}-BS, we studied interphases and their formation in epoxies due to segregation of the constituent components and due to selective diffusion of one component. In the latter case, we will demonstrate the influence of changing the boundary conditions of the diffusion process on the shape of the interphase.

  9. Brillouin backscattering from a double-pulse CO/sub 2/ laser incident on planar targets

    Energy Technology Data Exchange (ETDEWEB)

    Decoste, R.; Lavigne, P.; Pepin, H.; Mitchel, G.R.; Kieffer, J.

    1982-05-01

    The Brillouin backscattering instability is studied for a range of preformed plasma conditions and using a CO/sub 2/ laser in the 10/sup 12/--10/sup 13/ W/cm/sup 2/ regime. A short prepulse is incident on a planar target ahead of the main-pulse to produce the preformed plasma. The instability appears in a short burst of back-reflected light. Saturation of the backscatter level is observed for an individual increase of the prepulse energy, main-pulse intensity, and prepulse-to-main-pulse delay. Ion Landau damping is strong and average back-reflected intensities are limited to less than 30% of incident. Backscattered light spectra suggest that the critical surface is involved in the backscatter process when the laser beam is at best focus onto the target surface. Otherwise, the spectral signature is similar to those obtained from underdense plasmas.

  10. Stimulated Brillouin scattering gain bandwidth reduction and applications in microwave photonics and optical signal processing

    Science.gov (United States)

    Preussler, Stefan; Schneider, Thomas

    2016-03-01

    Stimulated Brillouin scattering (SBS) is one of the most dominant nonlinear effects in standard single-mode fibers and its unique spectral characteristics, especially the narrow bandwidth, enable many different applications. Most of the applications would benefit from a narrower bandwidth. Different methods for the bandwidth reduction of SBS in optical fibers are presented and discussed. A bandwidth reduction down to 17% of the natural gain can be achieved by the superposition of the gain with two losses or the utilization of a multistage system. Furthermore, applications in the field of microwave photonics and optical signal processing like high-resolution spectroscopy of communication signals, the storage of optical data packets as well as the processing of frequency combs including generation of millimeter waves and ideal sinc-shaped Nyquist pulses are presented.

  11. Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times

    Energy Technology Data Exchange (ETDEWEB)

    Korotkevich, Alexander O.; Lushnikov, Pavel M., E-mail: plushnik@math.unm.edu [Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Landau Institute for Theoretical Physics, 2 Kosygin Str., Moscow 119334 (Russian Federation); Rose, Harvey A. [Theoretical Division, Los Alamos National Laboratory, MS-B213, Los Alamos, New Mexico 87545 (United States); New Mexico Consortium, Los Alamos, New Mexico 87544 (United States)

    2015-01-15

    We developed a linear theory of backward stimulated Brillouin scatter (BSBS) of a spatially and temporally random laser beam relevant for laser fusion. Our analysis reveals a new collective regime of BSBS (CBSBS). Its intensity threshold is controlled by diffraction, once cT{sub c} exceeds a laser speckle length, with T{sub c} the laser coherence time. The BSBS spatial gain rate is approximately the sum of that due to CBSBS, and a part which is independent of diffraction and varies linearly with T{sub c}. The CBSBS spatial gain rate may be reduced significantly by the temporal bandwidth of KrF-based laser systems compared to the bandwidth currently available to temporally smoothed glass-based laser systems.

  12. Brillouin light scattering study of spin waves in NiFe/Co exchange spring bilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Haldar, Arabinda; Banerjee, Chandrima; Laha, Pinaki; Barman, Anjan, E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India)

    2014-04-07

    Spin waves are investigated in Permalloy(Ni{sub 80}Fe{sub 20})/Cobalt(Co) exchange spring bilayer thin films using Brillouin light scattering (BLS) experiment. The magnetic hysteresis loops measured by magneto-optical Kerr effect show a monotonic decrease in coercivity of the bilayer films with increasing Py thickness. BLS study shows two distinct modes, which are modelled as Damon-Eshbach and perpendicular standing wave modes. Linewidths of the frequency peaks are found to increase significantly with decreasing Py layer thickness. Interfacial roughness causes to fluctuate exchange coupling at the nanoscale regimes and the effect is stronger for thinner Py films. A quantitative analysis of the magnon linewidths shows the presence of strong local exchange coupling field which is much larger compared to macroscopic exchange field.

  13. Angle-resolved spin wave band diagrams of square antidot lattices studied by Brillouin light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gubbiotti, G.; Tacchi, S. [Istituto Officina dei Materiali del Consiglio Nazionale delle Ricerche (IOM-CNR), Sede di Perugia, c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, I-06123 Perugia (Italy); Montoncello, F.; Giovannini, L. [Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via G. Saragat 1, I-44122 Ferrara (Italy); Madami, M.; Carlotti, G. [Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06123 Perugia (Italy); Ding, J.; Adeyeye, A. O. [Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

    2015-06-29

    The Brillouin light scattering technique has been exploited to study the angle-resolved spin wave band diagrams of squared Permalloy antidot lattice. Frequency dispersion of spin waves has been measured for a set of fixed wave vector magnitudes, while varying the wave vector in-plane orientation with respect to the applied magnetic field. The magnonic band gap between the two most dispersive modes exhibits a minimum value at an angular position, which exclusively depends on the product between the selected wave vector magnitude and the lattice constant of the array. The experimental data are in very good agreement with predictions obtained by dynamical matrix method calculations. The presented results are relevant for magnonic devices where the antidot lattice, acting as a diffraction grating, is exploited to achieve multidirectional spin wave emission.

  14. Depolarized guided acoustic wave Brillouin scattering in hollow-core photonic crystal fibers

    CERN Document Server

    Zhong, Wenjia Elser née; Elser, Dominique; Heim, Bettina; Marquardt, Christoph; Leuchs, Gerd

    2015-01-01

    By performing quantum-noise-limited optical heterodyne detection, we observe polarization noise in light after propagation through a hollow-core photonic crystal fiber (PCF). We compare the noise spectrum to the one of a standard fiber and find an increase of noise even though the light is mainly transmitted in air in a hollow-core PCF. Combined with our simulation of the acoustic vibrational modes in the hollow-core PCF, we are offering an explanation for the polarization noise with a variation of guided acoustic wave Brillouin scattering (GAWBS). Here, instead of modulating the strain in the fiber core as in a solid core fiber, the acoustic vibrations in hollow-core PCF influence the effective refractive index by modulating the geometry of the photonic crystal structure. This induces polarization noise in the light guided by the photonic crystal structure.

  15. Ultra-high Q sphere-like cavities for cascaded stimulated Brillouin lasing

    Science.gov (United States)

    Che, Kaijun; Zhang, Pan; Guo, Changlei; Tang, Deyu; Ren, Changyan; Xu, Huiying; Luo, Zhengqian; Cai, Zhiping

    2017-03-01

    High Q microsphere optical cavity is usually fabricated from a single mode fiber. Here, we propose a new method to fabricate sphere-like cavity by melting the tip of rotating quartz-rod with a CO2 laser. The cavities with diameter from 200 μm to 700 μm and resonant Q factors above 108 are obtained. Due to the rich resonances of the sphere-like cavity, up to 15-order cascaded stimulated Brillouin lasings(SBL) near 1.55 μm are observed in a cavity with a diameter of 760 μm by simply tuning the pump wavelength to a finely-selected resonance. We wish the ultra-high Q cavities with rich resonances and bulk rod mount can have practical applications in nonlinear optics and microwave photonics as an optical component.

  16. Brillouin-Wigner theory for Floquet topological phase transitions in spin-orbit-coupled materials

    Science.gov (United States)

    Mohan, Priyanka; Saxena, Ruchi; Kundu, Arijit; Rao, Sumathi

    2016-12-01

    We develop the high-frequency expansion based on the Brillouin-Wigner (B-W) perturbation theory for driven systems with spin-orbit coupling which is applicable to the cases of silicene, germanene, and stanene. We compute the effective Hamiltonian in the zero-photon subspace not only to order O (ω-1) but by keeping all the important terms to order O (ω-2) and obtain the photoassisted correction terms to both the hopping and the spin-orbit terms, as well as longer-ranged hopping terms. We then use the effective static Hamiltonian to compute the phase diagram in the high-frequency limit and compare it with the results of direct numerical computation of the Chern numbers of the Floquet bands and show that at sufficiently large frequencies, the B-W theory high-frequency expansion works well even in the presence of spin-orbit-coupling terms.

  17. Paraxial Wentzel-Kramers-Brillouin method applied to the lower hybrid wave propagation

    Energy Technology Data Exchange (ETDEWEB)

    Bertelli, N.; Phillips, C. K.; Valeo, E.; Wilson, J. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Maj, O.; Poli, E. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748, Garching (Germany); Harvey, R. [CompX, Del Mar, California 92014 (United States); Wright, J. C.; Bonoli, P. T. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Smirnov, A. P. [Lomonosov Moscow State University, Moscow (Russian Federation)

    2012-08-15

    The paraxial Wentzel-Kramers-Brillouin (pWKB) approximation, also called beam tracing method, has been employed in order to study the propagation of lower hybrid waves in a tokamak plasma. Analogous to the well-know ray tracing method, this approach reduces Maxwell's equations to a set of ordinary differential equations, while, in addition, retains the effects of the finite beam cross-section, and, thus, the effects of diffraction. A new code, LHBEAM (lower hybrid BEAM tracing), is presented, which solves the pWKB equations in tokamak geometry for arbitrary launching conditions and for analytic and experimental plasma equilibria. In addition, LHBEAM includes linear electron Landau damping for the evaluation of the absorbed power density and the reconstruction of the wave electric field in both the physical and Fourier space. Illustrative LHBEAM calculations are presented along with a comparison with the ray tracing code GENRAY and the full wave solver TORIC-LH.

  18. Stimulated Brillouin scattering mirror system, high power laser and laser peening method and system using same

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2007-04-24

    A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

  19. Method for pulse control in a laser including a stimulated brillouin scattering mirror system

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2007-10-23

    A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

  20. Highly precise distributed Brillouin scattering sensor for structural health monitoring of optical ground wire cable

    Science.gov (United States)

    Zou, Lufan; Ravet, Fabien; Bao, Xiaoyi; Chen, Liang

    2004-07-01

    A distributed Brillouin scattering sensor with high special precision has been developed for the measurement of small damages/cracks of 1.5 cm. The out-layer damaged regions in an optical ground wire (OPGW) cable have been identified successfully by measuring the strain distributions every 5 cm using this technology. The stress increased to 127 kN which corresponds to more than 7500 micro-strain in the fibers. The locations of structural indentations comprising repaired and undamaged regions are found and distinguished using their corresponding strain data. The elongation of repaired region increases with time on 127 kN. These results are quantified in terms of the fiber orientation, stress, and behavior relative to undamaged sections.

  1. Influence of medium parameters on power limiting characteristic in stimulated Brillouin scattering process

    Institute of Scientific and Technical Information of China (English)

    Huaping Gong; Zhiwei Lü; Dianyang Lin; Songjiang Liu

    2007-01-01

    By adopting noise initiation model of stimulated Brillouin scattering (SBS), the influence of phonon lifetime and gain coefficient of medium on power limiting characteristic is numerically investigated. Through using actual parameters of three media, CCl4, acetone, and CS2, the waveforms of transmitted pulses are simulated. The result shows that different media have little effect on the front peak of waveform,while have an obvious effect on the height of power limiting platform. When the medium which has short phonon lifetime and small gain coefficient is used, the height of power limiting platform is comparatively high. In experiment, by focusing 1064-nm, 8-ns, 18-mJ pulses into these three media, the waveforms of transmitted pulses are obtained. The experimental results are in good agreement with conclusions of theoretical simulations.

  2. Bayesian approach to the analysis of neutron Brillouin scattering data on liquid metals

    Science.gov (United States)

    De Francesco, A.; Guarini, E.; Bafile, U.; Formisano, F.; Scaccia, L.

    2016-08-01

    When the dynamics of liquids and disordered systems at mesoscopic level is investigated by means of inelastic scattering (e.g., neutron or x ray), spectra are often characterized by a poor definition of the excitation lines and spectroscopic features in general and one important issue is to establish how many of these lines need to be included in the modeling function and to estimate their parameters. Furthermore, when strongly damped excitations are present, commonly used and widespread fitting algorithms are particularly affected by the choice of initial values of the parameters. An inadequate choice may lead to an inefficient exploration of the parameter space, resulting in the algorithm getting stuck in a local minimum. In this paper, we present a Bayesian approach to the analysis of neutron Brillouin scattering data in which the number of excitation lines is treated as unknown and estimated along with the other model parameters. We propose a joint estimation procedure based on a reversible-jump Markov chain Monte Carlo algorithm, which efficiently explores the parameter space, producing a probabilistic measure to quantify the uncertainty on the number of excitation lines as well as reliable parameter estimates. The method proposed could turn out of great importance in extracting physical information from experimental data, especially when the detection of spectral features is complicated not only because of the properties of the sample, but also because of the limited instrumental resolution and count statistics. The approach is tested on generated data set and then applied to real experimental spectra of neutron Brillouin scattering from a liquid metal, previously analyzed in a more traditional way.

  3. Robust, Brillouin Active Embedded Fiber-Is-The-Sensor System in Smart Composite Structures

    Science.gov (United States)

    Yu, Chung

    1996-01-01

    Extensive review of our proposed sensing scheme, based mainly on the forward Guided Acoustic Wave Brillouin Scattering (GAWBS) with backward stimulated Brillouin scattering (sBs) as an auxiliary scheme for system fault tolerance has been completed during this project period. This preliminary study is conducted for a number of reasons. The most significant reasons lie in the essential capability of the system to measure temperature and pressure. These two measurands have been proposed to be sensed by sBs in our proposal. Temperature and pressure/strain are important measurands in structural monitoring, so that the effectiveness of sensing by sBs needs to be further examined. It has been pointed out initially that sBs shift will be dependent on temperature and pressure/strain simultaneously. The shift versus temperature or strain is linear. Now, the question is how can these two measurands be separated when sBs is used to sense an environment, in which both temperature and strain are changing simultaneously. Typical sBs shift plotted versus strain and varying temperature is shown in Fig. 1. As is clear, a fiber initially stressed will relax with rising temperature. This is verified by a displacement to the right with rising temperature of the sBs shift vs strain curves in the figure. A way to circumvent this ambiguity is by employing two fibers, one pre-stressed and the other is a free fiber. The latter will measure temperature and subtracting data in the latter fiber from those of the former will give us net strain readings. This is a laborious approach, since it involves the use of two identical fibers, and this is hard to accomplish, especially when many sensors are needed. Additional multiplexing of the data stream for data subtraction becomes a necessity.

  4. Spectrum parameter estimation in Brillouin scattering distributed temperature sensor based on cuckoo search algorithm combined with the improved differential evolution algorithm

    Science.gov (United States)

    Zhang, Yanjun; Yu, Chunjuan; Fu, Xinghu; Liu, Wenzhe; Bi, Weihong

    2015-12-01

    In the distributed optical fiber sensing system based on Brillouin scattering, strain and temperature are the main measuring parameters which can be obtained by analyzing the Brillouin center frequency shift. The novel algorithm which combines the cuckoo search algorithm (CS) with the improved differential evolution (IDE) algorithm is proposed for the Brillouin scattering parameter estimation. The CS-IDE algorithm is compared with CS algorithm and analyzed in different situation. The results show that both the CS and CS-IDE algorithm have very good convergence. The analysis reveals that the CS-IDE algorithm can extract the scattering spectrum features with different linear weight ratio, linewidth combination and SNR. Moreover, the BOTDR temperature measuring system based on electron optical frequency shift is set up to verify the effectiveness of the CS-IDE algorithm. Experimental results show that there is a good linear relationship between the Brillouin center frequency shift and temperature changes.

  5. Using Brillouin fiber-optic ring laser to provide base station with uplink optical carrier in a 10 GHz radio over fiber system

    Institute of Scientific and Technical Information of China (English)

    CHEN Hao-shuo; LIN Ru-jian; YE Jia-jun

    2009-01-01

    In this paper, a 10 GHz radio over fiber system is analyzed. The Brillouin fiber-optic ring laser is used in the center station (CS) to suppress the optical carrier for the modulation depth enhancement. Simultaneously, the Stockes waveinduced by the Brillouin amplification injects and locks the Fabry-Perot (FP) laser to output a signal-mode optical source,which works as the uplink optical carrier.

  6. A feature extraction method of the particle swarm optimization algorithm based on adaptive inertia weight and chaos optimization for Brillouin scattering spectra

    Science.gov (United States)

    Zhang, Yanjun; Zhao, Yu; Fu, Xinghu; Xu, Jinrui

    2016-10-01

    A novel particle swarm optimization algorithm based on adaptive inertia weight and chaos optimization is proposed for extracting the features of Brillouin scattering spectra. Firstly, the adaptive inertia weight parameter of the velocity is introduced to the basic particle swarm algorithm. Based on the current iteration number of particles and the adaptation value, the algorithm can change the weight coefficient and adjust the iteration speed of searching space for particles, so the local optimization ability can be enhanced. Secondly, the logical self-mapping chaotic search is carried out by using the chaos optimization in particle swarm optimization algorithm, which makes the particle swarm optimization algorithm jump out of local optimum. The novel algorithm is compared with finite element analysis-Levenberg Marquardt algorithm, particle swarm optimization-Levenberg Marquardt algorithm and particle swarm optimization algorithm by changing the linewidth, the signal-to-noise ratio and the linear weight ratio of Brillouin scattering spectra. Then the algorithm is applied to the feature extraction of Brillouin scattering spectra in different temperatures. The simulation analysis and experimental results show that this algorithm has a high fitting degree and small Brillouin frequency shift error for different linewidth, SNR and linear weight ratio. Therefore, this algorithm can be applied to the distributed optical fiber sensing system based on Brillouin optical time domain reflection, which can effectively improve the accuracy of Brillouin frequency shift extraction.

  7. Accuracy decline of the Brillouin optical time-domain analysis system induced by self-phase modulation

    Science.gov (United States)

    Zhou, Yuqing; Chen, Wei; Meng, Zhou

    2016-09-01

    The Brillouin optical time-domain analysis system (BOTDA) is a distributed optical fiber sensing system based on the measurement of the effective Brillouin gain, in which high power pumping pulse is demanded to fulfill optical time domain reflectometry (OTDR) spatial orientation. As for strict rectangular pulse, BGS can maintain Lorentz line profile along the sensor fiber, while the actual rectangular pulse has power transients like the rising edge and failing edge, making BGS broadened or even distorted by the effect of self-phase modulation (SPM), which will induce the decline of the measuring accuracy. A model concerning the effects of pumping pulse power transients on the BGS by means of SPM is established based on the nonlinear Schrodinger equation (NLSE) in regular single mode fiber (SMF).

  8. Determination of elastic, piezoelectric, and dielectric constants of an R: BaTiO3 single crystal by Brillouin scattering

    Institute of Scientific and Technical Information of China (English)

    He Xiao-Kang; Zeng Li-Bo; Wu Qiong-Shui; Zhang Li-Yan; Zhu Ke; Liu Yu-Long

    2012-01-01

    From the sound velocity measured using the Brillouin scattering technique,the elastic,piezoelectric,and dielectric constants of a high-quality monodomain tetragonal Rh:BaTiO3 single crystal are determined at room temperature.The elastic constants are in fairly good agreement with those of the BaTiO3 single crystal,measured previously by Brillouin scattering and the low-frequency equivalent circuit methods.However,their electromechanical properties are significantly different.Based on the sound propagation equations and these results,the directional dependence of the compressional modulus and the shear modulus of Rh:BaTiO3 in the (010) plane is investigated.Some properties of sound propagation and electromechanical coupling in the crystal are discussed.

  9. Stimulated Brillouin scattering in highly birefringent multimode tapered chalcogenide photonic crystal fiber for distributed optical sensors (Retraction Notice)

    Science.gov (United States)

    Baili, Amira; Cherif, Rim; Zghal, Mourad

    2016-09-01

    This paper, originally published on September 15, 2016, was retracted from the SPIE Digital Library on October 5, 2016, due to a high degree of similarity between specific portions of the text of the paper to the following publications: J. Tchahame, J. Beugnot, A. Kudlinski, and T. Sylvestre, "Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber," Opt. Lett. 40, 4281-4284 (2015). doi: 10.1364/OL.40.004281 W. W. Ke, X. J. Wang and X. Tang, "Stimulated Brillouin Scattering Model in Multi-Mode Fiber Lasers," in IEEE Journal of Selected Topics in Quantum Electronics, vol. 20, no. 5, pp. 305-314, Sept.-Oct. 2014. doi: 10.1109/JSTQE.2014.2303256.

  10. Effects of output coupler reflectivity on the performance of a linear cavity Brillouin/erbium fiber laser

    Indian Academy of Sciences (India)

    X S Cheng; S W Harun; H Ahmad

    2007-03-01

    The effect of output coupler reflectivity (or output coupling ratio) on the performance of a linear cavity Brillouin/erbium fiber laser (BEFL) is demonstrated. The operating wavelength, output laser power and number of channels vary with changes in the coupling ratio in the linear cavity system. The optimum BEFL operation is obtained with an output coupling of 40%, i.e., 60% of the laser power is allowed to oscillate in the cavity. A stable laser comb consisting of up to 40 channels with line spacings of approximately 0.09 nm are obtained at the Brillouin pump and 980 nm pump with powers of 2.5 mW and 100 mW, respectively. The linear cavity BEFL has the potential to be used in inexpensive wavelength division multiplexing system.

  11. Analytical expression of the magneto-optical Kerr effect and Brillouin light scattering intensity arising from dynamic magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Hamrle, Jaroslav [Centre for Advanced Innovation Technology, VSB-Technical University of Ostrava, 708 33 Ostrava-Poruba (Czech Republic); Pistora, JaromIr [Department of Physics, VSB-Technical University of Ostrava, 708 33 Ostrava-Poruba (Czech Republic); Hillebrands, Burkard [Fachbereich Physik and Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 56, D-67663 Kaiserslautern (Germany); Lenk, Benjamin; Muenzenberg, Markus, E-mail: jaroslav.hamrle@vsb.c [Institute of Physics, University of Goettingen, 37077 Goettingen (Germany)

    2010-08-18

    Time-resolved magneto-optical Kerr effect (MOKE) and Brillouin light scattering (BLS) spectroscopy are important techniques for the investigation of magnetization dynamics. In this paper, we analytically calculate the MOKE and BLS signals from prototypical spin-wave modes in a ferromagnetic layer. The reliability of the analytical expressions is confirmed by optically exact numerical calculations. Finally, we discuss the dependence of the MOKE and BLS signals on the ferromagnetic layer thickness.

  12. Brillouin/Raman compensation of the Kerr-effect-induced bias in a nonlinear ring laser gyroscope.

    Science.gov (United States)

    Luo, Zhang; Yuan, Xiaodong; Zhu, Zhihong; Liu, Ken; Ye, Weimin; Zeng, Chun; Ji, Jiarong

    2013-04-01

    In this Letter, the beat frequency at rest of a ring laser gyroscope with nonlinear effects is discussed in detail. Even without an additional intensity-stabilizing system, the random nullshift bias induced by the Kerr effect is compensated by the phase shift associated with the stimulated Brillouin/Raman scattering. And the nonlinear stimulated scattering also serves as the gain mechanism of the gyroscope. And thus the influence of the fluctuation of the injected pump intensity on the beat frequency is eliminated.

  13. Phenomenological model of stochastic, spatiotemporal, intensity dynamics of stimulated Brillouin scattering in a two-mode optical fiber.

    Science.gov (United States)

    Armstrong, Cameron R; David, John A; Thompson, John R

    2015-07-13

    We present a simple numerical model that is used in conjunction with a systematic algorithm for parameter optimization to understand the three-dimensional stochastic intensity dynamics of stimulated Brillouin scattering in a two-mode optical fiber. The primary factors driving the complex dynamics appear to be thermal density fluctuations, transverse pump fluctuations, and asymmetric transverse mode fractions over the beam cross-section.

  14. Couplage entre auto-focalisation et diffusion Brillouin stimulée pour une impulsion laser nanoseconde dans la silice

    OpenAIRE

    Mauger, Sarah

    2011-01-01

    As part of the studies on laser damage linked to the Megajoule project, we analyze the coupling between the Kerr induce self-focusing and the stimulated Brillouin backscattering pour nanosecond optical pulses propagating in silica samples. The influence of the incident power, phase or amplitude modulations as well as the spatial profile of the pulse of the filamentation dynamic is discussed. We show that an appropriate amplitude modulation dividing the incident pulse in pulse trains of picose...

  15. Tunable millimeter-wave frequency synthesis up to 100 GHz by dual-wavelength Brillouin fiber laser.

    Science.gov (United States)

    Gross, Michael C; Callahan, Patrick T; Clark, Thomas R; Novak, Dalma; Waterhouse, Rodney B; Dennis, Michael L

    2010-06-21

    We demonstrate the generation of microwave and millimeter-wave frequencies from 26 to 100 GHz by heterodyning the output modes of a dual-wavelength fiber laser based on stimulated Brillouin scattering. The output frequency is tunable in steps of 10.3 MHz, equal to the free spectral range of the resonator. The noise properties of the beat frequency indicate a microwave linewidth of <2 Hz. We discuss potential for operation into the terahertz regime.

  16. Brillouin distributed temperature sensing system for monitoring of submarine export cables of off-shore wind farms

    Science.gov (United States)

    Marx, Benjamin; Rath, Alexander; Kolm, Frederick; Schröder, Andreas; Buntebarth, Christian; Dreß, Albrecht; Hill, Wieland

    2016-05-01

    For high-voltage cables, the maximum temperature of the insulation must never be exceeded at any location and at any load condition. The local temperatures depend not only on the cable design and load history, but also on the local thermal environment of the cable. Therefore, distributed temperature monitoring of high-voltage cables is essential to ensure the integrity of the cable at high load. Especially, the load of the export cables of wind farms varies strongly in dependence on weather conditions. In this field study, we demonstrate the measurement performance of a new, robust Brillouin distributed temperature sensing system (Brillouin-DTS). The system is based on spontaneous Brillouin scattering and does not require a fibre loop. This is essential for long submarine high-voltage cables, where normally no loop can be formed in the seabed. It is completely passively cooled and does not contain any moving or wearing parts. The instrument is dedicated for use in industrial and other rough environments. With a measuring time below 10 min, the temperature resolution is better than 1 °C for distances up to 50 km. In the field study, the submarine export cable of an off-shore wind farm has been monitored. The temperature profile of the export cable shows several hot spots, mostly located at cable joints, and also several cold spots.

  17. Rayleigh-Brillouin scattering in SF6 in the kinetic regime

    Science.gov (United States)

    Wang, Yuanqing; Yu, Yin; Liang, Kun; Marques, Wilson; van de Water, Willem; Ubachs, Wim

    2017-02-01

    Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2-5 bar and for a wavelength of λ = 403.0 nm. The high quality data are compared to a number of light scattering models in order to address the effects of rotational and vibrational relaxation. While the vibrational relaxation rate is so slow that vibration degrees of freedom remain frozen, rotations relax on time scales comparable to those of the density fluctuations. Therefore, the heat capacity, the thermal conductivity and the bulk viscosity are all frequency-dependent transport coefficients. This is relevant for the Tenti model that depends on the values chosen for these transport coefficients. This is not the case for the other two models considered: a kinetic model based on rough-sphere interactions, and a model based on fluctuating hydrodynamics. The deviations with the experiment are similar between the three different models, except for the hydrodynamic model at pressures p≲ 2bar . As all models are in line with the ideal gas law, we hypothesize the presence of real gas effects in the measured spectra.

  18. Polarization multiplexed dual-loop optoelectronic oscillator based on stimulated Brillouin scattering

    Science.gov (United States)

    Han, Xiuyou; Ma, Liang; Shao, Yuchen; Ye, Qing; Gu, Yiying; Zhao, Mingshan

    2017-01-01

    A polarization multiplexed dual-loop optoelectronic oscillator (OEO) based on stimulated Brillouin scattering (SBS) is theoretically analyzed and experimentally demonstrated. The narrow bandwidth of SBS gain spectrum is utilized to implement the phase modulation to intensity modulation conversion and select the oscillation mode of the OEO. The polarization multiplexed dual-loop is constructed to suppress the side modes with Vernier effect. The output frequency of the OEO can be tuned by changing the frequency of the signal or the pump light wave. With the polarization multiplexed dual-loop the side-mode suppression ratio (SMSR) of 45 dB is achieved at 10 GHz. The generated oscillation frequency is tuned from 4 GHz to 16 GHz by changing the frequency of the signal light wave. The phase noise decreases with the power increase of the signal light wave when it is under the threshold of SBS. By adjusting the polarization state of the light wave, the influence of the power distribution between the long loop and the short loop on the phase noise of the OEO is investigated. The results show that more power in the long loop is helpful to suppress the near end phase noise.

  19. Brillouin amplification in phase coherent transfer of optical frequencies over 480 km fiber

    CERN Document Server

    Terra, O; Schnatz, H

    2010-01-01

    We describe the use of fiber Brillouin amplification (FBA) for the coherent transmission of optical frequencies over a 480 km long optical fiber link. FBA uses the transmission fiber itself for efficient, bi-directional coherent amplification of weak signals with pump powers around 30 mW. In a test setup we measured the gain and the achievable signal-to-noise ratio (SNR) of FBA and compared it to that of the widely used uni-directional Erbium doped fiber amplifiers (EDFA) and to our recently built bi-directional EDFA. We measured also the phase noise introduced by the FBA and used a new and simple technique to stabilize the frequency of the FBA pump laser. We then transferred a stabilized laser frequency over a wide area network with a total fiber length of 480 km using only one intermediate FBA station. After compensating the noise induced by the fiber, the frequency is delivered to the user end with an uncertainty below 2x10-18 and an instability sigma(tau) = 2x10-14/(tau/second).

  20. Brillouin amplification in phase coherent transfer of optical frequencies over 480 km fiber.

    Science.gov (United States)

    Terra, O; Grosche, G; Schnatz, H

    2010-07-19

    We describe the use of fiber Brillouin amplification (FBA) for the coherent transmission of optical frequencies over a 480 km long optical fiber link. FBA uses the transmission fiber itself for efficient, bi-directional coherent amplification of weak signals with pump powers around 30 mW. In a test setup we measured the gain and the achievable signal-to-noise ratio (SNR) of FBA and compared it to that of the widely used uni-directional Erbium doped fiber amplifiers (EDFA) and to our recently built bi-directional EDFA. We measured also the phase noise introduced by the FBA and used a new and simple technique to stabilize the frequency of the FBA pump laser. We then transferred a stabilized laser frequency over a wide area network with a total fiber length of 480 km using only one intermediate FBA station. After compensating the noise induced by the fiber, the frequency is delivered to the user end with an uncertainty below 2 x 10(-18) and an instability sigma y(tau) = 2 x 10(-14) /(tau/s).

  1. Low power, chip-based stimulated Brillouin scattering microwave photonic filter with ultrahigh selectivity

    CERN Document Server

    Marpaung, David; Pagani, Mattia; Pant, Ravi; Choi, Duk-Yong; Luther-Davies, Barry; Madden, Steve J; Eggleton, Benjamin J

    2014-01-01

    Highly selective and reconfigurable microwave filters are of great importance in radio-frequency signal processing. Microwave photonic (MWP) filters are of particular interest, as they offer flexible reconfiguration and an order of magnitude higher frequency tuning range than electronic filters. However, all MWP filters to date have been limited by trade-offs between key parameters such as tuning range, resolution, and suppression. This problem is exacerbated in the case of integrated MWP filters, blocking the path to compact, high performance filters. Here we show the first chip-based MWP band-stop filter with ultra-high suppression, high resolution in the MHz range, and 0-30 GHz frequency tuning. This record performance was achieved using an ultra-low Brillouin gain from a compact photonic chip and a novel approach of optical resonance-assisted RF signal cancellation. The results point to new ways of creating energy-efficient and reconfigurable integrated MWP signal processors for wireless communications an...

  2. Life is a Self-Organizing Machine Driven by the Informational Cycle of Brillouin

    Science.gov (United States)

    Michel, Denis

    2013-04-01

    Acquiring information is indisputably energy-consuming and conversely, the availability of information permits greater efficiency. Strangely, the scientific community long remained reluctant to establish a physical equivalence between the abstract notion of information and sensible thermodynamics. However, certain physicists such as Szilard and Brillouin proposed: (i) to give to information the status of a genuine thermodynamic entity ( k B T ln2 joules/bit) and (ii) to link the capacity of storing information inferred from correlated systems, to that of indefinitely increasing organization. This positive feedback coupled to the self-templating molecular potential could provide a universal basis for the spontaneous rise of highly organized structures, typified by the emergence of life from a prebiotic chemical soup. Once established, this mechanism ensures the longevity and robustness of life envisioned as a general system, by allowing it to accumulate and optimize microstate-reducing recipes, thereby giving rise to strong nonlinearity, decisional capacity and multistability. Mechanisms possibly involved in priming this cycle are proposed.

  3. Rayleigh-Brillouin scattering profiles of air at different temperatures and pressures

    CERN Document Server

    Gu, Ziyu; van de Water, Willem; Ubachs, Wim

    2013-01-01

    Rayleigh Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light detection and ranging (LIDAR) missions. The measurements performed at a wavelength of 366.8 nm detect spontaneous RB scattering at a 90 degree scattering angle from a sensitive intracavity setup, delivering scattering profiles at a 1 percent rms noise level or better. The elusive transport coefficient, the bulk viscosity, is effectively derived by a comparing the measurements to the model, yielding an increased trend. The calculated (Tenti S6) line shapes are consistent with experimental data at the level of 2 percent, meeting the requirements for the future RB scattering LIDAR missions in the Earth's atmosphere. However, the systematic 2 percent deviation may imply that the model has a limit to describe the finest details of RB scattering in air. Finally, it...

  4. High temperature surface Brillouin scattering study of mechanical properties of boron-doped epitaxial polysilicon

    Directory of Open Access Journals (Sweden)

    B. A. Mathe

    2017-02-01

    Full Text Available A study of the mechanical properties of a boron-doped epitaxial polysilicon layer deposited on a Si (100 substrate specimen has been carried out by surface Brillouin scattering at high temperatures. This type of specimen is widely used in micro-electro-mechanical systems (MEMS. By accumulating spectra with the Rayleigh mode and the Lamb continuum the isotropic elastic constants C44 and C11 were obtained, from which the values of the bulk, shear and Young’s moduli and Poisson’s ratio for the layer were determined over a range of temperatures from 20 °C to 110 °C. By contrast, an examination of the literature on polycrystalline silicon shows that other methods each provide a limited range of the above properties and thus additional experiments and techniques were needed. The SBS method is applicable to other polycrystalline materials such as silicon carbide, silicon nitride, silicon germanium and amorphous diamond that have also been used for MEMS applications.

  5. Study on two-cell stimulated Brillouin scattering system with mixture medium

    Institute of Scientific and Technical Information of China (English)

    HASI; Wuliji

    2007-01-01

    In this paper,a method of choosing mixture medium in two-cell stimulated Brillouinscattering(SBS)system to improve the system performance is proposed.The Brillouin frequency shift(BFS)of mixture medium varies with the mixing ratio andthus the difference of the BFS between the two cells can be eliminated.The two-cellSBS system with acetone(C3H6O)in its generator cell and mixture liquid ofCCl4/C2Cl4 in its amplifier cell is investigated.The C3H6O has a high optical breakdown threshold and the mixture liquid of CCl4/C2Cl4 has a small absorption coeffi-cient and the same BFS as that of C3H6O when the volume fraction of CCl4 is 4%.Compared with two-cell SBS system with the same liquid(C2Cl4)or different liquid(C3H6O and C2Cl4)in generator and amplifier cell,the SBS system with mixture liq-uid(CCl4/C2Cl4)in amplifier cell and C3H6O in generator cell improves thepower-load,energy reflectivity(ER),phase conjugation(PC)fidelity and ER stabil-ity.

  6. Lowering the risk of stimulated Brillouin backscatter from NIF hohlraums by re-pointing beams

    Science.gov (United States)

    Berger, Richard; Baker, K. L.; Thomas, C. A.; Milovich, J. L.; Langdon, A. B.; Strozzi, D. J.; Michel, M.

    2015-11-01

    The 64 beams that make a 50 degree angle with the hohlraum axis have been measured to reflect by Stimulated Brillouin Backscatter (SBS) enough laser light to cause optical damage and limit design parameter space. The amount of backscatter has been seen to depend on the initial plasma density filling the hohlraum, the hohlraum wall material, and the laser pulse length. The most important parameter causing SBS is the laser intensity on the hohlraum wall. In previous hohlraum designs, the intensity of the 50 degree beams has been controlled by cross-beam energy transfer (CBET). [P. Michel et al., Phys. Rev. Lett. 102, 025004 (2009)] Recent designs with reduced CBET have experienced an increase in SBS. Here we show that repointing beams can reduce the laser intensity at the wall and still maintain good beam smoothing. The reduction in intensity is achieved by separating the 44 and 50 degree cones of beams along the hohlraum axis and then repointing beams within each cone to reduce overlap while preserving polarization smoothing. PF3D simulations show dramatic reductions of SBS are possible. Experiments will determine whether increased laser entrance hole sizes will be required and whether this technique will open up new design options. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Brillouin optical time domain reflectometry for fast detection of dynamic strain incorporating double-edge technique

    CERN Document Server

    Shangguan, Mingjia; Xia, Haiyun; Qiu, Jiawei; Shentu, Guoliang; Dou, Xiankang; Zhang, Qiang; Pan, Jian-wei

    2016-01-01

    For the first time, a direct detection BOTDR is demonstrated for distributed dynamic strain sensing incorporating double-edge technique, time-division multiplexing technique and upconversion technique. The double edges are realized by using the transmission curve and reflection curve of an all-fiber Fabry-Perot interferometer (FPI). Benefiting from the low loss of the fiber at, the time-division multiplexing technique is performed to realize the double-edge technique by using only a single-channel FPI and only one piece of a detector. In order to detect the weak spontaneous Brillouin backscattering signal efficiently, a fiber-coupled upconversion detector is adopted to upconvert the backscattering signal at 1548.1 nm to 863 nm, which is detected by a Si-APD finally. In the experiment, dynamic strain disturbance up to 1.9m{\\epsilon} over 1.5 km of polarization maintaining fiber is detected at a sampling rate of 30 Hz. An accuracy of 30{\\mu}{\\epsilon} and spatial resolution of 0.6 m is realized.

  8. Optical limiting effect based on stimulated Brillouin scattering in CCl4

    Institute of Scientific and Technical Information of China (English)

    LueZhi-Wei; LueYue-Lan; YangJun

    2003-01-01

    The optical limiting effect based on stimulated Brillouin scattering(SBS) in a nonlinear medium was investigated. We numerically treated the nonlinear propagation process with a theoretical model, which includes the spontansous nature of the initiation of SBS, and obtained optical limiting effect in the process. Energy limiting,pulse reshaping and stabilization have been demonstrated on SBS mechanism with the nonlinear medium CCl4. The input optical signals were Nd:YAG nanosecond laser pulses with width varying from 16ns to 7ns then to 2ns, the relationship between the transmitted signal and launched pump signal was shown. In the experimental regime, the most stable pulse the transmitted signal and launched pump signal was shown. In the experimental regime, the most stable pulse and a superior energy stabilization of the transmitted pulse were obtained when the laser pulse-width became as short as 2ns. For the energy variation of laser pulses in a wide range of 14-88mJ, the output energy was limited in a quite narrow range 4.5-5.5mJ.

  9. Elasticity of the eye's crystalline lens: A Brillouin light scattering study.

    Science.gov (United States)

    Bailey, S.; Gump, J.; Sooryakumar, R.; Jayaprakash, C.; Venkiteshwar, M. S.; Bullimore, M.; Twa, M.

    2009-03-01

    Focusing the eye on a near object results in an increase in its optical power brought about by contraction of the ciliary muscles and an increase in the lens surface curvature. Distant vision occurs when the muscular force flattens the lens. Central to the ability of the lens to alter shape are its mechanical properties. Thus, given that hardening of the lens would impede deformation and reduce its ability to undergo the changes required for accommodation, a noninvasive approach to measure the elastic properties of the lens is valuable. We present results of Brillouin scattering from bovine and human lenses (from the organ donor program at The Ohio State University) that measure their high frequency acoustic response. These measurements are conducted with a few milli-watts of laser power and, in the case of bovine lenses, from entire intact eye globes, allow the stiffness of the lens to be mapped across its cross-section. The results will be compared to values of the shear- and bulk-moduli determined from other techniques and the implications of differences in these moduli discussed.

  10. Simulation of Stimulated Brillouin Scattering and Stimulated Raman Scattering In Shock Ignition

    CERN Document Server

    Hao, L; Liu, W D; Yan, R; Ren, C

    2016-01-01

    We study stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) in shock ignition by comparing fluid and PIC simulations. Under typical parameters for the OMEGA experiments [Theobald \\emph{et al}., Phys. Plasmas \\textbf{19}, 102706 (2012)], a series of 1D fluid simulations with laser intensities ranging between 2$\\times$10$^{15}$ and 2$\\times$10$^{16}$ W/cm$^2$ finds that SBS is the dominant instability, which increases significantly with the incident intensity. Strong pump depletion caused by SBS and SRS limits the transmitted intensity at the 0.17n$_c$ to be less than 3.5$\\times$10$^{15}$ W/cm$^2$. The PIC simulations show similar physics but with higher saturation levels for SBS and SRS convective modes and stronger pump depletion due to higher seed levels for the electromagnetic fields in PIC codes. Plasma flow profiles are found to be important in proper modeling of SBS and limiting its reflectivity in both the fluid and PIC simulations.

  11. Experimental Studies of the Stimulated Brillouin Scattering Instability in the Saturated Regime

    Energy Technology Data Exchange (ETDEWEB)

    Froula, D

    2002-10-29

    An experimental study of the stimulated Brillouin scattering (SBS) instability has investigated the effects of velocity gradients and kinetic effects on the saturation of ion-acoustic waves in a plasma. For intensities less than I < 1.5 x 10{sup 15} W cm{sup -2}, the SBS instability is moderated primarily by velocity gradients, and for intensities above this threshold, nonlinear trapping is invoked to saturate the instability. We report direct evidence of detuning of SBS by a velocity gradient which was achieved by directly measuring the frequency shift of the SBS driven acoustic wave relative to the local resonant acoustic frequency. Furthermore, a novel use of Thomson scattering has allowed us to gather direct evidence of kinetic effects associated with the SBS process. Specifically, a measured two-fold increase of the ion temperature has been linked with laser beam excitation of ion-acoustic waves to large amplitudes by the SBS instability. Ion-acoustic waves were excited to large amplitude with a 2{omega} 1.2-ns long interaction beam with intensities up to 5 x 10{sup 15} W cm{sup -2}. The local frequency, amplitude, and spatial range of these waves were measured with a 3{omega} 200ps Thomson-scattering probe beam. These detailed and accurate measurements in well-characterized plasma conditions allow for the first time a direct test of non-linear models of the saturation of SBS. The measured two-fold increase of the ion temperature and its correlation with SBS reactivity measurements is the first quantitative evidence of hot ions created by ion trapping in laser plasmas.

  12. Information-theoretic analysis of a stimulated-Brillouin-scattering-based slow-light system.

    Science.gov (United States)

    Lee, Myungjun; Zhu, Yunhui; Gauthier, Daniel J; Gehm, Michael E; Neifeld, Mark A

    2011-11-10

    We use an information-theoretic method developed by Neifeld and Lee [J. Opt. Soc. Am. A 25, C31 (2008)] to analyze the performance of a slow-light system. Slow-light is realized in this system via stimulated Brillouin scattering in a 2 km-long, room-temperature, highly nonlinear fiber pumped by a laser whose spectrum is tailored and broadened to 5 GHz. We compute the information throughput (IT), which quantifies the fraction of information transferred from the source to the receiver and the information delay (ID), which quantifies the delay of a data stream at which the information transfer is largest, for a range of experimental parameters. We also measure the eye-opening (EO) and signal-to-noise ratio (SNR) of the transmitted data stream and find that they scale in a similar fashion to the information-theoretic method. Our experimental findings are compared to a model of the slow-light system that accounts for all pertinent noise sources in the system as well as data-pulse distortion due to the filtering effect of the SBS process. The agreement between our observations and the predictions of our model is very good. Furthermore, we compare measurements of the IT for an optimal flattop gain profile and for a Gaussian-shaped gain profile. For a given pump-beam power, we find that the optimal profile gives a 36% larger ID and somewhat higher IT compared to the Gaussian profile. Specifically, the optimal (Gaussian) profile produces a fractional slow-light ID of 0.94 (0.69) and an IT of 0.86 (0.86) at a pump-beam power of 450 mW and a data rate of 2.5 Gbps. Thus, the optimal profile better utilizes the available pump-beam power, which is often a valuable resource in a system design.

  13. Micro-focused Brillouin light scattering: imaging spin waves at the nanoscale

    Directory of Open Access Journals (Sweden)

    Thomas eSebastian

    2015-06-01

    Full Text Available Spin waves constitute an important part of research in the field of magnetization dynamics. Spin waves are the elementary excitations of the spin system in a magnetically ordered material state and magnons are their quasi particles. In the following article, we will discuss the optical method of Brillouin light scattering (BLS spectroscopy which is a now a well established tool for the characterization of spin waves. BLS is the inelastic scattering of light from spin waves and confers several benefits: the ability to map the spin wave intensity distribution with spatial resolution and high sensitivity as well as the potential to simultaneously measure the frequency and the wave vector and, therefore, the dispersion properties.For several decades, the field of spin waves gained huge interest by the scientific community due to its relevance regarding fundamental issues of spindynamics in the field of solid states physics. The ongoing research in recent years has put emphasis on the high potential of spin waves regarding information technology. In the emerging field of textit{magnonics}, several concepts for a spin-wave based logic have been proposed and realized. Opposed to charge-based schemes in conventional electronics and spintronics, magnons are charge-free currents of angular momentum, and, therefore, less subject to scattering processes that lead to heating and dissipation. This fact is highlighted by the possibility to utilize spin waves as information carriers in electrically insulating materials. These developments have propelled the quest for ways and mechanisms to guide and manipulate spin-wave transport. In particular, a lot of effort is put into the miniaturization of spin-wave waveguides and the excitation of spin waves in structures with sub-micrometer dimensions.For the further development of potential spin-wave-based devices, the ability to directly observe spin-wave propagation with spatial resolution is crucial. As an optical

  14. Brillouin Scattering With Simultaneous X-Ray Diffraction at GSECARS, Advanced Photon Source: Toward Determination of Absolute Pressure Scales

    Science.gov (United States)

    Bass, J. D.; Sinogeikin, S. V.; Lakshtanov, D. L.; Prakapenka, V. B.; Shen, G.; Sanchez-Valle, C.; Perrillat, J.; Wang, J.; Chen, B.

    2006-12-01

    As one of the primary goals of the Elasticity Grand Challenge initiative and a COMPRES Infrastructure Development Project, a Brillouin spectrometer has been designed and installed at a synchrotron beam line (GSECARS, Sector 13 of the Advanced Photon Source). This facility allows one to simultaneously measure sound velocities (by Brillouin scattering) and density (by synchrotron X-ray diffraction measurements of the volume) on small single crystals at high pressure and/or temperature. One of the main motivations for this work was to perform measurements at high pressure on a variety of materials that would be useful as pressure standards for high-pressure research. It is now well known that through simultaneous velocity and density measurements at high pressure, one can solve for the pressure without resort to secondary standards such as the ruby pressure scale. Such measurements have thus far been carried out with several potential standards, such as NaCl and MgO. Single-crystal samples were loaded into diamond anvil cells along with ruby chips, and samples of standard metals such as Pt and Au. For NaCl and MgO, Brillouin spectra recording the longitudinal and transverse sound velocities, and simultaneous XRD were performed up to pressures of about 30 GPa. In addition, the velocities and density of polycrystalline B2 phase of NaCl were measured to >70 GPa. In this talk we describe this new facility and the measurements made thus far on NaCl and MgO. We further discuss the implications of our results on existing pressure scales.

  15. Thermal strain along optical fiber in lightweight composite FOG : Brillouin-based distributed measurement and finite element analysis

    Science.gov (United States)

    Minakuchi, Shu; Sanada, Teruhisa; Takeda, Nobuo; Mitani, Shinji; Mizutani, Tadahito; Sasaki, Yoshinobu; Shinozaki, Keisuke

    2014-05-01

    Thermal strain significantly affects stability of fiber optic gyroscope (FOG) performance. This study investigates thermal strain development in a lightweight carbon fiber reinforced plastic (CFRP) FOG under thermal vacuum condition simulating space environment. First, we measure thermal strain distribution along an optical fiber in a CFRP FOG using a Brillouin-based high-spatial resolution system. The key strain profile is clarified and the strain development is simulated using finite element analysis. Finally, several constituent materials for FOG are quantitatively compared from the aspect of the maximum thermal strain and the density, confirming the clear advantage of CFRP.

  16. Separated-pair independent particle model and the generalized Brillouin theorem: ab initio calculations on the dissociation of polyatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, K. R.

    1976-01-01

    A method is developed to optimize the separated-pair independent particle (SPIP) wave function; it is a special case of the separated-pair theory obtained by using two-term natural expansions of the geminals. The orbitals are optimized by a theory based on the generalized Brillouin theorem and iterative configuration interaction (CI) calculations in the space of the SPIP function and its single excitations. The geminal expansion coefficients are optimized by serial 2 x 2 CI calculations. Formulas are derived for the matrix elements. An algorithm to implement the method is presented, and the work needed to evaluate the molecular integrals is discussed. (auth)

  17. Adverse effect of the Brillouin optical time-domain analysis system caused by self-phase modulation

    Science.gov (United States)

    Zhou, Yuqing; Chen, Wei; Meng, Zhou

    2016-10-01

    Compared with strict rectangular pulse, the real rectangular pulse has power transients like the rising edge, failing edge and the oscillation times, which will cause self-phase modulation (SPM), leading to the BGS broadened or even be out of shape, and then result in the decline of the system measuring accuracy. Brillouin gain spectrum (BGS) can no longer maintain Lorentz line profile along the sensing fiber. In this paper, a model is established based on the nonlinear Schrodinger equation (NLSE) in regular single mode fiber (SMF) concerning the effects of pumping pulse power transients on the BGS. The noise is also taken into consideration to imitate the physical truth.

  18. Nonlinear phase shifts of modulated light waves with slow and superluminal group delay in stimulated Brillouin scattering.

    Science.gov (United States)

    Arditi, Tal; Granot, Er'el; Sternklar, Shmuel

    2007-09-15

    Brillouin amplification with counterpropagating modulated pump and Stokes light leads to nonlinear modulation-phase shifts of the interacting intensity waves. This is due to a partial transformation of the nonmodulated light component at the input into modulated light at the output as a result of a mixing process with the counterpropagating modulated component of the pump and results in an advance or delay of the input modulation. This occurs for interactions over less than half of a modulation wavelength. Milliwatts of power in a kilometer of standard single-mode fiber give significant tunability of the modulation phase.

  19. Brillouin light scattering study of magnetic-element normal modes in a square artificial spin ice geometry

    Science.gov (United States)

    Li, Y.; Gubbiotti, G.; Casoli, F.; Gonçalves, F. J. T.; Morley, S. A.; Rosamond, M. C.; Linfield, E. H.; Marrows, C. H.; McVitie, S.; Stamps, R. L.

    2017-01-01

    We report the results, from experimental and micromagnetic studies, of the magnetic normal modes in artificial square spin ice systems consisting of ferromagnetic-monodomain islands. Spin-wave properties are measured by Brillouin light scattering. The mode spectra contain several branches whose frequencies are sensitive to the magnitude and in-plane orientation of an applied magnetic field. We also identify soft modes that exhibit different behaviours depending on the direction of the applied magnetic field. The obtained results are well described with micromagnetic simulations of independent magnetic elements arranged along two sublattices.

  20. Investigation on the effect of beam divergence angle upon output waveform based on stimulated Brillouin scattering optical limiting

    Institute of Scientific and Technical Information of China (English)

    Hasi Wu-Li-Ji; Lu Huan-Huan; Gong Sheng; Fu Mei-Ling; Lin Zhi-Wei; Lin Dian-Yang; He Wei-Ming

    2009-01-01

    This paper investigates the effect of beam divergence angle on output waveform based on stimulated Brillouin scattering optical limiting. Output waveforms in the case of different pump divergence angles are numerically simulated,and validated in a Nd:YAG seed-injected laser system. The results indicate that a small pump divergence angle can lead to good interaction between pump and Stokes, and a platform can be easily realized in the transmitted waveform.In contrast, a peak followed by the platform appears when the divergence angle becomes large.

  1. The Wigner Band Random Matrix Model: Studied from the View Point of a Generalization of Brillouin-Wigner Perturbation Theory

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-Ge

    2001-01-01

    The Wigner band random matrix model is studied by making use of a generalization of Brillouin-Wigner perturbation theory. Energy eigenfunctions are shown to be divided into perturbative and nonperturbative parts. A relation between the average shape of eigenstates and that of the so-called local spectral density of states (LDOS) is derived by making use of some properties of energy eigenfunctions drawn from numerical results. Several perturbation strengths predicted by the perturbation theory are found to play important roles in the variation of the shape of the LDOS with perturbation strength.

  2. Theoretical study on pulse-shaping of Stokes pulse with steep leading edge by two Brillouin amplifiers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel configuration of two Brillouin amplifiers, which contains a main amplifier combined with a reshaping amplifier, is suggested to control pulse shape of Stokes pulses with steep leading edge. Dependences of pulse shapes on several parameters are numerically simulated. By changing the distance between the two amplifiers, the leading edge of amplified pulses can be finely adjusted. Smooth and symmetrical pulses or pulses with slow leading-edge are achieved. Theoretical researches prove that this system is fit for shaping pulses with steep leading edge, especially, for controlling leading edge of pulses. The results provide useful and necessary theoretical basis and guidance for the future experimental research.

  3. Photon-counting Brillouin optical time-domain reflectometry based on up-conversion detector and fiber Fabry-Perot scanning interferometer

    CERN Document Server

    Xia, Haiyun; Shentu, Guoliang; Wang, Chong; Qiu, Jiawei; Xia, Xiuxiu; Chen, Chao; Zheng, Mingyang; Xie, Xiuping; Zhang, Qiang; Dou, Xiankang; Pan, Jianwei

    2015-01-01

    A direct-detection Brillouin optical time-domain reflectometry (BOTDR) is proposed and demonstrated by using an up-conversion single-photon detector and a fiber Fabry-Perot scanning interferometer (FFP-SI). Taking advantage of high signal-to-noise ratio of the detector and high spectrum resolution of the FFP-SI, the Brillouin spectrum along a polarization maintaining fiber (PMF) is recorded on a multiscaler with a small data size directly. In contrast with conventional BOTDR adopting coherent detection, photon-counting BOTDR is simpler in structure and easier in data processing. In the demonstration experiment, characteristic parameters of the Brillouin spectrum including its power, spectral width and frequency center are analyzed simultaneously along a 10 km PMF at different temperature and stain conditions.

  4. Temperature-compensated distributed hydrostatic pressure sensor with a thin-diameter polarization-maintaining photonic crystal fiber based on Brillouin dynamic gratings.

    Science.gov (United States)

    Teng, Lei; Zhang, Hongying; Dong, Yongkang; Zhou, Dengwang; Jiang, Taofei; Gao, Wei; Lu, Zhiwei; Chen, Liang; Bao, Xiaoyi

    2016-09-15

    A temperature-compensated distributed hydrostatic pressure sensor based on Brillouin dynamic gratings (BDGs) is proposed and demonstrated experimentally for the first time, to the best of our knowledge. The principle is to measure the hydrostatic pressure induced birefringence changes through exciting and probing the BDGs in a thin-diameter pure silica polarization-maintaining photonic crystal fiber. The temperature cross-talk to the hydrostatic pressure sensing can be compensated through measuring the temperature-induced Brillouin frequency shift (BFS) changes using Brillouin optical time-domain analysis. A distributed measurement of hydrostatic pressure is demonstrated experimentally using a 4-m sensing fiber, which has a high sensitivity, with a maximum measurement error less than 0.03 MPa at a 20-cm spatial resolution.

  5. Distributed fiber strain and vibration sensor based on Brillouin optical time-domain reflectometry and polarization optical time-domain reflectometry.

    Science.gov (United States)

    Wang, Feng; Zhang, Xuping; Wang, Xiangchuan; Chen, Haisheng

    2013-07-15

    A distributed fiber strain and vibration sensor which effectively combines Brillouin optical time-domain reflectometry and polarization optical time-domain reflectometry is proposed. Two reference beams with orthogonal polarization states are, respectively, used to perform the measurement. By using the signal obtained from either reference beam, the vibration of fiber can be measured from the polarization effect. After combining the signals obtained by both reference beams, the strain can be measured from the Brillouin effect. In the experiment, 10 m spatial resolution, 0.6 kHz frequency measurement range, 2.5 Hz frequency resolution, and 0.2 MHz uncertainty of Brillouin frequency measurement are realized for a 4 km sensing distance.

  6. Zoning Districts, Zoning, Published in 2002, Freelance.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Zoning Districts dataset, was produced all or in part from Hardcopy Maps information as of 2002. It is described as 'Zoning'. Data by this publisher are often...

  7. Fast-light Enhanced Brillouin Laser Based Active Fiber Optics Sensor for Simultaneous Measurement of Rotation and Acceleration

    CERN Document Server

    Zhou, Minchuan; Fouda, Mohamed; Condon, Nicholas; Scheuer, Jacob; Shahriar, Selim M

    2016-01-01

    We have developed a conceptual design for an Active Fast Light Fiber Optic Sensor (AFLIFOS) that can perform simultaneously or separately as a gyroscope (differential mode effect) and a sensor for acceleration, strain, and other common mode effects. Two Brillouin lasers in opposite directions and separated in frequency by several free spectral ranges are used for this sensor. By coupling two auxiliary resonators to the primary fiber resonator, we produce superluminal effects for two laser modes. We develop a detailed theoretical model for optimizing the design of the AFLIFOS, and show that the enhancement factor of the sensitivity is $\\sim{187}$ and $\\sim{-187}$, respectively for the two Brillouin lasers under the optimized condition, when the effective change in perimeter of the primary fiber resonator is 0.1nm, corresponding to a rotation rate of 0.4 deg/sec for a ring resonator with radius 1m. It may be possible to get much higher enhancement by adjusting the parameters such as the perimeters and the coupl...

  8. Power limits and a figure of merit for stimulated Brillouin scattering in the presence of third and fifth order loss

    CERN Document Server

    Wolff, Christian; Steel, Michael J; Eggleton, Benjamin J; Poulton, Christopher G

    2015-01-01

    We derive a set of design guidelines and a figure of merit to aid the engineering process of on-chip waveguides for strong Stimulated Brillouin Scattering (SBS). To this end, we examine the impact of several types of loss on the total amplification of the Stokes wave that can be achieved via SBS. We account for linear loss and nonlinear loss of third order (two-photon absorption, 2PA) and fifth order, most notably 2PA-induced free carrier absorption (FCA). From this, we derive an upper bound for the output power of continuous-wave Brillouin-lasers and show that the optimal operating conditions and maximal realisable Stokes amplification of any given waveguide structure are determined by a dimensionless parameter $\\mathcal{F}$ involving the SBS-gain and all loss parameters. We provide simple expressions for optimal pump power, waveguide length and realisable amplification and demonstrate their utility in two example systems. Notably, we find that 2PA-induced FCA is a serious limitation to SBS in silicon and ge...

  9. Threshold level and gain of forward stimulated Brillouin scattering in a forward pumped s-band discrete DCF fibers Raman amplifier

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-feng; ZHANG Zai-xuan; DAI Bi-zhi; LI Chen-xia; INSOO S.KIM

    2006-01-01

    Amplification effect of forward stimulated Brillouin scattering (SBS) lines on the forward pumped s-band discrete DCF fiber Raman amplifier (FRA) has been studied.Pump threshold power of the forward first order Stokes SBS (FSB1- ),second order Stokes SBS (FSB2-) and third order SBS (FSB3-) in the forward pumped FRA are 1.5 mW,1.4 mW and 1.7 mW,respectively.The Stokes SBS lines are amplified by FRA and fiber Brillouin amplifier (FBA) at the same time.Gain of amplification is given as GA=GR·GB,where GR is Raman gain and GB is Brillouin gain.Saturation gain of FSB1-,FSB2- and FSB3- are about 52 dB,65 dB and 65 dB,respectively.The saturation Raman gain of 10 km DCF forward FRA is about 14 dB,so Brillouin gain of FSB1-,FSB2- and FSB3- are about 38 dB,51 dB and 51 dB,respectively.The forward cascaded SBS lines have been observed.

  10. High Compact, High Quality Single Longitudinal Mode Hundred Picoseconds Laser Based on Stimulated Brillouin Scattering Pulse Compression

    Directory of Open Access Journals (Sweden)

    Zhenxu Bai

    2016-01-01

    Full Text Available A high beam quality hundred picoseconds single-longitudinal-mode (SLM laser is demonstrated based on stimulated Brillouin scattering (SBS pulse compression and aberration compensation. Flash-lamp-pumped Q-switched Nd3+:Y3Al5O12 (Nd:YAG SLM laser with Cr4+:Y3Al5O12 (Cr4+:YAG as a saturable absorber is used as the seed source. By combining master-oscillator-power-amplifier (MOPA, a compact single-cell with FC-770 as working medium is generated as pulse compressor. The 7.8 ns SLM laser is temporally compressed to about 450 ps, and 200 mJ energy is obtained at 1064 nm without optical damage. The energy stability is better than 3% with beam quality factor M2 less than 1.8, which makes this laser system an attractive source for scientific and industrial applications.

  11. Large delay tunable slow-light based on high-gain stimulated-Brillouin-scattering amplification in optical fibers

    Institute of Scientific and Technical Information of China (English)

    XING Liang; ZHAN Li; XIA YuXing

    2009-01-01

    Tunable stimulated-Brillouin-scattering (SBS)-based slow-light in optical fibers has potential applications in optical buffering in the future all-optical router commutation systems.However,due to the low SBS threshold and relatively high realistic signal power,the gain in the usual SBS systems is limited at~30 dB.This paper presents a high-gain SBS scheme to realize large delay slow-light,which benefits from avoiding the depletion of the pump power in a short fiber as SBS media.The experiment demon strates that,up to 50 dB non-saturated gain has been observed in the single-stage 591.8 m fiber SBS amplification.The slow-light delay can be obtained 52 ns,and the fractional delay can exceed 1.

  12. Brillouin light scattering study of transverse mode coupling in confined yttrium iron garnet/barium strontium titanate multiferroic

    Energy Technology Data Exchange (ETDEWEB)

    Sadovnikov, A. V., E-mail: sadovnikovav@gmail.com; Nikitov, S. A. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation); Kotel' nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009 (Russian Federation); Beginin, E. N.; Bublikov, K. V.; Grishin, S. V.; Sheshukova, S. E.; Sharaevskii, Yu. P. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation)

    2015-11-28

    Using the space-resolved Brillouin light scattering spectroscopy we study the transformation of dynamic magnetization patterns in a bilayer multiferroic structure. We show that in the comparison with a single yttrium iron garnet (YIG) film magnetization distribution is transformed in the bilayer structure due to the coupling of waves propagating both in an YIG film (magnetic layer) and in a barium strontium titanate slab (ferroelectric layer). We present a simple electrodynamic model using the numerical finite element method to show the transformation of eigenmode spectrum of confined multiferroic. In particular, we demonstrate that the control over the dynamic magnetization and the transformation of spatial profiles of transverse modes in magnetic film of the bilayer structure can be performed by the tuning of the wavevectors of transverse modes. The studied confined multiferroic stripe can be utilized for fabrication of integrated dual tunable functional devices for magnonic applications.

  13. Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers.

    Science.gov (United States)

    Chin, Sanghoon; Thévenaz, Luc; Sancho, Juan; Sales, Salvador; Capmany, José; Berger, Perrine; Bourderionnet, Jérôme; Dolfi, Daniel

    2010-10-11

    We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters.

  14. Numerical modeling of the phase-conjugate laser with an intra-cavity stimulated Brillouin scattering mirror: Q-switching mode

    Science.gov (United States)

    Yashkir, Yuri

    2006-04-01

    We present a new computer numerical model of the phase-conjugate laser, utilizing an intra-cavity Stimulated Brillouin Scattering (SBS) element. The modelled laser system includes the active laser crystal which is placed between the output coupler mirror and a stimulated Brillouin scattering cell. The numerical model includes a set of rate equations for the active crystal inverse population, and for the photon density inside the laser cavity. The SBS backscattering model is based on a reduced set of coupled equations for electromagnetic fields for two waves (a pump wave and an SBS wave) propagating in opposite directions. The numerical integration of the set of equations simulates in detail the temporal dynamics of the laser. A wide range of realistic system parameters was numerically investigated. Different laser regimes (from a quasi -CW mode to a Q-switched mode) were numerically tested. The method of numerical modelling of such laser system can be efficiently used for an optimal laser design.

  15. ZoneLib

    DEFF Research Database (Denmark)

    Jessen, Jan Jacob; Schiøler, Henrik

    2006-01-01

    We present a dynamic model for climate in a livestock building divided into a number of zones, and a corresponding modular Simulink library (ZoneLib). While most literature in this area consider air flow as a control parameter we show how to model climate dynamics using actual control signals...... development of ZoneLib....

  16. On the moving interface effect in the stimulated Brillouin scattering in a nano-scale photonic waveguide

    CERN Document Server

    Su, Xiao-Xing; Li, Xiao-Shuang

    2016-01-01

    We present a theoretical research on the moving interface (MI) effect that may exist as a nonnegligible surface complementarity to the bulk photoelastic effect in the stimulated Brillouin scattering (SBS) process in a nano-scale photonic waveguide. Compared with the existing literature, we gain a deeper insight into the detailed physical mechanism on how the MI effect come into play in the three-wave interaction process of SBS, by arguing that the field changes of an optical wave caused by the motion of a sharp interface are further amplitude-modulated by a rectangular-wave envelop synchronizing with the acoustic wave that drives the interface motion. Based on a detailed theoretical analysis on the amplitude-modulation process, the rigorous expressions of the field perturbations on a participating optical wave in SBS caused by the interface motion are derived. As a direct application of the obtained rigorous expressions of the optical field perturbations, we further derive the opto-acoustical coupling coeffic...

  17. Discrete modes of a ferromagnetic stripe dipolarly coupled to a ferromagnetic film: a Brillouin light scattering study.

    Science.gov (United States)

    Gubbiotti, G; Tacchi, S; Carlotti, G; Ono, T; Roussigné, Y; Tiberkevich, V S; Slavin, A N

    2007-06-20

    Spin wave excitations in a magnetic structure consisting of a series of long permalloy stripes of a rectangular cross section magnetized along the stripe length and situated above a continuous permalloy film are studied both experimentally and theoretically. Stripes and continuous film are coupled by dipole-dipole interaction across 10 nm thick Cu spacers. Experimental measurements made using the Brillouin light scattering technique (with the light wavevector oriented along the stripe width) provide evidence for one dispersive spin wave mode associated with the continuous film and several discrete non-dispersive modes resonating within the finite width of the stripes.To interpret the experimental spectra, an analytic theory based on the spin wave formalism for finite-width magnetic stripes has been developed, achieving a good qualitative and partly quantitative description of the experimentally observed spin wave spectrum of the system. In particular, it is explained why the presence of a continuous magnetic film near the magnetic stripe leads to a substantial decrease of the frequencies of the discrete dipolar spin wave modes localized within the stripes. A more quantitative description of the measured frequencies and of the spatial profiles of the spin wave eigenmodes has been obtained by numerical calculations performed using a finite element method.

  18. Bismuth-based erbium-doped fiber as a gain medium for L-band amplification and Brillouin fiber laser

    Science.gov (United States)

    Ahmad, H.; Shahi, S.; Harun, S. W.

    2010-03-01

    Bismuth-based erbium-doped fiber (Bi-EDF) is demonstrated as an alternative medium for optical amplification and nonlinear applications. The bismuth glass host provides the opportunity to be doped heavily with erbium ions to allow a compact optical amplifier design. The bismuth-based erbium-doped fiber amplifier (Bi-EDFA) is demonstrated to operate at wavelength region from 1570 to 1620 nm using only a 215 cm long of gain medium. The maximum gain of 15.8 dB is obtained at signal wavelength of 1610 nm with the corresponding noise figure of about 6.3 dB. A multi-wavelength laser comb is also demonstrated using a stimulated Brillouin scattering in the 215 cm long Bi-EDF assisted by the 1480 nm pumping. The laser generates more than 40 lines of optical comb with a line spacing of approximately 0.08 at 1612.5 nm region using 152 mW of 1480 nm pump power.

  19. pF3D Simulations of Large Outer-Beam Brillouin Scattering from NIF Rugby Hohlraums

    Science.gov (United States)

    Langer, Steven; Strozzi, David; Chapman, Thomas; Amendt, Peter

    2015-11-01

    We assess the cause of large outer-beam stimulated Brillouin scattering (SBS) in a NIF shot with a rugby-shaped hohlraum, which has less wall surface loss and thus higher x-ray drive than a cylindrical hohlraum of the same radius. This shot differed from a prior rugby shot with low SBS in three ways: outer beam pointing, split-pointing of the four beams within each outer-beam quadruplet, and a small amount of neon added to the hohlraum helium fill gas. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles from the radiation-hydrodynamics code Lasnex. We determine which change between the two shots increased the SBS by adding them one at a time to the simulations. We compare the simulations to experimental data for total SBS power, its spatial distribution at the lens, and the SBS spectrum. For each shot, we use profiles from Lasnex simulations with and without a model for mix at the hohlraum wall-gas interface. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674893.

  20. A theoretical study of transient stimulated Brillouin scattering in optical fibers seeded with phase-modulated light.

    Science.gov (United States)

    Zeringue, Clint; Dajani, Iyad; Naderi, Shadi; Moore, Gerald T; Robin, Craig

    2012-09-10

    Beam combining of phase-modulated kilowatt fiber amplifiers has generated considerable interest recently. We describe in the time domain how stimulated Brillouin scattering (SBS) is generated in an optical fiber under phase-modulated laser conditions, and we analyze different phase modulation techniques. The temporal and spatial evolutions of the acoustic phonon, laser, and Stokes fields are determined by solving the coupled three-wave interaction system. Numerical accuracy is verified through agreement with the analytical solution for the un-modulated case and through the standard photon conservation relation for counter-propagating optical fields. As a test for a modulated laser, a sinusoidal phase modulation is examined for a broad range of modulation amplitudes and frequencies. We show that, at high modulation frequencies, our simulations agree with the analytical results obtained from decomposing the optical power into its frequency components. At low modulation frequencies, there is a significant departure due to the appreciable cross talk among the laser and Stokes sidebands. We also examine SBS suppression for a white noise source and show significant departures for short fibers from analytically derived formulas. Finally, SBS suppression through the application of pseudo-random bit sequence modulation is examined for various patterns. It is shown that for a fiber length of 9 m the patterns at or near n=7 provide the best mitigation of SBS with suppression factors approaching 17 dB at a modulation frequency of 5 GHz.

  1. Three-dimensional simulations of the angular and polarization dependence of stimulated Brillouin backscattering from NIF hohlraums

    Science.gov (United States)

    Berger, Richard; Langdon, A. B.; Thomas, C. A.; Baker, K. L.; Goyon, C. S.; Turnbull, D. P.

    2016-10-01

    The National Ignition Facility (NIF) groups its 192 beams in 48 quads, 2/3 of which are `outer' beams and 1/3 `inner' beams. Half of the outer quads are focused at the laser entrance hole (LEH) at an mean angle of 44° and the other half at 50° with respect to the hohlraum axis. The majority of the stimulated Brillouin scatter (SBS) is reflected into the 50° quads, and most of that into the 52° beams. That observation we reproduce with our simulations that use the wave propagation code, pF3D. Simulations considered a number of different pulse shapes, wall materials, capsule materials, and initial fill gas density with the plasma properties taken from 2D cylindrically-symmetric, radiation-hydrodynamic simulations of the hohlraum, capsule included. The simulations predict that different hohlraum designs have different fractions, between 20% and 50%, of the total SBS reflected into the backscattered light collection optics (the so-called FABS). The amount of light backscattered outside of FABS is not currently measured but is assumed to be 70% of the light backscattered. That assumption is a reasonable but not accurate estimate. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  3. Shanghai's Development Zones

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Since the early 1980s,development zones began appearing in China.Their Success largely stems from the preferential policies they offer and the safe investment environment they work hard to create.As zones have personalities themselves,it is essential to look beyond the pamphlets and published information and get down to the nittygritty.Shanghai has more State designated Economic and Technology Development Zones than any other city in China.In the following article,we have chosen development zones located around Shanghai and conducted a comparison.

  4. Subduction of fracture zones

    Science.gov (United States)

    Constantin Manea, Vlad; Gerya, Taras; Manea, Marina; Zhu, Guizhi; Leeman, William

    2013-04-01

    Since Wilson proposed in 1965 the existence of a new class of faults on the ocean floor, namely transform faults, the geodynamic effects and importance of fracture zone subduction is still little studied. It is known that oceanic plates are characterized by numerous fracture zones, and some of them have the potential to transport into subduction zones large volumes of water-rich serpentinite, providing a fertile water source for magma generated in subduction-related arc volcanoes. In most previous geodynamic studies, subducting plates are considered to be homogeneous, and there is no clear indication how the subduction of a fracture zone influences the melting pattern in the mantle wedge and the slab-derived fluids distribution in the subarc mantle. Here we show that subduction of serpentinized fracture zones plays a significant role in distribution of melt and fluids in the mantle wedge above the slab. Using high-resolution tree-dimensional coupled petrological-termomechanical simulations of subduction, we show that fluids, including melts and water, vary dramatically in the region where a serpentinized fracture zone enters into subduction. Our models show that substantial hydration and partial melting tend to concentrate where fracture zones are being subducted, creating favorable conditions for partially molten hydrous plumes to develop. These results are consistent with the along-arc variability in magma source compositions and processes in several regions, as the Aleutian Arc, the Cascades, the Southern Mexican Volcanic Arc, and the Andean Southern Volcanic Zone.

  5. Characteristics of perfluorinated amine media for stimulated Brillouin scattering in hundreds of picoseconds pulse compression at 532 nm

    Institute of Scientific and Technical Information of China (English)

    Wuliji Hasi; Hang Zhao; Dianyang Lin; Weiming He; Zhiwei Lü

    2015-01-01

    The characteristics of stimulated Brillouin scattering (SBS) in perfluorinated amine media and the experimental structure used in hundreds of picoseconds pulse compression at 532 nm are demonstrated.A two-stage SBS pulse compression structure is adopted for this work.The compact double-cell SBS compression structure and the scattering media FC-70 are chosen to compress the incident light from 9.5 to about 1 ns in the first stage.Then,the light is used as the pumping source for the second pulse compression.In the second stage,using a single-cell SBS structure in a pulse compression system,perfluorinated amine media with different phonon lifetimes,such as FC-3283,FC-40,FC-43,and FC-70,are chosen to run the comparative experimental study.The narrowest compressed pulse times obtained are 294,274,277,and 194 ps;they respectively correspond to the above listed media.The average width of the compressed pulse width is 320 ps for FC-3283,with a fluctuation range of 87 ps.For FC-40,the average pulse width is 320 ps,with a fluctuation range of 72 ps.And for FC-43,the average pulse width is 335 ps,with a fluctuation range of 88 ps.However,the average pulse width is only 280 ps for FC-70,with a fluctuation range of 57 ps.The highest energy reflectivity is more than 80% for all of the media.The experimental results show that a two-stage SBS pulse compression system has lower pump energy requirements,thus making it easier to achieve a compressed pulse waveform.The results also show that the shorter the phonon lifetime of the medium,the narrower the obtained compressed pulse width.

  6. Brillouin-Wigner theory for high-frequency expansion in periodically driven systems: Application to Floquet topological insulators

    Science.gov (United States)

    Mikami, Takahiro; Kitamura, Sota; Yasuda, Kenji; Tsuji, Naoto; Oka, Takashi; Aoki, Hideo

    2016-04-01

    We construct a systematic high-frequency expansion for periodically driven quantum systems based on the Brillouin-Wigner (BW) perturbation theory, which generates an effective Hamiltonian on the projected zero-photon subspace in the Floquet theory, reproducing the quasienergies and eigenstates of the original Floquet Hamiltonian up to desired order in 1 /ω , with ω being the frequency of the drive. The advantage of the BW method is that it is not only efficient in deriving higher-order terms, but even enables us to write down the whole infinite series expansion, as compared to the van Vleck degenerate perturbation theory. The expansion is also free from a spurious dependence on the driving phase, which has been an obstacle in the Floquet-Magnus expansion. We apply the BW expansion to various models of noninteracting electrons driven by circularly polarized light. As the amplitude of the light is increased, the system undergoes a series of Floquet topological-to-topological phase transitions, whose phase boundary in the high-frequency regime is well explained by the BW expansion. As the frequency is lowered, the high-frequency expansion breaks down at some point due to band touching with nonzero-photon sectors, where we find numerically even more intricate and richer Floquet topological phases spring out. We have then analyzed, with the Floquet dynamical mean-field theory, the effects of electron-electron interaction and energy dissipation. We have specifically revealed that phase transitions from Floquet-topological to Mott insulators emerge, where the phase boundaries can again be captured with the high-frequency expansion.

  7. Effects of Fe-deficiency on magnetic properties and Brillouin function characteristics for NiCuZn ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Linglong; Yu, Zhong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yang, Yan [Department of Communication Engineering, Chengdu Technological University, Chengdu 611730 (China); Guo, Rongdi; Jiang, Xiaona; Sun, Ke; Wu, Chuanjian; Lan, Zhongwen [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2015-08-01

    The polycrystalline Ni{sub 0.56}Cu{sub 0.10}Zn{sub 0.34}Fe{sub 2−x}O{sub 4−3/2x} (x=0.00~0.14) ferrites have been prepared by conventional oxide ceramics process. The effects of Fe-deficiency content on magnetic properties and Brillouin function characteristics for NiCuZn ferrites have been investigated in details. With the increase of Fe-deficiency content, the opposite variation trend are observed for the saturation magntic induction B{sub s} and the coercivity H{sub c}. More importantly, based on the Néel molecular field theory, for the spinel ferrites which do not only contain Fe{sup 3+} but also some other multiple magnetic ions (Ni{sup 2+} and Cu{sup 2+}), the molecular field coefficients ω{sub aa}, ω{sub bb} and ω{sub ab=}ω{sub ba} are calculated by non-linear fitting method, and the Curie temperature T{sub c} formula has been modified. With the increase of Fe-deficiency content, the values of ω{sub aa} and ω{sub bb} increase gradually, however, the value of ω{sub ab}=ω{sub ba} has a contrary trend which results in the decrease of the Curie temperature. In addition, the fitting Curie temperatures values are coincided well with the Curie temperatures calculated by the modified formula. - Highlights: • Néel molecular field theory model of multi-magnetic ions (Fe{sup 3+}, Ni{sup 2+}, Cu{sup 2+}) is completed and the correlation formula of Curie temperature has been derived. • The calculating for the molecular field coefficients has been completed from absolute zero degree to Curie temperature. • The corresponding values and variation trend of molecular field coefficients have been completely investigated.

  8. An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, K.S. [Univ. of California, Davis, CA (US)

    1993-02-11

    Despite the apparent simplicity of controlled fusion, there are many phenomena which have prevented its achievement. One phenomenon is laser-plasma instabilities. An investigation of one such instability, stimulated Brillouin scattering (SBS), is reported here. SBS is a parametric process whereby an electromagnetic wave (the parent wave) decays into another electromagnetic wave and an ion acoustic wave (the daughter waves). SBS impedes controlled fusion since it can scatter much or all of the incident laser light, resulting in poor drive symmetry and inefficient laser-plasma coupling. It is widely believed that SBS becomes convectively unstable--that is, it grows as it traverses the plasma. Though it has yet to be definitively tested, convective theory is often invoked to explain experimental observations, even when one or more of the theory`s assumptions are violated. In contrast, the experiments reported here not only obeyed the assumptions of the theory, but were also conducted in plasmas with peak densities well below quarter-critical density. This prevented other competing or coexisting phenomena from occurring, thereby providing clearly interpretable results. These are the first SBS experiments that were designed to be both a clear test of linear convective theory and pertinent to controlled fusion research. A crucial part of this series of experiments was the development of a new instrument, the Multiple Angle Time Resolving Spectrometer (MATRS). MATRS has the unique capability of both spectrally and temporally resolving absolute levels of scattered light at many angles simultaneously, and is the first of its kind used in laser-plasma experiments. A detailed comparison of the theoretical predictions and the experimental observations is made.

  9. Brillouin scattering, DSC, dielectric and X-ray diffraction studies of phase transitions in antiferroelectric PbHfO{sub 3}:Sn

    Energy Technology Data Exchange (ETDEWEB)

    Mączka, Mirosław, E-mail: m.maczka@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Kim, Tae Hyun [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Gągor, Anna [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Jankowska-Sumara, Irena [Institute of Physics, Pedagogical University, ul. Podchorążych 2, 30-084 Kraków (Poland); Majchrowski, Andrzej [Institute of Applied Physics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Kojima, Seiji [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

    2015-02-15

    Highlights: • Phase transition mechanisms were studied in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3.} • Acoustic phonons showed anomalies at 472 and 426 K due to phase transitions. • Brillouin data showed evidence for presence of polar clusters in paraelectric phase. • An order-disorder mechanism of the PE to AFE2 transition was proved. - Abstract: Specific heat, dielectric, powder X-ray diffraction and Brillouin scattering studies of phase transitions in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3} crystal were performed. The specific heat data revealed clear anomalies at T{sub 1} = 473.5 and T{sub 2} = 426.3 K on cooling, which could be attributed to onset of first order phase transitions from the paraelectric (PE) phase to an intermediate antiferroelectric phase (AFE2) and the AFE2 phase to another antiferroelectric phase (AFE1), respectively. The estimated entropy changes at T{sub 1} and T{sub 2} pointed to mainly an order-disorder and displacive character of these transitions, respectively. X-ray diffraction data showed a complex superstructure of the intermediate phase with a = 11.895(6) Å, b = 11.936(4) Å, c = 8.223(3) Å at 453 K. Brillouin studies revealed pronounced softening of longitudinal acoustic (LA) mode in the PE phase associated with its broadening. The broadening and softening exhibited maximum values at T{sub 1}. Additional acoustic anomalies, that is, abrupt frequency shifts for LA and transverse acoustic (TA) modes were also observed at T{sub 2}. Brillouin scattering data also showed presence of a broad central peak (CP) that exhibited highest intensity at T{sub 1}. The observed temperature dependences of acoustic modes and CP indicate order-disorder character of the FE to AFE2 phase transition and importance of polar precursor clusters in the PE phase. The obtained data also suggest that the intermediate antiferroelectric phases in Sn{sup 4+} doped PbHfO{sub 3} and PbZrO{sub 3} may have very similar structures

  10. Microgravity silicon zoning investigation

    Science.gov (United States)

    Kern, E. L.; Gill, G. L., Jr.

    1985-01-01

    The flow instabilities in floating zones of silicon were investigated and methods for investigation of these instabilities in microgravity were defined. Three principal tasks were involved: (1) characterization of the float zone in small diameter rods; (2) investigation of melt flow instabilities in circular melts in silicon disks; and (3) the development of a prototype of an apparatus that could be used in near term space experiments to investigate flow instabilities in a molten zone. It is shown that in a resistance heated zoner with 4 to 7 mm diameter silicon rods that the critical Marangoni number is about 1480 compared to a predicted value of 14 indicative that viable space experiments might be performed. The prototype float zone apparatus is built and specifications are prepared for a flight zoner should a decision be reached to proceed with a space flight experimental investigation.

  11. The gray zone.

    Science.gov (United States)

    Kisner, H J

    1998-01-01

    Think for a minute about the terms equivocal and indeterminate. Equivocal is defined as "of uncertain significance", and indeterminate is defined as "indefinite, uncertain". Now think of the context in which laboratory results are reported: either by using the exact words equivocal or indeterminate or cloaked in technical jargon (e.g., cytologic diagnoses "ASCUS" or "AGUS"). Clinicians expect (or at least want) laboratory results to be black or white (i.e., bimodally distributed), whereas laboratorians strive for the perfect shade of gray because of data that often are bimodal but overlapping. A consequence of this color war is "the gray zone" (often confused with the "twilight zone"), a noncommittal zone that leaves laboratorians and clinicians alike plenty of wiggle room, allowing us to interpret results on either side of the fence. This article examines the root causes of the gray zone, with several clinical examples of how it permeates laboratory interpretation.

  12. Promise Zones for Applicants

    Data.gov (United States)

    Department of Housing and Urban Development — This tool assists applicants to HUD's Promise Zone initiative prepare data to submit with their application by allowing applicants to draw the exact location of the...

  13. BLM Solar Energy Zones

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — Priority development areas for utility-scale solar energy facilities as identified in the Solar PEIS Record of Decision. An additional Solar Energy Zone identified...

  14. Simulated floating zone method

    OpenAIRE

    Ozawa, Ryo; Kato, Yasuyuki; Motome, Yukitoshi

    2016-01-01

    This paper provides the simulated floating zone (SFZ) method that is an efficient simulation technique to obtain thermal equilibrium states, especially useful when domain formation prevents the system from reaching a spatially-uniform stable state. In the SFZ method, the system is heated up locally, and the heated region is steadily shifted, similar to the floating zone method for growing a single crystal with less lattice defect and impurity in experiments. We demonstrate that the SFZ method...

  15. Determination of the electron temperature in the modified ionosphere over HAARP using the HF pumped Stimulated Brillouin Scatter (SBS emission lines

    Directory of Open Access Journals (Sweden)

    P. A. Bernhardt

    2009-12-01

    Full Text Available An ordinary mode electromagnetic wave can decay into an ion acoustic wave and a scattered electromagnetic wave by a process called stimulated Brillouin scatter (SBS. The first detection of this process during ionospheric modification with high power radio waves was reported by Norin et al. (2009 using the HAARP transmitter in Alaska. Subsequent experiments have provided additional verification of this process and quantitative interpretation of the scattered wave frequency offsets to yield measurements of the electron temperatures in the heated ionosphere. Using the SBS technique, electron temperatures between 3000 and 4000 K were measured over the HAARP facility. The matching conditions for decay of the high frequency pump wave show that in addition to the production of an ion-acoustic wave, an electrostatic ion cyclotron wave may also be produced by the generalized SBS processes. Based on the matching condition theory, the first profiles of the scattered wave amplitude are produced using the stimulated Brillouin scatter (SBS matching conditions. These profiles are consistent with maximum ionospheric interactions at the upper-hybrid resonance height and at a region just below the plasma resonance altitude where the pump wave electric fields reach their maximum values.

  16. Temperature-dependent strain and temperature sensitivities of fused silica single mode fiber sensors with pulse pre-pump Brillouin optical time domain analysis

    Science.gov (United States)

    Bao, Yi; Chen, Genda

    2016-06-01

    This paper reports a distributed temperature and strain sensor based on pulse pre-pump Brillouin optical time domain analysis. An uncoated, telecom-grade fused silica single-mode fiber as a distributed sensor was calibrated for its sensitivity coefficients under various strains and temperatures up to 800 °C. The Brillouin frequency of fiber samples changed nonlinearly with temperature and linearly with strain. The temperature sensitivity decreased from 1.113 to 0.830 MHz /°C in the range of 22-800 °C. The strain sensitivity was reduced from 0.054 to 0.042 MHz /μɛ as the temperature increased from 22 to 700 °C and became unstable at higher temperatures due to creep effect. The strain measurement range was reduced from 19 100 to 6000 μɛ in the temperature range of 22-800 °C due to fused silica’s degradation. The calibrated fiber optic sensor demonstrated adequate accuracy and precision for strain and temperature measurements and stable performance in heating-cooling cycles. It was validated in an application setting.

  17. A novel-configuration multi-wavelength Brillouin erbium fiber laser and its application in switchable high-frequency microwave generation

    Science.gov (United States)

    Fu, J.; Chen, D.; Sun, B.; Gao, S.

    2010-10-01

    A novel configuration of compound-cavity multi-wavelength Brillouin erbium fiber laser is proposed and experimentally demonstrated. With an incident optical carrier power of 8 dBm, at least 14 lasing lines are obtained with a wavelength spacing of ˜0.08 nm. Stability and power uniformity of the multi-wave-length lasing are ensured by the flat hybrid gain of Brillouin and erbium, the compound-cavity structure, and the four-wave mixing suppression using a long (10 km) single-mode fiber. A stable and frequency-switchable microwave can be achieved by incorporating a fiber Bragg grating filter to select the desired nth-order Stokes wave and beating it with the optical carrier at a photodetector. In our experiment, the 1st-4th-order Stokes waves are filtered respectively and hence a high-quality microwave with a switchable frequency from ˜10 to ˜40 GHz and a tuning step of ˜10 GHz is achieved. The signal-to-noise ratio is measured to be >25 dB.

  18. Zones of emotional labour

    DEFF Research Database (Denmark)

    Strøbæk, Pernille Solveig

    2011-01-01

    is put forth among 25 Danish public family law caseworkers. The study points to personal, professional, and social zones of emotional labour through which the caseworkers carry out their work. Emotional labour zones mark emotion structures that may be challenging due to complex emotional intersections......The paper suggests that due to the difficult nature of their work public family law caseworkers are to be included in the definition of emotional labour even though they are omitted by Hochschild. Based upon a review of the structures involved in emotional labour an explorative qualitative study...

  19. Flexible 'zoning' aids adaptability.

    Science.gov (United States)

    Corben, Simon

    2013-09-01

    Simon Corben, business development director at Capita Symonds' Health team, examines how 'clever use of zoning' when planning new healthcare facilities could improve hospital design, increase inherent flexibility, and reduce lifetime costs, and argues that a 'loose-fit, non-bespoke approach' to space planning will lead to 'more flexible buildings that are suitable for conversion to alternative uses'.

  20. DNS zones revisited

    NARCIS (Netherlands)

    Wanrooij, van Ward; Pras, Aiko; Delgado Kloos, Carlos

    2005-01-01

    Recent research [Pap04b] suggests DNS reliability and performance is not up to the levels it should be due to misconfigurations. This paper checks the configuration of nameserver zones against additional requirements, recommendations and best-practices. It shows that almost one in four domains fails

  1. Compressibility of hydrated and anhydrous sodium silicate-based liquids and glasses, as analogues for natural silicate melts, by Brillouin scattering spectroscopy

    Science.gov (United States)

    Tkachev, Sergey Nikolayevich

    A mathematical formalism was tested on compressibility studies of water, before applying it to the high pressure-temperature compressibility studies of hydrated and anhydrous sodium silicate-based liquids and glasses. The hypersonic sound velocity, refractive index and attenuation coefficient obtained using Brillouin light scattering spectroscopy technique were in agreement with literature data. From the measured sound velocities, the pressure dependence of the bulk moduli and density of liquid water were calculated, using Vinet equation of state. The formalism was extended to the Brillouin scattering studies of the elastic properties of alkaline-calcium silica hydrogels and float glass, which exhibits a dramatic increase in the pressure dependence of longitudinal velocity and a discontinuity in the compressibility at about 6 GPa. It is demonstrated that an apparent second-order transition to a new amorphous phase can form via the abrupt onset of a new compressional mechanism, which may be triggered by a shift in polymerization of the glass or an onset of a change in coordination of silicon. Brillouin scattering measurements were carried out on an aqueous solution of Na2O-2SiO2 and anhydrous Na2O-2SiO 2 glass and liquid at high P-T conditions. The "modified" platelet scattering geometry has allowed a determination of the longitudinal velocity independently from refractive index, and hence the adiabatic compressibility and density of liquids as a function of pressure and temperature. The observed increase in density of the melt and glass phases formed at high P-T conditions is likely associated with structural effects. The large values of KS' of the liquid phase illustrate that the means of compaction of the liquid differs substantially from that of the glass, and that the liquid is able to access a wider range of compaction mechanisms. The measured bulk modulus of Na2O-2SiO2 aqueous solution is closer to values of silicate melts than to that of end-member water at

  2. Empowerment Zones and Enterprise Districts - MDC_EnterpriseZone

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Polygon feature class of Miami Dade County Enterprise Zones. Enterprise Zones are special areas in the county where certain incentives from the State are available...

  3. The Habitable Zone Gallery

    CERN Document Server

    Kane, Stephen R

    2012-01-01

    The Habitable Zone Gallery (www.hzgallery.org) is a new service to the exoplanet community which provides Habitable Zone (HZ) information for each of the exoplanetary systems with known planetary orbital parameters. The service includes a sortable table with information on the percentage of orbital phase spent within the HZ, planetary effective temperatures, and other basic planetary properties. In addition to the table, we also plot the period and eccentricity of the planets with respect to their time spent in the HZ. The service includes a gallery of known systems which plot the orbits and the location of the HZ with respect to those orbits. Also provided are animations which aid in orbit visualization and provide the changing effective temperature for those planets in eccentric orbits. Here we describe the science motivation, the under-lying calculations, and the structure of the web site.

  4. ZONE OF COOPERATION

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The China-ASEAN Economic Zone is attracting more and more investors from both Southeast Asia and China Compared with other countries that have established free trade areas with ASEAN, China owns millions of unique advantages. Millions, after all, is the quantity of Chinese living in ASEAN countries. "With ties of blood, geography and commerce, business people of Chinese descent can be the best candidates to pro-

  5. Bend-insensitive distributed sensing in singlemode-multimode-singlemode optical fiber structure by using Brillouin optical time-domain analysis

    Science.gov (United States)

    Xu, Pengbai; Zhang, Hongying; Lu, Zhiwei; Chen, Liang; Bao, Xiaoyi; Dong, Yongkang

    2015-09-01

    We propose a bend-insensitive distributed Brillouin optical fiber sensing by using a singlemode-multimode-singlemode optical fiber structure for the first time to the best of our knowledge. The sensing fiber is a graded-index multimode fiber (GI-MMF) sandwiched by two standard single-mode fibers (SMFs) with centrally alignment splicing at the interface between GI-MMF and SMF to excite the fundamental mode only in GI-MMF. The sensing system can resist a minimal bend radius of 1.25mm while maintaining the measurement performance, with which the measured coefficient of strain is 421.6MHz/%. We also demonstrate that the higher-order modes exciting in GI-MMF can be easily influenced by bending, so that the fundamental mode exciting is essential for bend-insensitive distributed sensing.

  6. The pinning effect in a polar semiconductor quantum dot with Gaussian confinement: A study using the improved Wigner–Brillouin perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    P J, Monisha, E-mail: pjmonisha@gmail.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Mukhopadhyay, Soma [Department of Physics, D V R college of Engineering and Technology, Hyderabad 502285 (India)

    2015-05-01

    The effect of electron–phonon interaction on a few low-lying energy levels in a polar semiconductor quantum dot with Gaussian confinement is studied by using an improved Wigner–Brillouin perturbation theory (IWBPT). In the absence of the electron–phonon interaction, the electronic ground state plus one phonon state is degenerate with the first excited electronic state plus the zero-phonon state at some value of the confinement length. Similarly, the electronic ground state plus one phonon state is also degenerate with the second excited electronic state plus the zero-phonon state at a larger value of the confinement length. It is shown that the electron–phonon interaction lifts these degeneracies and as a result, the excited state energy levels bend downward and get pinned to the ground state plus one phonon state as the confinement frequency is increased. Our calculations are finally applied to GaAs and InSb quantum dots.

  7. Surface Brillouin scattering measurement of the elastic constants of single crystal InAs{sub 0.91}Sb{sub 0.09}

    Energy Technology Data Exchange (ETDEWEB)

    Kotane, L M; Comins, J D; Every, A G [Materials Physics Research Institute, School of Physics, University of the Witwatersrand, Johannesburg, Wits 2050 (South Africa); Botha, J R, E-mail: Lesias.Kotane@wits.ac.z [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

    2011-01-01

    Surface Brillouin scattering of light has been used to measure the angular dependence of the Rayleigh surface acoustic wave (SAW), pseudo surface acoustic wave (PSAW) and longitudinal lateral wave (LLW) speeds in a (100)-oriented single crystal of the ternary semiconductor alloy InAs{sub 0.91}Sb{sub 0.09}. The wave speed measurements have been used to determine the room temperature values of the elastic constants C{sub 11}, C{sub 12} and C{sub 44} of the alloy. A simple and robust fitting procedure has been implemented for recovering the elastic constants, in which the merit function is constructed from explicit secular functions that determine the surface and lateral wave speeds in the [001] and [011] crystallographic directions. In the fitting, relatively larger weighting factors have been assigned to the SAW and PSAW data because of the greater precision with which the surface modes can be measured as compared with the lateral wave.

  8. Ecological zones of California deserts

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The dataset delineates ecological zones within California deserts. We derived ecological zones by reclassifying LANDFIRE vegetation biophysical setting types, plus...

  9. Radiant zone heated particulate filter

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-12-27

    A system includes a particulate matter (PM) filter including an upstream end for receiving exhaust gas and a downstream end. A radiant zoned heater includes N zones, where N is an integer greater than one, wherein each of the N zones includes M sub-zones, where M is an integer greater than or equal to one. A control module selectively activates at least a selected one of the N zones to initiate regeneration in downstream portions of the PM filter from the one of the N zones, restricts exhaust gas flow in a portion of the PM filter that corresponds to the selected one of the N zones, and deactivates non-selected ones of the N zones.

  10. The uncomfortable comfort zone

    Directory of Open Access Journals (Sweden)

    Carlos Renato Zacharias

    2012-04-01

    Full Text Available Whenever we achieve the satisfaction of our expectations and anxiety dissolves, we feel as if we were in a comfort zone – safe, complete, free from risks and in peace with ourselves. We might even have a little taste of heaven when we feel that we have fulfilled our duty. And as a fact, scientists are entitled to this kind of reward… but not for too long! In science, to enter a comfort zone can be as pleasant as dangerous. On one hand we may have a safe ground available to develop new modes of reasoning, protocols and theories. And on the other, we may stay stuck in a conventional but fragile ground, missing opportunities to reveal novel secrets or to address edge issues. ... The community of HD researchers seems to have entered a new comfort zone when nanostructures were found in HD. Nanostructures have been raised to the level of ultimate evidence doing away with Avogadro’s limit and leading homeopathy and HD research into mainstream science. We really should enjoy this moment and collect more information about the HD phenomenon. However, we must be wary to not fall into a trap.

  11. Smartphones and Time Zones

    Science.gov (United States)

    Baird, William; Secrest, Jeffery; Padgett, Clifford; Johnson, Wayne; Hagrelius, Claire

    2016-09-01

    Using the Sun to tell time is an ancient idea, but we can take advantage of modern technology to bring it into the 21st century for students in astronomy, physics, or physical science classes. We have employed smartphones, Google Earth, and 3D printing to find the moment of local noon at two widely separated locations. By reviewing GPS time-stamped photos from each place, we are able to illustrate that local noon is longitude-dependent and therefore explain the need for time zones.

  12. Parapapillary atrophy: histological gamma zone and delta zone.

    Directory of Open Access Journals (Sweden)

    Jost B Jonas

    Full Text Available BACKGROUND: To examine histomorphometrically the parapapillary region in human eyes. METHODOLOGY/PRINCIPAL FINDINGS: The histomorphometric study included 65 human globes (axial length:21-37 mm. On anterior-posterior histological sections, we measured the distance Bruch's membrane end (BME-optic nerve margin ("Gamma zone", BME-retinal pigment epithelium (RPE ("Beta zone", BME-beginning of non-occluded choriocapillaris, and BME-beginning of photoreceptor layer. "Delta zone" was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm was significantly (P = 0.01 larger in the glaucoma group than in the non-glaucomatous group. It was not significantly (P = 0.28 associated with axial length. Beta zone was significantly (P = 0.004 larger than the region with occluded choriocapillaris. Gamma zone (mean length:0.63±1.25 mm was associated with axial length (P50 µm diameter within gamma zone was present only in highly axially elongated globes and was not related with glaucoma. Beta zone (Bruch's membrane without RPE was correlated with glaucoma but not with globe elongation. Since the region with occluded choriocapillaris was smaller than beta zone, complete loss of RPE may have occurred before complete choriocapillaris closure.

  13. The Near Zone to Far Zone Transformation (N2F)

    Energy Technology Data Exchange (ETDEWEB)

    Blackfield, Donald T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Poole, Brian R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-03-11

    N2F is a C/C++ code used to calculate the far zone electromagnetic (EM) field, given E and H near zone field data. The method used by N2F can be found in Ref. 1 and 2. N2F determines the far field EΦ and Eθ in spherical coordinates for near zone data calculated in either Cartesian or Cylindrical geometry.

  14. Empowerment Zones and Enterprise Districts - Volusia County Enterprise Zones

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Florida's Enterprise Zone Program encourages economic growth and investment in distressed areas by offering tax advantages and incentives to businesses that are...

  15. Saturated Zone Colloid Transport

    Energy Technology Data Exchange (ETDEWEB)

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant

  16. Learning About Intervention Target Zones

    OpenAIRE

    Klein, Michael W; Karen K. Lewis

    1991-01-01

    This paper provides a framework for evaluating how market participants' beliefs about foreign exchange target zones change as they learn about central bank intervention policy. In order to examine this behavior, we first generalize the standard target zone model to allow for intra-marginal intervention. Intra-marginal intervention implies that the position of market participants' beliefs about the target zone can be determined from their beliefs about the likelihood of intervention. As an app...

  17. Zoning should promote public health.

    Science.gov (United States)

    Hirschhorn, Joel S

    2004-01-01

    Legally, governments use their police powers to protect public health, safety, and welfare through zoning. This paper presents a case for revisiting zoning on the basis of increasing evidence that certain types of community design promote public health, as opposed to the dominant pattern of sprawl development, which does not. Zoning, and the land use planning linked to it, that prohibits or disfavors health-promoting community designs contradicts the inherent public policy goal on which it is based. If there is a paradigm shift underway, from traditional sprawl to health-promoting community designs, then health professionals and others should understand why zoning must be reassessed.

  18. Work Zone Data Collection Trailer

    Data.gov (United States)

    Federal Laboratory Consortium — The Work Zone Data Collection Trailer was designed and constructed to enhance data collection and analysis capabilities for the "Evaluating Roadway Construction Work...

  19. 光纤放大器中的受激布里渊散射阈值%Stimulated Brillouin scattering threshold in fiber amplifiers

    Institute of Scientific and Technical Information of China (English)

    梁丽萍; 常丽萍

    2011-01-01

    从受激布里渊散射(SBS)耦合波理论出发,根据双包层光纤放大器中的受激布里渊散射阈值模型,理论仿真了信号带宽、纤芯直径、放大器增益对SBS阈值的影响,并从实验上研究了单频百纳秒脉冲信号在掺镱双包层光纤放大器中的受激布里渊散射现象.实验中输入脉冲信号重复频率1 Hz,脉宽200 ns,对不同的输入脉冲信号放大,前向放大脉冲在脉冲能量660nJ、峰值功率3.3W时出现畸变,产生后向SBS窄脉冲,达到了SBS阈值,实验计算的SBS阈值与理论分析结果基本一致.%Based on the wave coupling theory and the evolution model of the critical pump power (or Brillouin threshold) for stimulated Brillouin scattering(SBS) in double-clad fiber amplifiers, the influence of signal bandwidth, fiber-core diameter and amplifier gain on SBS threshold is simulated theoretically. And experimental measurements of SBS are presented in ytterbium-doped double-clad fiber amplifiers with single-frequency hundred nanosecond pulse amplification. Under different input signal pulses, the fqrward amplified pulse distortion is observed when the pulse energy is up to 660 Nj and the peak power is up to 3. 3 W in the pulse amplification with pulse duration of 200 ns and repetition rate of 1 Hz. And the backward SBS narrow pulse appears. The pulse peak power equals to SBS threshold. Good agreement is shown between the modeled and experimental data.

  20. Excavation damaged zone

    Energy Technology Data Exchange (ETDEWEB)

    Poulain, S.; Sergeant, C.; Vesvres, M.H.; Simonoff, M.; Lavielle, B.; Thomas, B.; Gilabert, E. [Bordeaux-1 Univ., I and 2/CNRS and GdR FORPRO 0788, Nuclear Analytical and Bioenvironmental Chemistry 33 - Gradignan (France); Poulain, S.; Altmann, S.; Lenoir, N.; Barnichon, J.D.; Wileveau, Y.; Lebon, P. [ANDRA - Agence Nationale pour la Gestion des Dechets Radioactifs, 92 - Chatenay Malabry (France); Le Marrec, C. [Bordeaux-1 Univ., ISTAB, INRA, UMR Oenologie - ISVV, 33 - Talence (France); Vinsot, A.; Dewonck, S.; Wileveau, Y.; Armand, G.; Cruchaudet, P.; Rebours, H.; Morel, J. [Agence Nationale pour la Gestion des Dechets Radioactifs, Lab. de Souterrain de Meuse/Haute-Marne, 55 - Bure (France); Lanyon, G.W. [Fracture Systems Ltd, Tregurrian, Ayr, St Ives, Cornwall (United Kingdom); Marschall, P.; Vietor, T. [NAGRA - National Cooperative for the Disposal of Radioactive Waste, Wettingen (Switzerland); Bourdeau, C.; Dedecker, F.; Billaux, D. [ITASCA Consultants, S.A.S., 69 - Ecully (France); Lenoir, N.; Desrues, J.; Viggiani, G.; Besuelle, P. [Laboratoire 3S-R - Sols Solides Structures-Risques, 38 - Grenoble (France); Bornert, M. [Ecole Polytechnique, LMS - Lab. de Mecanique des Solides, 91 - Palaiseau (France); Arson, C.; Gatmiri, B. [CERMES, Ecole Nationale des Ponts et Chaussees, 77 - Marne-la-Vallee (France); Gatmiri, B. [University of Tehran (Iran, Islamic Republic of); Bernier, F. [ESV EURIDICE GIE - European Underground Research Infrastructure for Disposal of Nuclear Waste in Clay Environment (Belgium); Nussbaum, C.; Mori, O. [Geotechnical Institute Ltd., Fabrique de Chaux, St-Ursanne (Switzerland); Bossart, P. [Swisstopo - Federal Office of Topography, Wabern (Switzerland); Schuster, K.; Alheid, H.J. [BGR - Bundesanstalt fur Geowissenschaften und Rohstoffe, Hannover (Germany); Lavanchy, J.M.; Croise, J.; Schwarz, R. [Colenco Power Engineering AG, Groundwater Protection and Waste Disposal, Baden (Switzerland)] [and others

    2007-07-01

    This session gathers 13 articles dealing with: autochthonous and colonizing microorganisms in argillaceous underground environments (S. Poulain, C. Sergeant, C. Le Marrec, M.H. Vesvres, A. Vinsot, S. Dewonck, M. Simonoff, S. Altmann); the discrete fracture network modelling of the Hg-a experiment at the Mont Terri rock Laboratory (G.W. Lanyon, P. Marschall, T. Vietor); the discrete modelling of drift behaviour in the Meuse/Haute-Marne URL, France (C. Bourdeau, F. Dedecker, D. Billaux); the fracturing in Callovo-Oxfordian argillite under triaxial compression studied by X-ray microtomography (N. Lenoir, J. Desrues, G. Viggiani, P. Besuelle, M. Bornert, J.D. Barnichon); a general review of the damage models for the EDZ creation (C. Arson, B. Gatmiri); similarities in the Hydro-Mechanical response of Callovo-Oxfordian clay and Boom clay during gallery excavation (Y. Wileveau, F. Bernier); the different geometries of the EDZ fracture networks in the Mont Terri and Meuse/Haute-Marne rock laboratories: Structural approach (C. Nussbaum, Y. Wileveau, P. Bossart, A. Moeri, G. Armand); the characterisation of the Excavation-Damaged Zone in the Meuse/Haute-Marne Underground Research Laboratory (G. Armand, P. Lebon, M. Cruchaudet, H. Rebours, J. Morel, Y. Wileveau); the EDZ characterisation with ultrasonic interval velocity measurements in the Meuse/Haute-Marne URL, performed between depth of 85 m and 504 m (K. Schuster, H.J. Alheid); the clay formation at the Meuse Haute Marne URL: evaluation of the impact of resin filled slots on flow paths characteristics within the EDZ (J.M. Lavanchy, J. Croise, R. Schwarz, G. Armand, M. Cruchaudet); the characterisation and evolution of EDZ by extraction and analyse of noble gases in pore waters in the Meuse/Haute Marne URL site (B. Lavielle, B. Thomas, E. Gilabert); in-situ gas test for the characterisation of Excavation Disturbed Zone at the Meuse/Haute Marne URL (H. Shao, K. Schuster, J. Soennke, V. Braeuer); and the flow and reactive

  1. Management of coastal zone vegetation

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.

    stream_size 14 stream_content_type text/plain stream_name Trg_Course_Coast_Zone_Manage_1993_22.pdf.txt stream_source_info Trg_Course_Coast_Zone_Manage_1993_22.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  2. Instrumentation for coastal zone management

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    stream_size 11 stream_content_type text/plain stream_name Trg_Course_Coast_Zone_Manage_1993_91.pdf.txt stream_source_info Trg_Course_Coast_Zone_Manage_1993_91.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  3. Zone refining of plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Michael S. [Univ. of Idaho, Moscow, ID (United States)

    1994-08-01

    The zone refining process was applied to Pu metal containing known amounts of impurities. Rod specimens of plutonium metal were melted into and contained in tantalum boats, each of which was passed horizontally through a three-turn, high-frequency coil in such a manner as to cause a narrow molten zone to pass through the Pu metal rod 10 times. The impurity elements Co, Cr, Fe, Ni, Np, U were found to move in the same direction as the molten zone as predicted by binary phase diagrams. The elements Al, Am, and Ga moved in the opposite direction of the molten zone as predicted by binary phase diagrams. As the impurity alloy was zone refined, {delta}-phase plutonium metal crystals were produced. The first few zone refining passes were more effective than each later pass because an oxide layer formed on the rod surface. There was no clear evidence of better impurity movement at the slower zone refining speed. Also, constant or variable coil power appeared to have no effect on impurity movement during a single run (10 passes). This experiment was the first step to developing a zone refining process for plutonium metal.

  4. Volcanic Zone, New Zealand

    Directory of Open Access Journals (Sweden)

    Graham J. Weir

    2001-01-01

    Full Text Available A conceptual model of the Taupo Volcanic Zone (TVZ is developed, to a depth of 25 km, formed from three constant density layers. The upper layer is formed from eruption products. A constant rate of eruption is assumed, which eventually implies a constant rate of extension, and a constant rate of volumetric creation in the middle and bottom layers. Tectonic extension creates volume which can accomodate magmatic intrusions. Spreading models assume this volume is distributed throughout the whole region, perhaps in vertical dykes, whereas rifting models assume the upper crust is thinned and the volume created lies under this upper crust. Bounds on the heat flow from such magmatic intrusions are calculated. Heat flow calculations are performed and some examples are provided which match the present total heat output from the TVZ of about 4200 MW, but these either have extension rates greater than the low values of about 8 ± 4 mm/a being reported from GPS measurements, or else consider extension rates in the TVZ to have varied over time.

  5. Micro-focused Brillouin light scattering study of the magnetization dynamics driven by Spin Hall effect in a transversely magnetized NiFe nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Madami, M., E-mail: marco.madami@fisica.unipg.it; Carlotti, G. [Dipartimento di Fisica e Geologia, Università di Perugia, Perugia (Italy); Gubbiotti, G.; Tacchi, S. [Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, Perugia (Italy); Moriyama, T.; Tanaka, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Kyoto (Japan); Siracusano, G.; Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, Messina (Italy); Carpentieri, M. [Department of Electrical and Information Engineering, Politecnico of Bari, Bari (Italy)

    2015-05-07

    We employed micro-focused Brillouin light scattering to study the amplification of the thermal spin wave eigenmodes by means of a pure spin current, generated by the spin-Hall effect, in a transversely magnetized Pt(4 nm)/NiFe(4 nm)/SiO{sub 2}(5 nm) layered nanowire with lateral dimensions 500 × 2750 nm{sup 2}. The frequency and the cross section of both the center (fundamental) and the edge spin wave modes have been measured as a function of the intensity of the injected dc electric current. The frequency of both modes exhibits a clear redshift while their cross section is greatly enhanced on increasing the intensity of the injected dc. A threshold-like behavior is observed for a value of the injected dc of 2.8 mA. Interestingly, an additional mode, localized in the central part of the nanowire, appears at higher frequency on increasing the intensity of the injected dc above the threshold value. Micromagnetic simulations were used to quantitatively reproduce the experimental results and to investigate the complex non-linear dynamics induced by the spin-Hall effect, including the modification of the spatial profile of the spin wave modes and the appearance of the extra mode above the threshold.

  6. Development of low-temperature and high-pressure Brillouin scattering spectroscopy and its application to the solid I form of hydrogen sulphide

    CERN Document Server

    Murase, S; Sasaki, S; Kume, T; Shimizu, H

    2002-01-01

    A new experimental system has been developed for low-temperature and high-pressure Brillouin scattering measurements. The new system allows us to investigate the elastic properties of samples in a diamond anvil cell (DAC) down to liquid N sub 2 temperature (approx 80 K). In contrast to the case in our conventional technique, the optics in the system can be rotated for measuring the direction dependence of acoustic velocities of the samples in the DAC fixed in the cryostat. The new experimental technique was applied to the solid I form of hydrogen sulphide (H sub 2 S). As a result, three ratios of elastic constants to density were successfully determined at P = 3.70 GPa, T = 240 K: C sub 1 sub 1 /rho = 16.4, C sub 1 sub 2 /rho = 12.4, C sub 4 sub 4 /rho = 7.57 x 10 sup 6 m sup 2 s sup - sup 2. These values are almost the same as those obtained at room temperature.

  7. 49 CFR 71.8 - Mountain zone.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Mountain zone. 71.8 Section 71.8 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.8 Mountain zone. The fourth zone, the mountain standard time zone, includes that part of the United States that is west of...

  8. Formalized morphostructural zoning of the mountain zone of the Andes

    Energy Technology Data Exchange (ETDEWEB)

    Gabrielov, A.M.; Gvishiani, A.D.; Zhidkov, M.P.

    1982-01-01

    A plan is presented for morphostructural zoning of the Andes compiled according to formalized signs for purposes of seismic forecasting. Characteristics are presented for the basic morphostructural subdivisions of the Andes.

  9. Chaotic zones around gravitating binaries

    CERN Document Server

    Shevchenko, Ivan I

    2014-01-01

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound bodies (a double star, a double black hole, a binary asteroid, etc.) is estimated analytically, in function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the binary periods. The binary's mass ratio, above which such a chaotic zone is universally present, is also estimated.

  10. ShoreZone Survey Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a point file showing GPS trackline data collected during a ShoreZone aerial imaging survey. This flight trackline is recorded at 1-second intervals...

  11. In situ vadose zone bioremediation.

    Science.gov (United States)

    Höhener, Patrick; Ponsin, Violaine

    2014-06-01

    Contamination of the vadose zone with various pollutants is a world-wide problem, and often technical or economic constraints impose remediation without excavation. In situ bioremediation in the vadose zone by bioventing has become a standard remediation technology for light spilled petroleum products. In this review, focus is given on new in situ bioremediation strategies in the vadose zone targeting a variety of other pollutants such as perchlorate, nitrate, uranium, chromium, halogenated solvents, explosives and pesticides. The techniques for biostimulation of either oxidative or reductive degradation pathways are presented, and biotransformations to immobile pollutants are discussed in cases of non-degradable pollutants. Furthermore, research on natural attenuation in the vadose zone is presented.

  12. Offshore Wind Technology Depth Zones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Coastal bathymetric depth, measured in meters at depth values of: -30, -60, -900 Shallow Zone (0-30m): Technology has been demonstrated on a commercial scale at...

  13. NEPR Geographic Zone Map 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geographic zone map was created by interpreting satellite and aerial imagery, seafloor topography (bathymetry model), and the new NEPR Benthic Habitat Map...

  14. Development Zones Flourish in Beijing

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Based on the Beijing Municipal Government's plans for developing the city and neighboring suburbs,and after more than 10 years in development,the Beijing Development Zones have taken shape,each with their own characteristics.

  15. Demarcation of secondary hyperalgesia zones

    DEFF Research Database (Denmark)

    Ringsted, Thomas K; Enghuus, Casper; Petersen, Morten A;

    2015-01-01

    of analgesic drug effects in humans. However, since the methods applied in demarcating the secondary hyperalgesia zone seem inconsistent across studies, we examined the effect of a standardized approach upon the measurement of SHA following a first degree burn injury (BI). NEW METHOD: The study was a two...... presented. CONCLUSIONS: This is the first study to demonstrate that demarcation of secondary hyperalgesia zones depends on the developed pressure of the punctate stimulator used....

  16. The global aftershock zone

    Science.gov (United States)

    Parsons, Thomas E.; Margaret Segou,; Warner Marzocchi,

    2014-01-01

    The aftershock zone of each large (M ≥ 7) earthquake extends throughout the shallows of planet Earth. Most aftershocks cluster near the mainshock rupture, but earthquakes send out shivers in the form of seismic waves, and these temporary distortions are large enough to trigger other earthquakes at global range. The aftershocks that happen at great distance from their mainshock are often superposed onto already seismically active regions, making them difficult to detect and understand. From a hazard perspective we are concerned that this dynamic process might encourage other high magnitude earthquakes, and wonder if a global alarm state is warranted after every large mainshock. From an earthquake process perspective we are curious about the physics of earthquake triggering across the magnitude spectrum. In this review we build upon past studies that examined the combined global response to mainshocks. Such compilations demonstrate significant rate increases during, and immediately after (~ 45 min) M > 7.0 mainshocks in all tectonic settings and ranges. However, it is difficult to find strong evidence for M > 5 rate increases during the passage of surface waves in combined global catalogs. On the other hand, recently published studies of individual large mainshocks associate M > 5 triggering at global range that is delayed by hours to days after surface wave arrivals. The longer the delay between mainshock and global aftershock, the more difficult it is to establish causation. To address these questions, we review the response to 260 M ≥ 7.0 shallow (Z ≤ 50 km) mainshocks in 21 global regions with local seismograph networks. In this way we can examine the detailed temporal and spatial response, or lack thereof, during passing seismic waves, and over the 24 h period after their passing. We see an array of responses that can involve immediate and widespread seismicity outbreaks, delayed and localized earthquake clusters, to no response at all. About 50% of the

  17. Zone and double zone diagrams in abstract spaces

    CERN Document Server

    Reem, Daniel

    2007-01-01

    A zone diagram of order $n$ is a relatively new concept which was first defined and studied by T. Asano, J. Matousek and T. Tokuyama. It can be interpreted as a state of equilibrium between $n$ mutually hostile kingdoms. Formally, it is a fixed point of a certain mapping. These authors considered the Euclidean plane and proved the existence and uniqueness of zone diagrams there. In the present paper we generalize this concept in various ways. We consider $m$-spaces (a simple generalization of metric spaces) and prove some existence and (non)uniqueness results there. In contrast to previous works, our proofs are based on purely order theoretic arguments. Many explicit examples are given, and some of them illustrate new phenomena which occur in the general case. We also re-interpret zone diagrams as a stable configuration in a certain combinatorial game, and provide an algorithm for finding this configuration in a particular case.

  18. SEMIAUTOMATIC DETECTION OF TUMORAL ZONE

    Directory of Open Access Journals (Sweden)

    Ezzeddine Zagrouba

    2011-05-01

    Full Text Available This paper describes a robust method based on the cooperation of fuzzy classification and regions segmentation algorithms, in order to detect the tumoral zone in the brain Magnetic Resonance Imaging (MRI. On one hand, the classification in fuzzy sets is done by the Fuzzy C-Means algorithm (FCM, where a study of its different parameters and its complexity has been previously realised, which led us to improve it. On the other hand, the segmentation in regions is obtained by an hierarchical method through adaptive thresholding. Then, an operator expert selects a germ in the tumoral zone, and the class containing the sick zone is localised in return for the FCM algorithm. Finally, the superposition of the two partitions of the image will determine the sick zone. The originality of our approach is the parallel exploitation of different types of information in the image by the cooperation of two complementary approaches. This allows us to carry out a pertinent approach for the detection of sick zone in MRI images.

  19. The shape of Brillouin zone of body-centered cubic crystal is not normal dodecahedron%体心立方晶格的布里渊区形状不是正十二面体

    Institute of Scientific and Technical Information of China (English)

    汪乔欣; 田强

    2007-01-01

    介绍了可能的五种正多面体,指出正十二面体是晶体结构及其布里渊区不可能具有的正多面体形状.体心立方晶格的布里渊区是菱形十二面体,不是正十二面体.

  20. The Methods to Draw the First Brillouin Zone for Face-centered Cubic and Body-centered Cubic Lattice%面心立方、体心立方晶格第一布里渊区的画法

    Institute of Scientific and Technical Information of China (English)

    黄宝歆

    2016-01-01

    本文通过先分解再组合的方法给出面心立方和体心立方晶格第一布里渊区的立体结构,即先确定出一个1/8倒格子晶胞空间对应的第一布里渊区,再将其与另外7个小倒格子晶胞的第一布里渊区空间进行组合,最终标识出完整的第一布里渊区结构.分别计算了其体积的大小,为同学们学习相关知识提供一个借鉴.

  1. A Band Structure Based Nonuniform Brillouin Zone Tetrahedron Approach%基于能带结构的布里渊区非均匀四面体网格生成技术

    Institute of Scientific and Technical Information of China (English)

    陈勇; RAVAIOLI Umberto

    2006-01-01

    基于非局域赝势能带计算及四面体网格单元中能量满足线性关系,提出一种布里渊区非均匀四面体网格产生方法,在满足精度条件下能自动得出数目最少的四面体网格,使布里渊区积分计算的精度和效率大为提高.通过对硅、锗两种金刚石结构半导体简约布里渊区所产生网格的比较,表明该方法可以根据能带结构的特点自动生成优化的非均匀网格.对现有的态密度四面体计算公式进行了补充完善,并根据生成的网格和完善后的公式计算了硅和锗导带第一、二能带的态密度.

  2. Quasiparticle dynamics across the full Brillouin zone of Bi2Sr2CaCu2O8+δ traced with ultrafast time and angle-resolved photoemission spectroscopy

    Directory of Open Access Journals (Sweden)

    Georgi L. Dakovski

    2015-09-01

    Full Text Available A hallmark in the cuprate family of high-temperature superconductors is the nodal-antinodal dichotomy. In this regard, angle-resolved photoemission spectroscopy (ARPES has proven especially powerful, providing band structure information directly in energy-momentum space. Time-resolved ARPES (trARPES holds great promise of adding ultrafast temporal information, in an attempt to identify different interaction channels in the time domain. Previous studies of the cuprates using trARPES were handicapped by the low probing energy, which significantly limits the accessible momentum space. Using 20.15 eV, 12 fs pulses, we show for the first time the evolution of quasiparticles in the antinodal region of Bi2Sr2CaCu2O8+δ and demonstrate that non-monotonic relaxation dynamics dominates above a certain fluence threshold. The dynamics is heavily influenced by transient modification of the electron-phonon interaction and phase space restrictions, in stark contrast to the monotonic relaxation in the nodal and off-nodal regions.

  3. Plumes in stellar convection zones

    CERN Document Server

    Zahn, J P

    1999-01-01

    All numerical simulations of compressible convection reveal the presence of strong downwards directed flows. Thanks to helioseismology, such plumes have now been detected also at the top of the solar convection zone, on super- granular scales. Their properties may be crudely described by adopting Taylor's turbulent entrainment hypothesis, whose validity is well established under various conditions. Using this model, one finds that the strong density stratification does not prevent the plumes from traversing the whole convection zone, and that they carry upwards a net energy flux (Rieutord & Zahn 1995). They penetrate to some extent in the adjacent stable region, where they establish a nearly adiabatic stratification. These plumes have a strong impact on the dynamics of stellar convection zones, and they play probably a key role in the dynamo mechanism.

  4. 76 FR 7107 - Quarterly Listings; Safety Zones, Security Zones, Special Local Regulations, Drawbridge Operation...

    Science.gov (United States)

    2011-02-09

    ...-0997 New York, NY Security Zones (Part 165).... 9/23/2008 USCG-2008-0998 Puerto Rico Safety Zones (Part...-0358 Puerto Rico Safety Zones (Part 165)...... 5/31/2009 USCG-2009-0360 Cincinnati, OH Safety Zones...-1042 Baton Rouge, LA Safety Zones (Part 165)...... 12/4/2009 USCG-2009-1043 South Padre Island,...

  5. Strain distribution in thin concrete pavement panels under three-point loading to failure with pre-pulse-pump Brillouin optical time domain analysis (Presentation Video)

    Science.gov (United States)

    Bao, Yi; Cain, John; Chen, Yizheng; Huang, Ying; Chen, Genda; Palek, Leonard

    2015-04-01

    Thin concrete panels reinforced with alloy polymer macro-synthetic fibers have recently been introduced to rapidly and cost-effectively improve the driving condition of existing roadways by laying down a fabric sheet on the roadways, casting a thin layer of concrete, and then cutting the layer into panels. This study is aimed to understand the strain distribution and potential crack development of concrete panels under three-point loading. To this end, six full-size 6ft×6ft×3in concrete panels were tested to failure in the laboratory. They were instrumented with three types of single-mode optical fiber sensors whose performance and ability to measure the strain distribution and detect cracks were compared. Each optical fiber sensor was spliced and calibrated, and then attached to a fabric sheet using adhesive. A thin layer of mortar (0.25 ~ 0.5 in thick) was cast on the fabric sheet. The three types of distributed sensors were bare SM-28e+ fiber, SM-28e+ fiber with a tight buffer, and concrete crack cable, respectively. The concrete crack cable consisted of one SM-28e+ optical fiber with a tight buffer, one SM-28e+ optical fiber with a loose buffer for temperature compensation, and an outside protective tight sheath. Distributed strains were collected from the three optical fiber sensors with pre-pulse-pump Brillouin optical time domain analysis in room temperature. Among the three sensors, the bare fiber was observed to be most fragile during construction and operation, but most sensitive to strain change or micro-cracks. The concrete crack cable was most rugged, but not as sensitive to micro-cracks and robust in micro-crack measurement as the bare fiber. The ruggedness and sensitivity of the fiber with a tight buffer were in between the bare fiber and the concrete crack cable. The strain distribution resulted from the three optical sensors are in good agreement, and can be applied to successfully locate cracks in the concrete panels. It was observed that the

  6. ISOLDE target zone control room

    CERN Multimedia

    2016-01-01

    Operating the ISOLDE target handling robots from the dedicated control room in building 197. Monitors showing the movements of the robots (GPS in this case) in the target zone. The footage shows the actual operation by the operator as well as the different equipment such as camera electronics, camera motor controls, camera monitors and Kuka robot controls touch panel.

  7. Land Governance as Grey Zone

    DEFF Research Database (Denmark)

    Kjær, Anne Mette

    2017-01-01

    demonstrates that in Uganda, the need to maintain the ruling coalition in a clientelist political settlement to build electoral support, and the desire to attract economic investors, constitute political incentives to maintain land governance as a grey zone, even if there is apparent political...

  8. Cerebellar Zones: A Personal History

    NARCIS (Netherlands)

    J. Voogd (Jan)

    2011-01-01

    textabstractCerebellar zones were there, of course, before anyone noticed them. Their history is that of young people, unhindered by preconceived ideas, who followed up their observations with available or new techniques. In the 1960s of the last century, the circumstances were fortunate because thr

  9. Building a Subduction Zone Observatory

    Science.gov (United States)

    Gomberg, Joan S.; Bodin, Paul; Bourgeois, Jody; Cashman, Susan; Cowan, Darrel; Creager, Kenneth C.; Crowell, Brendan; Duvall, Alison; Frankel, Arthur; Gonzalez, Frank; Houston, Heidi; Johnson, Paul; Kelsey, Harvey; Miller, Una; Roland, Emily C.; Schmidt, David; Staisch, Lydia; Vidale, John; Wilcock, William; Wirth, Erin

    2016-01-01

    Subduction zones contain many of Earth’s most remarkable geologic structures, from the deepest oceanic trenches to glacier-covered mountains and steaming volcanoes. These environments formed through spectacular events: Nature’s largest earthquakes, tsunamis, and volcanic eruptions are born here.

  10. ShoreZone Mapped Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is a polyline file of mapped ShoreZone units which correspond with data records found in the Unit, Xshr, BioUnit, and BioBand tables of this...

  11. Objects as Temporary Autonomous Zones

    Directory of Open Access Journals (Sweden)

    Tim Morton

    2011-09-01

    Full Text Available From Hakim Bey's instructions on creating temporary autonomous zones we see an oscillation "between performance art and politics, circus clowning and revolution." In this essay Tim Morton discusses anarchist politics as, "the creation of fresh objects in a reality without a top or a bottom object, or for that matter a middle object."

  12. Objects as Temporary Autonomous Zones

    OpenAIRE

    Tim Morton

    2011-01-01

    From Hakim Bey's instructions on creating temporary autonomous zones we see an oscillation "between performance art and politics, circus clowning and revolution." In this essay Tim Morton discusses anarchist politics as, "the creation of fresh objects in a reality without a top or a bottom object, or for that matter a middle object."

  13. CHAOTIC ZONES AROUND GRAVITATING BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, Ivan I., E-mail: iis@gao.spb.ru [Pulkovo Observatory of the Russian Academy of Sciences, Pulkovskoje ave. 65, St. Petersburg 196140 (Russian Federation)

    2015-01-20

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.

  14. Priority Education Zones in Mauritius

    Science.gov (United States)

    Kumar, Mahadeo Santosh; Gurrib, Mahomed Aniff

    2008-01-01

    This article discusses the Priority Education Zones project (ZEP) in Mauritius. The original and innovative dimensions of the project are described, together with the difficulties encountered during the setting-up of the ZEP schools. The article covers five main issues: the status of the ZEP project; the minimal conditions for success; the…

  15. Zone refining of plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The purpose of this study was to investigate zone refining techniques for the purification of plutonium metal. The redistribution of 10 impurity elements from zone melting was examined. Four tantalum boats were loaded with plutonium impurity alloy, placed in a vacuum furnace, heated to 700{degrees}C, and held at temperature for one hour. Ten passes were made with each boat. Metallographic and chemical analyses performed on the plutonium rods showed that, after 10 passes, moderate movement of certain elements were achieved. Molten zone speeds of 1 or 2 inches per hour had no effect on impurity element movement. Likewise, the application of constant or variable power had no effect on impurity movement. The study implies that development of a zone refining process to purify plutonium is feasible. Development of a process will be hampered by two factors: (1) the effect on impurity element redistribution of the oxide layer formed on the exposed surface of the material is not understood, and (2) the tantalum container material is not inert in the presence of plutonium. Cold boat studies are planned, with higher temperature and vacuum levels, to determine the effect on these factors. 5 refs., 1 tab., 5 figs.

  16. Unsaturated Zone and Saturated Zone Transport Properties (U0100)

    Energy Technology Data Exchange (ETDEWEB)

    J. Conca

    2000-12-20

    This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion.

  17. TASK 2: QUENCH ZONE SIMULATION

    Energy Technology Data Exchange (ETDEWEB)

    Fusselman, Steve

    2015-09-30

    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual

  18. Zone Denmark - gasell Taanist / Reet Krause

    Index Scriptorium Estoniae

    Krause, Reet, 1967-

    2006-01-01

    Taanis Viborgis asuva firma Zone Company Denmark, kaubamärgi Zone Denmark ja firma disainerite tutvustus. Ettevõte valmistab disainitooteid roostevabast terasest, klaasist, puidust, kummist jm. Disainer Naja Utzon Popov endast, oma loomingust

  19. United States Stateplane Zones - NAD83

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — U.S. State Plane Zones (NAD 1983) represents the State Plane Coordinate System (SPCS) Zones for the 1983 North American Datum within United States.

  20. United States Stateplane Zones - NAD27

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — U.S. State Plane Zones (NAD 1927) represents the State Plane Coordinate System (SPCS) Zones for the 1927 North American Datum within United States.

  1. GIS modeling of introduction zones in Sochi

    Directory of Open Access Journals (Sweden)

    Annenkova Irina Vladimirovna

    2014-11-01

    Defined the mean monthly temperature and precipitation for each zone. The diagram shows the dependence of the probability distribution of the three groups resistance from the mean annual temperature and mean annual precipitation. Describes the climatic conditions of the zones.

  2. Zoning, 2004, East Baton Rouge Parish, Louisiana

    Data.gov (United States)

    Louisiana Geographic Information Center — This is a graphical polygon dataset depicting the zoning boundaries of the East Baton Rouge Parish of the State of Louisiana. Zoning can be defined as the range of...

  3. Experiential reflective learning and comfort zone

    Directory of Open Access Journals (Sweden)

    Jan Nehyba

    2011-09-01

    Full Text Available The article deals with the issue of experiential reflective learning. Firstlyit aims to discuss the concept of comfort zone in this area. It goes beyond the usualdefinition of the domestic comfort zone and it reflects in terms of experiential reflectivelearning in the world. The conclusions point to possible parallels with the concept ofcomfort zones and K. Lewin theory. Overall, the article focuses on topics that help toexpand the view on the issue of comfort zone.

  4. 46 CFR 76.35-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Zoning. 76.35-5 Section 76.35-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Manual Alarm System, Details § 76.35-5 Zoning. (a) The zoning of the manual alarm system shall meet the same requirements...

  5. 46 CFR 76.23-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Zoning. 76.23-5 Section 76.23-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Manual Sprinkling System, Details § 76.23-5 Zoning. (a) Separate zones may be used for each deck, and on any...

  6. 46 CFR 76.33-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Zoning. 76.33-5 Section 76.33-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Smoke Detecting System, Details § 76.33-5 Zoning. (a) The smoke detecting system shall be divided into separate zones...

  7. Export Processing Zones and Global Class Formation

    NARCIS (Netherlands)

    Neveling, Patrick

    2015-01-01

    This chapter is concerned with one of the most striking developments in the global political economy of capitalism after the Second World War; the rise of export processing zones and special economic zones. Building on long-term ethnohistorical research on the zones’ global spread from one zone in P

  8. 40 CFR 265.278 - Unsaturated zone (zone of aeration) monitoring.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Unsaturated zone (zone of aeration) monitoring. 265.278 Section 265.278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., STORAGE, AND DISPOSAL FACILITIES Land Treatment § 265.278 Unsaturated zone (zone of aeration)...

  9. The stretch zone of automotive steel sheets

    Indian Academy of Sciences (India)

    Ľ Ambriško; L Pešek

    2014-04-01

    The paper deals with an experimental determination of the stretch zone dimensions in the notch tip in thin steel sheets. The stretch zone dimensions depend on steel grade, on the rolling direction as well as on the loading rate. Stretch zones were observed and measured on three steel grades. Fracture area and stretch zones were analysed by SEM. Stable crack growth was monitored by videoextensometry techniques on CT (Compact Tension) specimens. Specimens were loaded under two loading rates by eccentric tension, whereby the deformation in the notch surrounding area was recorded using a non-contact measurement–videoextensometry technique. Linear relation between the stretch zone dimensions was determined.

  10. Investigations of Near-Zone Doppler Effects.

    Science.gov (United States)

    Prouty, Dale Austen

    Far away from an electromagnetic source the normal Doppler shifts in frequency occur--a red shift for receding and a blue shift for approaching. As indicated by previous work with an infinitesimal dipole, different frequency shifts occur when the source and observer move closer together, into the near-zone. These "near-zone Doppler effects" are investigated for general sources and subsequently two specific examples are presented. The general results show that near-zone shifts are similar to far-zone shifts, but the local phase velocity must be used, i.e. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). In the far zone the phase velocity is the speed of light; in the near zone it differs. Fundamentally, the distance between surfaces of constant phase in the near zone is changed. The surfaces of constant phase for the waves are no longer spherical, but more ellipsoidal or spheroidal, so that a moving observer sees a different frequency shift. Two specific examples are presented to indicate the actual magnitude of near-zone effects. The examples include a prolate spheroidal antenna and a circular aperture. Once the magnitude of the effects is determined, the measurability of near-zone Doppler effects is discussed. The investigation concentrates on Fresnel zone effects due to the measurement problem. Finally, it is shown that for an electrically large wire antenna (the spheroidal example) near-zone Doppler effects are measurable.

  11. Holdridge life zone physical inconsistency

    Science.gov (United States)

    Martínez, A., Sr.; Ochoa, A.

    2015-12-01

    Life zones is a very used classification system, developed by L.R. Holdridge in 1967, used to discern why plants have different adaptation mechanism to their surrounding environment. In this paper, the relation between potential evapotranspiration rate (ETr ), anual precipitation (P ) and biotemperature (Tb ) in the Holdridge triangle, is parametrized (P = (500/9)*ETr) to evaluate if the rain process is conserved in Colombia. Further, an adiabatic ascent of air with diurnal and interannual variability, and cluster analysis is view as a classification example of the advantage of using physical process to evaluate the plants adaptation mechanisms . The most inconsistency life zones are situated in the rainiest places of Colombian pacific costs in tropical latitudinal region, are non-exist places in holdridge triangle with annual biotemperature higher than 26◦ C, annual precipitation about 10.000mm and annual potential evapotranspiration rate about 0.1. The difference between Holdridge predicted precipitation and the precipitation measured with TRMM are about 5.000mm in these places. Classification systems based on an annual average, do not stablish adaptation as a function of diurnal variability, for example, the difference between valley sides vegetation could not being determined. This kind of limitations, added to a validation procces and the auscence of a physic procces in the variable interaction, make the Holdridge Life Zones a very useful tool, but physically inconsistent for caracterice vegetation as a function of precipitation. The rain process is very complex, depend of mass and energy exchanges and is still a controversial topic in atmospheric modeling, as a biotic pump.

  12. Synaptic vesicle proteins and active zone plasticity

    Directory of Open Access Journals (Sweden)

    Robert J Kittel

    2016-04-01

    Full Text Available Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone. The complex molecular architecture of active zones mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of active zones vary significantly, even for a given connection. Thus, there appear to be distinct active zone states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the active zone.The protein-rich cytomatrix at the active zone (CAZ provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1 and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and active zone states, which has heretofore received little attention.

  13. Plan de Negocios: Networking Zone

    OpenAIRE

    Espol; Cárdenas Sáenz, Daniel Alejandro; Seminario Benalcázar, Ivette Dennisse

    2016-01-01

    Networking Zone se define coma una empresa que alquila espacios de trabajo totalmente amoblados y equipados, necesarios para los profesionales / emprendedores, ubicado en la ciudad de Guayaquil en un área de unos 800 metros cuadrados. Esta propuesta atiende la ausencia de espacios físicos amoblados para profesionales independientes, emprendedores, FreeLancer quienes buscan un lugar cómodo, accesible, con tecnología adecuada para cumplir sus necesidades de trabajo a un bajo costo, evtándole...

  14. Subventricular zone microglia transcriptional networks.

    Science.gov (United States)

    Starossom, Sarah C; Imitola, Jaime; Wang, Yue; Cao, Li; Khoury, Samia J

    2011-07-01

    Microglia play an important role in inflammatory diseases of the central nervous system. There is evidence of microglial diversity with distinct phenotypes exhibiting either neuroprotection and repair or neurotoxicity. However the precise molecular mechanisms underlying this diversity are still unknown. Using a model of experimental autoimmune encephalomyelitis (EAE) we performed transcriptional profiling of isolated subventricular zone microglia from the acute and chronic disease phases of EAE. We found that microglia exhibit disease phase specific gene expression signatures, that correspond to unique gene ontology functions and genomic networks. Our data demonstrate for the first time, distinct transcriptional networks of microglia activation in vivo, that suggests a role as mediators of injury or repair.

  15. 光纤中基于布里渊激光振荡的超光速传输首次在实验上实现%Superluminal Propagation in Optical Fibers Based on Brillouin Lasing Oscillation First Demonstrated

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    上海交通大学物理系詹黎教授(图1)以及其博士研究生张亮(图2)首次在实验上实现了光纤中基于布里渊激光振荡的低损耗长距离超光速传输,其研究成果以"Superluminal propagation at negative groupvelocity in optical fibers based on Brillouin lasing oscillation"为标题发表在物理领域国际顶级期刊物理评论快报( Physical Review Letters)(Phys.Rev.Lett.,Vol.107,093903,2011).

  16. Wood zone plate fishnet metalens

    Directory of Open Access Journals (Sweden)

    Orazbayev Bakhtiyar

    2015-01-01

    Full Text Available Fresnel-zone plate lenses provide focusing performance while having low profile. Unfortunately, they usually display higher reflection losses than conventional dielectric lenses. Here, we demonstrate a low-profile Wood zone plate metalens based on the fishnet metamaterial working in a near-zero regime with an equivalent refractive index less than unity (nf = 0.51. The metalens is made of alternating dielectric and fishnet metamaterial concentric rings. The use of fishnet metamaterial allows reducing the reflections from the lens, while maintaining low profile, low cost and ease of manufacturing. The lens is designed to work at the W-band of the millimeter-waves range with a focal length FL = 22.8 mm (7.5 λ0 aiming at antenna or radar system applications. The focusing performance of the lens along with its radiation characteristics in a lens antenna configuration have been studied numerically and confirmed experimentally, showing a gain improvement of ~2.5 dB with respect to a fishnet Soret metalens.

  17. Euphotic Zone Study moves forward

    Science.gov (United States)

    Denman, Kenneth

    The Global Ocean Euphotic Zone Study (GOEZS), a potential core program of the International Geosphere-Biosphere Programme (IGBP) being planned jointly with the Scientific Committee on Oceanic Research (SCOR), was recently given the go-ahead by IGBP's Scientific Committee to move on to the next level of developing its scientific program.The GOEZS program will focus on the coupled physical, biological, and chemical processes operating in the euphotic zone, which is the ocean surface layer where sufficient light penetrates for photosynthesis by phytoplankton to exceed their metabolic energy losses. The upper ocean is extremely important to understanding the atmosphereocean system because it mediates exchanges of heat, momentum, carbon dioxide, sulphur, and nitrogen between the atmosphere and the ocean interior. For the major greenhouse gas carbon dioxide for example, there is more carbon in the upper ocean than in the whole atmosphere. Essentially all carbon dioxide from the atmosphere that passes from the upper ocean to the ocean interior has been transformed chemically or biologically in the upper ocean. Moreover, the upper ocean is the site of all marine shipping and most recreation and industrial activity and contains the planktonic food chain and most fish stocks.

  18. Crustal growth in subduction zones

    Science.gov (United States)

    Vogt, Katharina; Castro, Antonio; Gerya, Taras

    2015-04-01

    There is a broad interest in understanding the physical principles leading to arc magmatisim at active continental margins and different mechanisms have been proposed to account for the composition and evolution of the continental crust. It is widely accepted that water released from the subducting plate lowers the melting temperature of the overlying mantle allowing for "flux melting" of the hydrated mantle. However, relamination of subducted crustal material to the base of the continental crust has been recently suggested to account for the growth and composition of the continental crust. We use petrological-thermo-mechanical models of active subduction zones to demonstrate that subduction of crustal material to sublithospheric depth may result in the formation of a tectonic rock mélange composed of basalt, sediment and hydrated /serpentinized mantle. This rock mélange may evolve into a partially molten diapir at asthenospheric depth and rise through the mantle because of its intrinsic buoyancy prior to emplacement at crustal levels (relamination). This process can be episodic and long-lived, forming successive diapirs that represent multiple magma pulses. Recent laboratory experiments of Castro et al. (2013) have demonstrated that reactions between these crustal components (i.e. basalt and sediment) produce andesitic melt typical for rocks of the continental crust. However, melt derived from a composite diapir will inherit the geochemical characteristics of its source and show distinct temporal variations of radiogenic isotopes based on the proportions of basalt and sediment in the source (Vogt et al., 2013). Hence, partial melting of a composite diapir is expected to produce melt with a constant major element composition, but substantial changes in terms of radiogenic isotopes. However, crustal growth at active continental margins may also involve accretionary processes by which new material is added to the continental crust. Oceanic plateaus and other

  19. Saltwater upconing zone of influence

    Science.gov (United States)

    Jakovovic, Danica; Werner, Adrian D.; de Louw, Perry G. B.; Post, Vincent E. A.; Morgan, Leanne K.

    2016-08-01

    In this study, we define and characterize the saltwater upconing zone of influence (SUZI). The SUZI is the region around a pumping well within which significant rise in the saltwater-freshwater interface occurs. While the zone of influence of a pumping well can be clearly defined in terms of hydraulics (e.g., drawdown), the SUZI has not been recognised and characterised, despite its importance for groundwater decision-making in coastal regions. We explore the SUZI under various conditions and compare common methods of investigation using both axisymmetric (1D and 2D vertical cross-section) and 3D simulations of saltwater upconing at the field scale, based on a combination of numerical and analytical approaches. The SUZI was found to be dependent on the relative magnitudes of pumping, regional flow, distance of the well from the coast, and position of the well above the interface, as expected. The three-dimensional coastal setting simulations revealed an asymmetric shape of the lateral extent of the SUZI, which is largest in the direction parallel to the coast. This occurs because the ocean and the inland extent of the seawater wedge limit the propagation of the SUZI perpendicular to the coast. Predictions of the SUZI using the Ghyben-Herzberg approximation, including cases where sloping interfaces occur (i.e., in contrast to the artificiality of horizontal interfaces used in axisymmetric approaches), provide reasonable first approximations of the SUZI. Numerical modelling of dispersive upconing in the 3D inclined interface case is influenced by practical limits to the model domain size and grid resolution. For example, the no-flow boundary condition at 1500 m from the pumping well elongates the SUZI in the direction parallel to the coast. This study extends previous concepts of well interference, which have previously been based on hydraulics only, by introducing the SUZI and characterising its extent, with consideration given to differences in commonly adopted

  20. Zone refining of cadmium and related characterization

    Indian Academy of Sciences (India)

    N R Munirathnam; D S Prasad; Ch Sudheer; J V Rao; T L Prakash

    2005-06-01

    We present the zone refining results of cadmium using horizontal resistive zone refiner under constant flow of moisture free hydrogen gas. The boron impurity in cadmium can be avoided using quartz (GE 214 grade) boat in lieu of high pure graphite boat. The analytical results using inductively coupled plasma optical emission spectrometry (ICPOES) show that majority of the impurities are less than the detection limits. Comparatively, zinc is the most difficult impurity element to remove in cadmium matrix by zone refining.

  1. NOAA Average Annual Salinity (3-Zone)

    Data.gov (United States)

    California Department of Resources — The 3-Zone Average Annual Salinity Digital Geography is a digital spatial framework developed using geographic information system (GIS) technology. These salinity...

  2. Policy Change Implication Toward Integrated Wonorejo Zone as A Strategic Economic Development Zone

    Directory of Open Access Journals (Sweden)

    Akbar Pandu Dwinugraha

    2014-04-01

    Full Text Available Integrated Wonorejo Zone is one of the development zone in Lumajang Regency with significant goals to improve potensial condition in three aspect namely tourism, agriculture and SMEs. Based on RTRW in 2008-2028, which was established in 2008, the development strategy of this zone is change. Integrated Wonorejo Zone was mentioned as a Strategic Economic Development Zone. This research describe and analyse about how the implication of policy change toward Integrated Wonorejo Zone. This research using method of descriptive research with qualitative approach as well as analysis of data by John Seidel about QDA (qualitative data analysis. The result of this research explain that the policy change implication, from description, implementation and implication point of view did not give significant expectation. Key Words: Policy Change, Integrated Wonorejo Zone, Strategic Economic Development Zone.

  3. 76 FR 18393 - Safety Zones: Fireworks Displays in the Captain of the Port Columbia River Zone

    Science.gov (United States)

    2011-04-04

    ... determination based on the fact that this rule only changes the period during which the safety zone established...: The owners or operators of vessels wishing to transit the safety zone established by this rule....

  4. 78 FR 25410 - Safety Zone; Tall Ship Safety Zones; War of 1812 Bicentennial Commemoration, Great Lakes

    Science.gov (United States)

    2013-05-01

    ... in the Tall Ships Challenge Great Lakes 2013 and the War of 1812 Bicentennial Commemoration. These... Safety Zones; War of 1812 Bicentennial Commemoration, Great Lakes. (a) Locations. The following are... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Tall Ship Safety Zones; War of...

  5. Land use zones and land use patterns in the Atlantic Zone of Costa Rica

    NARCIS (Netherlands)

    Huising, E.J.

    1993-01-01

    This thesis describes an approach to land use inventory at the sub-regional scale in the Guacimo-Rio Jiménez-Siquirres (GRS) area in the Atlantic Zone of Costa Rica. Therefore, the concept of "land use zones" is introduced. The land use zone (LUZ) plays a central role in the definition of an observa

  6. 76 FR 18674 - Security Zones; Sector Southeastern New England Captain of the Port Zone

    Science.gov (United States)

    2011-04-05

    ... security zone encompassing all navigable waters around any cruise ship anchored or moored and 200-yard radius security zone encompassing all navigable waters around any cruise ship underway that is being... navigable waters within the Southeastern New England COTP zone. We propose to define a ``cruise ship'' as...

  7. 46 CFR 76.27-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Zoning. 76.27-5 Section 76.27-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Electric Fire Detecting System, Details § 76.27-5 Zoning. (a) The fire detecting system shall be divided into...

  8. 46 CFR 76.30-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Zoning. 76.30-5 Section 76.30-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Pneumatic Fire Detecting System, Details § 76.30-5 Zoning. (a) The fire detecting system shall be divided into...

  9. Special Economic Zones Blaze New Trails

    Institute of Scientific and Technical Information of China (English)

    徐现祥; 陈小飞

    2008-01-01

    Special economic zones(SEZ) are starting points of incremental reform and opening-up in China. On the 30th anniversay of reform and opening-up,this article attempts to present a systematic review of the evolution,mechanism and performance of special economic zones as well as a pespective on SEZs’ furture development.

  10. CareZone adgangskontrol og demenshegn

    DEFF Research Database (Denmark)

    Hauberg, Nanna

    2015-01-01

    Rapporten er skrevet på baggrund af afprøvning af CareZone, adgangskontrol og demenshegn på Solgaven, Mariagerfjord kommune i perioden april 2014 til januar 2015.......Rapporten er skrevet på baggrund af afprøvning af CareZone, adgangskontrol og demenshegn på Solgaven, Mariagerfjord kommune i perioden april 2014 til januar 2015....

  11. A Novel Offset Fresnel Zone Plate Antenna

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A novel offset Fresnel Zone Plate reflector Antenna (FZPA) is proposed, the phase correcting zone of this FZPA is elliptic. Based on Physical Optics Method, the focusing characteristics of the reflector are analyzed. The comparison of this new FZPA with the circular FZPA and Mawzones FZPA is made.

  12. Treating tar sands formations with karsted zones

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX)

    2010-03-09

    Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

  13. 46 CFR 76.25-5 - Zoning.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS FIRE PROTECTION EQUIPMENT Automatic Sprinkling System, Details § 76.25-5 Zoning. (a) The automatic sprinkling system shall be divided into separate... more than 250 sprinkler heads. (c) The sprinkling zone may cover more than one deck, in which case,...

  14. Remote sensing applications for coastal zone management

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, L.V.G.

    stream_size 4 stream_content_type text/plain stream_name Trg_Course_Coast_Zone_Manage_1993_5.pdf.txt stream_source_info Trg_Course_Coast_Zone_Manage_1993_5.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  15. Brief Introduction to Five Key Zones

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Liaoning Jinzhou Development Zone This zone includes Jinzhou Xihai Industrial Park and Huludao Beigang Industrial Park. The Jinzhou Xihai Industrial Park has a planned development area of 22.76 square km and a gross investment of 737 million yuan. It is featured in the sub-industries of heavy chemicals and petrochemicals that Include motor tool elements, medicine and production of containers.

  16. 受激布里渊散射光纤陀螺(SBS-FOG)中 传输光偏振稳定性的研究%Study on polarization stability of transmitting light for stimulated Brillouin scattering fiber optic gyros (SBS-FOG)

    Institute of Scientific and Technical Information of China (English)

    延凤平; 单英; 简水生

    2001-01-01

    研究了受激布里渊散射光纤陀螺(SBS-FOG)敏感环中,在保偏光纤熔接点处进行θ角的偏振主轴旋转后传输光的偏振稳定性。得出当θ=90°时,在敏感环中的传输光不仅具有最大偏振度,而且还使其中的两个本征偏振态(ESOP)达到稳定的结论。%The characteristics of the eigen state of polarization (ESOP) of the pump light and the stimulated Brillouin scattering light in the sensing coil were theoretically analyzed for the stimulated Brillouin scattering fiber optic gyros (SBS-FOG), and the conclusions about stability of the ESOP and polarization degree of the transmitting light were obtained.

  17. Louisiana Speaks Regional Plan Vision Special Economic Zones, UTM Zone 15N NAD83, Louisiana Recovery Authority (2007), [louisiana_speaks_vision_special_economic_zones

    Data.gov (United States)

    Louisiana Geographic Information Center — This GIS shapefile data illustrates special economic zones included in the Louisiana Speaks Regional Plan Vision. Special economic zones include existing national,...

  18. Earthcasting the future Critical Zone

    Directory of Open Access Journals (Sweden)

    Yves Goddéris

    2013-12-01

    Full Text Available Abstract As humans continue to impact the Critical Zone, we need to project how our environment will evolve into the future. To model such change requires the ability to simulate interactions among the lithosphere, pedosphere, hydrosphere, biosphere, and atmosphere — including the activities of humans. Such projections, which some have called earthcasts, must be made with mechanistic models that capture the important phenomena, as well as scenarios of human behavior. As an example, we present earthcasts of future weathering in the mid-continent of the USA into the next century of projected warming. Rates of sequestration of CO2 from the atmosphere due to weathering will change in the future as carbonate and silicate minerals are dissolved or precipitated in soil. The downward or upward advance of the carbonate reaction front in the soil is an analogue of the oceanic lysocline. Like the movement of the oceanic lysocline in response to oceanic acidification, this terrestrial lysocline will likely move due to fluxes of CO2 driven by human activity. Understanding this and other responses to perturbations will best be achieved using multiple models for earthcasting.

  19. UV Habitable Zones Further Constrain Possible Life

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    Where should we search for life in the universe? Habitable zones are traditionallydetermined based on the possibility of liquid water existing on a planet but ultraviolet (UV) radiation also plays a key role.The UV Habitable ZoneSchematic showing how the traditional habitable zones location and width changes around different types of stars. The UV habitable zone also hasdifferent locations and widths depending on the mass and metallicity of the star. [NASA/Kepler Mission/Dana Berry]Besides the presence of liquid water, there are other things life may need to persist. For life as we know it, one important elementis moderate UV radiation: if a planet receives too little UV flux, many biological compounds cant be synthesized. If it receives too much, however, then terrestrial biological systems (e.g. DNA) can be damaged.To determinethe most likely place to findpersistent life, we should therefore look for the region where a stars traditional habitable zone, within which liquid water is possible, overlaps with its UV habitable zone, within which the UV flux is at the right level to support life.Relationship between the stellar mass and location of the boundaries of the traditional and UV habitable zones for a solar-metallicity star. din and dout denote inner and outer boundaries, respectively. ZAMS and TMS denote when the star joins and leaves the main sequence, respectively. The traditional and UV habitable zones overlap only for stars of 11.5 solar masses. [Adapted from Oishi and Kamaya 2016]Looking for OverlapIn a recent study, two scientists from the National Defense Academy of Japan, Midori Oishi and Hideyuki Kamaya, explored howthe location of this UV habitable zone and that of its overlap with the traditional habitable zone might be affected by a stars mass and metallicity.Oishi and Kamaya developed a simple evolutional model of the UV habitable zone in stars in the mass range of 0.084 solar masses with metallicities of roughly solar metallicity (Z=0.02), a

  20. Trading Zones in Early Modern Europe.

    Science.gov (United States)

    Long, Pamela O

    2015-12-01

    This essay adopts the concept of trading zones first developed for the history of science by Peter Galison and redefines it for the early modern period. The term "trading zones" is used to mean arenas in which substantive and reciprocal communication occurred between individuals who were artisanally trained and learned (university-trained) individuals. Such trading zones proliferated in the sixteenth century. They tended to arise in certain kinds of places and not in others, but their existence must be determined empirically. The author's work on trading zones differs from the ideas of Edgar Zilsel, who emphasized the influence of artisans on the scientific revolution. In contrast, in this essay, the mutual influence of artisans and the learned on each other is stressed, and translation is used as a modality that was important to communication within trading zones.

  1. Formulating a coastal zone health metric for landuse impact management in urban coastal zones.

    Science.gov (United States)

    Anilkumar, P P; Varghese, Koshy; Ganesh, L S

    2010-11-01

    The need for ICZM arises often due to inadequate or inappropriate landuse planning practices and policies, especially in urban coastal zones which are more complex due to the larger number of components, their critical dimensions, attributes and interactions. A survey of literature shows that there is no holistic metric for assessing the impacts of landuse planning on the health of a coastal zone. Thus there is a need to define such a metric. The proposed metric, CHI (Coastal zone Health Indicator), developed on the basis of coastal system sustainability, attempts to gauge the health status of any coastal zone. It is formulated and modeled through an expert survey and pertains to the characteristic components of coastal zones, their critical dimensions, and relevant attributes. The proposed metric is applied to two urban coastal zones and validated. It can be used for more coast friendly and sustainable landuse planning/masterplan preparation and thereby for the better management of landuse impacts on coastal zones.

  2. TUM Critical Zone Observatory, Germany

    Science.gov (United States)

    Völkel, Jörg; Eden, Marie

    2014-05-01

    Founded 2011 the TUM Critical Zone Observatory run by the Technische Universität München and partners abroad is the first CZO within Germany. TUM CZO is both, a scientific as well as an education project. It is a watershed based observatory, but moving behind this focus. In fact, two mountainous areas are integrated: (1) The Ammer Catchment area as an alpine and pre alpine research area in the northern limestone Alps and forelands south of Munich; (2) the Otter Creek Catchment in the Bavarian Forest with a crystalline setting (Granite, Gneiss) as a mid mountainous area near Regensburg; and partly the mountainous Bavarian Forest National Park. The Ammer Catchment is a high energy system as well as a sensitive climate system with past glacial elements. The lithology shows mostly carbonates from Tertiary and Mesozoic times (e.g. Flysch). Source-to-sink processes are characteristic for the Ammer Catchment down to the last glacial Ammer Lake as the regional erosion and deposition base. The consideration of distal depositional environments, the integration of upstream and downstream landscape effects are characteristic for the Ammer Catchment as well. Long term datasets exist in many regards. The Otter Creek catchment area is developed in a granitic environment, rich in saprolites. As a mid mountainous catchment the energy system is facing lower stage. Hence, it is ideal comparing both of them. Both TUM CZO Catchments: The selected catchments capture the depositional environment. Both catchment areas include historical impacts and rapid land use change. Crosscutting themes across both sites are inbuilt. Questions of ability to capture such gradients along climosequence, chronosequence, anthroposequence are essential.

  3. A Volcanic Hydrogen Habitable Zone

    Science.gov (United States)

    Ramirez, Ramses M.; Kaltenegger, Lisa

    2017-03-01

    The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N2–CO2–H2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N2–CO2–H2O–H2) can be sustained as long as volcanic H2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H2 warming is reduced in dense H2O atmospheres. The atmospheric scale heights of such volcanic H2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

  4. Radiation danger of exclusion zone objects

    Energy Technology Data Exchange (ETDEWEB)

    Kholosha, V.I.; Proskura, N.I.; Ivanov, Yu.A.; Kazakov, S.V.; Arkhipov, A.N. [Ministry of Ukraine of Emergencies and Affairs of Population Protection from the Consequences of Chornobyl Catastrophe (Ukraine)

    2001-03-01

    The analysis of radiation danger of the Exclusion Zone objects was made. Here, the Zone is defined as the territory from which the population has been evacuated in 1986 owing to the Chernobyl accident and possible outflow of the contaminated substances out of the borders is potentially dangerous to the Ukraine. In the present work were analyzed such problems as sources of radiation danger in the Zone, ways of radionuclide migration out of the borders of the Zone in normal and emergency situations, the non-radiation (ecological) danger factors of the Zone objects, doses (individual and collective) from various sources and on separate ways of their formation, and the characteristics of radiation danger of the Zone objects. The conclusions are: (1) Radionuclide flows both from technologic and natural sources exceed those from Shelter objects, (2) Under emergency conditions, radionuclide flows and doze loading remain comparable with those from emergency sources, (3) To solve some management tasks in radiation situation, the basic works on the Shelter objects should be oriented to decrease probability of emergency occurrence and to reduce radiation influence (prevention wash-outs during high waters, fire-prevention measures in forests and strengthening of the control behind non-authorized use of objects in the Zone). (S. Ohno)

  5. Shear zone junctions: Of zippers and freeways

    Science.gov (United States)

    Passchier, Cees W.; Platt, John P.

    2017-02-01

    Ductile shear zones are commonly treated as straight high-strain domains with uniform shear sense and characteristic curved foliation trails, bounded by non-deforming wall rock. Many shear zones, however, are branched, and if movement on such branches is contemporaneous, the resulting shape can be complicated and lead to unusual shear sense arrangement and foliation geometries in the wall rock. For Y-shaped shear zone triple junctions with three joining branches and transport direction at a high angle to the branchline, only eight basic types of junction are thought to be stable and to produce significant displacement. The simplest type, called freeway junctions, have similar shear sense in all three branches. The other types show joining or separating behaviour of shear zone branches similar to the action of a zipper. Such junctions may have shear zone branches that join to form a single branch (closing zipper junction), or a single shear zone that splits to form two branches, (opening zipper junction). All categories of shear zone junctions show characteristic foliation patterns and deflection of markers in the wall rock. Closing zipper junctions are unusual, since they form a non-active zone with opposite deflection of foliations in the wall rock known as an extraction fault or wake. Shear zipper junctions can form domains of overprinting shear sense along their flanks. A small and large field example are given from NE Spain and Eastern Anatolia. The geometry of more complex, 3D shear zone junctions with slip parallel and oblique to the branchline is briefly discussed.

  6. Knowledge-based flow field zoning

    Science.gov (United States)

    Andrews, Alison E.

    1988-01-01

    Automation flow field zoning in two dimensions is an important step towards easing the three-dimensional grid generation bottleneck in computational fluid dynamics. A knowledge based approach works well, but certain aspects of flow field zoning make the use of such an approach challenging. A knowledge based flow field zoner, called EZGrid, was implemented and tested on representative two-dimensional aerodynamic configurations. Results are shown which illustrate the way in which EZGrid incorporates the effects of physics, shape description, position, and user bias in a flow field zoning.

  7. New national seismic zoning map of China

    Institute of Scientific and Technical Information of China (English)

    高孟潭

    2003-01-01

    A new set of seismic zoning maps were published in August 1,200l. It includes two maps, one is the seismic zon-ing map of peak acceleration, and the other is the zoning map of the characteristic period of the response spectrum.The exceeding probability of the map is 10% within 50 years. The scale of the map is 1:4 000 000. These mapsserve as the national standard. The background of this project, technical approach and key scientific measures, thebasic feature and the application of the maps are introduced in this paper.

  8. Flow and transport in Riparian Zones

    DEFF Research Database (Denmark)

    Jensen, Jannick Kolbjørn

    of riparian zones are extended by accounting for the effect of flooding and a key result is that flooding enhances nitrate removal given the right hydrogeological characteristics. Moreover the re-established riparian zones were characterized to understand the effects of flooding on subsurface hydrological......) and easurements of discharge to the river by seepage meter and river bed temperatures. The numerical model was used to simulate how observed dynamic seasonal flooding affects groundwater flow paths, residence times, and formation of zones with flow stagnation, all of which are key aspects in evaluating...

  9. Relaxation dynamics of lead-free (Na1/2Bi1/2)TiO3-BaTiO3 single crystals studied by Brillouin scattering

    Science.gov (United States)

    Lee, Byoung Wan; Ko, Jae-Hyeon; Li, Xiaobing; Luo, Haosu

    2016-10-01

    The acoustic properties of 0.95(Na1/2Bi1/2)TiO3-0.05BaTiO3 (NBT-0.05BT) single crystals were investigated in a hypersonic frequency range and compared to those of archetypal relaxor Pb(Mg1/3Nb2/3)O3 (PMN). Temperature dependences of the Brillouin frequency shift of the longitudinal acoustic (LA) mode, as well as its half width, of NBT-5%BT and PMN exhibited diffuse and broad anomalies over a wide temperature range, which were related to the softening of the sound velocity and substantial increase in the hypersonic damping toward the dielectric maximum temperature. These broad acoustic anomalies of unpoled NBT-0.05BT suggest the existence of noncentrosymmetric polar nanoregions in the paraelectric phase which do not evolve into a long-range ferroelectric order. The calculated relaxation times of NBT-0.05BT exhibited much longer values compared to those of PMN, which suggests that the size of polar nanoregions of NBT-0.05BT is larger than that of PMN.

  10. Relaxation dynamics of lead-free (Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}–BaTiO{sub 3} single crystals studied by Brillouin scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byoung Wan [Department of Physics, Hallym University, Chuncheon, Gangwondo 24252 (Korea, Republic of); Ko, Jae-Hyeon, E-mail: hwangko@hallym.ac.kr [Department of Physics, Hallym University, Chuncheon, Gangwondo 24252 (Korea, Republic of); Li, Xiaobing; Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-10-01

    The acoustic properties of 0.95(Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}–0.05BaTiO{sub 3} (NBT–0.05BT) single crystals were investigated in a hypersonic frequency range and compared to those of archetypal relaxor Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} (PMN). Temperature dependences of the Brillouin frequency shift of the longitudinal acoustic (LA) mode, as well as its half width, of NBT–5%BT and PMN exhibited diffuse and broad anomalies over a wide temperature range, which were related to the softening of the sound velocity and substantial increase in the hypersonic damping toward the dielectric maximum temperature. These broad acoustic anomalies of unpoled NBT–0.05BT suggest the existence of noncentrosymmetric polar nanoregions in the paraelectric phase which do not evolve into a long-range ferroelectric order. The calculated relaxation times of NBT–0.05BT exhibited much longer values compared to those of PMN, which suggests that the size of polar nanoregions of NBT–0.05BT is larger than that of PMN.

  11. Global challenges in integrated coastal zone management

    DEFF Research Database (Denmark)

    integration of data and information in policy and management, combining expertise from nature and social science, to reach a balanced and sustainable development of the coastal zone. This important book comprises the proceedings of The International Symposium on Integrated Coastal Zone Management, which took......Growing pressure from increasingly diverse human activities coupled with climate change impacts threaten the functional integrity of coastal ecosystems around the globe. A multi-disciplinary approach towards understanding drivers, pressures and impacts in the coastal zone requires effective....../mitigation to change in coastal systems Coastal governance Linking science and management Comprising a huge wealth of information, this timely and well-edited volume is essential reading for all those involved in coastal zone management around the globe. All libraries in research establishments and universities where...

  12. White Light Photorefractive Phase Zone Plates

    Institute of Scientific and Technical Information of China (English)

    GAO Yuan-Mei; LIU Si-Min

    2008-01-01

    Incoherent white light from an incandescent source is employed to Fabricate volume phase zone plates in LiNbO3:Fe,for the first time to our knowledge,which can guide and modulate the input white light or laser light.The diffractive efficiency of the white light volume phase zone plates fabricated can reach as high as 12%.In addition,we test the volume phase zone plates by a probe beam and find that the volume phase zone plate is present in the direction perpendicular to the c-axis and absent in the direction parallel to the c-axis.This directly proves the existence of photovoltalc photorefractive anisotropy of white light.

  13. Strategic metal deposits of the Arctic Zone

    Science.gov (United States)

    Bortnikov, N. S.; Lobanov, K. V.; Volkov, A. V.; Galyamov, A. L.; Vikent'ev, I. V.; Tarasov, N. N.; Distler, V. V.; Lalomov, A. V.; Aristov, V. V.; Murashov, K. Yu.; Chizhova, I. A.; Chefranov, R. M.

    2015-11-01

    Mineral commodities rank high in the economies of Arctic countries, and the status of mineral resources and the dynamics of their development are of great importance. The growing tendency to develop strategic metal resources in the Circumarctic Zone is outlined in a global perspective. The Russian Arctic Zone is the leading purveyor of these metals to domestic and foreign markets. The comparative analysis of tendencies in development of strategic metal resources of the Arctic Zone in Russia and other countries is crucial for the elaboration of trends of geological exploration and research engineering. This paper provides insight into the development of Arctic strategic metal resources in global perspective. It is shown that the mineral resource potential of the Arctic circumpolar metallogenic belt is primarily controlled by large and unique deposits of nonferrous, noble, and rare metals. The prospective types of economic strategic metal deposits in the Russian Arctic Zone are shown.

  14. EPA Region 1 No Discharge Zones

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset details No Discharge Zones (NDZ) for New England. Boaters may not discharge waste into these areas. Boundaries were determined mostly by Federal...

  15. WVSAMB Color Digital Orthophotos North Zone

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Digital color orthophotography of the State of West Virginia (West Virginia State Plane Coordinate System North Zone). The W.V. state plane system has two...

  16. Schools K-12 - School Board Zones

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This dataset contains polygons and attributes which represent the School District Board Zones for the Public School Districts in the State of Arkansas. It includes...

  17. VT New Market Tax Credit - Hot Zones

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The EconOther_NMTC layer delineates New Market Tax Credit (NMTC) "hot zones" and qualified counties and census tracts. This dataset is designed to...

  18. Treating nahcolite containing formations and saline zones

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J

    2013-06-11

    A method for treating a nahcolite containing subsurface formation includes removing water from a saline zone in or near the formation. The removed water is heated using a steam and electricity cogeneration facility. The heated water is provided to the nahcolite containing formation. A fluid is produced from the nahcolite containing formation. The fluid includes at least some dissolved nahcolite. At least some of the fluid is provided to the saline zone.

  19. Zone heated diesel particulate filter electrical connection

    Science.gov (United States)

    Gonze, Eugene V.; Paratore, Jr., Michael J.

    2010-03-30

    An electrical connection system for a particulate filter is provided. The system includes: a particulate filter (PF) disposed within an outer shell wherein the PF is segmented into a plurality of heating zones; an outer mat disposed between the particulate filter and the outer shell; an electrical connector coupled to the outer shell of the PF; and a plurality of printed circuit connections that extend along the outer surface of the PF from the electrical connector to the plurality of heating zones.

  20. Euro zone and its monetary policy

    OpenAIRE

    Dorel Dumitru CHIRIŢESCU; Andreea ANDRAŞIU

    2010-01-01

    In this article I have tried to make a short presentation of the Euro Zone and it’s monetary policy. At the present moment the Euro Zone has 16 countries that have adopted the Euro as a national currency and also 4 small countries that have monetary agreements with their neighbours. The monetary policy represents all the regulations of the money supply and interest rates adopted by the European Central Bank in order to control the inflation rate and to stabilize ...

  1. Clinical crown lengthening in the esthetic zone.

    Science.gov (United States)

    Camargo, Paulo M; Melnick, Philip R; Camargo, Luciano M

    2007-07-01

    Periodontal surgical procedures consisting of gingival flaps and osseous recontouring are indicated for crown lengthening of several contiguous teeth in the esthetic zone; both in cases where restorations are required and in cases where no restorations are planned, such as in patients with excessive gingival display due to altered passive eruption. Forced tooth eruption via orthodontic extrusion is the technique of choice when clinical crown lengthening is necessary on isolated teeth in the esthetic zone.

  2. MANIFESTATION OF FAULT ZONES IN GEOPHYSICAL FIELDS

    Directory of Open Access Journals (Sweden)

    A. A. Spivak

    2015-09-01

    Full Text Available Geophysical fields influenced by tectonics faults were observed, and instrumental observation results are analysed in the article. It is shown that fault zones are characterized by geophysical fields that are more variable than those in midmost segments of crustal blocks, more intense responses to weak external impacts such as lunar and solar tides and atmospheric pressure variations, and intensive relaxation. Transformation of energy between geophysical fields varying in origin takes place mainly in the fault zones.

  3. Zone conditioning in a California foothill house

    Energy Technology Data Exchange (ETDEWEB)

    Jump, D.; Modera, M.

    1993-12-01

    The principal focus of the reported research is the performance of the installed zoned air distribution system in a house located in the foothills northeast of Sacramento California. The 297 m{sup 2} two story house contained a central air conditioner and an air distribution system with four dampered supply duct legs. The air conditioning system included a two speed fan and two speed compressor, with the air handler placed inside a closet and almost all the ducts located inside the building envelope. The uninsulated sheet metal ducts ran inside a space between stories and in interior walls. The performance parameters examined included: (1) duct leakage, (2) duct conduction, (3) zoning performance and (4) equipment efficiency impacts. In conclusion, two major points were made concerning the test house. The first was that substantial energy benefits were obtained by placing the ducts inside the conditioned space. The second was that the energy benefits from zoning the house were not realized, primarily due to thermal stratification and the open floor plan in the house. Secondary impacts lowering zoning performance were the k& of return duct dampers and leakage and conduction losses in the air distribution system. Utility programs or building standards promoting zoning as a means of conserving energy or reducing peak power demand should be aware of the many potential pitfalls that can arise with zone conditioning, particularly with dampered air distribution systems.

  4. Standardized precipitation index zones for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Giddings, L.; Soto, M. [Instituto de Ecologia, A.C., Xalapa, Veracruz (Mexico); Rutherford, B.M.; Maarouf, A. [Faculty of Environmental Studies, York University, Toronto, Ontario (Canada)

    2005-01-01

    Precipitation zone systems exists for Mexico based on seasonality, quantity of precipitation, climates and geographical divisions, but none are convenient for the study of the relation of precipitation with phenomena such as El nino. An empirical set of seven exclusively Mexican and six shared zones was derived from three series of Standardized Precipitation Index (SPI) images, from 1940 through 1989: a whole year series (SPI-12) of 582 monthly images, a six month series (SPI-6) of 50 images for winter months (November through April), and a six month series (SPI-6) of 50 images for summer months (May through October). By examination of principal component and unsupervised classification images, it was found that all three series had similar zones. A set of basic training fields chosen from the principal component images was used to classify all three series. The resulting thirteen zones, presented in this article, were found to be approximately similar, varying principally at zones edges. A set of simple zones defined by just a few vertices can be used for practical operations. In general the SPI zones are homogeneous, with almost no mixture of zones and few outliers of one zone in the area of others. They are compared with a previously published map of climatic regions. Potential applications for SPI zones are discussed. [Spanish] Existen varios sistemas de zonificacion de Mexico basados en la estacionalidad, cantidad de precipitacion, climas y divisiones geograficas, pero ninguno es conveniente para el estudio de la relacion de la precipitacion con fenomenos tales como El Nino. En este trabajo se presenta un conjunto de siete zonas empiricas exclusivamente mexicanas y seis compartidas, derivadas de tres series de imagenes de SPI (Indice Estandarizado de la Precipitacion), desde 1940 a 1989: una serie de 582 imagenes mensuales (SPI-12), una series de 50 imagenes (SPI-6) de meses de invierno (noviembre a abril), y otra de 50 imagenes (SPI-6) de meses de verano

  5. En echelon knolls in the Nosappu Fracture Zone, NW Pacific: A possible leaky transform fault zone

    Science.gov (United States)

    Ogawa, Y.; Hirano, N.; Shipboard Scientific Party Kr03-07, .

    2003-12-01

    During JAMSTEC R/V KAIREI cruise KR03-07, we mapped significant en echelon arrays of knolls and ridges on the NNW-trending Nosappu Fracture Zone between Hokkaido and Shatsky Rise, NW Pacific. This fracture zone has been known to be irregular, including a deep-sea channel, the Nakwe Channel, enigmatic for inside the wide oceanic plate. Considering the previously recognized magnetic lineament dislocation, the fracture zone has long (more than 150 km) left-lateral strike-slip component as a ridge-ridge transform fault zone between the Izanagi and Pacific plates during Early Cretaceous. Detail multi-narrowbeam mapping around 37 N latitude, 150 E longitude (covering 78 km x 137 km), indicated many small knolls and ridges that form en echelon arrangement. Some are boomerang, sock or E-letter in shape. The two dominant directions of ridges are recognized, one is parallel to the fracture zone and the other is in left-handed en echelon fashion. Besides these ridges, there are other types of ridges or conical knolls lower than 500 m in relief; one is a group of rather large knolls extending to NE, roughly perpendicular to the fracture zone direction, and the other is independent small knolls, summing up to five or six in number. Another expression of a depression zone was recognized with a moderate angle to the fracture zone in a crank fashion. This may correspond to the so-called _gNakwe Channel_h which has been wrongly mistaken. Such en echelon arrays are involved in a 50 km wide NNW-SSE zone, which is sharply demarcated by fault scarps. These characteristics in the fracture zone area and associated knolls suggest that this part of the Nosappu Fracture Zone might have developed in a fault interaction area which has a left-lateral component of leaky transform faulting close to the spreading ridge.

  6. Pollution concentration estimates in ecologically important zones

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, Y.N. [Mexico City Univ. (Mexico). Center for Atmospheric Sciences

    1995-12-31

    Method based on using the pollutant transport equation and the adjoint technique is described here for estimating the pollutant concentration level in ecologically important zones. The method directly relates the pollution level in such zones with the power of the pollution sources and the initial pollution field. Assuming that the wind or current velocities are known (from climatic data or dynamic model), the main and adjoint pollutant transport equations can be considered in a limited area to solve such theoretically and practically important problems as: (1) optimal location of new industries in a given region with the aim to minimize the pollution concentration in certain ecologically important zones, (2) optimization of emissions from operating industries, (3) detection of the plants violating sanitary regulations, (4) analysis of the emissions coming from the vehicle traffic (such emissions can be included in the model by means of the linear pollution sources located along the main roadways), (5) estimation of the oil pollution in various ecologically important oceanic (sea) zones in case of accident with the oil tanker, (6) evaluation of the sea water desalination level in estuary regions, and others. These equations considered in a spherical shell domain can also be applied to the problems of transporting the pollutants from a huge industrial complex, or from the zone of an ecological catastrophe similar to the Chernobyl one

  7. Mesopelagic zone ecology and biogeochemistry - a synthesis

    Science.gov (United States)

    Robinson, Carol; Steinberg, Deborah K.; Anderson, Thomas R.; Arístegui, Javier; Carlson, Craig A.; Frost, Jessica R.; Ghiglione, Jean-François; Hernández-León, Santiago; Jackson, George A.; Koppelmann, Rolf; Quéguiner, Bernard; Ragueneau, Olivier; Rassoulzadegan, Fereidoun; Robison, Bruce H.; Tamburini, Christian; Tanaka, Tsuneo; Wishner, Karen F.; Zhang, Jing

    2010-08-01

    The mesopelagic zone is the oceanic region through which carbon and other elements must pass in order to reach deeper waters or the sea floor. However, the food web interactions that occur in the mesopelagic zone are difficult to measure and so, despite their crucial importance to global elemental cycles, are not very well known. Recent developments in technology and new approaches have advanced the study of the variability in and controls upon the distribution and diversity of organisms in the mesopelagic zone, including the roles of respiration, recycling, and repackaging of particulate and dissolved organic material. However, there are remarkably few syntheses of the ecology and biogeochemistry of the microbes and metazoa that permanently reside or habitually visit this 'twilight zone'. Without this synthesis, it is difficult to assess the impact of ongoing changes in ocean hydrography and chemistry, due to increasing atmospheric carbon dioxide levels, on the biological carbon pump. This paper reviews what is known about the distribution of microbes and metazoa in the mesopelagic zone in relation to their activity and impact on global biogeochemical cycles. Thus, gaps in our knowledge are identified and suggestions made for priority research programmes that will improve our ability to predict the effects of climate change on carbon sequestration.

  8. Risk-based zoning for urbanizing floodplains.

    Science.gov (United States)

    Porse, Erik

    2014-01-01

    Urban floodplain development brings economic benefits and enhanced flood risks. Rapidly growing cities must often balance the economic benefits and increased risks of floodplain settlement. Planning can provide multiple flood mitigation and environmental benefits by combining traditional structural measures such as levees, increasingly popular landscape and design features (green infrastructure), and non-structural measures such as zoning. Flexibility in both structural and non-structural options, including zoning procedures, can reduce flood risks. This paper presents a linear programming formulation to assess cost-effective urban floodplain development decisions that consider benefits and costs of development along with expected flood damages. It uses a probabilistic approach to identify combinations of land-use allocations (residential and commercial development, flood channels, distributed runoff management) and zoning regulations (development zones in channel) to maximize benefits. The model is applied to a floodplain planning analysis for an urbanizing region in the Baja Sur peninsula of Mexico. The analysis demonstrates how (1) economic benefits drive floodplain development, (2) flexible zoning can improve economic returns, and (3) cities can use landscapes, enhanced by technology and design, to manage floods. The framework can incorporate additional green infrastructure benefits, and bridges typical disciplinary gaps for planning and engineering.

  9. GEODESIC RECONSTRUCTION, SADDLE ZONES & HIERARCHICAL SEGMENTATION

    Directory of Open Access Journals (Sweden)

    Serge Beucher

    2011-05-01

    Full Text Available The morphological reconstruction based on geodesic operators, is a powerful tool in mathematical morphology. The general definition of this reconstruction supposes the use of a marker function f which is not necessarily related to the function g to be built. However, this paper deals with operations where the marker function is defined from given characteristic regions of the initial function f, as it is the case, for instance, for the extrema (maxima or minima but also for the saddle zones. Firstly, we show that the intuitive definition of a saddle zone is not easy to handle, especially when digitised images are involved. However, some of these saddle zones (regional ones also called overflow zones can be defined, this definition providing a simple algorithm to extract them. The second part of the paper is devoted to the use of these overflow zones as markers in image reconstruction. This reconstruction provides a new function which exhibits a new hierarchy of extrema. This hierarchy is equivalent to the hierarchy produced by the so-called waterfall algorithm. We explain why the waterfall algorithm can be achieved by performing a watershed transform of the function reconstructed by its initial watershed lines. Finally, some examples of use of this hierarchical segmentation are described.

  10. 78 FR 5717 - Safety Zone; Military Ocean Terminal Concord Safety Zone, Suisun Bay, Military Ocean Terminal...

    Science.gov (United States)

    2013-01-28

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Military Ocean Terminal Concord Safety Zone, Suisun Bay, Military Ocean Terminal Concord, CA AGENCY: Coast Guard, DHS. ACTION: Interim rule and... Suisun Bay near Military Ocean Terminal Concord, CA in support of military onload and offload...

  11. 75 FR 16370 - Regulated Navigation Areas, Safety Zones, Security Zones; Deepwater Ports in Boston Captain of...

    Science.gov (United States)

    2010-04-01

    ... standards (e.g., specifications of materials, performance, design, or operation; test methods; sampling... do not individually or cumulatively have a significant effect on the human environment. A preliminary... zones for Neptune consist of circular zones, each with a 500-meter radius and centered on each...

  12. 76 FR 41073 - Security Zones; Sector Southeastern New England Captain of the Port Zone

    Science.gov (United States)

    2011-07-13

    ... cruise ship anchored or moored, and 200-yard radius security zone encompassing all navigable waters around any cruise ship underway that is being escorted by Coast Guard or law enforcement agencies.... These security zones will be activated and enforced only when a cruise ship is transiting, anchored,...

  13. 23 CFR 750.708 - Acceptance of state zoning.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Acceptance of state zoning. 750.708 Section 750.708... BEAUTIFICATION Outdoor Advertising Control § 750.708 Acceptance of state zoning. (a) 23 U.S.C. 131(d) provide...) further provides, “The States shall have full authority under their own zoning laws to zone areas...

  14. Zoning for Day Care (from Models for Day Care Licensing).

    Science.gov (United States)

    Day Care and Child Development Council of America, Inc., Washington, DC.

    Recommendations and regulations regarding the zoning of child development day care programs are discussed. Zoning in general is discussed, as is the treatment of child development day care in zoning ordinance, the background of program planning, modular housing, the impelmentation of zoning, and model provisions regarding characteristics of…

  15. 33 CFR 334.5 - Disestablishment of a danger zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Disestablishment of a danger zone..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.5 Disestablishment of a danger zone. (a) Upon receipt of a request from any agency for the disestablishment of a danger zone, the...

  16. 33 CFR 2.30 - Exclusive Economic Zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Exclusive Economic Zone. 2.30... JURISDICTION Jurisdictional Terms § 2.30 Exclusive Economic Zone. (a) With respect to the United States... States exercises sovereignty, exclusive economic zone means the zone seaward of and adjacent to...

  17. 49 CFR 1105.9 - Coastal Zone Management Act requirements.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Coastal Zone Management Act requirements. 1105.9... ENVIRONMENTAL LAWS § 1105.9 Coastal Zone Management Act requirements. (a) If the proposed action affects land or water uses within a State coastal zone designated pursuant to the Coastal Zone Management Act (16...

  18. Dynamics of Vadose Zone Transport: a Field and Modeling Study using the Vadose Zone Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Carrigan, C R

    2001-01-01

    A stated need of the DOE EM program is a better understanding of basic vadose zone fluid flow and contaminant transport processes for the purpose of making improved estimates of contaminant release rates and fluxes across the vadose zone to the water table at DOE sites such as the tank farms at Hanford. We investigate details of the modes of contaminant transport with the aid of infiltration experiments designed to elucidate how vadose zone characteristics such as preferential pathways, heterogeneities, and relative permeabilities influence the transport of contamination in liquid, gas and colloidal phases to the water table. Beyond enhancing our basic understanding of vadose zone transport processes, this EMSP project is designed result in a vadose-zone-transport-characterization methodology that can be generalized to other DOE sites.

  19. Zoned electrical heater arranged in spaced relationship from particulate filter

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-11-15

    A system comprises a particulate matter (PM) filter that comprises an upstream end for receiving exhaust gas and a downstream end. A zoned heater is arranged spaced from the upstream end and comprises N zones, where N is an integer greater than one, wherein each of the N zones comprises M sub-zones, where M is an integer greater than one. A control module selectively activates at least a selected one of the N zones to initiate regeneration in downstream portions of the PM filter from the one of the N zones and deactivates non-selected ones of the N zones.

  20. Brillouin Scattering Study on Molecular Liquid under High Pressure and High Temperature Conditions%小分子液体的高温布里渊散射研究

    Institute of Scientific and Technical Information of China (English)

    马春丽; 武晓鑫; 黄凤仙; 李敏; 王晓霞; 周强; 李芳菲; 崔启良

    2015-01-01

    High-pressure and high-temperature Brillouin scattering studies have been performed on molecular liquids,including water (H2O),ammonia (NH3),ammonia dihydrate (NH3·2H2O)and methane (CH4)by using a diamond anvil cell (DAC).The acoustic velocity and adiabatic bulk modulus have been determined from measured Brillouin frequency shifts in both 180° and 60° scattering geometries under pressure up to freezing point,along room temperature (296 K)and high temperature (410 K)isotherms,and the pressure dependence of acoustic velocity and adiabatic bulk modulus were compared in different molecular systems.The acoustic velocities increase smoothly with the increasing pressure,methane possesses the highest velocity increasement and the lowest adiabatic bulk modulus under similar pressure and temperature,indicating the hydrogen bond impact on elasticity in these liquids.A change in the slope of pressure dependence of the bulk modulus in liquid ammonia dihydrate was observed around 1 .5 GPa,suggesting a possible structure change in liquid and analysing the effect of hydrogen on elasticity.This study improves our understanding of the pressure-and temperature-induced molecular structure changes in other molecular liquid systems.%利用金刚石对顶砧技术,采用180°背向散射和60°前向对称散射两种几何配置,对水、氨、二水合氨和甲烷等含氢小分子液体进行了高温高压布里渊散射研究,计算了在室温(296 K)和高温(410 K)下的声速,比较了不同小分子液体中的声速及绝热体弹模量随压力的变化关系。在等温条件下,各体系中声速随着压力的增加逐渐增加;在相同温度下,甲烷液体的声速随着压力增加的速率明显高于水、氨及二水合氨液体;在相同的温度和压力条件下,水、氨及二水合氨液体的体弹模量明显高于甲烷液体的体弹模量,表明氢键的存在对于小分子液体弹性具有较大影响。二水合氨的体

  1. Urban planning as a trading zone

    CERN Document Server

    Mäntysalo, Raine

    2013-01-01

    'Trading zone' is a concept introduced by Peter Galison in his social scientific research on how scientists representing different sub-cultures and paradigms have been able to coordinate their interaction locally. In this book, Italian and Finnish planning researchers extend the use of the concept to different contexts of urban planning and management, where there is a need for new ideas and tools in managing the interaction of different stakeholders. The trading zone concept is approached as a tool in organizing local platforms and support systems for planning participation, knowledge production, decision making and local conflict management. In relation to the former theses of communicative planning theory that stress the ideals of consensus, mutual understanding and universal reason, the 'trading zone approach', outlined in this book, offers a different perspective. It focuses on the potentiality to coordinate locally the interaction of different stakeholders without requiring the deeper sharing of underst...

  2. Subduction zones seen by GOCE gravity gradients

    DEFF Research Database (Denmark)

    Švarc, Mario; Herceg, Matija; Cammarano, Fabio

    In this study, the GOCE (Gravity field and steady state Ocean Circulation Explorer) gradiometry data were used to study geologic structures and mass variations within the lithosphere in areas of known subduction zones. The advantage of gravity gradiometry over other gravity methods...... is that gradients are extremely sensitive to localized density contrasts within regional geological settings, which makes it ideally suited for detecting subduction zones. Second order gravity gradients of disturbing potential were extracted from global geopotential model, the fifth release GOCE model ‘EGM_TIM_RL05......’. In order to remove the signal which mainly corresponds to the gravity signal of the lower mantle, long wavelength part of the gravity signal was removed up to degree and order 60. Because the areas with notable topography differences coincide with subduction zones, topography correction was also performed...

  3. A systems approach framework for coastal zones

    DEFF Research Database (Denmark)

    Hopkins, Tom Sawyer; Bailly, Denis; Støttrup, Josianne

    2011-01-01

    This Special Feature Volume examines the potential value of the Systems Approach Framework (SAF) as a methodological framework for the transition to sustainable development in coastal zones. This article provides insight on the Systems Approach, the theory behind it, and how its practical...... application to coastal zone systems (CZSs) was developed. The SAF is about information for management through a focus on how to generate a higher, dynamic level of information about complex CZSs and how to render this information more useful to end users through a participatory suite of communication methods...... of this Volume synthesizes these results in the context of the SAF as a higher level instrument for integrated coastal zone management...

  4. Magnetic Fields in the Solar Convection Zone

    Directory of Open Access Journals (Sweden)

    Yuhong Fan

    2009-12-01

    Full Text Available Active regions on the solar surface are generally thought to originate from a strong toroidal magnetic field generated by a deep seated solar dynamo mechanism operating at the base of the solar convection zone. Thus the magnetic fields need to traverse the entire convection zone before they reach the photosphere to form the observed solar active regions. Understanding this process of active region flux emergence is therefore a crucial component for the study of the solar cycle dynamo. This article reviews studies with regard to the formation and rise of active region scale magnetic flux tubes in the solar convection zone and their emergence into the solar atmosphere as active regions.

  5. Seismomagnetic response of a fault zone

    Science.gov (United States)

    Adushkin, V. V.; Loktev, D. N.; Spivak, A. A.

    2017-01-01

    Based on the results of instrumental observations of geomagnetic variations caused by the propagation of seismic waves through a fault zone, the dependences between the amplitudes of the induced seismomagnetic effect and seismic signal as a function of distance r to the midline of the fault are obtained. For the first time, it is shown that the amplitude of the seismomagnetic effect is maximal in the fault damage zone. The phenomenological model describing the generation of magnetic signals by seismic waves propagating through the crushed rock in the tectonic fault zone is suggested. It is assumed that geomagnetic variations are generated by the changes in the electrical conductivity of the fragmented rocks as a result of the deformation of the rock pieces contacts. The amplitudes of the geomagnetic variations calculated from the model agree with the instrumental observations.

  6. Multi-zone cooling/warming garment

    Science.gov (United States)

    Koscheyev, Victor S. (Inventor); Leon, Gloria R. (Inventor); Dancisak, Michael J. (Inventor)

    2006-01-01

    A thermodynamically efficient garment for cooling and/or heating a human body. The thermodynamic efficiency is provided in part by targeting the heat exchange capabilities of the garment to specific areas and/or structures of the human body. The heat exchange garment includes heat exchange zones and one or more non-heat exchange zones, where the heat exchange zones are configured to correspond to one or more high density tissue areas of the human body when the garment is worn. A system including the garment can be used to exchange heat with the adjacent HD tissue areas under the control of a feedback control system. Sensed physiological parameters received by the feedback control system can be used to adjust the characteristics of heat exchange fluid moving within the heat exchange garment.

  7. Compositional zoning of the bishop tuff

    Science.gov (United States)

    Hildreth, W.; Wilson, C.J.N.

    2007-01-01

    Compositional data for >400 pumice clasts, organized according to eruptive sequence, crystal content, and texture, provide new perspectives on eruption and pre-eruptive evolution of the >4600 km3 of zoned rhyolitic magma ejected as the BishopTuff during formation of Long Valley caldera. Proportions and compositions of different pumice types are given for each ignimbrite package and for the intercalated plinian pumice-fall layers that erupted synchronously. Although withdrawal of the zoned magma was less systematic than previously realized, the overall sequence displays trends toward greater proportions of less evolved pumice, more crystals (0-5 24 wt %), and higher FeTi-oxide temperatures (714-818??C). No significant hiatus took place during the 6 day eruption of the BishopTuff, nearly all of which issued from an integrated, zoned, unitary reservoir. Shortly before eruption, however, the zoned melt-dominant portion of the chamber was invaded by batches of disparate lower-silica rhyolite magma, poorer in crystals than most of the resident magma but slightly hotter and richer in Ba, Sr, andTi. Interaction with resident magma at the deepest levels tapped promoted growth ofTi-rich rims on quartz, Ba-rich rims on sanidine, and entrapment of near-rim melt inclusions relatively enriched in Ba and CO2.Varied amounts of mingling, even in higher parts of the chamber, led to the dark gray and swirly crystal-poor pumices sparsely present in all ashflow packages. As shown by FeTi-oxide geothermometry, the zoned rhyolitic chamber was hottest where crystal-richest, rendering any model of solidification fronts at the walls or roof unlikely.The main compositional gradient (75-195 ppm Rb; 0.8-2.2 ppm Ta; 71-154 ppm Zr; 0.40-1.73% FeO*) existed in the melt, prior to crystallization of the phenocryst suite observed, which included zircon as much as 100 kyr older than the eruption.The compositions of crystals, though themselves largely unzoned, generally reflect magma temperature and

  8. Unsaturated Zone Flow Model Expert Elicitation Project

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, K. J.

    1997-05-30

    This report presents results of the Unsaturated Zone Flow Model Expert Elicitation (UZFMEE) project at Yucca Mountain, Nevada. This project was sponsored by the US Department of Energy (DOE) and managed by Geomatrix Consultants, Inc. (Geomatrix), for TRW Environmental Safety Systems, Inc. The objective of this project was to identify and assess the uncertainties associated with certain key components of the unsaturated zone flow system at Yucca Mountain. This assessment reviewed the data inputs, modeling approaches, and results of the unsaturated zone flow model (termed the ''UZ site-scale model'') being developed by Lawrence Berkeley National Laboratory (LBNL) and the US Geological Survey (USGS). In addition to data input and modeling issues, the assessment focused on percolation flux (volumetric flow rate per unit cross-sectional area) at the potential repository horizon. An understanding of unsaturated zone processes is critical to evaluating the performance of the potential high-level nuclear waste repository at Yucca Mountain. A major goal of the project was to capture the uncertainties involved in assessing the unsaturated flow processes, including uncertainty in both the models used to represent physical controls on unsaturated zone flow and the parameter values used in the models. To ensure that the analysis included a wide range of perspectives, multiple individual judgments were elicited from members of an expert panel. The panel members, who were experts from within and outside the Yucca Mountain project, represented a range of experience and expertise. A deliberate process was followed in facilitating interactions among the experts, in training them to express their uncertainties, and in eliciting their interpretations. The resulting assessments and probability distributions, therefore, provide a reasonable aggregate representation of the knowledge and uncertainties about key issues regarding the unsaturated zone at the Yucca

  9. Pathogenesis of splenic marginal zone lymphoma

    Directory of Open Access Journals (Sweden)

    Ming-Qing Du

    2015-11-01

    Full Text Available Splenic marginal zone lymphoma (SMZL is a distinct low grade B-cell lymphoma with an immunophenotype similar to that of splenic marginal zone B-cells. Like the normal splenic marginal zone B-cells, SMZLs also show variable features in somatic mutations of their rearranged immunoglobulin genes, with ∼90% of cases harbouring somatic mutations but at remarkably variable degrees, suggesting that SMZL may have multiple cell of origins, deriving from the heterogeneous B-cells of the splenic marginal zone. Notably, ∼30% of SMZLs show biased usage of IGHV1-2*04, with the expressed BCR being potentially polyreactive to autoantigens. Recent exome and targeted sequencing studies have identified a wide spectrum of somatic mutations in SMZL with the recurrent mutations targeting multiple signalling pathways that govern the development of splenic marginal zone B-cells. These recurrent mutations occur in KLF2 (20–42%, NOTCH2 (6.5–25%, NF-κB (CARD11 ∼7%, IKBKB ∼7%, TNFAIP3 7–13%, TRAF3 5%, BIRC3 6.3% and TLR (MYD88 5–13% signalling pathways. Interestingly, the majority of SMZL with KLF2 mutation have both 7q32 deletion and IGHV1-2 rearrangement, and these cases also have additional mutations in NOTCH2, or TNFAIP3, or TRAF3. There is a potential oncogenic cooperation among concurrent genetic changes, for example between the IGHV1-2 expressing BCR and KLF2 mutation in activation of the canonical NF-κB pathway, and between KLF2 and TRAF3 mutations in activation of the non-canonical NF-κB pathway. These novel genetic findings have provided considerable insights into the pathogenesis of SMZL and will stimulate the research in both normal and malignant marginal zone B-cells.

  10. Toward a self-consistent pressure scale: elastic moduli and equation of state of MgO by simultaneous x-ray density and Brillouin sound velocity measurements at high-pressure high-temperature conditions

    Science.gov (United States)

    Sinogeikin, S. V.; Lakshtanov, D. L.; Prakapenka, V. B.; Sanchez-Valle, C.; Wang, J.; Chen, B.; Shen, G.; Bass, J. D.

    2007-12-01

    Accurate phase diagrams and PVT equations of state (EOS) of materials strongly depend on the PVT calibrations of standard materials (e.g. MgO, NaCl, Au, Pt), which currently do not predict identical pressures at the same experimental conditions. MgO is commonly used as a pressure standard in a variety of high pressure and high- temperature experiments. Despite being one of the simplest and most studied materials, its accurate EOS is still uncertain, especially at high PT. The direct way of obtaining a self consistent pressure scale is by measuring acoustic velocities (Vp and Vs) and density simultaneously. Such P-V-T-Vp-Vs measurements allow one to determine the pressure directly, without resort to a separate calibration standard. Recently, as part of a major COMPRES initiative, we have constructed a Brillouin spectrometer at GSECARS, APS (13-BM-D) which allows accurate simultaneous sound velocity and lattice parameter measurements at high pressures and high temperatures. Such measurements were performed on single crystal MgO at simultaneously high pressures (up to 30 GPa) and high temperatures (up to 873K) in diamond cells with Ne or Ar as pressure medium. At each PT point we measured the unit cell parameters and the acoustic velocities of MgO in several crystallographic directions, and directly obtained all three single crystal elastic moduli, as well as isotropic adiabatic bulk (KS) and shear (μ) moduli. Unit cell parameters of pressure medium (Ne, Ar) and additional pressure calibrants (Au, Pt, NaCl) were measured at each PT for cross calibration. The results of these experiments and implications for a self consistent P-V-T(-Vp-Vs) pressure scale will be presented and discussed.

  11. Toward a self-consistent pressure scale: elastic moduli and equation of state of MgO and Ringwoodite by simultaneous x-ray density and Brillouin sound velocity measurements at high-pressure high-temperature conditions

    Science.gov (United States)

    Sinogeikin, S.; Lakshtanov, D.; Prakapenka, V.; Sanchez-Valle, C.; Wang, J.; Shen, G.; Bass, J.

    2009-05-01

    Accurate phase diagrams and PVT equations of state (EOS) of materials strongly depend on the PVT calibrations of standard materials (e.g. MgO, NaCl, Au, Pt), which currently do not predict identical pressures at the same experimental conditions. MgO is commonly used as a pressure standard in a variety of high pressure and high-temperature experiments. Despite being one of the simplest and most studied materials, its accurate EOS is still uncertain, especially at high PT. The direct way of obtaining a self consistent pressure scale is by measuring acoustic velocities (Vp and Vs) and density simultaneously. Such P-V-T-Vp-Vs measurements allow one to determine the pressure directly, without resort to a separate calibration standard. Recently, as part of a major COMPRES initiative, we have constructed a Brillouin spectrometer at GSECARS, APS (13-BM-D) which allows accurate simultaneous sound velocity and lattice parameter measurements at high pressures and high temperatures. Such measurements were performed on single crystal MgO at simultaneously high pressures (up to 30 GPa) and high temperatures (up to 873K) in diamond cells. At each PT point we measured the unit cell parameters and the acoustic velocities of MgO in several crystallographic directions, and directly obtained all three single crystal elastic moduli, as well as isotropic adiabatic bulk (Ks) and shear (μ) moduli. Unit cell parameters of pressure medium (Ne, Ar) and additional pressure calibrants (Au, Pt, NaCl) were measured at each PT for cross calibration. In addition we demonstrate that successful P-V-T-Vp-Vs measurements can be performed on certain polycrystalline materials, e.g. Ringwoodite (γ-Mg2SiO4). The results of these experiments and implications for a self consistent P-V-T(-Vp-Vs) pressure scale will be presented and discussed.

  12. Sound velocities and hypersonic dampings of Pb[(Mg1/3Nb2/3)0.45Ti0.55]O3 single crystals studied by Brillouin light scattering.

    Science.gov (United States)

    Ko, Jae-Hyeon; Kim, Tae Hyun; Kojima, Seiji; Bokov, Alexei A; Ye, Zuo-Guang

    2010-12-08

    A Brillouin spectroscopic investigation was carried out on PMN-55%PT single crystals, which are known to have no chemically ordered regions and undergo a well-defined structural phase transition at T(C) ∼ 521 K. The longitudinal and transverse sound velocities probed on a right-angle scattering geometry exhibited a remarkable softening and increasing hypersonic damping on approaching T(C) from T(B) ∼ 610 K that was characterized by the deviation of the dielectric permittivity from the high-temperature Curie-Weiss behavior. The acoustic anomalies of the longitudinal acoustic mode at the backward scattering were more substantial than those observed at the right-angle scattering, which could be understood in the framework of normal acoustic dispersion considering the difference in the acoustic frequency. The softening of the transverse sound velocity was more significant than that of the longitudinal one upon cooling toward T(C), suggesting that this acoustic anomaly may be related to the local rhombohedral transformation, occurring in polar nano-regions (PNRs). The observed acoustic behaviors combined with the central peak dynamics clearly indicated the existence of dynamic polar nano-regions in PMN-55%PT where there are no chemically ordered regions, and seem to suggest that the order parameter fluctuations due to two kinds of coupling contribute to the acoustic anomalies in the temperature range of T(C) ∼ T(B): electrostrictive coupling between the acoustic waves and the dynamic PNRs, and linear coupling between the acoustic waves and the precursor polar clusters, i.e., the ordering unit responsible for the order-disorder-type slowing down behavior probed by the central peak.

  13. SAR observations of coastal zone conditions

    Science.gov (United States)

    Meadows, G. A.; Kasischke, E. S.; Shuchman, R. A.

    1980-01-01

    Applications of Synthetic Aperture Radar (SAR) technology to the observation of coastal zones phenomena are detailed. The conditions observed include gravity wave detection, surf zone location, surface currents, and long-period 'surf beats'. Algorithms have been developed and successfully tested that determine significant wave and current parameters from the sea surface backscatter of microwave energy. Doppler information from the SAR optical correlator allows a rough estimation of near shore surface flow velocities that has been found in agreement with both theory and in situ observations as well. Seasat SAR data of the Scotland and North Carolina coasts are considered, as well as the results of bathymetric updating of coastal area charts.

  14. Building fire zone model with symbolic mathematics

    Institute of Scientific and Technical Information of China (English)

    武红梅; 郜冶; 周允基

    2009-01-01

    To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential equations (ODEs) were required to solve. A typical fire modelling with two-room structure was studied. Accordingly,the source terms included in the ODEs were simplified and modelled,and the fourth Runge-Kutta method was used to solve the ordinary differential equations (ODEs) with symbolic mathematics. Then a zone model could be used with symbolic mathematics. It is proposed that symbolic mathematics is possible for use by fire engineer.

  15. Recent Study of the Changjiang Fault Zone

    Institute of Scientific and Technical Information of China (English)

    Hou Kangming; Zong Kaihong; Guo Jiangning; Xiong Zhen; Li Limei; Zhou Caixia; Jiang Bo

    2009-01-01

    The Changjiang fault zone, also known as the Mufushan-Jiaoshan fault, is a famous fault located at the southern bank of the Changjiang River, near the Nanjing downtown area. Based on multidisciplinary data from shallow artificial seismic explorations in the target detecting area (Nanjing city and the nearby areas), trenching and drilling explorations, classification of Quaternary strata and chronology dating data, this paper provides the most up-to-date results regarding activities of the Changjiang fault zone, including the most recent active time, activity nature, related active parameters, and their relation to seismic activity.

  16. La zone nouvelle de Pudong (Shangai

    Directory of Open Access Journals (Sweden)

    Gabriel Weissberg

    2000-09-01

    Full Text Available Depuis 1990 et au prix de lourds investissements en infrastructures, le gouvernement et les autorités locales espèrent faire de la Zone Nouvelle de Pudong un élément clé de l’expansion de Shanghai. Neuf zones d’activités accueillent habitat, services et industries. Le développement de la ZNP reste cependant marqué par certaines faiblesses qui posent la question de son rôle dans le renouveau attendu de Shanghai.

  17. 33 CFR 3.40-35 - Sector Corpus Christi Marine Inspection Zone and Captain of the Port Zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Sector Corpus Christi Marine... ZONES, AND CAPTAIN OF THE PORT ZONES Eighth Coast Guard District § 3.40-35 Sector Corpus Christi Marine Inspection Zone and Captain of the Port Zone. Sector Corpus Christi's office is located in Corpus Christi,...

  18. 32 CFR 256.9 - Real estate interests to be considered for clear zones and accident potential zone.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Real estate interests to be considered for clear zones and accident potential zone. 256.9 Section 256.9 National Defense Department of Defense (Continued....9 Real estate interests to be considered for clear zones and accident potential zone. (a) The...

  19. 33 CFR 165.169 - Safety and Security Zones: New York Marine Inspection Zone and Captain of the Port Zone.

    Science.gov (United States)

    2010-07-01

    ... Point, NY; and Coast Guard Aids to Navigation Team New York, Bayonne, NJ. (3) Part 105 Facilities—(i) Definition. For the purposes of this section, Part 105 Facility means any facility subject to the regulations... that security zone is not being enforced. (13) Liquefied Hazardous Gas (LHG) Vessels—(i)...

  20. Traffic Analysis Zones - TRAFFIC_ZONES_TIGER00_IN: Indiana Traffic Analysis Zones (U.S. Census Bureau, 1:100,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — TRAFFIC_ZONES_TIGER00_IN contains traffic analysis zones in Indiana identified by the US Bureau of the Census. Vigo, Madison, and Monroe counties were not available...

  1. Evaluation of rear-end crash risk at work zone using work zone traffic data.

    Science.gov (United States)

    Meng, Qiang; Weng, Jinxian

    2011-07-01

    This paper aims to evaluate the rear-end crash risk at work zone activity area and merging area, as well as analyze the impacts of contributing factors by using work zone traffic data. Here, the rear-end crash risk is referred to as the probability that a vehicle is involved in a rear-end crash accident. The deceleration rate to avoid the crash (DRAC) is used in measuring rear-end crash risk. Based on work zone traffic data in Singapore, three rear-end crash risk models are developed to examine the relationship between rear-end crash risk at activity area and its contributing factors. The fourth rear-end crash risk model is developed to examine the effects of merging behavior on crash risk at merging area. The ANOVA results show that the rear-end crash risk at work zone activity area is statistically different from lane positions. Model results indicate that rear-end crash risk at work zone activity area increases with heavy vehicle percentage and lane traffic flow rate. An interesting finding is that the lane closer to work zone is strongly associated with higher rear-end crash risk. A truck has much higher probability involving in a rear-end accident than a car. Further, the expressway work zone activity area is found to have much larger crash risk than arterial work zone activity area. The merging choice has the dominated effect on risk reduction, suggesting that encouraging vehicles to merge early may be the most effective method to reduce rear-end crash risk at work zone merging area.

  2. ISOLDE target zone control room HD

    CERN Multimedia

    2016-01-01

    Operating the ISOLDE target handling robots from the dedicated control room in building 197. Monitors showing the movements of the robots (GPS in this case) in the target zone. The footage shows the actual operation by the operator as well as the different equipment such as camera electronics, camera motor controls, camera monitors and Kuka robot controls touch panel.

  3. Fault Zones in the Gulf Coast [gcfltzoneg

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent major fault zones as indicated on Plate 2, Principal structural features, Gulf of Mexico Basin (compiled by T.E. Ewing and R.F. Lopez) in volume...

  4. Techniques For Focusing In Zone Electrophoresis

    Science.gov (United States)

    Sharnez, Rizwan; Twitty, Garland E.; Sammons, David W.

    1994-01-01

    In two techniques for focusing in zone electrophoresis, force of applied electrical field in each charged particle balanced by restoring force of electro-osmosis. Two techniques: velocity-gradient focusing (VGF), suitable for rectangular electrophoresis chambers; and field-gradient focusing (FGF), suitable for step-shaped electrophoresis chambers.

  5. Fresnel zones for ground-based antennas

    DEFF Research Database (Denmark)

    Andersen, J. Bach

    1964-01-01

    The ordinary Fresnel zone concept is modified to include the influence of finite ground conductivity. This is important for ground-based antennas because the influence on the radiation pattern of irregularities near the antenna is determined by the amplitude and phase of the groundwave. A new...

  6. Family Day Care Zoning. Local Officials Guide.

    Science.gov (United States)

    Cohen, Abby; And Others

    This guide discusses city planning issues related to family day care zoning. The guide is divided into five sections. The first section discusses child care as a planning issue and focuses on changes in working patterns of families and in residential neighborhoods. The second section describes components of the child care delivery system, which…

  7. Framework Al zoning in zeolite ECR-1.

    Science.gov (United States)

    Shin, Jiho; Ahn, Nak Ho; Cho, Sung June; Ren, Limin; Xiao, Feng-Shou; Hong, Suk Bong

    2014-02-25

    Rietveld analyses of the synchrotron X-ray diffraction data for various cation forms of zeolite ECR-1 have demonstrated framework Al zoning, which parallels the alternation of Al-rich maz and Al-poor mor layers. This can be further supported by notable differences in the average bond valence of its 10 crystallographically distinct tetrahedral sites.

  8. Analysis Links Zoning Policies and Disparities

    Science.gov (United States)

    Shah, Nirvi

    2012-01-01

    Location, location, location. This mantra of real estate agents and their clients alike is now the target of a new report from the Brookings Institution linking housing prices and zoning practices to effectively depriving low-income students of high-quality schools. Using test scores from schools in the 100 largest metropolitan areas in the…

  9. Ethnographies of Grey Zones in Eastern Europe

    DEFF Research Database (Denmark)

    ’ and internationally minded ‘new citizens’ has left some in poverty, unemployment and social insecurity, leading them to rely on normative coping and semi-autonomous strategies for security and social guarantees. This anthology explores how grey zones of governance, borders, relations and invisibilities affect...

  10. Family Day Care Zoning Advocacy Guide.

    Science.gov (United States)

    Stevenson, Carol; And Others

    Designed to help family day care providers and the agencies that support them reform local zoning laws that make it difficult or impossible to legally care for children in their homes, this guide outlines the process of obtaining a use permit, changing local laws, and strategizing for the passage of state legislation that preempts local laws. A…

  11. The Alpine loop of the tethys zone

    NARCIS (Netherlands)

    Bemmelen, R.W. van

    1969-01-01

    The Alpine loop in Europe results from semi-autochthonous crustal movements which are restricted to the mobile Tethys zone. Its evolution cannot be explained by a uniform northward drift and push of the African continent; it has to be sought, in the first place, in geodynamic processes occurring in

  12. Wood-framed houses for earthquake zones

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg

    Wood-framed houses with a sheathing are suitable for use in earthquake zones. The Direction describes a method of determining the earthquake forces in a house and shows how these forces can be resisted by diaphragm action in the walls, floors, and roof, of the house. An appendix explains how...

  13. English Higher Education and Its Vocational Zones

    Science.gov (United States)

    Parry, Gareth

    2015-01-01

    Distinctions between academic, vocational and professional education inform but do not define the divisions of English higher education. Nevertheless, there are zones where courses, qualifications and institutions are specifically oriented to the world of work. These include most short-cycle higher education, large parts of undergraduate and…

  14. Site-Scale Saturated Zone Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    G. Zyvoloski

    2003-12-17

    The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca

  15. The concept of the Economic Exclusive Zone

    Directory of Open Access Journals (Sweden)

    Dorina Patuzi

    2015-03-01

    Full Text Available The important and the new concept that brought the third UN Conference of the Law of the Sea was the Economic Exclusive Zone (EEZ, requested by countries whose coasts are bordering on the oceans, seas, but also in harmony with the interests of countries which have extensive coastline or those with specific geographical features, which have a very narrow coastal zone. On December 10, 1982, nearly 120 countries signed the new United Nations Convention on the Law of the Sea, as one of the most significant international conferences. Part V of that Convention (more precisely Articles 55 to 75 provides for an “Exclusive Economic Zone” extending 200 nautical miles seaward from the coast. If all coastal states thus exercised their jurisdiction over their own EEZ, some 38 million square nautical miles would become their “economic patrimony”. It should be mentioned that the ocean represents 71% of the total surface of the earth and that 32% of that falls under the jurisdiction of coastal states. Consequently inside these economic zones would lie 90% of global fishing, 87% of oil deposits and 10 % of polymetallic nodules. The EEZ provisions have received widespread support and have become an integral part of international practice especially when the Convention of 1982 entered into force, also articles 55 and 86 of the Convention make it clear that the EEZ is not a part of the territorial sea, but it is a zone sui generis, with a statute of its own. Some countries had claimed 200-mile EEZ and other have established a 200- mile Exclusive Fishing Zone (EFZ. The countries benefiting the most from the EEZ concept are in order of the size of their zones: USA, Australia, Indonesia, New Zealand, Canada and Russia. If this concept was to be applied by all coastal Mediterranean States, the entire sea would be covered by EEZs of the littoral countries. The countries of the Mediterranean that would most benefit from the EEZ are Greece, Cyprus, Italy and Malta

  16. Does Zoning Winter Recreationists Reduce Recreation Conflict?

    Science.gov (United States)

    Miller, Aubrey D; Vaske, Jerry J; Squires, John R; Olson, Lucretia E; Roberts, Elizabeth K

    2017-01-01

    Parks and protected area managers use zoning to decrease interpersonal conflict between recreationists. Zoning, or segregation, of recreation-often by non-motorized and motorized activity-is designed to limit physical interaction while providing recreation opportunities to both groups. This article investigated the effectiveness of zoning to reduce recreation conflict in the Vail Pass Winter Recreation Area in Colorado, USA. Despite a zoning management system, established groomed travel routes were used by both non-motorized recreationists (backcountry skiers, snowboarders, snowshoers) and motorized recreationists (snowmobilers). We hypothesized that persistent recreation conflict reported by non-motorized recreationists was the result of recreation occurring in areas of mixed non-motorized and motorized use, mostly along groomed routes. We performed a geospatial analysis of recreation [from Global Positioning System (GPS) points, n = 1,233,449] in the Vail Pass Winter Recreation Area to identify areas of mixed non-motorized and motorized use. We then surveyed non-motorized recreationists (n = 199) to test whether reported conflict is higher for respondents who traveled in areas of mixed-use, compared with respondents traveling outside areas of mixed-use. Results from the geospatial analysis showed that only 0.7 % of the Vail Pass Winter Recreation Area contained recreation from both groups, however that area contained 14.8 % of all non-motorized recreation and 49.1 % of all motorized recreation. Survey analysis results showed higher interpersonal conflict for all five standard conflict variables among non-motorized respondents who traveled in areas of mixed-use, compared with those traveling outside mixed-use areas. Management implications and recommendations for increasing the effectiveness of zoning are provided.

  17. Does Zoning Winter Recreationists Reduce Recreation Conflict?

    Science.gov (United States)

    Miller, Aubrey D.; Vaske, Jerry J.; Squires, John R.; Olson, Lucretia E.; Roberts, Elizabeth K.

    2017-01-01

    Parks and protected area managers use zoning to decrease interpersonal conflict between recreationists. Zoning, or segregation, of recreation—often by non-motorized and motorized activity—is designed to limit physical interaction while providing recreation opportunities to both groups. This article investigated the effectiveness of zoning to reduce recreation conflict in the Vail Pass Winter Recreation Area in Colorado, USA. Despite a zoning management system, established groomed travel routes were used by both non-motorized recreationists (backcountry skiers, snowboarders, snowshoers) and motorized recreationists (snowmobilers). We hypothesized that persistent recreation conflict reported by non-motorized recreationists was the result of recreation occurring in areas of mixed non-motorized and motorized use, mostly along groomed routes. We performed a geospatial analysis of recreation [from Global Positioning System (GPS) points, n = 1,233,449] in the Vail Pass Winter Recreation Area to identify areas of mixed non-motorized and motorized use. We then surveyed non-motorized recreationists ( n = 199) to test whether reported conflict is higher for respondents who traveled in areas of mixed-use, compared with respondents traveling outside areas of mixed-use. Results from the geospatial analysis showed that only 0.7 % of the Vail Pass Winter Recreation Area contained recreation from both groups, however that area contained 14.8 % of all non-motorized recreation and 49.1 % of all motorized recreation. Survey analysis results showed higher interpersonal conflict for all five standard conflict variables among non-motorized respondents who traveled in areas of mixed-use, compared with those traveling outside mixed-use areas. Management implications and recommendations for increasing the effectiveness of zoning are provided.

  18. FIGHT ZONE WITH POINTS OF THE SHOTOKAN KARATE FEMALE COMPETITION

    Directory of Open Access Journals (Sweden)

    Nelson Kautzner Marques Junior

    2014-04-01

    Full Text Available The objective of the study was to determine the fight zone with point during the female kumite of competition. This study used a quantitative research for identify the fight zone with point (ippon or waza-ari or not during the female kumite of competition. Were selected on the Internet several championship of kumite of the JKA and of the ITKF. The study detected a high probability of point in the zone 7 and in the zone 2. The study determined that the most points at the corner occurred when the karateka practiced the attack in fight zone. Kruskal-Wallis ANOVA verified significant difference between the fight zone with points, H (10 = 29,49, p = 0,001. The Mann Whitney U test detected significant difference between the zone 5 with waza-ari versus all the zone. The greatest number of points in the fight zone was in agreement with the size of the fight zone. The central zone or zone 5 has 6x6 m, during the female kumite occurred more points, total of 68 waza-aris and 5 ippons. The study on the fight zone with points of the female kumite permits that the karateka has knowledge about the combat zones and guides the karateka before, during and after the female kumite. However, more studies should be done to confirm these findings.

  19. Automatic detection and classification of damage zone(s) for incorporating in digital image correlation technique

    Science.gov (United States)

    Bhattacharjee, Sudipta; Deb, Debasis

    2016-07-01

    Digital image correlation (DIC) is a technique developed for monitoring surface deformation/displacement of an object under loading conditions. This method is further refined to make it capable of handling discontinuities on the surface of the sample. A damage zone is referred to a surface area fractured and opened in due course of loading. In this study, an algorithm is presented to automatically detect multiple damage zones in deformed image. The algorithm identifies the pixels located inside these zones and eliminate them from FEM-DIC processes. The proposed algorithm is successfully implemented on several damaged samples to estimate displacement fields of an object under loading conditions. This study shows that displacement fields represent the damage conditions reasonably well as compared to regular FEM-DIC technique without considering the damage zones.

  20. Louisiana Coastal Zone Boundary, Geographic NAD83, LDNR (1998)[coastal_zone_boundary_LDNR_1998

    Data.gov (United States)

    Louisiana Geographic Information Center — This is a polygon dataset representing the extent of the LDNR regulatory area defined as the Louisiana Coastal Zone. This area comprises a band across the southern...

  1. Kelvin-Helmholtz instability with mixing zone; Instabilite de Kelvin-Helmholtz avec zone de melange

    Energy Technology Data Exchange (ETDEWEB)

    Chong-Techer, R. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DM2S/DIR-SFME), 91 - Gif sur Yvette (France)

    2008-07-01

    This thesis is part of the FATHER experiment and the analyze of the hydrodynamical instabilities which appear during the mixing of two liquids of same volume mass with shearing speed in the mixing zone. The aim is to understand the possible influence of a Kelvin-Helmholtz hydrodynamical instability with mixing zone, compared to classical Kelvin-Helmholtz instability with interface and with theoretical results of Rayleigh-Taylor instability. (A.L.B.)

  2. Reductive dechlorination of trichloroethene DNAPL source zones: source zone architecture versus electron donor availability

    Science.gov (United States)

    Krol, M.; Kokkinaki, A.; Sleep, B.

    2014-12-01

    The persistence of dense-non-aqueous-phase liquids (DNAPLs) in the subsurface has led practitioners and regulatory agencies to turn towards low-maintenance, low-cost remediation methods. Biological degradation has been suggested as a possible solution, based on the well-proven ability of certain microbial species to break down dissolved chlorinated ethenes under favorable conditions. However, the biodegradation of pure phase chlorinated ethenes is subject to additional constraints: the continuous release of electron acceptor at a rate governed by mass transfer kinetics, and the temporal and spatial heterogeneity of DNAPL source zones which leads to spatially and temporally variable availability of the reactants for reductive dechlorination. In this work, we investigate the relationship between various DNAPL source zone characteristics and reaction kinetics using COMPSIM, a multiphase groundwater model that considers non-equilibrium mass transfer and Monod-type kinetics for reductive dechlorination. Numerical simulations are performed for simple, homogeneous trichloroethene DNAPL source zones to demonstrate the effect of single source zone characteristics, as well as for larger, more realistic heterogeneous source zones. It is shown that source zone size, and mass transfer kinetics may have a decisive effect on the predicted bio-enhancement. Finally, we evaluate the performance of DNAPL bioremediation for realistic, thermodynamically constrained, concentrations of electron donor. Our results indicate that the latter may be the most important limitation for the success of DNAPL bioremediation, leading to reduced bio-enhancement and, in many cases, comparable performance with water flooding.

  3. Synaptic Vesicle Proteins and Active Zone Plasticity.

    Science.gov (United States)

    Kittel, Robert J; Heckmann, Manfred

    2016-01-01

    Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone (AZ). The complex molecular architecture of AZs mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of AZs vary significantly, even for a given connection. Thus, there appear to be distinct AZ states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the AZ. The protein-rich cytomatrix at the active zone (CAZ) provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1) and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and AZ states, which has heretofore received little attention.

  4. Diamagnetic pumping in a rotating convection zone

    Science.gov (United States)

    Kitchatinov, L. L.; Nepomnyashchikh, A. A.

    2016-10-01

    Solar dynamo models require some mechanism for magnetic field concentration near the base of the convection zone in order to generate super-kilogauss toroidal fields with sufficiently large (∼ 1024 Mx) magnetic flux. We consider the downward diamagnetic pumping near the base of the convection zone as a possible concentration mechanism and derive the pumping velocities with allowance for the effect of rotation. Transport velocities for poloidal and toroidal fields differ in rotating fluid. The toroidal field is transported downward along the radius only but the pumping velocity for the poloidal field has an equatorward meridional component also. Previous results for cases of slow and rapid rotation are reproduced and the diamagnetic pumping expressions adapted for use in dynamo models are presented.

  5. Diamagnetic pumping in a rotating convection zone

    CERN Document Server

    Kitchatinov, L

    2016-01-01

    Solar dynamo models require some mechanism for magnetic field concentration near the base of the convection zone in order to generate super-kilogauss toroidal fields with sufficiently large (~10^{24} Mx) magnetic flux. We consider the downward diamagnetic pumping near the base of the convection zone as a possible concentration mechanism and derive the pumping velocities with allowance for the effect of rotation. Transport velocities for poloidal and toroidal fields differ in rotating fluid. The toroidal field is transported downward along the radius only but the pumping velocity for the poloidal field has an equatorward meridional component also. Previous results for cases of slow and rapid rotation are reproduced and the diamagnetic pumping expressions adapted for use in dynamo models are presented.

  6. UV habitable zones around M stars

    CERN Document Server

    Buccino, Andrea P; Mauas, Pablo J D

    2007-01-01

    During the last decade, there was a paradigm-shift in order to consider terrestrial planets within liquid-water habitable zones (LW-HZ) around M stars, as suitable places for the emergence and evolution of life. Here we analyze the influence of UV boundary conditions to three planetary systems around dM (HIP 74995, HIP 109388 and HIP 113020). We apply our model of UV habitable zone (UV-HZ) (Buccino et al. 2006) to these cases and show that during the quiescent UV output there would not be enough UV radiation within the LW-HZ in order to trigger biogenic processes. We also analyze the cases of two other M flare stars and show that the flares of moderate intensity could provide the necessary energy to trigger those biogenic processes, while the strong flares not necessary rule-out the possibility of life-bearing planets.

  7. FACTOR ANALYSIS OF MULTISTOREY RESIDENTIAL BUILDINGS ZONE

    Directory of Open Access Journals (Sweden)

    Петр Матвеевич Мазуркин

    2016-02-01

    Full Text Available According to the UN classification of 11 classes of soil cover, the first three are grass, trees and shrubs and forests. In the city they correspond to the three elements of vegetation: lawns, tree plantings (trees and shrubs. We have adopted zoning for city-building to identify statistical regularities. Map dimensions in GIS "Map 2011" Yoshkar-Ola was allocated to "residential zone" and "Area of construction of multi-storey residential buildings (cadastral 58 quart crystals". The parameters of the elements of the vegetation cover have been considered: the number of elements of different levels, area and perimeter, the absolute and relative form, and activity of vegetation. As the result, we have obtained equations of binomial rank distributions, conducted the ratings and selected the best of cadastral quarter on environmental conditions.

  8. Vadose Zone Transport Field Study: Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Andy L.; Conrad, Mark E.; Daily, William D.; Fink, James B.; Freedman, Vicky L.; Gee, Glendon W.; Hoversten, Gary M.; Keller, Jason M.; Majer, Ernest L.; Murray, Christopher J.; White, Mark D.; Yabusaki, Steven B.; Zhang, Z. F.

    2006-07-31

    From FY 2000 through FY 2003, a series of vadose zone transport field experiments were conducted as part of the U.S. Department of Energy’s Groundwater/Vadose Zone Integration Project Science and Technology Project, now known as the Remediation and Closure Science Project, and managed by the Pacific Northwest National Laboratory (PNNL). The series of experiments included two major field campaigns, one at a 299-E24-11 injection test site near PUREX and a second at a clastic dike site off Army Loop Road. The goals of these experiments were to improve our understanding of vadose zone transport processes; to develop data sets to validate and calibrate vadose zone flow and transport models; and to identify advanced monitoring techniques useful for evaluating flow-and-transport mechanisms and delineating contaminant plumes in the vadose zone at the Hanford Site. This report summarizes the key findings from the field studies and demonstrates how data collected from these studies are being used to improve conceptual models and develop numerical models of flow and transport in Hanford’s vadose zone. Results of these tests have led to a better understanding of the vadose zone. Fine-scale geologic heterogeneities, including grain fabric and lamination, were observed to have a strong effect on the large-scale behavior of contaminant plumes, primarily through increased lateral spreading resulting from anisotropy. Conceptual models have been updated to include lateral spreading and numerical models of unsaturated flow and transport have revised accordingly. A new robust model based on the concept of a connectivity tensor was developed to describe saturation-dependent anisotropy in strongly heterogeneous soils and has been incorporated into PNNL’s Subsurface Transport Over Multiple Phases (STOMP) simulator. Application to field-scale transport problems have led to a better understanding plume behavior at a number of sites where lateral spreading may have dominated waste

  9. Radioactive waste disposal in thick unsaturated zones.

    Science.gov (United States)

    Winogard, I J

    1981-06-26

    Portions of the Great Basin are undergoing crustal extension and have unsaturated zones as much as 600 meters thick. These areas contain multiple natural barriers capable of isolating solidified toxic wastes from the biosphere for tens of thousands to perhaps hundreds of thousands of years. An example of the potential utilization of such arid zone environments for toxic waste isolatic is the burial of transuranic radioactive wastes at relatively shallow depths (15 to 100 meters) in Sedan Crater, Yucca Flat, Nevada. The volume of this man-made crater is several times that of the projected volume of such wastes to the year 2000. Disposal in Sedan Crater could be accomplished at a savings on the order of $0.5 billion, in comparison with current schemes for burial of such wastes in mined repositories at depths of 600 to 900 meters, and with an apparently equal likelihood of waste isolation from the biosphere.

  10. An Auto-control Method of Pulsed Light Extinction Ratio in the Brillouin Sensing System%布里渊传感系统脉冲光源消光比自动控制方法

    Institute of Scientific and Technical Information of China (English)

    胡佳成; 王婵媛; 李国扬; 沈小燕

    2016-01-01

    针对布里渊光时域反射型(BOTDR)分布式光纤传感系统中脉冲光源消光比易受偏置电压漂移影响的问题,本文提出了一种结合双电极串联结构电光调制器(EOM)及“扫描⎯步进跟踪”算法的脉冲光源消光比自动控制方法。实验结果表明,该方法可将EOM输出脉冲光的消光比稳定在50 dB以上。在150 min的测试时间里,输出脉冲光消光比的最大值为52.4 dB,最小值为51.1 dB,波动值仅为1.3 dB。该方法对BOTDR光纤传感系统及高功率激光驱动装置等设备中脉冲光源性能的提升具有重要意义。%A novel method to control the pulsed light extinction ratio automatically, which combines a double electrode series structure EOM with “scanning & step-tracking” algorithm, is proposed. It aims to address the problem that extinction ratio of pulsed light is affected by bias voltage shifting in a Brillouin Optical-fiber Time-domain Reflectometry (BOTDR) based on distributed optical fiber sensing system. Based on the method, some experiments are conducted and important conclusions are deduced. The results show that it could keep the extinction ratio of pulsed light above 50 dB steadily. The fluctuation of extinction ratio is only 1.3 dB, maximum value of extinction ratio is 52.4 dB and the minimum value is 51.1 dB. It is indicated that the proposed method will have important significance for enhancing the performance of pulsed light source in BOTDR optical fiber sensing system and high power laser driving device.

  11. 基于布里渊载波相移的宽带可调谐二倍频微波信号生成*%Widely tunable frequency-doubling microwaves generated using Brillouin-assisted carrier phase shift

    Institute of Scientific and Technical Information of China (English)

    郑狄; 潘炜; 闫连山; 罗斌; 邹喜华; 刘新开; 易安林

    2014-01-01

    本文提出并实验验证了一种基于光纤中受激布里渊散射效应的光子二倍频微波信号生成技术。利用布里渊增益谱内的强色散特性,对光强度调制器产生的双边带调制信号的载波进行π/2相移,可实现载波与±1阶边带拍频仅生成二倍频微波信号。由于光纤中受激布里渊散射的窄带特性以及仅对双边带调制信号的载波进行相移,不影响调制信号两个边带的幅值和相位,因而生成的二倍频微波信号可实现宽带调谐,调谐范围仅受其他光器件的工作带宽限制。此外,信号光和产生受激布里渊散射的抽运光均来自同一光源,因而不受波长漂移的影响,系统具良好的稳定性。%An optically tunable frequency-doubling microwave generation technique based on stimulated Brillouin scattering (SBS) in optical fibers is proposed and experimentally demonstrated. Due to the strong dispersion characteristics in SBS, when a π/2 phase shift is imposed on the optical carrier of an amplitude-modulated signal by SBS, only a frequency-doubling microwave signal from the beating between the optical carrier and the ±1st sidebands is generated. Due to the inherent narrowband character of SBS and the phase shift being only imported on to the optical carrier while the sidebands are kept unchanged, the frequency-doubling with large frequency tunability is realized, the operational bandwidth is just limited by other optical device deployed. In addition, all the required optical signals and pumps can be generated from the same laser source, the influence from the wavelength drifting is eliminated, so the stability of the system is established.

  12. Fractal zone plate beam based optical tweezers

    Science.gov (United States)

    Cheng, Shubo; Zhang, Xinyu; Ma, Wenzhuo; Tao, Shaohua

    2016-01-01

    We demonstrate optical manipulation with an optical beam generated by a fractral zone plate (FZP). The experimental results show that the FZP beam can simultaneously trap multiple particles positioned in different focal planes of the FZP beam, owing to the multiple foci and self-reconstruction property of the FZP beam. The FZP beam can also be used to construct three-dimensional optical tweezers for potential applications. PMID:27678305

  13. Two-Temperature-Zone Silicon Reactor

    Science.gov (United States)

    Sanjurjo, A.; Nanis, L.; Kapur, V. K.; Weaver, R. D.

    1983-01-01

    When high purity silicon is synthesized by reduction of silicon tetrafluoride by sodium, very-fast highly exothermic reaction takes place. Controlled reaction is proposed in which SiF4-pressurized vertical reactor operates with two temperature zones. Liquid sodium feeds from nozzle at top of rector without reacting with SiF4. When sodium reaches higher temperature region at bottom, reaction takes place immediately.

  14. Nonvolcanic tremors in the Mexican subduction zone

    Science.gov (United States)

    Payero, J. S.; Kostoglodov, V.; Mikumo, T.; Perez-Campos, X.; Iglesias, A.; Clayton, R.

    2007-05-01

    Nonvolcanic low frequency tremors (NVT) have been discovered and studied recently in Japan and Cascadia subduction zones and deep beneath the San Andreas Fault. The tremors activity is increasing during so-called silent earthquakes (SQ) in Japan and Cascadia. NVT clusters also migrate following the propagation of the SQ. The origin of the NVT is still unclear. The studies of NVT and SQ in different subduction zones are required to understand the cause for these phenomena. We discovered a number of NVT from daily spectrograms of continuous broad band records at seismic stations of Servicio Seismológico Nacional (SSN) an MASE project. The analyzed data cover a period of 2001-2004 (SSN) when in 2002 a large SQ has occurred in the Guerrero- Oaxaca region, and a steady-state interseismic epoch of 2005 and a new large SQ in 2006 (MASE). NVT occurred in the central part of the Mexican subduction zone (Guerrero) at approximately 200 km from the coast. We can not accurately localize the tremors because of sparse station coverage in 2001-2004. The MASE data of 2005-2006 show that NVT records in Mexico are very similar to those obtained in Cascadia subduction zone. The tremors duration is of 10-60 min, and they appear to travel at S-wave velocities. More than 100 strong NVT were recorded by most of the MASE stations with the epicenters clustered in the narrow band of ~40x150 km to the south of Iguala city and parallel to the coast line. NVT depths are poorly constrained but seem to be less than 40 km deep. We noticed a some increase of NVT activity during the 2001-2002 and 2006 SQs compared with an NVT activity for the "SQ quiet" period of 2003-2004 nevertheless. A lack of NVT for the period of 2-3 months after the SQ is apparent in 2002 and 2006.

  15. Nursing in the world's war zones.

    Science.gov (United States)

    Malone, Jasmine

    2012-06-01

    This article describes the difficult decisions faced by healthcare workers providing treatment in conflict areas to civilians as well as combatants. While endeavouring to provide the best possible care including, where practicable, follow-up treatment, they daily face the risk of kidnap, attack, takeover of hospital facilities, the seizure of drugs and medical equipment, as well as having to negotiate checkpoints. Care is provided in conflict zones by charities and military medical facilities.

  16. Marginal Ice Zone: Biogeochemical Sampling with Gliders

    Science.gov (United States)

    2015-09-30

    ocean and base of marine food webs, are responding to changing conditions in the Arctic Ocean . The high-level project goals are to use underwater...observing array (Fig. 1). The glider sensor suite included temperature , temperature microstructure, salinity , oxygen, chlorophyll fluorescence, optical...presented at the Arctic Science Summit Week in Toyama, Japan, in April 2015 (Direct Observations of Ocean Variability Across the Arctic Marginal Ice Zone

  17. Cellular Automation of Galactic Habitable Zone

    CERN Document Server

    Vukotic, Branislav

    2010-01-01

    We present a preliminary results of our Galactic Habitable Zone (GHZ) 2D probabilistic cellular automata models. The relevant time-scales (emergence of life, it's diversification and evolution influenced with the global risk function) are modeled as the probability matrix elements and are chosen in accordance with the Copernican principle to be well-represented by the data inferred from the Earth's fossil record. With Fermi's paradox as a main boundary condition the resulting histories of astrobiological landscape are discussed.

  18. Rural Productivity Zones (RPZs) for microenterprises

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, R.D.

    1997-12-01

    In this paper the authors discuss the concept of rural productivity zones (RPZs) which are defined as a business incubator to foster income-producing opportunities for the rural poor. The essential ingredients of such a program include: electric power; business development assistance; office services; and quality work space. The electric power source must be a good quality system, consisting of a diesel/wind/photovoltaic hybrid type system, providing reliable service, with a local maintenance program and a functional load management program.

  19. Diesel particulate filter with zoned resistive heater

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-03-08

    A diesel particulate filter assembly comprises a diesel particulate filter (DPF) and a heater assembly. The DPF filters a particulate from exhaust produced by an engine. The heater assembly has a first metallic layer that is applied to the DPF, a resistive layer that is applied to the first metallic layer, and a second metallic layer that is applied to the resistive layer. The second metallic layer is etched to form a plurality of zones.

  20. Shipping Fairways, Lanes, and Zones for US waters

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Various shipping zones delineate activities and regulations for marine vessel traffic. Traffic lanes define specific traffic flow, while traffic separation zones...

  1. Coastal zone: Shelf-EEZ and land sea interface

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, B.N.; Parulekar, A.H.

    Among the few vibrant ecotopes is the coastal zone, where multifaceted interactions among air, sea and land are dynamically balanced. An area of intense clash of interest of user community, the coastal zone harbouring vast potential of renewable...

  2. 21 CFR 866.2850 - Automated zone reader.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2850 Automated zone reader. (a) Identification. An automated zone reader is a mechanical device intended for medical purposes...

  3. Ecotype Zones for Minnesota and Iowa Prairie Lands

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains a map of local ecotype seed harvest zones for Iowa and Minnesota. A local ecotype zone is defined as a geographic area with generally similar...

  4. The Study on Provincial-level Land Consolidation Zoning

    Institute of Scientific and Technical Information of China (English)

    Guoping; CHEN; Xiaowei; WU

    2013-01-01

    The principles and methods of regional land consolidation in Yunnan Province are expounded. On the basis of differences in topography, climate, soil, hydrology and other natural conditions and the characteristics of spatial layout of land use, agricultural zoning, cropping system and land consolidation measures, the land consolidation zoning indicator system composed of five indicators covering ecological environment, socio-economy, land use, land consolidation and land quality is established by using the GIS spatial analysis and mathematical analysis. Against this backdrop, the Yunnan Province is divided into five first-level land consolidation zones, including the middle-mountain lake basin plateau consolidation zone in central Yunnan, the middle and low mountain wide valley basin consolidation zone in southwest Yunnan, the karst middle and low mountains consolidation zone in southeast Yunnan, the high-mountain and highlands consolidation zone in northeast Yunnan, the middle -mountain and mountain plateau consolidation zone in northeast Yunnan.

  5. Blending zone determination for aerial orthimage mosaicking

    Science.gov (United States)

    Lin, Chao-Hung; Chen, Bo-Heng; Lin, Bo-Yi; Chou, Han-Szu

    2016-09-01

    Creating a composed image from a set of aerial images is a fundamental step in orthomosaic generation. One of the processes involved in this technique is determining an optimal seamline in an overlapping region to stitch image patches seamlessly. Most previous studies have solved this optimization problem by searching for a one-pixel-wide seamline with an objective function. This strategy significantly reduced pixel mismatches on the seamline caused by geometric distortions of images but did not fully consider color discontinuity and mismatch problems that occur around the seamline, which sometimes cause mosaicking artifacts. This study proposes a blending zone determination scheme with a novel path finding algorithm to reduce the occurrence of unwanted artifacts. Instead of searching for a one-pixel-wide seamline, a blending zone, which is a k-pixel-wide seamline that passes through high-similarity pixels in the overlapping region, is determined using a hierarchical structure. This strategy allows for not only seamless stitching but also smooth color blending of neighboring image patches. Moreover, the proposed method searches for a blending zone without the pre-process of highly mismatched pixel removal and additional geographic data of road vectors and digital surface/elevation models, which increases the usability of the approach. Qualitative and quantitative analyses of aerial images demonstrate the superiority of the proposed method to related methods in terms of avoidance of passing highly mismatched pixels.

  6. Multispectral observations of the surf zone

    Science.gov (United States)

    Schoonmaker, Jon S.; Dirbas, Joseph; Gilbert, Gary

    2003-09-01

    Airborne multispectral imagery was collected over various targets on the beach and in the water in an attempt to characterize the surf zone environment with respect to electro-optical system capabilities and to assess the utility of very low cost, small multispectral systems in mine counter measures (MCM) and intelligence, surveillance and reconnaissance applications. The data was collected by PAR Government Systems Corporation (PGSC) at the Army Corps of Engineers Field Research Facility at Duck North Carolina and on the beaches of Camp Pendleton Marine Corps Base in Southern California. PGSC flew the first two of its MANTIS (Mission Adaptable Narrowband Tunable Imaging Sensor) systems. Both MANTIS systems were flown in an IR - red - green - blue (700, 600, 550, 480 nm) configuration from altitudes ranging from 200 to 700 meters. Data collected has been lightly analyzed and a surf zone index (SZI) defined and calculated. This index allows mine hunting system performance measurements in the surf zone to be normalized by environmental conditions. The SZI takes into account water clarity, wave energy, and foam persistence.

  7. Study on rupture zone of the M=8.1 Kunlun Mountain earthquake using fault-zone trapped waves

    Institute of Scientific and Technical Information of China (English)

    李松林; 张先康; 樊计昌

    2005-01-01

    The observation of the fault-zone trapped waves was conducted using a seismic line with dense receivers across surface rupture zone of the M=8.1 Kunlun Mountain earthquake. The fault zone trapped waves were separated from seismograms by numerical filtering and spectral analyzing. The results show that: a) Both explosion and earthquake sources can excite fault-zone trapped waves, as long as they locate in or near the fault zone; b) Most energy of the fault-zone trapped waves concentrates in the fault zone and the amplitudes strongly decay with the distance from observation point to the fault zone; c) Dominant frequencies of the fault-zone trapped waves are related to the width of the fault zone and the velocity of the media in it. The wider the fault zone or the lower the velocity is, the lower the dominant frequencies are; d) For fault zone trapped waves, there exist dispersions; e) Based on the fault zone trapped waves observed in Kunlun Mountain Pass region, the width of the rupture plane is deduced to be about 300 m and is greater than that on the surface.

  8. Intra-Operational Area Coordination: The Zone EOC Concept

    Science.gov (United States)

    2015-09-01

    the horizon before one is the blackest. – Mahatma Gandhi The San Francisco Bay Area lies in a highly active seismic zone with numerous active...Mutual Aid System coordination in the San Mateo County OA utilizes the same corresponding zones, along with the OA public safety communications...county OES zone that also corresponded with the Law Enforcement Mutual Aid System coordination zone. Exercise scenarios were assigned as follows

  9. SATURATED ZONE IN-SITU TESTING

    Energy Technology Data Exchange (ETDEWEB)

    P.W. REIMUS

    2004-11-08

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in ''Site-Scale Saturated Zone Flow Model (BSC 2004 [DIRS 170037]), Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass

  10. Fluid migration in ductile shear zones

    Science.gov (United States)

    Fusseis, Florian; Menegon, Luca

    2014-05-01

    Fluid migration in metamorphic environments depends on a dynamically evolving permeable pore space, which was rarely characterised in detail. The data-base behind our understanding of the 4-dimensional transport properties of metamorphic rocks is therefore fragmentary at best, which leaves conceptual models poorly supported. Generally, it seems established that deformation is a major driver of permeability generation during regional metamorphism, and evidence for metamorphic fluids being channelled in large scale shear zones has been found in all depth segments of the continental crust. When strain localizes in ductile shear zones, the microfabric is modified until a steady state mylonite is formed that supports large deformations. A dynamic porosity that evolves during mylonitisation controls the distinct transport pathways along which fluid interacts with the rock. This dynamic porosity is controlled by a limited number of mechanisms, which are intrinsically linked to the metamorphic evolution of the rock during its deformational overprint. Many mid- and lower-crustal mylonites comprise polyphase mixtures of micron-sized grains that show evidence for deformation by dissolution/precipitation-assisted viscous grain boundary sliding. The establishment of these mineral mixtures is a critical process, where monomineralic layers are dispersed and grain growth is inhibited by the heterogeneous nucleation of secondary mineral phases at triple junctions. Here we show evidence from three different mid- and lower-crustal shear zones indicating that heterogeneous nucleation occurs in creep cavities. Micro- and nanotomographic observations show that creep cavities provide the dominant form of porosity in these ultramylonites. They control a "granular fluid pump" that directs fluid migration and hence mass transport. The granular fluid pump operates on the grain scale driven by viscous grain boundary sliding, and requires only small amounts of fluid. The spatial arrangement of

  11. 33 CFR 147.825 - Chevron Genesis Spar safety zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Chevron Genesis Spar safety zone... (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.825 Chevron Genesis Spar safety zone. (a) Description. The Chevron Genesis Spar, Green Canyon 205A (GC205A), is located at position 27°46′46.365″ N,...

  12. 76 FR 58401 - Safety Zone; Swim Around Charleston, Charleston, SC

    Science.gov (United States)

    2011-09-21

    ... Zone; Swim Around Charleston, Charleston, SC in the Federal Register (76 FR 38586). We received no... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Swim Around Charleston, Charleston, SC... temporary moving safety zone during the Swim Around Charleston, a swimming race occurring on waters of...

  13. 77 FR 35846 - Safety Zone; Sheboygan Harbor Fest, Sheboygan, WI

    Science.gov (United States)

    2012-06-15

    .... SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Sheboygan Harbor Fest, Sheboygan, WI AGENCY... safety zone on Lake Michigan and the Sheboygan River, Sheboygan, WI. This safety zone is intended...

  14. 75 FR 34361 - Safety Zone, Milwaukee Harbor, Milwaukee, WI

    Science.gov (United States)

    2010-06-17

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Milwaukee Harbor, Milwaukee, WI AGENCY: Coast Guard, DHS..., call ] or e-mail BM1 Adam Kraft, Prevention Department, Coast Guard Sector Lake Michigan, Milwaukee, WI... enforce the safety zone listed in 33 CFR 165.935, Safety Zone, Milwaukee Harbor, Milwaukee, WI, for...

  15. 75 FR 49848 - Safety Zone; Milwaukee Harbor, Milwaukee, WI

    Science.gov (United States)

    2010-08-16

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Milwaukee Harbor, Milwaukee, WI AGENCY..., WI at 414-747-7154, e-mail Adam.D.Kraft@uscg.mil . SUPPLEMENTARY INFORMATION: The Coast Guard will enforce the safety zone listed in 33 CFR 165.935, Safety Zone, Milwaukee Harbor, Milwaukee, WI, for...

  16. 75 FR 22234 - Safety Zone; Milwaukee Harbor, Milwaukee, WI

    Science.gov (United States)

    2010-04-28

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Milwaukee Harbor, Milwaukee, WI AGENCY... BM1 Adam Kraft, Prevention Department, Coast Guard Sector Lake Michigan, Milwaukee, WI at 414-747-7154... zone listed in 33 CFR 165.935, Safety Zones, Milwaukee Harbor, Milwaukee, WI, for the following...

  17. Distribution of some vascular plants and anthropopressure zones in Warsaw

    Directory of Open Access Journals (Sweden)

    Barbara Sudnik-Wójcikowska

    2014-01-01

    Full Text Available The cartogramms of the species distribution within Warsaw were compared to the anthropopressure zones distinguished conventionally. Floras of individual zones differboth quantitatively and qualitatively. Some species are more confined to specific zones some have even an indicator value. The most interesting taxa are those found in sites where anthropopressure is the greatest.

  18. 36 CFR 28.15 - Approval of local zoning ordinances.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Approval of local zoning... INTERIOR FIRE ISLAND NATIONAL SEASHORE: ZONING STANDARDS Federal Standards and Approval of Local Ordinances § 28.15 Approval of local zoning ordinances. (a) The Secretary shall approve local ordinances...

  19. RURAL ZONING--PEOPLE, PROPERTY, AND PUBLIC POLICY.

    Science.gov (United States)

    BLOCK, WILLIAM J.

    WHILE COMPREHENSIVE PLANNING IS MANDATORY PRIOR TO PASSAGE OF ANY ZONING ORDINANCES, ZONING IN RURAL AREAS IS RELATIVELY NEW. ALTHOUGH MANY CONTROVERSIAL ISSUES ARISE DURING PLANNING, THE FACT REMAINS THAT THE BENEFITS ARE GREATER WHEN ZONING IS PROPERLY PLANNED AND EXECUTED. PROPERTY OWNERS OBJECT IN MANY INSTANCES TO PROBLEMS THAT MAY ARISE,…

  20. School Zoning, Equity and Freedom: The Case of New Zealand.

    Science.gov (United States)

    McCulloch, Gary

    1991-01-01

    Discusses implications of major reforms in secondary school zoning in New Zealand, highlighting freedom and equity considerations. Zoning's primary aim has changed from balancing out different schools' declared needs to emphasizing parents' rights. The new zoning provisions involve both a strong role for freedom and a weak role for equity. (72…