WorldWideScience

Sample records for atmospheric neutrino-induced cascades

  1. First search for atmospheric and extraterrestrial neutrino-induced cascades with the IceCube detector

    NARCIS (Netherlands)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J.A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S.W.; Bay, R.; Alba, J.L.B.; Beattie, K.; Beatty, J.J.; Bechet, S.; Becker, J.K.; Becker, K.H.; Benabderrahmane, M.L.; BenZvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D.Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D.J.; Bohm, C.; Bose, D.; Boser, S.; Botner, O.; Braun, J.; Brown, A.M.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D.F.; D'Agostino, M.V.; Danninger, M.; Daughhetee, J.; Davis, J.C.; Clercq, C. De; Demirors, L.; Depaepe, O.; Descamps, F.; Desiati, P.; Vries-Uiterweerd, G. de; DeYoung, T.; Diaz-Velez, J.C.; Dierckxsens, M.; Dreyer, J.; Dumm, J.P.; Ehrlich, R.; Eisch, J.; Ellsworth, R.W.; Engdegard, O.; Euler, S.; Evenson, P.A.; Fadiran, O.; Fazely, A.R.; Fedynitch, A.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Foerster, M.M.; Fox, B.D.; Franckowiak, A.; Franke, R.; Gaisser, T.K.; Gallagher, J.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glusenkamp, T.; Goldschmidt, A.; Goodman, J.A.; Grant, D.; Griesel, T.; Gross, A.; Grullon, S.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heinen, D.; Helbing, K.; Herquet, P.; Hickford, S.; Lafebre, S.J.

    2011-01-01

    We report on the first search for atmospheric and for diffuse astrophysical neutrino-induced showers (cascades) in the IceCube detector using 257 days of data collected in the year 2007-2008 with 22 strings active. A total of 14 events with energies above 16 TeV remained after event selections in

  2. Search for neutrino-induced cascade events in the icecube detector

    Energy Technology Data Exchange (ETDEWEB)

    Panknin, Sebastian

    2011-09-15

    This thesis presents results of a search for a diffuse flux of high energetic neutrinos from extra-terrestrial origin. Such a flux is predicted by several models of sources of cosmic ray particles. In a neutrino detector, such as IceCube, there are mainly two signatures available for detection of neutrinos: The track-like light signal of a neutrino induced muon and the spherical light pattern of a neutrino induced particle shower, called cascades in this context. The search is based on the measurement of neutrino induced cascades within the IceCube neutrino detector. The data were taken in 2008/2009 with a total uptime of 367 days. At that time the detector was still under construction and had just reached half of its final size. A search for a neutrino flux using cascades is sensitive to all neutrino flavors. A cascade develops within few meters, in contrast to the muon track of several kilometers length. Therefore a good energy reconstruction is possible. With such a reconstruction the astrophysical neutrino flux can be statistically distinguished from the background of atmospheric neutrinos. In the simulation of cascades so far it was not included, that in hadronic cascades muons are produced. This can influence the shape of the cascade, to a less spherical one. Therefore the effect was parameterized in this thesis and included in the simulation. Further cuts on the event topology and reconstructed energy were developed, in order to reduce the background of atmospheric muons and atmospheric neutrinos. Four events from the measured data pass these cuts. Taking the high systematic uncertainties into account, this result is in agreement with the expected background of 0.72{+-}0.28{+-}{sup 1.54}{sub 0.49} events. For an assumed flavor ratio of {nu}{sub e}:{nu}{sub {mu}}:{nu}{sub {tau}}=1:1:1 the upper limit for the all flavor neutrino flux is 9.5.10{sup -8}E{sup -2} GeVs{sup -1}sr{sup -1}cm{sup -2}.

  3. Atmospheric Neutrino Induced Muons in the MINOS Far Detector

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Aftabur Dipu [Univ. of Minnesota, Minneapolis, MN (United States)

    2007-02-01

    The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment. The MINOS Far Detector, located in the Soudan Underground Laboratory in Soudan MN, has been collecting data since August 2003. The scope of this dissertation involves identifying the atmospheric neutrino induced muons that are created by the neutrinos interacting with the rock surrounding the detector cavern, performing a neutrino oscillation search by measuring the oscillation parameter values of Δm$2\\atop{23}$ and sin223, and searching for CPT violation by measuring the charge ratio for the atmospheric neutrino induced muons. A series of selection cuts are applied to the data set in order to extract the neutrino induced muons. As a result, a total of 148 candidate events are selected. The oscillation search is performed by measuring the low to high muon momentum ratio in the data sample and comparing it to the same ratio in the Monte Carlo simulation in the absence of neutrino oscillation. The measured double ratios for the ''all events'' (A) and high resolution (HR) samples are RA = R$data\\atop{low/high}$/R$MC\\atop{low/high}$ = 0.60$+0.11\\atop{-0.10}$(stat) ± 0.08(syst) and RHR = R$data\\atop{low/high}$/R$MC\\atop{low/high}$ = 0.58$+0.14\\atop{-0.11}$(stat) ± 0.05(syst), respectively. Both event samples show a significant deviation from unity giving a strong indication of neutrino oscillation. A combined momentum and zenith angle oscillation fit is performed using the method of maximum log-likelihood with a grid search in the parameter space of Δm2 and sin2 2θ. The best fit point for both event samples occurs at Δm$2\\atop{23}$ = 1.3 x 10-3 eV2, and sin223 = 1. This result is compatible with previous measurements from the Super Kamiokande experiment and Soudan 2 experiments. The MINOS Far Detector is the first

  4. First search for extraterrestrial neutrino-induced cascades with IceCube

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Kiryluk, Joanna

    2009-05-22

    We report on the first search for extraterrestrial neutrino-induced cascades in IceCube.The analyzed data were collected in the year 2007 when 22 detector strings were installed and operated. We will discuss the analysis methods used to reconstruct cascades and to suppress backgrounds. Simulated neutrino signal events with a E-2 energy spectrum, which pass the background rejection criteria, are reconstructed with a resolution Delta(log E) ~;; 0.27 in the energy range from ~;; 20 TeV to a few PeV. We present the range of the diffuse flux of extra-terrestrial neutrinos in the cascade channel in IceCube within which we expect to be able to put a limit.

  5. Atmospheric neutrino-induced muons in the MACRO detector

    CERN Document Server

    Ronga, F

    1999-01-01

    A measurement of the flux of neutrino-induced muons using the MACRO detector is presented. Different event topologies, corresponding to different neutrino parent energies can be detected. The upward throughgoing muon sample is the larger event sample. The observed upward-throughgoing muons are 26% fewer than expected and the zenith angle distribution does not fit with the expected one. Assuming neutrino oscillations, both measurements suggest maximum mixing and Dm2 of a few times 10-3 eV2. The other samples are due to the internally produced events and to upward-going stopping muons. These data show a regular deficit of observed events in each angular bin, as expected assuming neutrino oscillations with maximum mixing, in agreement with the analysis of the upward-throughgoing muon sample.

  6. Search for neutrino-induced cascades with five years of AMANDA data

    NARCIS (Netherlands)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Actis, O.; Adams, J.; Aguilar, J.A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S.W.; Bay, R.; Alba, J.L.B.; Beattie, K.; Beatty, J.J.; Bechet, S.; Becker, J.K.; Becker, K.H.; Benabderrahmane, M.L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D.Z.; Bissok, M.; Blaufuss, E.; Boersma, D.J.; Bohm, C.; Boser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitirik, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D.F.; D'Agostino, M.V.; Danninger, M.; Davis, J.C.; Clercq, C. De; Demirors, L.; Depaepe, O.; Descamps, F.; Desiati, P.; Vries-Uiterweerd, G. de; DeYoung, T.; Diaz-Velez, J.C.; Dreyer, J.; Dumm, J.P.; Duvoort, M.R.; Ehrlich, R.; Eisch, J.; Ellsworth, R.W.; Engdegard, O.; Euler, S.; Evenson, P.A.; Fadiran, O.; Fazely, A.R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M.M.; Fox, B.D.; Franckowiak, A.; Franke, R.; Gaisser, T.K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glusenkamp, T.; Goldschmidt, A.; Goodman, J.A.; Grant, D.; Griesel, T.; Gross, A.; Grullon, S.; Gunasingha, R.M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G.C.; Hoffman, K.D.; Homeier, A.; Hoshina, K.; Hubert, D.; Lafebre, S.J.

    2011-01-01

    We report on the search for electromagnetic and hadronic showers ("cascades") produced by a diffuse flux of extraterrestrial neutrinos in the AMANDA neutrino telescope. Data for this analysis were recorded during 1001 days of detector livetime in the years 2000-2004. The observed event rates are

  7. Search for tau-neutrino induced cascades in the IceCube detector

    Energy Technology Data Exchange (ETDEWEB)

    Usner, Marcel; Kowalski, Marek [DESY, Zeuthen (Germany); Collaboration: IceCube-Collaboration

    2016-07-01

    The IceCube Neutrino Observatory at the South Pole is a Cherenkov detector built to measure high-energy neutrinos from cosmic sources. A total volume of about one cubic kilometer of the Antarctic ice is instrumented with 5160 optical modules. A tau lepton is created in the charged current interaction of a tau neutrino with an ice nucleus. The Double Bang signature links two subsequent cascades from the hadronic interaction and the tau decay within the detection volume. It can only be resolved at the highest energies around 1 PeV where the decay length of the tau is about 50 m. The work is focused on optimizing reconstruction methods of Double Bang events incorporating the latest ice model. The goal is to measure a flavor ratio that, for the first time, is sensitive to tau neutrinos.

  8. Search for neutrino-induced particle showers with IceCube-40

    DEFF Research Database (Denmark)

    Aartsen, M.G.; Abbasi, R.; Ackermann, M.

    2014-01-01

    We report on the search for neutrino-induced particle-showers, so-called cascades, in the IceCube-40 detector. The data for this search was collected between April 2008 and May 2009 when the first 40 IceCube strings were deployed and operational. Three complementary searches were performed, each......-only hypothesis. Our observation of neutrino event candidates above 100 TeV complements IceCube's recently observed evidence for high-energy astrophysical neutrinos....

  9. Development of electromagnetic cascades in the atmosphere including the Landau-Pomeranchuk-Migdal effect

    Science.gov (United States)

    Streitmatter, R. E.; Stephens, S. A.

    1985-01-01

    Numerical solutions have been obtained for the one-dimensional atmospheric electromagnetic cascade diffusion equations, including the Landau-Pomeranchuk-Migdal and screening effects. Spectra produced by primary gamma rays of various energies are given at a number of deths in the atmosphere.

  10. Measurement of the Cosmic Ray and Neutrino-Induced Muon Flux at the Sudbury Neutrino Observatory

    Energy Technology Data Exchange (ETDEWEB)

    SNO collaboration; Aharmim, B.; Ahmed, S.N.; Andersen, T.C.; Anthony, A.E.; Barros, N.; Beier, E.W.; Bellerive, A.; Beltran, B.; Bergevin, M.; Biller, S.D.; Boudjemline, K.; Boulay, M.G.; Burritt, T.H.; Cai, B.; Chan, Y.D.; Chen, M.; Chon, M.C.; Cleveland, B.T.; Cox-Mobrand, G.A.; Currat, C.A.; Dai, X.; Dalnoki-Veress, F.; Deng, H.; Detwiler, J.; Doe, P.J.; Dosanjh, R.S.; Doucas, G.; Drouin, P.-L.; Duncan, F.A.; Dunford, M.; Elliott, S.R.; Evans, H.C.; Ewan, G.T.; Farine, J.; Fergani, H.; Fleurot, F.; Ford, R.J.; Formaggio, J.A.; Gagnon, N.; Goon, J.TM.; Grant, D.R.; Guillian, E.; Habib, S.; Hahn, R.L.; Hallin, A.L.; Hallman, E.D.; Hargrove, C.K.; Harvey, P.J.; Harvey, P.J.; Heeger, K.M.; Heintzelman, W.J.; Heise, J.; Helmer, R.L.; Hemingway, R.J.; Henning, R.; Hime, A.; Howard, C.; Howe, M.A.; Huang, M.; Jamieson, B.; Jelley, N.A.; Klein, J.R.; Kos, M.; Kruger, A.; Kraus, C.; Krauss, C.B.; Kutter, T.; Kyba, C.C.M.; Lange, R.; Law, J.; Lawson, I.T.; Lesko, K.T.; Leslie, J.R.; Levine, I.; Loach, J.C.; Luoma, S.; MacLellan, R.; Majerus, S.; Mak, H.B.; Maneira, J.; Marino, A.D.; Martin, R.; McCauley, N.; McDonald, A.B.; McGee, S.; Mifflin, C.; Miller, M.L.; Monreal, B.; Monroe, J.; Noble, A.J.; Oblath, N.S.; Okada, C.E.; O?Keeffe, H.M.; Opachich, Y.; Orebi Gann, G.D.; Oser, S.M.; Ott, R.A.; Peeters, S.J.M.; Poon, A.W.P.; Prior, G.; Rielage, K.; Robertson, B.C.; Robertson, R.G.H.; Rollin, E.; Schwendener, M.H.; Secrest, J.A.; Seibert, S.R.; Simard, O.; Simpson, J.J.; Sinclair, D.; Skensved, P.; Smith, M.W.E.; Sonley, T.J.; Steiger, T.D.; Stonehill, L.C.; Tagg, N.; Tesic, G.; Tolich, N.; Tsui, T.; Van de Water, R.G.; VanDevender, B.A.; Virtue, C.J.; Waller, D.; Waltham, C.E.; Wan Chan Tseung, H.; Wark, D.L.; Watson, P.; Wendland, J.; West, N.; Wilkerson, J.F.; Wilson, J.R.; Wouters, J.M.; Wright, A.; Yeh, M.; Zhang, F.; Zuber, K.

    2009-02-16

    Results are reported on the measurement of the atmospheric neutrino-induced muon flux at a depth of 2 kilometers below the Earth's surface from 1229 days of operation of the Sudbury Neutrino Observatory (SNO). By measuring the flux of through-going muons as a function of zenith angle, the SNO experiment can distinguish between the oscillated and un-oscillated portion of the neutrino flux. A total of 514 muon-like events are measured between -1 {le} cos {theta}{sub zenith} 0.4 in a total exposure of 2.30 x 10{sup 14} cm{sup 2} s. The measured flux normalization is 1.22 {+-} 0.09 times the Bartol three-dimensional flux prediction. This is the first measurement of the neutrino-induced flux where neutrino oscillations are minimized. The zenith distribution is consistent with previously measured atmospheric neutrino oscillation parameters. The cosmic ray muon flux at SNO with zenith angle cos {theta}{sub zenith} > 0.4 is measured to be (3.31 {+-} 0.01 (stat.) {+-} 0.09 (sys.)) x 10{sup -10} {micro}/s/cm{sup 2}.

  11. Measurement of the Cosmic Ray and Neutrino-Induced Muon Flux at the Sudbury Neutrino Observatory

    Science.gov (United States)

    SNO collaboration; Aharmim, B.; Ahmed, S. N.; Andersen, T. C.; Anthony, A. E.; Barros, N.; Beier, E. W.; Bellerive, A.; Beltran, B.; Bergevin, M.; Biller, S. D.; Boudjemline, K.; Boulay, M. G.; Burritt, T. H.; Cai, B.; Chan, Y. D.; Chen, M.; Chon, M. C.; Cleveland, B. T.; Cox-Mobrand, G. A.; Currat, C. A.; Dai, X.; Dalnoki-Veress, F.; Deng, H.; Detwiler, J.; Doe, P. J.; Dosanjh, R. S.; Doucas, G.; Drouin, P.-L.; Duncan, F. A.; Dunford, M.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Fleurot, F.; Ford, R. J.; Formaggio, J. A.; Gagnon, N.; Goon, J. TM.; Grant, D. R.; Guillian, E.; Habib, S.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hargrove, C. K.; Harvey, P. J.; Harvey, P. J.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Hemingway, R. J.; Henning, R.; Hime, A.; Howard, C.; Howe, M. A.; Huang, M.; Jamieson, B.; Jelley, N. A.; Klein, J. R.; Kos, M.; Kruger, A.; Kraus, C.; Krauss, C. B.; Kutter, T.; Kyba, C. C. M.; Lange, R.; Law, J.; Lawson, I. T.; Lesko, K. T.; Leslie, J. R.; Levine, I.; Loach, J. C.; Luoma, S.; MacLellan, R.; Majerus, S.; Mak, H. B.; Maneira, J.; Marino, A. D.; Martin, R.; McCauley, N.; McDonald, A. B.; McGee, S.; Mifflin, C.; Miller, M. L.; Monreal, B.; Monroe, J.; Noble, A. J.; Oblath, N. S.; Okada, C. E.; O'Keeffe, H. M.; Opachich, Y.; Orebi Gann, G. D.; Oser, S. M.; Ott, R. A.; Peeters, S. J. M.; Poon, A. W. P.; Prior, G.; Rielage, K.; Robertson, B. C.; Robertson, R. G. H.; Rollin, E.; Schwendener, M. H.; Secrest, J. A.; Seibert, S. R.; Simard, O.; Simpson, J. J.; Sinclair, D.; Skensved, P.; Smith, M. W. E.; Sonley, T. J.; Steiger, T. D.; Stonehill, L. C.; Tagg, N.; Tesic, G.; Tolich, N.; Tsui, T.; Van de Water, R. G.; VanDevender, B. A.; Virtue, C. J.; Waller, D.; Waltham, C. E.; Wan Chan Tseung, H.; Wark, D. L.; Watson, P.; Wendland, J.; West, N.; Wilkerson, J. F.; Wilson, J. R.; Wouters, J. M.; Wright, A.; Yeh, M.; Zhang, F.; Zuber, K.

    2009-07-10

    Results are reported on the measurement of the atmospheric neutrino-induced muon flux at a depth of 2 kilometers below the Earth's surface from 1229 days of operation of the Sudbury Neutrino Observatory (SNO). By measuring the flux of through-going muons as a function of zenith angle, the SNO experiment can distinguish between the oscillated and un-oscillated portion of the neutrino flux. A total of 514 muon-like events are measured between -1 {le} cos {theta}{sub zenith} 0.4 in a total exposure of 2.30 x 10{sup 14} cm{sup 2} s. The measured flux normalization is 1.22 {+-} 0.09 times the Bartol three-dimensional flux prediction. This is the first measurement of the neutrino-induced flux where neutrino oscillations are minimized. The zenith distribution is consistent with previously measured atmospheric neutrino oscillation parameters. The cosmic ray muon flux at SNO with zenith angle cos {theta}{sub zenith} > 0.4 is measured to be (3.31 {+-} 0.01 (stat.) {+-} 0.09 (sys.)) x 10{sup -10} {micro}/s/cm{sup 2}.

  12. Application of cascade lasers to detection of trace gaseous atmospheric pollutants

    Science.gov (United States)

    Miczuga, Marcin; Kopczyński, Krzysztof

    2016-12-01

    Understanding the impact of gaseous pollutants on the earth's atmosphere, as well as more and more felt by mankind negative effects of its contamination, result in increasing the level of environmental awareness and contribute to the intensification of actions aimed at reducing the emission of harmful gases into the atmosphere. At the same time, the extensive studies are conducted in order to continuously monitor the level of air contamination with harmful gases and the industry compliance with the standards limited the amount of emitted pollutants. Over recent years, there has been increasing use of cascade lasers and multi-pass cells in optical systems detecting the gaseous atmospheric pollutants and measuring the gas concentrations. The paper presents the use of a tunable quantum cascade laser as a source of the IR radiation in an advanced detection system enabling the trace gaseous atmospheric pollutants to be identified. Apart from the laser, the main elements of the system are: a multi-pass cell, an IR detector and a module for control and analysis. Operation of the system is exemplified by measuring the level of the air pollution with ammonia, carbon oxide and nitrous oxide.

  13. Neutrino Induced Nucleosynthesis of Radioactive Nuclei in Core-Collapse Supernovae

    Science.gov (United States)

    Sieverding, Andre; Martínez-Pinedo, Gabriel; Langanke, Karlheinz; Heger, Alexander

    We study the impact of neutrino-nucleus reactions on the nucleosynthesis in shock-heated supernova ejecta. Nucleosynthesis calculations with an extensive set of neutrino-induced reactions are performed, including updated insights into expected neutrino properties in a Supernova environment. Sensitivities and mechanisms of the production of the the main ν process products 7Li,11B,19F,138La,180Ta, and effects on radioactive nuclei like 26Al are explored.

  14. An algorithm for the reconstruction of high-energy neutrino-induced particle showers and its application to the ANTARES neutrino telescope.

    Science.gov (United States)

    Albert, A; André, M; Anghinolfi, M; Anton, G; Ardid, M; Aubert, J-J; Avgitas, T; Baret, B; Barrios-Martí, J; Basa, S; Bertin, V; Biagi, S; Bormuth, R; Bourret, S; Bouwhuis, M C; Bruijn, R; Brunner, J; Busto, J; Capone, A; Caramete, L; Carr, J; Celli, S; Chiarusi, T; Circella, M; Coelho, J A B; Coleiro, A; Coniglione, R; Costantini, H; Coyle, P; Creusot, A; Deschamps, A; De Bonis, G; Distefano, C; Di Palma, I; Domi, A; Donzaud, C; Dornic, D; Drouhin, D; Eberl, T; El Bojaddaini, I; Elsässer, D; Enzenhöfer, A; Felis, I; Folger, F; Fusco, L A; Galatà, S; Gay, P; Giordano, V; Glotin, H; Grégoire, T; Gracia Ruiz, R; Graf, K; Hallmann, S; van Haren, H; Heijboer, A J; Hello, Y; Hernández-Rey, J J; Hößl, J; Hofestädt, J; Hugon, C; Illuminati, G; James, C W; de Jong, M; Jongen, M; Kadler, M; Kalekin, O; Katz, U; Kießling, D; Kouchner, A; Kreter, M; Kreykenbohm, I; Kulikovskiy, V; Lachaud, C; Lahmann, R; Lefèvre, D; Leonora, E; Lotze, M; Loucatos, S; Marcelin, M; Margiotta, A; Marinelli, A; Martínez-Mora, J A; Mele, R; Melis, K; Michael, T; Migliozzi, P; Moussa, A; Nezri, E; Organokov, M; Păvălaş, G E; Pellegrino, C; Perrina, C; Piattelli, P; Popa, V; Pradier, T; Quinn, L; Racca, C; Riccobene, G; Sánchez-Losa, A; Saldaña, M; Salvadori, I; Samtleben, D F E; Sanguineti, M; Sapienza, P; Schüssler, F; Sieger, C; Spurio, M; Stolarczyk, Th; Taiuti, M; Tayalati, Y; Trovato, A; Turpin, D; Tönnis, C; Vallage, B; Van Elewyck, V; Versari, F; Vivolo, D; Vizzoca, A; Wilms, J; Zornoza, J D; Zúñiga, J

    2017-01-01

    A novel algorithm to reconstruct neutrino-induced particle showers within the ANTARES neutrino telescope is presented. The method achieves a median angular resolution of [Formula: see text] for shower energies below 100 TeV. Applying this algorithm to 6 years of data taken with the ANTARES detector, 8 events with reconstructed shower energies above 10 TeV are observed. This is consistent with the expectation of about 5 events from atmospheric backgrounds, but also compatible with diffuse astrophysical flux measurements by the IceCube collaboration, from which 2-4 additional events are expected. A [Formula: see text] C.L. upper limit on the diffuse astrophysical neutrino flux with a value per neutrino flavour of [Formula: see text] is set, applicable to the energy range from 23 TeV to 7.8 PeV, assuming an unbroken [Formula: see text] spectrum and neutrino flavour equipartition at Earth.

  15. Simultaneous detection of atmospheric nitrous oxide and carbon monoxide using a quantum cascade laser

    Science.gov (United States)

    Khan, Amir; Sun, Kang; Miller, David J.; Zondlo, Mark A.

    2011-06-01

    We describe a non-intrusive, open-path, fast-response compact sensor for simultaneous measurements of nitrous-oxide (N2O) and carbon-monoxide (CO) primarily designed for UAV applications. N2O is the third most important anthropogenic greenhouse gas, but the spatial and temporal distributions of N2O emissions are poorly quantified. On the other hand, CO is an important tracer to distinguish between fossil fuel and biogenic sources. We use a 4.5 micron thermoelectrically-cooled, distributed feedback, continuous wave quantum cascade laser as a mid-infrared radiation source to scan CO and N2O transitions centered at 4538.9 nm and 4539.8 nm respectively. Detection was achieved by a thermo-electrically (TE) cooled 5 micron Indium-Phosphide (InSb) infrared detector. For the first time in this application, a compact cylindrical cell with a pattern configuration to minimize the sensor size with a pathlength of 10 meters (2.54 cm radius mirrors, 25 cm basepath). Wavelength modulation spectroscopy was employed to achieve high sensitivity detection. The detection limit of 10-5 fractional absorbance was achieved at a 10 sec. averaging time. This is equivalent to less than 1 ppbv of N2O and 2 ppbv of CO out of 320 ppbv and 200 ppbv ambient levels respectively. In summary we report a cryogen-free, consumable-free sensor that can operate with 10s W of electrical power and packaged in a small shoe-box size which is ideal for UAV or airborne applications.

  16. Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

    Directory of Open Access Journals (Sweden)

    Banerjee Projjwal

    2016-01-01

    Full Text Available We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of Z ≲ 10−3 Z⊙. We find that for progenitors of ∼ 11–15 M⊙, the neutrons released by 4He(ν¯ee, e+n3H in He shells can be captured to produce nuclei with mass numbers up to A ∼ 200. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of 9Be in He shells. The first mechanism produces 9Be via 7Li(n,γ8Li(n,γ9Li(e− ν¯ee9Be and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of ∼ 8 M⊙, where 9Be can be produced directly via 7Li(3H, n09Be during the rapid expansion of the shocked Heshell material. The light nuclei 7Li and 3H involved in these mechanisms are produced by neutrino interactions with 4He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

  17. Mapping Atmospheric Ammonia Emissions Using a Mobile Quantum Cascade Laser-based Open-path Sensor

    Science.gov (United States)

    Sun, K.; Tao, L.; Miller, D. J.; Khan, M. A.; Zondlo, M. A.

    2012-12-01

    Ammonia (NH3) is a key precursor to atmospheric fine particulate matter, with strong implications for regional air quality and global climate change. Despite the importance of atmospheric ammonia, its spatial/temporal variation is poorly characterized, and the knowledge of its sources, sinks, and transport is severely limited. Existing measurements suggest that traffic exhaust may provide significant amounts of ammonia in urban areas, which cause greater impacts on particulate matter formation and urban air quality. To capture the spatial and temporal variation of ammonia emissions, a portable, low power sensor with high time resolution is necessary. We have developed a portable open-path ammonia sensor with a detection limit of 0.5 ppbv ammonia for 1 s measurements. The sensor has a power consumption of about 60 W and is capable of running on a car battery continuously for 24 hours. An additional laser has been coupled to the sensor to yield concurrent N2O and CO measurements as tracers for determining various sources. The overall sensor prototype fits on a 60 cm × 20 cm aluminum breadboard. Roadside measurements indicated NH3/CO emission ratios of 4.1±5.4 ppbv/ppmv from a fleet of 320 vehicles, which agree with existing on-ramp measurements. Urban measurements in the Baltimore and Washington, DC metropolitan areas have shown significant ammonia mixing ratios concurrent with carbon monoxide levels from the morning and evening rush hours. On-road measurements of our open-path sensor have also been performed continuously from the Midwest to Princeton, NJ including urban areas such as Pittsburgh, tunnels, and relatively clean conditions. The emission ratios of ammonia against CO and/or CO2 help identify the sources and amounts of both urban and agricultural ammonia emissions. Preliminary data from both spatial mapping, monitoring, and vehicle exhaust measurements suggest that urban ammonia emissions from fossil fuel combustion are significant and may provide an

  18. Leading order analysis of neutrino induced dimuon events in the CHORUS experiment

    CERN Document Server

    Kayis-Topaksu, A; Van Dantzig, R; De Jong, M; Oldeman, R G C; Güler, M; Kama, S; Köse, U; Serin-Zeyrek, M; Tolun, P; Catanesi, M G; Muciaccia, M T; Bülte, A; Winter, Klaus; Van de Vyver, B; Vilain, P; Wilquet, G; Saitta, B; Di Capua, E; Ogawa, S; Shibuya, H; Hristova, I R; Kawamura, T; Kolev, D; Litmaath, M; Meinhard, H; Panman, J; Rozanov, A; Tsenov, R; Uiterwijk, J W E; Zucchelli, P; Goldberg, J; Chikawa, M; Song, J S; Yoon, C S; Kodama, K; Ushida, N; Aoki, S; Hara, T; Delbar, T; Favart, D; Grégoire, G; Kalinin, S; Makhlioueva, I; Artamonov, A; Gorbunov, P; Khovansky, V; Shamanov, V; Tsukerman, I; Bruski, N; Frekers, D; Rondeshagen, D; Wolff, T; Hoshino, K; Kawada, J; Komatsu, M; Miyanishi, M; Nakamura, M; Nakano, T; Narita, K; Niu, K; Niwa, K; Nonaka, N; Sato, O; Toshito, T; Buontempo, S; Cocco, A G; D'Ambrosio, N; De Lellis, G; De Rosa, G; Di Capua, F; Fiorillo, G; Marotta, A; Messina, M; Migliozzi, P; Santorelli, R; Scotto-Lavina, L; Strolin, P; Tioukov, V; Okusawa, T; Dore, U; Loverre, P F; Ludovici, L; Rosa, G; Santacesaria, R; Satta, A; Spada, F R; Barbuto, E; Bozza, C; Grella, G; Romano, G; Sirignano, C; Sorrentino, S; Sato, Y; Tezuka, I

    2008-01-01

    We present a leading order QCD analysis of a sample of neutrino induced charged-current events with two muons in the final state originating in the lead-scintillating fibre calorimeter of the CHORUS detector. The results are based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign dimuon events collected during the exposure of the detector to the CERN Wide Band Neutrino Beam between 1995 and 1998. The analysis yields a value of the charm quark mass of $m_c=(1.26+- 0.16+-0.09) GeV/c^2$ and a value of the ratio of the strange to non-strange sea in the nucleon of $\\kappa=0.33+-0.05+-0.05$, improving the results obtained in similar analyses by previous experiments.

  19. Neutrino-induced reactions and neutrino scattering with nuclei in low and high neutrino energy

    Energy Technology Data Exchange (ETDEWEB)

    Cheoun, Myung-Ki, E-mail: cheoun@ssu.ac.kr; Ha, Eunja; Yang, Ghil-Seok [Department of Physics and OMEG institute, Soongsil Univ., Seoul 156-743 (Korea, Republic of); Kim, K. S. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Kajino, T. [National Astronomical Observatory of Japan, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2016-06-21

    We reviewed present status regarding theoretical approaches for neutrino-induced reactions and neutrino scattering. With a short introduction of relevant data, our recent calculations by distorted-wave Born approximation (DWBA) for quasielastic region are presented for MiniBooNE data. We also discussed that one step-process estimated by the DWBA is comparable to the two-step process, which has been usually used in the neutrino-nucleosynthesis. For much higher energy neutrino data, such as NOMAD data, elementary process approach was shown to be useful instead of using complicated nuclear models. But, in the low energy region, detailed nuclear structure model, such as QRPA and shell model, turn out to be inescapable to explain the reaction data.

  20. Study on lateral distribution of neutron cascade induced by only one nucleon in the atmosphere; Estudo da distribuicao lateral da cascata nucleonica induzida por um unico nucleon na atmosfera

    Energy Technology Data Exchange (ETDEWEB)

    Bellandi, J.; Covolan, R.J.M.; Dobrigkeit, C.; Costa, C.G.S.; Mundim, L.M. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica

    1993-12-31

    Some aspects of lateral behavior of nucleonic cascade induced by only one nucleon which interacts with the atmosphere, such as: energy dependence, height of interaction, lateral dispersion and average matter quantity crossed by cascade, are discussed. (M.C.K.). 6 refs, 6 figs.

  1. Open-path Atmospheric N2O, CO, and NH3 Measurements Using Quantum Cascade Laser Spectroscopy

    Science.gov (United States)

    Sun, K.; Khan, A.; Miller, D. J.; Rafferty, K.; Schreiber, J.; Puzio, C.; Portenti, M.; Silver, J.; Zondlo, M. A.

    2010-12-01

    We develop a compact, mid-infrared quantum cascade (QC) laser based sensor to perform high precision measurements of N2O and CO simultaneously. Since CO is a good tracer of anthropogenic emissions, simultaneous measurements of CO and N2O allow us to correlate the sources of N2O emissions. The thermoelectrically (TE) cooled, and continuous wave QC laser enables room-temperature and unattended operation. The laser is scanned over the absorption features of N2O and CO near 4.54 μm by laser current modulation. A novel cylindrical multi-pass optical cell terminated at the (N/2)th spot is used to simplify the optical configuration by separating the laser and TE cooled detector. Our systems are open-path and non-cryogenic, which avoids vacuum pump and liquid nitrogen. This configuration enables a future design of a non-intrusive, compact (shoe box size), and low-power (10W) sensor. Wavelength modulation spectroscopy (WMS) is used to enhance measurement sensitivity. Higher-harmonic detection (4f and 6f) is performed to improve the resolution between the nearly overlapping N2O and CO lines. Relevant atmospheric N2O and CO concentration is measured, with a detection limit of 0.3 ppbv for N2O and 2 ppbv for CO for 1 s averaging in terms of noise. We also develop an open-path high sensitivity atmospheric ammonia (NH3) sensor using a very similar instrument design. A 9.06 μm QC laser is used to probe absorption features of NH3. Open-path detection of NH3 is even more beneficial due to the surface absorption effect of NH3 and its tendency to readily partition into condensed phases. The NH3 sensor was deployed at the CALNEX 2010 field campaign. The entire system was stable throughout the campaign and acquired data with 10 s time resolution under adverse ambient temperatures and dusty conditions. The measurements were in general agreement with other NH3 and trace gases sensors. Both the N2O/CO and NH3 sensors will be deployed in a local eddy-covariance station to examine long

  2. Characterizing a Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS for measurements of atmospheric ammonia

    Directory of Open Access Journals (Sweden)

    R. A. Ellis

    2010-03-01

    Full Text Available A compact, fast-response Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS for measurements of ammonia (NH3 has been evaluated under both laboratory and field conditions. Absorption of radiation from a pulsed, thermoelectrically cooled QC laser occurs at reduced pressure in a 0.5 L multiple pass absorption cell with an effective path length of 76 m. Detection is achieved using a thermoelectrically-cooled Mercury Cadmium Telluride (HgCdTe infrared detector. A novel sampling inlet was used, consisting of a short, heated, quartz tube with a hydrophobic coating to minimize the adsorption of NH3 to surfaces. The inlet contains a critical orifice that reduces the pressure, a virtual impactor for separation of particles, and additional ports for delivering NH3-free background air and calibration gas standards. The level of noise in this instrument has been found to be 0.23 ppb at 1 Hz. The sampling technique has been compared to the results of a conventional lead salt Tunable Diode Laser Absorption Spectrometer (TDLAS during a laboratory intercomparison. The effect of humidity and heat on the surface interaction of NH3 with sample tubing was investigated at mixing ratios ranging from 30–1000 ppb. Humidity was seen to worsen the NH3 time response and considerable improvement was observed when using a heated sampling line. A field intercomparison of the QC-TILDAS with a modified Thermo 42CTL chemiluminescence-based analyzer was also performed at Environment Canada's Centre for Atmospheric Research Experiments (CARE in the rural town of Egbert, ON between May–July 2008. Background tests and calibrations using two different permeation tube sources and an NH3 gas cylinder were regularly carried out throughout the study. Results indicate a very good correlation at 1 min time resolution (R2 = 0.93 between the two instruments at the

  3. A Measurement of Neutrino-Induced Charged-Current Neutral Pion Production

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Robert H. [Univ. of Colorado, Boulder, CO (United States)

    2010-01-01

    This work presents the first comprehensive measurement of neutrino-induced charged-current neutral pion production (CCπ0) off a nuclear target. The Mini Booster Neutrino Experiment (MiniBooNE) and Booster Neutrino Beam (BNB) are discussed in detail. MiniBooNE is a high-statistics (~ 1, 000, 000 interactions) low-energy (Evϵ 2 0.5 - 2.0 GeV) neutrino experiment located at Fermilab. The method for selecting and reconstructing CCπ0 events is presented. The π0 and μ- are fully reconstructed in the final state allowing for the measurement of, among other things, the neutrino energy. The total observable CCπ0 cross-section is presented as a function of neutrino energy, along with five differential cross-sections in terms of the final state kinematics and Q2. The results are combined to yield a flux-averaged total cross-section of <σ>Φ = (9.2 ± 0.3stat. ± 1.5syst.) × 10-39 cm2/CH2 at energy 965 MeV. These measurements will aid future neutrino experiments with the prediction of their neutrino interaction rates.

  4. The Measurement of Neutrino Induced Quasi-Elastic Cross Section In NOMAD

    CERN Document Server

    Kim, Jae Jun

    2010-01-01

    NOMAD (Neutrino Oscillation MAgnetic Detector) was a short baseline neutrino experiment conducted at CERN (the European Laboratory for Particle physics) West Area Neutrino Facility (WANF) with a neutrino beam provided by the super proton synchrotron (SPS) accelerator. In this dissertation, we present a measurement of muon-neutrino induced quasi-elastic cross section and its axial-mass off an isoscalar target in the NOMAD detector. The incident neutrino energy in NOMAD experiment spans from 2.5 to 300 GeV. The measurement of cross-section is conducted in two seperate kinematic-based topology, two-track and one-track topologies, where a proton is not properly reconstructed. The QEL cross-section as a function of the incoming neutrino energy is consistent for the two different topologies, and within errors , constant as a function of the neutrino energy. We determine the energy-averaged cross-section. From the shape-comparisons of kinematics of QEL-like events, the parameter of QEL axial mass is estimated. It i...

  5. An algorithm for the reconstruction of high-energy neutrino-induced particle showers and its application to the ANTARES neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Albert, A.; Drouhin, D.; Racca, C. [GRPHE, Universite de Haute Alsace, Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit, BP 50568, Colmar (France); Andre, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposicio, Barcelona (Spain); Anghinolfi, M. [INFN-Sezione di Genova, Genoa (Italy); Anton, G.; Folger, F.; Graf, K.; Hallmann, S.; Hoessl, J.; Hofestaedt, J.; James, C.W.; Kalekin, O.; Katz, U.; Kiessling, D.; Lahmann, R.; Sieger, C. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Ardid, M.; Felis, I.; Martinez-Mora, J.A.; Saldana, M. [Universitat Politecnica de Valencia, Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Gandia (Spain); Aubert, J.J.; Bertin, V.; Brunner, J.; Busto, J.; Carr, J.; Costantini, H.; Coyle, P.; Dornic, D.; Enzenhoefer, A.; Quinn, L.; Salvadori, I.; Turpin, D. [Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille (France); Avgitas, T.; Baret, B.; Bourret, S.; Coelho, J.A.B.; Creusot, A.; Galata, S.; Gregoire, T.; Gracia Ruiz, R.; Lachaud, C. [APC, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, Paris (France); Barrios-Marti, J.; Hernandez-Rey, J.J.; Illuminati, G.; Lotze, M.; Toennis, C.; Zornoza, J.D.; Zuniga, J. [IFIC, Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia) c/Catedratico Jose Beltran, 2, 46980, Paterna, Valencia (Spain); Basa, S.; Marcelin, M.; Nezri, E. [LAM, Laboratoire d' Astrophysique de Marseille, Pole de l' Etoile Site de Chateau-Gombert, Marseille Cedex 13 (France); Biagi, S.; Coniglione, R.; Distefano, C.; Piattelli, P.; Riccobene, G.; Sapienza, P.; Trovato, A. [INFN, Laboratori Nazionali del Sud (LNS), Catania (Italy); Bormuth, R.; Jong, M. de; Samtleben, D.F.E. [Nikhef, Amsterdam (Netherlands); Universiteit Leiden, Huygens-Kamerlingh Onnes Laboratorium, Leiden (Netherlands); Bouwhuis, M.C.; Heijboer, A.J.; Jongen, M.; Michael, T. [Nikhef, Amsterdam (Netherlands); Bruijn, R.; Melis, K. [Nikhef, Amsterdam (Netherlands); Universiteit van Amsterdam, Instituut voor Hoge-Energie Fysica, Amsterdam (Netherlands); Capone, A.; De Bonis, G.; Di Palma, I.; Perrina, C.; Vizzoca, A. [INFN, Sezione di Roma, Rome (Italy); Dipartimento di Fisica dell' Universita La Sapienza, Rome (Italy); Caramete, L.; Pavalas, G.E.; Popa, V. [Institute for Space Science, 077125, Bucharest, Magurele (Romania); Celli, S. [INFN, Sezione di Roma, Rome (Italy); Dipartimento di Fisica dell' Universita La Sapienza, Rome (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Chiarusi, T. [INFN, Sezione di Bologna, Bologna (Italy); Circella, M.; Sanchez-Losa, A. [INFN, Sezione di Bari, Bari (Italy); Coleiro, A. [APC, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, Paris (France); IFIC, Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia) c/Catedratico Jose Beltran, 2, 46980, Paterna, Valencia (Spain); Deschamps, A.; Hello, Y. [CNRS, IRD, Observatoire de la Cote d' Azur, Geoazur, UCA, Sophia Antipolis (France); Domi, A.; Hugon, C.; Sanguineti, M.; Taiuti, M. [INFN-Sezione di Genova, Genoa (Italy); Dipartimento di Fisica dell' Universita, Genoa (Italy); Donzaud, C. [APC, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, Paris (France); Universite Paris-Sud, Orsay Cedex (France); Eberl, T. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); El Bojaddaini, I.; Moussa, A. [University Mohammed I, Laboratory of Physics of Matter and Radiations, B.P.717, Oujda (Morocco); Elsaesser, D.; Kadler, M.; Kreter, M. [Universitaet Wuerzburg, Institut fuer Theoretische Physik und Astrophysik, Wuerzburg (Germany); Fusco, L.A.; Margiotta, A.; Pellegrino, C.; Spurio, M.; Versari, F. [INFN, Sezione di Bologna, Bologna (Italy); Dipartimento di Fisica e Astronomia dell' Universita, Bologna (Italy); Gay, P. [APC, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, Paris (France); Universite Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, Clermont Universite, BP 10448, Clermont-Ferrand (France); Giordano, V. [INFN, Sezione di Catania, Catania (Italy); Glotin, H. [LSIS, Aix Marseille Universite CNRS ENSAM LSIS UMR 7296, Marseille (France); Universite de Toulon CNRS LSIS UMR 7296, La Garde (France); Institut Universitaire de France, Paris (France); Haren, H. van [Royal Netherlands Institute for Sea Research (NIOZ), ' t Horntje (Texel) (Netherlands); Kouchner, A.; Van Elewyck, V. [APC, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite (France); Institut Universitaire de France, Paris (France); Kreykenbohm, I.; Wilms, J. [Universitaet Erlangen-Nuernberg, Dr. Remeis-Sternwarte and ECAP, Bamberg (Germany); Kulikovskiy, V. [Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille (France); Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (RU); Lefevre, D. [Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Marseille Cedex 9 (FR); Universite du Sud Toulon-Var, CNRS-INSU/IRD UM 110, La Garde Cedex (FR); Leonora, E. [INFN, Sezione di Catania, Catania (IT); Dipartimento di Fisica ed Astronomia dell' Universita, Catania (IT); Loucatos, S.; Vallage, B. [APC, Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, Paris (FR); Direction des Sciences de la Matiere, Institut de Recherche sur les Lois Fondamentales de l' Univers, Service de Physique des Particules, CEA Saclay, Gif-sur-Yvette (FR); Marinelli, A. [INFN, Sezione di Pisa, Pisa (IT); Dipartimento di Fisica dell' Universita, Pisa (IT); Mele, R.; Vivolo, D. [INFN, Sezione di Napoli, Naples (IT); Dipartimento di Fisica dell' Universita Federico II di Napoli, Naples (IT); Migliozzi, P. [INFN, Sezione di Napoli, Naples (IT); Organokov, M.; Pradier, T. [Universite de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg (FR); Schuessler, F.; Stolarczyk, T. [Direction des Sciences de la Matiere, Institut de Recherche sur les Lois Fondamentales de l' Univers, Service de Physique des Particules, CEA Saclay, Gif-sur-Yvette (FR); Tayalati, Y. [University Mohammed V in Rabat, Faculty of Sciences, Rabat (MA)

    2017-06-15

    A novel algorithm to reconstruct neutrino-induced particle showers within the ANTARES neutrino telescope is presented. The method achieves a median angular resolution of 6 {sup circle} for shower energies below 100 TeV. Applying this algorithm to 6 years of data taken with the ANTARES detector, 8 events with reconstructed shower energies above 10 TeV are observed. This is consistent with the expectation of about 5 events from atmospheric backgrounds, but also compatible with diffuse astrophysical flux measurements by the IceCube collaboration, from which 2-4 additional events are expected. A 90% C.L. upper limit on the diffuse astrophysical neutrino flux with a value per neutrino flavour of E{sup 2} . Φ{sup 90%} = 4.9 . 10{sup -8} GeV . cm{sup -2} . s{sup -1} . sr{sup -1} is set, applicable to the energy range from 23 TeV to 7.8 PeV, assuming an unbroken E{sup -2} spectrum and neutrino flavour equipartition at Earth. (orig.)

  6. Atmospheric Deposition and Surface-Water Chemistry in Mount Rainier and North Cascades National Parks, U.S.A., Water Years 2000 and 2005-2006

    Science.gov (United States)

    Clow, David W.; Campbell, Donald H.

    2008-01-01

    High-elevation aquatic ecosystems in Mount Rainier and North Cascades National Parks are highly sensitive to atmospheric deposition of nitrogen and sulfur. Thin, rocky soils promote fast hydrologic flushing rates during snowmelt and rain events, limiting the ability of basins to neutralize acidity and assimilate nitrogen deposited from the atmosphere. Potential effects of nitrogen and sulfur deposition include episodic or chronic acidification of terrestrial and aquatic ecosystems. In addition, nitrogen deposition can cause eutrophication of water bodies and changes in species composition in lakes and streams. This report documents results of a study performed by the U.S. Geological Survey, in cooperation with the National Park Service, of the effects of atmospheric deposition of nitrogen and sulfur on surface-water chemistry in Mount Rainier and North Cascades National Parks. Inorganic nitrogen in wet deposition was highest in the vicinity of North Cascades National Park, perhaps due to emissions from human sources and activities in the Puget Sound area. Sulfur in wet deposition was highest near the Pacific coast, reflecting the influence of marine aerosols. Dry deposition generally accounted for less than 30 percent of wet plus dry inorganic nitrogen and sulfur deposition, but occult deposition (primarily fog) represents a potentially substantial unmeasured component of total deposition. Trend analyses indicate inorganic nitrogen in wet deposition was relatively stable during 1986-2005, but sulfur in wet deposition declined substantially during that time, particularly after 2001, when emissions controls were added to a large powerplant in western Washington. Surface-water sulfate concentrations at the study site nearest the powerplant showed a statistically significant decrease between 2000 and 2005-06, but there was no statistically significant change in alkalinity, indicating a delayed response in surface-water alkalinity. Seasonal patterns in surface

  7. A Search for Neutrino Induced Coherent NC($\\pi^{0}$) Production in the MINOS Near Detector

    Energy Technology Data Exchange (ETDEWEB)

    Cherdack, Daniel David [Tufts Univ., Medford, MA (United States)

    2011-02-01

    The production of single, highly forward π0 mesons by NC coherent neutrino-nucleus interactions (νμ + N → νμ + N + π0) is a process which probes fundamental aspects of the weak interaction. This reaction may also pose as a limiting background for long baseline searches for νμ → νe oscillations if the neutrino mixing angle θ13 is very small. The high-statistics sample of neutrino interactions recorded by the MINOS Near Detector provides an opportunity to measure the cross section of this coherent reaction on a relatively large-A nucleus at an average Ev = 4.9 GeV. A major challenge for this measurement is the isolation of forward-going electromagnetic (EM) showers produced by the relatively rare coherent NC(π0) process amidst an abundant rate of incoherently produced EM showers. The backgrounds arise from single π0 dominated NC events and also from quasi-elastic-like CC scattering of electron neutrinos. In this Thesis the theory of coherent interactions is summarized, and previous measurements of the coherent NC(π0) cross section are reviewed. Then, methods for selecting a sample of coherent NC(π0) like events, extracting the coherent NC(π0) event rate from that sample, estimating the analysis uncertainties, and calculating a cross section, are presented. A signal for neutrino-induced NC(π0) production is observed in the relevant kinematic regime as an excess of events of three standard deviations above background. The reaction cross sections, averaged over an energy window of 2.5 ≤ Ev ≤ 9.0 GeV is determined to be (31.6±10.5) x 10-40 cm2/nucleus. The result is the first evidence obtained for neutrino-nucleus coherent NC(π0) scattering on iron, and is the first measurement on an average nuclear target above A = 30. The cross section measurement

  8. Quantum cascade laser absorption spectroscopy with the amplitude-to-time conversion technique for atmospheric-pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Yumii, Takayoshi; Kimura, Noriaki [Mitsui Engineering and Shipbuilding Co., Ltd., Tamahara 3-16-1, Tamano, Okayama 706-0014 (Japan); Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Hamaguchi, Satoshi [Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan)

    2013-06-07

    The NO{sub 2} concentration, i.e., density, in a small plasma of a nitrogen oxide (NOx) treatment reactor has been measured by highly sensitive laser absorption spectroscopy. The absorption spectroscopy uses a single path of a quantum cascade laser beam passing through a plasma whose dimension is about 1 cm. The high sensitivity of spectroscopy is achieved by the amplitude-to-time conversion technique. Although the plasma reactor is designed to convert NO in the input gas to NO{sub 2}, it has been demonstrated by this highly sensitive absorption spectroscopy that NO{sub 2} in a simulated exhaust gas that enters the reactor is decomposed by the plasma first and then NO{sub 2} is formed again, possibly more than it was decomposed, through a series of gas-phase reactions by the time the gas exits the reactor. The observation is consistent with that of an earlier study on NO decomposition by the same type of a plasma reactor [T. Yumii et al., J. Phys. D 46, 135202 (2013)], in which a high concentration of NO{sub 2} was observed at the exit of the reactor.

  9. High-accuracy and high-sensitivity spectroscopic measurement of dinitrogen pentoxide (N2O5) in an atmospheric simulation chamber using a quantum cascade laser.

    Science.gov (United States)

    Yi, Hongming; Wu, Tao; Lauraguais, Amélie; Semenov, Vladimir; Coeur, Cecile; Cassez, Andy; Fertein, Eric; Gao, Xiaoming; Chen, Weidong

    2017-09-15

    A spectroscopic instrument based on a mid-infrared external cavity quantum cascade laser (EC-QCL) was developed for high-accuracy measurements of dinitrogen pentoxide (N2O5) at the ppbv-level. A specific concentration retrieval algorithm was developed to remove, from the broadband absorption spectrum of N2O5, both etalon fringes resulting from the EC-QCL intrinsic structure and spectral interference lines of H2O vapour absorption, which led to a significant improvement in measurement accuracy and detection sensitivity (by a factor of 10), compared to using a traditional algorithm for gas concentration retrieval. The developed EC-QCL-based N2O5 sensing platform was evaluated by real-time tracking N2O5 concentration in its most important nocturnal tropospheric chemical reaction of NO3 + NO2 ↔ N2O5 in an atmospheric simulation chamber. Based on an optical absorption path-length of Leff = 70 m, a minimum detection limit of 15 ppbv was achieved with a 25 s integration time and it was down to 3 ppbv in 400 s. The equilibrium rate constant Keq involved in the above chemical reaction was determined with direct concentration measurements using the developed EC-QCL sensing platform, which was in good agreement with the theoretical value deduced from a referenced empirical formula under well controlled experimental conditions. The present work demonstrates the potential and the unique advantage of the use of a modern external cavity quantum cascade laser for applications in direct quantitative measurement of broadband absorption of key molecular species involved in chemical kinetic and climate-change related tropospheric chemistry.

  10. Cold atmospheric plasma (CAP), a novel physicochemical source, induces neural differentiation through cross-talk between the specific RONS cascade and Trk/Ras/ERK signaling pathway.

    Science.gov (United States)

    Jang, Ja-Young; Hong, Young June; Lim, Junsup; Choi, Jin Sung; Choi, Eun Ha; Kang, Seongman; Rhim, Hyangshuk

    2018-02-01

    Plasma, formed by ionization of gas molecules or atoms, is the most abundant form of matter and consists of highly reactive physicochemical species. In the physics and chemistry fields, plasma has been extensively studied; however, the exact action mechanisms of plasma on biological systems, including cells and humans, are not well known. Recent evidence suggests that cold atmospheric plasma (CAP), which refers to plasma used in the biomedical field, may regulate diverse cellular processes, including neural differentiation. However, the mechanism by which these physicochemical signals, elicited by reactive oxygen and nitrogen species (RONS), are transmitted to biological system remains elusive. In this study, we elucidated the physicochemical and biological (PCB) connection between the CAP cascade and Trk/Ras/ERK signaling pathway, which resulted in neural differentiation. Excited atomic oxygen in the plasma phase led to the formation of RONS in the PCB network, which then interacted with reactive atoms in the extracellular liquid phase to form nitric oxide (NO). Production of large amounts of superoxide radical (O2-) in the mitochondria of cells exposed to CAP demonstrated that extracellular NO induced the reversible inhibition of mitochondrial complex IV. We also demonstrated that cytosolic hydrogen peroxide, formed by O2- dismutation, act as an intracellular messenger to specifically activate the Trk/Ras/ERK signaling pathway. This study is the first to elucidate the mechanism linking physicochemical signals from the CAP cascade to the intracellular neural differentiation signaling pathway, providing physical, chemical and biological insights into the development of therapeutic techniques to treat neurological diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. An algorithm for the reconstruction of high-energy neutrino-induced particle showers and its application to the ANTARES neutrino telescope

    NARCIS (Netherlands)

    Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M.C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coelho, C.O.A.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Domi, A.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhofer, A.; Felis, I.; Folger, F.; Fusco, L.A.; Galata, S.; Gay, P.; Giordano, V.; Glotin, H.; Grégoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A.J.; Hello, Y.; Hernandez-Rey, J.J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C.W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefevre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martinez-Mora, J.A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Nezri, E.; Organokov, M.; Pavalas, G.E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Sanchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D.F.E.; Sanguineti, M.; Sapienza, P.; Schussler, F.; Sieger, C.; Spurio, M.; Stolarczyk, T.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Turpin, D.; Tönnis, C.; Vallage, B.; Van Elewyck, V.; Versari, F.; Vivolo, D.; Vizzoca, A.; Wilms, J.; Zornoza, J.D.; Zuniga, J.

    2017-01-01

    A novel algorithm to reconstruct neutrino-induced particle showers within the ANTARES neutrino telescope is presented. The method achieves a median angular resolution of 6∘ for shower energies below 100 TeV. Applying this algorithm to 6 years of data taken with the ANTARES detector, 8 events with

  12. The SPIRIT airborne instrument: a three-channel infrared absorption spectrometer with quantum cascade lasers for in situ atmospheric trace-gas measurements

    Science.gov (United States)

    Catoire, Valéry; Robert, Claude; Chartier, Michel; Jacquet, Patrick; Guimbaud, Christophe; Krysztofiak, Gisèle

    2017-09-01

    An infrared absorption spectrometer called SPIRIT (SPectromètre Infra-Rouge In situ Toute altitude) has been developed for airborne measurements of trace gases in the troposphere. At least three different trace gases can be measured simultaneously every 1.6 s using the coupling of a single Robert multipass optical cell with three Quantum Cascade Lasers (QCLs), easily interchangeable to select species depending on the scientific objectives. Absorptions of the mid-infrared radiations by the species in the cell at reduced pressure (path lengths adjustable up to 167.78 m, are quantified using an HgCdTe photodetector cooled by Stirling cycle. The performances of the instrument are assessed: a linearity with a coefficient of determination R 2 > 0.979 for the instrument response is found for CO, CH4, and NO2 volume mixing ratios under typical tropospheric conditions. In-flight comparisons with calibrated gas mixtures allow to show no instrumental drift correlated with atmospheric pressure and temperature changes (when vertical profiling) and to estimate the overall uncertainties in the measurements of CO, CH4, and NO2 to be 0.9, 22, and 0.5 ppbv, respectively. In-flight precision (1 σ) for these species at 1.6 s sampling is 0.3, 5, and 0.3 ppbv, respectively.

  13. Observation of neutrino induced diffractive $D_s^{*+}$ production and subsequent decay $D_s^{*+} \\to D_s^+ \\to \\tau^+ \\to \\mu^+$

    CERN Document Server

    Annis, P; Artamonov, S A; Barbuto, E; Di Bartolomeo, A; Bonekämper, D; Bozza, C; Brooijmans, G; Brunner, J; Bülte, A; Buontempo, S; Capone, A; Cassol, F; Catanesi, M G; Chikawa, M; Cocco, A G; Cussans, D G; D'Ambrosio, N; Van Dantzig, R; De Lellis, G; De Pedis, D; Di Capua, E; Dore, U; El-Aidi, R; Ereditato, A; Favart, D; Ferreira, R; Fiorillo, G; Frekers, D; Goldberg, J; Gorbunov, P; Grégoire, G; Grella, G; Hara, T; Hérin, J; Hoshino, K; Iovane, G; Ishi, Y; De Jong, M; Kawamura, T; Kayis, A; Kazuno, M; Khovanskii, V D; Kodama, K; Komatsu, M; Konijn, J; Kotaka, Y; Kozaki, T; Litmaath, M; Loverre, P F; Ludovici, L; Meinhard, H; Melzer, O; Messina, M; Migliozzi, P; Miyanishi, M; Muciaccia, M T; Nakamura, K; Nakamura, M; Nakano, T; Niu, E; Niu, K; Niwa, K; Obayashi, Y; Ogawa, S; Okusawa, T; Oldeman, R G C; Onengüt, G; Øverås, H; Palladino, Vittorio; Panman, J; Papadopoulos, I M; Park, I G; Pesen, E; Piredda, G; Van der Poel, C A F J; Radicioni, E; Ricciardi, S; Righini, P; Romano, G; Rondeshagen, D; Rosa, G; Saltzberg, D; Saitta, B; Santacesaria, R; Sato, O; Sato, Y; Satta, A; Shamanov, V V; Shibuya, H; Simone, S; Song, J S; Sorrentino, S; Strolin, P; Tezuka, I; Tioukov, V; Tolun, P; Toshito, T; Tsenov, R V; Uiterwijk, J W E; Ushida, N; Van der Donckt, M; Van de Vyver, B L; Vilain, P; Visschers, J L; Vivolo, L; Weinheimer, C; Wilquet, G; Winter, Klaus; Wolff, T; Wong, H; Yoon, C S; Zeyrek, M T; Zucchelli, P

    1998-01-01

    We report on the first direct observation of a neutrino induced charged-current interaction with two subsequent decays of short-lived particles close to the interaction vertex. This rare double- kink signature in the CHORUS emulsion target is interpreted as a $D_s^{*+}$ production followed by the decay chain $D_s^{*+} \\rightarrow D_s^+ \\gamma, D_s^+ \\rightarrow \\tau^+ \

  14. Neutrino-induced upward-going muons in Super-Kamiokande

    CERN Document Server

    Habig, A

    1999-01-01

    Upward-going muons observed by the Super-Kamiokande detector are produced by high-energy atmospheric neutrinos which interact in rock around the detector. Those which pass completely through the detector have a mean parent neutrino energy of ~100 GeV, while those which range out inside the detector come from neutrinos of mean energy ~10 GeV. The neutrino baseline varies with the observed muon zenith angle, allowing for an independent test via nu-mu disappearance of the neutrino oscillations observed in the Super-Kamiokande contained events. 614 upward through-going and 137 upward stopping muons were observed over 537 (516) live days, resulting in a flux of Phi_t=1.74\\pm0.07(stat.)\\pm0.02(sys.), Phi_s=0.380\\pm0.038(stat.)^{+0.019}_{-0.016}(sys.) x10^{-13}cm^{-2}s^{-1}sr^{-1}. The observed stopping/through-going ratio R=0.218\\pm0.023(stat.)^{+0.014}_{-0.013}(syst.) is 2.9 sigma lower than the expectation of 0.368^{+0.049}_{-0.044}(theo.). Both the shape of the zenith angle distribution of the observed flux and ...

  15. Learning Cascading

    CERN Document Server

    Covert, Michael

    2015-01-01

    This book is intended for software developers, system architects and analysts, big data project managers, and data scientists who wish to deploy big data solutions using the Cascading framework. You must have a basic understanding of the big data paradigm and should be familiar with Java development techniques.

  16. Expenditure Cascades

    OpenAIRE

    Frank, R; Levine, A.; Dijk, O.

    2014-01-01

    Prevailing economic models of consumer behavior completely ignore the well-documented link between context and evaluation. We propose and test a theory that explicitly incorporates this link. Changes in one group's spending shift the frame of reference that defines consumption standards for others just below them on the income scale, giving rise to expenditure cascades. Our model, a descendant of James Duesenberry's relative income hypothesis, predicts the observed ways in which individual sa...

  17. Atmospheric deposition, water-quality, and sediment data for selected lakes in Mount Rainer, North Cascades, and Olympic National Parks, Washington, 2008-10

    Science.gov (United States)

    Sheibley, Rich W.; Foreman, James R.; Moran, Patrick W.; Swarzenski, Peter W.

    2012-01-01

    To evaluate the potential effect from atmospheric deposition of nitrogen to high-elevation lakes, the U.S. Geological Survey partnered with the National Park Service to develop a "critical load" of nitrogen for sediment diatoms. A critical load is defined as the level of a given pollutant (in this case, nitrogen) at which detrimental effects to a target endpoint (sediment diatoms) result. Because sediment diatoms are considered one of the "first responders" to ecosystem changes from nitrogen, they are a sensitive indicator for nitrogen deposition changes in natural areas. This report presents atmospheric deposition, water quality, sediment geochronology, and sediment diatom data collected from July 2008 through August 2010 in support of this effort.

  18. Measurement of the Atmospheric $\

    CERN Document Server

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beattie, K; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Bell, M; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose1, D; Boser, S; Botner, O; Brayeur, L; Brown, A M; Bruijn, R; Brunner, J; Buitink, S; Carson, M; Casey, J; Casier, M; Chirkin, D; Christy, B; Clark, K; Clevermann, F; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Diaz-Velez, J C; Dreyer, J; Dumm, J P; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Engdegard, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glusenkamp, T; Goldschmidt, A; Golup, G; Goodman, J A; Gora, D; Grant, D; Gross, A; Grullon, S; Gurtner, M; Ha, C; Ismail, A Haj; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heimann, P; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Jlelati, O; Kappes, A; Karg, T; Karle, A; Kiryluk, J; Kislat, F; Klas, J; Klein, S R; Kohne, J -H; Kohnen, G; Kolanoski, H; Kopke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lauer, R; Lesiak-Bzdak, M; Lunemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meszaros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Panknin, S; Paul, L; Pepper, J A; Heros, C Perez de los; Pieloth, D; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Radel, L; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schoneberg, S; Schonherr, L; Schonwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Seo, S H; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soiron, M; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stoss, A; Strahler, E A; Strom, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge1, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Wasserman, R; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zilles, A; Zoll, M

    2012-01-01

    We report the first observation in a high energy neutrino telescope of cascades induced by atmospheric electron neutrinos and by neutral current interactions of atmospheric neutrinos of all flavors. Using data recorded during the first year of operation of IceCube's DeepCore low energy extension, a sample of 1029 events is observed in 281 days of data. The number of observed cascades is $N_{\\rm cascade} = 496 \\pm 66 (stat.) \\pm 88(syst.)$ and the rest of the sample consists of residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is determined in the energy range between approximately 80 GeV and 6 TeV and is consistent with models of atmospheric neutrinos.

  19. Injectorless quantum cascade lasers

    Science.gov (United States)

    Katz, Simeon; Vizbaras, Augustinas; Meyer, Ralf; Amann, Markus-Christian

    2011-04-01

    This review focuses on recent progress on injectorless quantum cascade lasers, an increasingly attractive approach in comparison to the "classical" injectorbased concepts. This particularly holds for the wavelength range between 7 and 12 μm, where fundamental vibrational modes of many important molecules exist, so that sensor systems for medical, industrial and military applications highly benefit from these laser sources. The atmospheric transmission window between 8 and 12 μm, with very low damping, also enables free space applications like communication, military countermeasures, and environmental sensors. Injectorless devices operate closer to the original design principle for intersubband lasers as suggested by Suris and Kazarinov [Sov. Phys. Semicond. 5, 707 (1971)]. Therefore, a short description of their features is given in comparison to injectorbased devices. Within recent years, injectorless devices have seen rapid improvement in performance. Best injectorless devices reach threshold current densities of 450 A/cm2 at 300 K, a factor of 1.6 smaller than that for the best injectorbased devices. Their output efficiency has also increased from 2% to more than 7% within the last 2 years, reaching comparable levels and making the injectorless device concept competitive and very attractive for applications.

  20. Astrophysical neutrinos and atmospheric leptons

    Directory of Open Access Journals (Sweden)

    Gaisser T.K.

    2017-01-01

    Full Text Available IceCube measurements of the neutrino flux from TeV to PeV show the signal of astrophysical neutrinos standing out at high energy well above the steeply falling foreground of atmospheric neutrinos. The astrophysical signal appears both in measurements of neutrino-induced muons and in the starting event sample, which responds preferentially to electron and tau neutrinos, but which also includes muon neutrinos. Searches for point sources of astrophysical neutrinos have, however, not yet identified a single source or class of sources for the astrophysical component. Some constraints on astrophysical sources implied by the current observations will be described in this talk. Uncertainties in the fluxes of atmospheric leptons resulting from an incomplete knowledge of the primary cosmic-ray spectrum and from a limited understanding of meson production, including charm will also be reviewed. The ultimate goal is to improve the understanding of the astrophysical spectrum in the transition to lower energy where atmospheric neutrinos dominate. The main aspects of this presentation will be included in the author's Review Talk at the end of the Symposium.

  1. Cascade Organic Solar Cells

    KAUST Repository

    Schlenker, Cody W.

    2011-09-27

    We demonstrate planar organic solar cells consisting of a series of complementary donor materials with cascading exciton energies, incorporated in the following structure: glass/indium-tin-oxide/donor cascade/C 60/bathocuproine/Al. Using a tetracene layer grown in a descending energy cascade on 5,6-diphenyl-tetracene and capped with 5,6,11,12-tetraphenyl- tetracene, where the accessibility of the π-system in each material is expected to influence the rate of parasitic carrier leakage and charge recombination at the donor/acceptor interface, we observe an increase in open circuit voltage (Voc) of approximately 40% (corresponding to a change of +200 mV) compared to that of a single tetracene donor. Little change is observed in other parameters such as fill factor and short circuit current density (FF = 0.50 ± 0.02 and Jsc = 2.55 ± 0.23 mA/cm2) compared to those of the control tetracene-C60 solar cells (FF = 0.54 ± 0.02 and Jsc = 2.86 ± 0.23 mA/cm2). We demonstrate that this cascade architecture is effective in reducing losses due to polaron pair recombination at donor-acceptor interfaces, while enhancing spectral coverage, resulting in a substantial increase in the power conversion efficiency for cascade organic photovoltaic cells compared to tetracene and pentacene based devices with a single donor layer. © 2011 American Chemical Society.

  2. Howling about Trophic Cascades

    Science.gov (United States)

    Kowalewski, David

    2012-01-01

    Following evolutionary theory and an agriculture model, ecosystem research has stressed bottom-up dynamics, implying that top wild predators are epiphenomenal effects of more basic causes. As such, they are assumed expendable. A more modern co-evolutionary and wilderness approach--trophic cascades--instead suggests that top predators, whose…

  3. Quantum Cascade Lasers Modulation and Applications

    Science.gov (United States)

    Luzhansky, Edward

    The mid-wave IR (MWIR) spectral band, extending from 3 to 5 microns, is considered to be a low loss atmospheric window. There are several spectral sub-bands with relatively low atmospheric attenuation in this region making it popular for various commercial and military applications. Relatively low thermal and solar background emissions, effective penetration through the natural and anthropogenic obscurants and eye safety add to the long list of advantages of MWIR wavelengths. Quantum Cascade Lasers are compact semiconductor devices capable of operating in MWIR spectrum. They are based on inter-subband transitions in a multiple-quantum-well (QW) hetero-structure, designed by means of band-structure engineering. The inter-subband nature of the optical transition has several key advantages. First, the emission wavelength is primarily a function of the QW thickness. This characteristic allows choosing well-understood and reliable semiconductors for the generation of light in a wavelength range of interest. Second, a cascade process in which tens of photons are generated per injected electron. This cascading process is behind the intrinsic high-power capabilities of QCLs. This dissertation is focused on modulation properties of Quantum Cascade Lasers. Both amplitude and phase/frequency modulations were studied including modulation bandwidth, modulation efficiency and chirp linearity. Research was consisted of the two major parts. In the first part we describe the theory of frequency modulation (FM) response of Distributed Feedback Quantum Cascade Lasers (DFB QCL). It includes cascading effect on the QCL's maximum modulation frequency. The "gain levering" effect for the maximum FM response of the two section QCLs was studied as well. In the second part of research we concentrated on the Pulse Position Amplitude Modulation of a single section QCL. The low complexity, low size, weight and power Mid-Wavelength Infra-Red optical communications transceiver concept is

  4. Cascades in helical turbulence

    CERN Document Server

    Ditlevsen, P D

    2001-01-01

    The existence of a second quadratic inviscid invariant, the helicity, in a turbulent flow leads to coexisting cascades of energy and helicity. An equivalent of the four-fifth law for the longitudinal third order structure function, which is derived from energy conservation, is easily derived from helicity conservation cite{Procaccia,russian}. The ratio of dissipation of helicity to dissipation of energy is proportional to the wave-number leading to a different Kolmogorov scale for helicity than for energy. The Kolmogorov scale for helicity is always larger than the Kolmogorov scale for energy so in the high Reynolds number limit the flow will always be helicity free in the small scales, much in the same way as the flow will be isotropic and homogeneous in the small scales. A consequence is that a pure helicity cascade is not possible. The idea is illustrated in a shell model of turbulence.

  5. A cascade generator based on the quark-gluon string model

    Energy Technology Data Exchange (ETDEWEB)

    Popova, L.; Trifonov, A.; Rossenov, I.; Petrova, P. (Institute of Nuclear Research and Nuclear Energy-Bulgaria (Bulgaria)); Portella, H.; Maldonado, R.H.C. (Instituto de Fisica-Universidade Federal Fluminense-Brazil (Brazil)); Amato, N. (Centro Brasileiro de Pesquisas Fisicas, RJ (Brazil))

    1993-06-15

    A computer generator for simulation of hadron cascades in the atmosphere is developed on the basis of the quark-gluon string model. Preliminary results that can be used for interpretation of emulsion chamber are presented.

  6. Fractal Levy correlation cascades

    Energy Technology Data Exchange (ETDEWEB)

    Eliazar, Iddo [Department of Technology Management, Holon Institute of Technology, Holon 58102 (Israel); Klafter, Joseph [School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

    2007-04-20

    The correlation structure of a wide class of random processes, driven by stable non-Gaussian Levy noise sources, is explored. Since these noises are of infinite variance, correlations cannot be measured via auto-covariance functions. Exploiting the underlying Poissonian structure of Levy noises, we present a cascade of 'Poissonian correlation functions' which characterize the correlation structure and the process distribution of the processes under consideration. The theory developed is applied to various examples including motions, Ornstein-Uhlenbeck and moving-average processes, and fractional motions and noises-all driven by stable non-Gaussian Levy noises. (fast track communication)

  7. Cascading Corruption News

    DEFF Research Database (Denmark)

    Damgaard, Mads

    2018-01-01

    Through a content analysis of 8,800 news items and six months of front pages in three Brazilian newspapers, all dealing with corruption and political transgression, this article documents the remarkable skew of media attention to corruption scandals. The bias is examined as an information...... phenomenon, arising from systemic and commercial factors of Brazil’s news media: An information cascade of news on corruption formed, destabilizing the governing coalition and legitimizing the impeachment process of Dilma Rousseff. As this process gained momentum, questions of accountability were disregarded...

  8. Cascading off Davis Strait as seen from a NEMO simulation

    Science.gov (United States)

    Marson, Juliana M.; Myers, Paul G.; Hu, Xianmin; Petrie, Brian; Azetsu-Scott, Kumiko; Lee, Craig

    2017-04-01

    Cascading occurs when dense waters form and accumulate on the continental shelf, eventually sliding down the slope and reaching intermediate and deep layers of the ocean. It is an important process for ventilating the deep ocean and capturing carbon from the atmosphere. Although observed in several different locations, especially at high latitudes, cascading has never been reported for the western Greenland shelf. We use the results from a 2002-2014 NEMO ocean model simulation to show that cascading could happen sporadically at Davis Strait. Over the time span of the model run, cascading occurred during five winters with each event starting around February and persisting until the end of May. The occurrence of those events seems to be dependent on (1) the balance between sea ice formation and melting in the region; (2) the amount of freshwater coming from the Arctic through Fram Strait; (3) the presence of West Greenland Irminger Water on the shelf. The cascading water primarily flows into deep Baffin Bay, although not at a sufficient rate to be a primary source of Baffin Bay Deep Water. The simulation's temperature and salinity interannual variability in Davis Strait agrees reasonably with observations (CTD profiles and moorings) but overestimates the peak salinity and density and consequently the strength of the cascade process. Nonetheless, the model simulation indicates that this phenomenon has the potential to occur in this location.

  9. Cascade Distillation System Development

    Science.gov (United States)

    Callahan, Michael R.; Sargushingh, Miriam; Shull, Sarah

    2014-01-01

    NASA's Advanced Exploration Systems (AES) Life Support System (LSS) Project is chartered with de-veloping advanced life support systems that will ena-ble NASA human exploration beyond low Earth orbit (LEO). The goal of AES is to increase the affordabil-ity of long-duration life support missions, and to re-duce the risk associated with integrating and infusing new enabling technologies required to ensure mission success. Because of the robust nature of distillation systems, the AES LSS Project is pursuing develop-ment of the Cascade Distillation Subsystem (CDS) as part of its technology portfolio. Currently, the system is being developed into a flight forward Generation 2.0 design.

  10. Unsteady turbulence cascades.

    Science.gov (United States)

    Goto, Susumu; Vassilicos, J C

    2016-11-01

    We have run a total of 311 direct numerical simulations (DNSs) of decaying three-dimensional Navier-Stokes turbulence in a periodic box with values of the Taylor length-based Reynolds number up to about 300 and an energy spectrum with a wide wave-number range of close to -5/3 power-law dependence at the higher Reynolds numbers. On the basis of these runs, we have found a critical time when (i) the rate of change of the square of the integral length scale turns from increasing to decreasing, (ii) the ratio of interscale energy flux to high-pass filtered turbulence dissipation changes from decreasing to very slowly increasing in the inertial range, (iii) the signature of large-scale coherent structures disappears in the energy spectrum, and (iv) the scaling of the turbulence dissipation changes from the one recently discovered in DNSs of forced unsteady turbulence and in wind tunnel experiments of turbulent wakes and grid-generated turbulence to the classical scaling proposed by G. I. Taylor [Proc. R. Soc. London, Ser. A 151, 421 (1935)1364-502110.1098/rspa.1935.0158] and A. N. Kolmogorov [Dokl. Akad. Nauk SSSR 31, 538 (1941)]. Even though the customary theoretical basis for this Taylor-Kolmogorov scaling is a statistically stationary cascade where large-scale energy flux balances dissipation, this is not the case throughout the entire time range of integration in all our DNS runs. The recently discovered dissipation scaling can be reformulated physically as a situation in which the dissipation rates of the small and large scales evolve together. We advance two hypotheses that may form the basis of a theoretical approach to unsteady turbulence cascades in the presence of large-scale coherent structures.

  11. Inferring network structure from cascades

    Science.gov (United States)

    Ghonge, Sushrut; Vural, Dervis Can

    2017-07-01

    Many physical, biological, and social phenomena can be described by cascades taking place on a network. Often, the activity can be empirically observed, but not the underlying network of interactions. In this paper we offer three topological methods to infer the structure of any directed network given a set of cascade arrival times. Our formulas hold for a very general class of models where the activation probability of a node is a generic function of its degree and the number of its active neighbors. We report high success rates for synthetic and real networks, for several different cascade models.

  12. Cascade Mountain Range in Oregon

    Science.gov (United States)

    Sherrod, David R.

    2016-01-01

    The Cascade mountain system extends from northern California to central British Columbia. In Oregon, it comprises the Cascade Range, which is 260 miles long and, at greatest breadth, 90 miles wide (fig. 1). Oregon’s Cascade Range covers roughly 17,000 square miles, or about 17 percent of the state, an area larger than each of the smallest nine of the fifty United States. The range is bounded on the east by U.S. Highways 97 and 197. On the west it reaches nearly to Interstate 5, forming the eastern margin of the Willamette Valley and, farther south, abutting the Coast Ranges. 

  13. Cascading effects following intervention.

    Science.gov (United States)

    Patterson, Gerald R; Forgatch, Marion S; Degarmo, David S

    2010-11-01

    Four different sources for cascade effects were examined using 9-year process and outcome data from a randomized controlled trial of a preventive intervention using the Parent Management Training-Oregon Model (PMTO™). The social interaction learning model of child antisocial behavior serves as one basis for predicting change. A second source addresses the issue of comorbid relationships among clinical diagnoses. The third source, collateral changes, describes events in which changes in one family member correlate with changes in another. The fourth component is based on the long-term effects of reducing coercion and increasing positive interpersonal processes within the family. New findings from the 9-year follow-up show that mothers experienced benefits as measured by standard of living (i.e., income, occupation, education, and financial stress) and frequency of police arrests. It is assumed that PMTO reduces the level of coercion, which sets the stage for a massive increase in positive social interaction. In effect, PMTO alters the family environment and thereby opens doors to healthy new social environments.

  14. Cascade dynamics on complex networks.

    OpenAIRE

    Hackett, Adam W.

    2011-01-01

    peer-reviewed The network topologies on which many natural and synthetic systems are built provide ideal settings for the emergence of complex phenomena. One well-studied manifestation of this, called a cascade or avalanche, is observed when interactions between the components of a system allow an initially localized effect to propagate globally. For example, the malfunction of technological systems like email networks or electrical power grids is often attributable to a cascade o...

  15. Interband Cascade Photovoltaic Cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rui Q. [Univ. of Oklahoma, Norman, OK (United States); Santos, Michael B. [Univ. of Oklahoma, Norman, OK (United States); Johnson, Matthew B. [Univ. of Oklahoma, Norman, OK (United States)

    2014-09-24

    In this project, we are performing basic and applied research to systematically investigate our newly proposed interband cascade (IC) photovoltaic (PV) cells [1]. These cells follow from the great success of infrared IC lasers [2-3] that pioneered the use of quantum-engineered IC structures. This quantum-engineered approach will enable PV cells to efficiently convert infrared radiation from the sun or other heat source, to electricity. Such cells will have important applications for more efficient use of solar energy, waste-heat recovery, and power beaming in combination with mid-infrared lasers. The objectives of our investigations are to: achieve extensive understanding of the fundamental aspects of the proposed PV structures, develop the necessary knowledge for making such IC PV cells, and demonstrate prototype working PV cells. This research will focus on IC PV structures and their segments for utilizing infrared radiation with wavelengths from 2 to 5 μm, a range well suited for emission by heat sources (1,000-2,000 K) that are widely available from combustion systems. The long-term goal of this project is to push PV technology to longer wavelengths, allowing for relatively low-temperature thermal sources. Our investigations address material quality, electrical and optical properties, and their interplay for the different regions of an IC PV structure. The tasks involve: design, modeling and optimization of IC PV structures, molecular beam epitaxial growth of PV structures and relevant segments, material characterization, prototype device fabrication and testing. At the end of this program, we expect to generate new cutting-edge knowledge in the design and understanding of quantum-engineered semiconductor structures, and demonstrate the concepts for IC PV devices with high conversion efficiencies.

  16. Atmospheric and Astrophysics Neutrinos with MACRO

    CERN Document Server

    Montaruli, T

    1999-01-01

    MACRO can detect three topologies of neutrino induced events, corresponding to different parent neutrino energies. The most numerous sample is made of upward throughgoing muons induced by atmospheric neutrinos of average energy 100 GeV. We have observed less events than expected events and the observed zenith distribution does not fit the expected one in the no-oscillation hypothesis, giving a maximum probability of 0.1 percent. Considering the neutrino (numu-nutau) oscillation hypothesis the best probability (17 percent) is obtained for maximum mixing and difference of square masses of a few times 10-3 eV2. The other detected samples are due to internally produced events and upward-going stopping muons, corresponding to an average neutrino energy of around 4 GeV. The results concerning these lower energy sample show a deficit and a shape of the angular distributions in agreement with that predicted by the oscillation model suggested by the higher energy sample. No evidence of a neutrino signal due to dark ma...

  17. Cascading climate effects and related ecological consequences during past centuries

    OpenAIRE

    Naef-Daenzer, B; J. Luterbacher; M. Nuber; T. Rutishauser; W. Winkel

    2012-01-01

    The interface between climate and ecosystem structure and function is incompletely understood, partly because few ecological records start before the recent warming phase. Here, we analyse an exceptional 100-yr long record of the great tit (Parus major) population in Switzerland in relation to climate and habitat phenology. Using structural equation analysis, we demonstrate an uninterrupted cascade of significant influences of the large-scale atmospheric circulation (North-...

  18. Cascaded FSO-VLC Communication System

    KAUST Repository

    Gupta, Akash

    2017-08-28

    The proposed cascaded free space optics (FSO)-visible light communication (VLC) system consists of multiple VLC access points which caters the end users connected via a decode and forward (DF) relay to the FSO backhaul link. The FSO link is assumed to be affected by path-loss, pointing error and atmospheric turbulence while the end-to-end signal-to-noise ratio (SNR) of VLC downlinks are statistically characterized considering the randomness of users position. In this study, the novel closed form expressions of the statistics like probability density function (PDF) and cumulative distribution function (CDF) of the equivalent SNR are derived. Capitalizing on these, the closed form expressions for various performance metrics such as outage probability and error probability are provided. The simulation results are provided to verify the functional curves of mathematical analysis.

  19. Cascaded failures in weighted networks

    Science.gov (United States)

    Mirzasoleiman, Baharan; Babaei, Mahmoudreza; Jalili, Mahdi; Safari, Mohammadali

    2011-10-01

    Many technological networks can experience random and/or systematic failures in their components. More destructive situations can happen if the components have limited capacity, where the failure in one of them might lead to a cascade of failures in other components, and consequently break down the structure of the network. In this paper, the tolerance of cascaded failures was investigated in weighted networks. Three weighting strategies were considered including the betweenness centrality of the edges, the product of the degrees of the end nodes, and the product of their betweenness centralities. Then, the effect of the cascaded attack was investigated by considering the local weighted flow redistribution rule. The capacity of the edges was considered to be proportional to their initial weight distribution. The size of the survived part of the attacked network was determined in model networks as well as in a number of real-world networks including the power grid, the internet in the level of autonomous system, the railway network of Europe, and the United States airports network. We found that the networks in which the weight of each edge is the multiplication of the betweenness centrality of the end nodes had the best robustness against cascaded failures. In other words, the case where the load of the links is considered to be the product of the betweenness centrality of the end nodes is favored for the robustness of the network against cascaded failures.

  20. Supersymmetric cascade decays at NLO

    Energy Technology Data Exchange (ETDEWEB)

    Popenda, Eva; Muehlleitner, Margarete; Hangst, Christian [KIT, Institut fuer Theoretische Physik (Germany); Kraemer, Michael [RWTH Aachen University, Institut fuer Theoretische Teilchenphysik und Kosmologie (Germany); Spira, Michael [Paul Scherrer Institut, Theory Group LTP (Switzerland)

    2012-07-01

    The search for supersymmetric particles and determination of their properties is a major task at the LHC and is based on the analysis of the cascade decay chains in which SUSY particles are produced. This project aims at improving predictions for SUSY cascade decays through the inclusion of higher-order corrections in the production and decay processes and by embedding them in a fully flexible Monte Carlo program. In this talk we report on the progress of the implementation of squark pair production followed by the decay into a quark and the lightest neutralino including supersymmetric QCD corrections at next-to-leading order in a completely differential form.

  1. Bosonic cascades of indirect excitons

    Science.gov (United States)

    Nalitov, A. V.; De Liberato, S.; Lagoudakis, P.; Savvidis, P. G.; Kavokin, A. V.

    2017-08-01

    Recently, the concept of the terahertz bosonic cascade laser (BCL) based on a parabolic quantum well (PQW) embedded in a microcavity was proposed. We refine this proposal by suggesting transitions between indirect exciton (IX) states as a source of terahertz emission. We explicitly propose a structure containing a narrow-square QW and a wide-parabolic QW for the realisation of a bosonic cascade. Advantages of this type of structures are in large dipole matrix elements for terahertz transitions and in long exciton radiative lifetimes which are crucial for realisation of threshold and quantum efficiency BCLs.

  2. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  3. Cascaded logic gates in nanophotonic plasmon networks

    National Research Council Canada - National Science Library

    Wei, Hong; Wang, Zhuoxian; Tian, Xiaorui; Käll, Mikael; Xu, Hongxing

    2011-01-01

    ... integrated logic units and cascade devices have not been reported. Here we demonstrate that a plasmonic binary NOR gate, a 'universal logic gate', can be realized through cascaded OR and NOT gates in four-terminal plasmonic nanowire networks...

  4. Cascade Support Vector Machines with Dimensionality Reduction

    Directory of Open Access Journals (Sweden)

    Oliver Kramer

    2015-01-01

    Full Text Available Cascade support vector machines have been introduced as extension of classic support vector machines that allow a fast training on large data sets. In this work, we combine cascade support vector machines with dimensionality reduction based preprocessing. The cascade principle allows fast learning based on the division of the training set into subsets and the union of cascade learning results based on support vectors in each cascade level. The combination with dimensionality reduction as preprocessing results in a significant speedup, often without loss of classifier accuracies, while considering the high-dimensional pendants of the low-dimensional support vectors in each new cascade level. We analyze and compare various instantiations of dimensionality reduction preprocessing and cascade SVMs with principal component analysis, locally linear embedding, and isometric mapping. The experimental analysis on various artificial and real-world benchmark problems includes various cascade specific parameters like intermediate training set sizes and dimensionalities.

  5. Activation Cascading in Sign Production

    Science.gov (United States)

    Navarrete, Eduardo; Peressotti, Francesca; Lerose, Luigi; Miozzo, Michele

    2017-01-01

    In this study, we investigated how activation unfolds in sign production by examining whether signs that are not produced have their representations activated by semantics (cascading of activation). Deaf signers were tested with a picture-picture interference task. Participants were presented with pairs of overlapping pictures and named the green…

  6. Dynamics robustness of cascading systems.

    Directory of Open Access Journals (Sweden)

    Jonathan T Young

    2017-03-01

    Full Text Available A most important property of biochemical systems is robustness. Static robustness, e.g., homeostasis, is the insensitivity of a state against perturbations, whereas dynamics robustness, e.g., homeorhesis, is the insensitivity of a dynamic process. In contrast to the extensively studied static robustness, dynamics robustness, i.e., how a system creates an invariant temporal profile against perturbations, is little explored despite transient dynamics being crucial for cellular fates and are reported to be robust experimentally. For example, the duration of a stimulus elicits different phenotypic responses, and signaling networks process and encode temporal information. Hence, robustness in time courses will be necessary for functional biochemical networks. Based on dynamical systems theory, we uncovered a general mechanism to achieve dynamics robustness. Using a three-stage linear signaling cascade as an example, we found that the temporal profiles and response duration post-stimulus is robust to perturbations against certain parameters. Then analyzing the linearized model, we elucidated the criteria of when signaling cascades will display dynamics robustness. We found that changes in the upstream modules are masked in the cascade, and that the response duration is mainly controlled by the rate-limiting module and organization of the cascade's kinetics. Specifically, we found two necessary conditions for dynamics robustness in signaling cascades: 1 Constraint on the rate-limiting process: The phosphatase activity in the perturbed module is not the slowest. 2 Constraints on the initial conditions: The kinase activity needs to be fast enough such that each module is saturated even with fast phosphatase activity and upstream changes are attenuated. We discussed the relevance of such robustness to several biological examples and the validity of the above conditions therein. Given the applicability of dynamics robustness to a variety of systems, it

  7. Cascaded Bragg scattering in fiber optics.

    Science.gov (United States)

    Xu, Y Q; Erkintalo, M; Genty, G; Murdoch, S G

    2013-01-15

    We report on a theoretical and experimental study of cascaded Bragg scattering in fiber optics. We show that the usual energy-momentum conservation of Bragg scattering can be considerably relaxed via cascade-induced phase-matching. Experimentally we demonstrate frequency translation over six- and 11-fold cascades, in excellent agreement with derived phase-matching conditions.

  8. Neutrino induced events in the MINOS detectors

    Energy Technology Data Exchange (ETDEWEB)

    Litchfield, Reuben Phillip [Univ. of Oxford (United Kingdom). Keble College

    2008-01-01

    The MINOS experiment is designed to study neutrino oscillations. It uses an accelerator generated beam of neutrinos and two detectors, the smaller at a distance of 1km and the larger at 735 km. By comparing the spectrum and flavour composition of the beam at the two detectors precise determinations of the oscillation parameters are possible. This thesis concentrates on the analysis of data from the larger Far Detector. By studying the spectrum of neutral current events it is possible to look for evidence of non-interacting 'sterile' neutrinos. The thesis describes how events are selected for this analysis, and a method for discriminating between charged current and neutral current events. The systematic uncertainties resulting from these cuts are evaluated. Several techniques for using Near Detector data to eliminate systematic uncertainties in the predicted Far Detector spectrum are compared. An oscillation analysis, based on the first year of MINOS data, uses the selected events to make a measurement of f{sub s}, the fraction of unseen neutrinos that are sterile. The measured value is fs = 0.07+0.32 at 68%C.L., and is consistent with the standard three-neutrino picture, which has no sterile neutrino.

  9. Neutrino-induced deuteron disintegration experiment

    CERN Document Server

    Riley, S P; Kropp, W R; Price, L R; Reines, F; Sobel, H W; Déclais, Y; Etinko, A; Skorokhvatov, M

    1999-01-01

    Cross sections for the disintegration of the deuteron via neutral-current (NCD) and charged-current (CCD) interactions with reactor antineutrinos are measured to be 6.08 +/- 0.77 x 10^(-45) cm-sq and 9.83 +/- 2.04 x 10^(-45) cm-sq per neutrino, respectively, in excellent agreement with current calculations. Since the experimental NCD value depends upon the CCD value, if we use the theoretical value for the CCD reaction, we obtain the improved value of 5.98 +/- 0.54 x 10^(-45) for the NCD cross section. The neutral-current reaction allows a unique measurement of the isovector-axial vector coupling constant in the hadronic weak interaction (beta). In the standard model, this constant is predicted to be exactly 1, independent of the Weinberg angle. We measure a value of beta^2 = 1.01 +/- 0.16. Using the above improved value for the NCD cross section, beta^2 becomes 0.99 +/- 0.10.

  10. Check of the accuracy of the relativity theory with atmospheric muon neutrinos from the AMANDA data of the years 2000 to 2003; Ueberpruefung der Genauigkeit der Relativitaetstheorie mit atmosphaerischen Myonneutrinos aus den AMANDA-Daten der Jahre 2000 bis 2003

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, J.C.

    2006-11-08

    Atmospheric neutrinos allow one to test the principles of the Theory of Relativity in particular Lorentz invariance and the equivalence principle. Small deviations from these principles could lead, according to some theories, to detectable neutrino oscillations. Such oscillation effects are analysed in this thesis, using the data collected by the AMANDA detector. The neutrino telescope AMANDA is located at the South Pole and embedded in the Antarctic ice shield at a depth between 1500 m and 2000 m. AMANDA detects muon neutrinos via the Cherenkov light of neutrino induced muons allowing the reconstruction of the original neutrino direction. From the data of the years 2000 to 2003, which contain about seven billion recorded events and which mainly consist of the background of atmospheric muons, a sample of 3401 neutrino induced events has been selected. No indication for alternative oscillation effects has been found. For maximal mixing angles, a lower limit for parameters which violate Lorentz invariance or the equivalence principle could be set to {delta}{beta}(2 vertical stroke {phi} vertical stroke {delta}{gamma}){<=}5.15.10{sup -27}. (orig)

  11. Bankruptcy cascades in interbank markets.

    Directory of Open Access Journals (Sweden)

    Gabriele Tedeschi

    Full Text Available We study a credit network and, in particular, an interbank system with an agent-based model. To understand the relationship between business cycles and cascades of bankruptcies, we model a three-sector economy with goods, credit and interbank market. In the interbank market, the participating banks share the risk of bad debits, which may potentially spread a bank's liquidity problems through the network of banks. Our agent-based model sheds light on the correlation between bankruptcy cascades and the endogenous economic cycle of booms and recessions. It also demonstrates the serious trade-off between, on the one hand, reducing risks of individual banks by sharing them and, on the other hand, creating systemic risks through credit-related interlinkages of banks. As a result of our study, the dynamics underlying the meltdown of financial markets in 2008 becomes much better understandable.

  12. Thermal cascaded lattice Boltzmann method

    CERN Document Server

    Fei, Linlin

    2016-01-01

    In this paper, a thermal cascaded lattice Boltzmann method (TCLBM) is developed in combination with the double-distribution-function (DDF) approach. A density distribution function relaxed by the cascaded scheme is employed to solve the flow field, and a total energy distribution function relaxed by the BGK scheme is used to solve temperature field, where two distribution functions are coupled naturally. The forcing terms are incorporated by means of central moments, which is consistent with the previous force scheme [Premnath \\emph{et al.}, Phys. Rev. E \\textbf{80}, 036702 (2009)] but the derivation is more intelligible and the evolution process is simpler. In the method, the viscous heat dissipation and compression work are taken into account, the Prandtl number and specific-heat ratio are adjustable, the external force is considered directly without the Boussinesq assumption, and the low-Mach number compressible flows can also be simulated. The forcing scheme is tested by simulating a steady Taylor-Green f...

  13. Lens Coupled Quantum Cascade Laser

    Science.gov (United States)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor)

    2013-01-01

    Terahertz quantum cascade (QC) devices are disclosed that can operate, e.g., in a range of about 1 THz to about 10 THz. In some embodiments, QC lasers are disclosed in which an optical element (e.g., a lens) is coupled to an output facet of the laser's active region to enhance coupling of the lasing radiation from the active region to an external environment. In other embodiments, terahertz amplifier and tunable terahertz QC lasers are disclosed.

  14. Turbulence: does energy cascade exist?

    CERN Document Server

    Josserand, Christophe; Lehner, Thierry; Pomeau, Yves

    2016-01-01

    To answer the question whether a cascade of energy exists or not in turbulence, we propose a set of correlation functions able to test if there is an irreversible transfert of energy, step by step, from large to small structures. These tests are applied to real Eulerian data of a turbulent velocity flow, taken in the wind grid tunnel of Modane, and also to a prototype model equation for wave turbulence. First we demonstrate the irreversible character of the flow by using multi-time correlation function at a given point of space. Moreover the unexpected behavior of the test function leads us to connect irreversibility and finite time singularities (intermittency). Secondly we show that turbulent cascade exists, and is a dynamical process, by using a test function depending on time and frequency. The cascade shows up only in the inertial domain where the kinetic energy is transferred more rapidly (on average) from the wavenumber $k_{1}$ to $k_{2}$ than from $k_{1}$ to $k'_{2}$ larger than $k_{2}$.

  15. Azobenzene-functionalized cascade molecules

    DEFF Research Database (Denmark)

    Archut, A.; Vogtle, F.; De Cola, L.

    1998-01-01

    Cascade molecules bearing up to 32 azobenzene groups in the periphery have been prepared from poly(propylene imine) dendrimers and N-hydroxysuccinimide esters. The dendritic azobenzene species show similar isomerization properties as the corresponding azobenzene monomers. The all-E azobenzene...... shows there is so far no effective steric constraint towards photoisomerism on increasing dimension (generation) of the dendrimer, The first attempts to use dendrimers for holography materials are described: It is shown that holographic gratings with diffraction efficiencies up to about 20 % can...

  16. Disaster Mythology and Availability Cascades

    Directory of Open Access Journals (Sweden)

    Lisa Grow Sun

    2013-04-01

    Full Text Available Sociological research conducted in the aftermath of natural disasters has uncovered a number of “disaster myths” – widely shared misconceptions about typical post-disaster human behavior. This paper discusses the possibility that perpetuation of disaster mythology reflects an “availability cascade,” defined in prior scholarship as a “self-reinforcing process of collective belief formation by which an expressed perception triggers a chain reaction that gives the perception increasing plausibility through its rising availability in public discourse.” (Kuran and Sunstein 1999. Framing the spread of disaster mythology as an availability cascade suggests that certain tools may be useful in halting the myths’ continued perpetuation. These tools include changing the legal and social incentives of so-called “availability entrepreneurs” – those principally responsible for beginning and perpetuating the cascade, as well as insulating decision-makers from political pressures generated by the availability cascade. This paper evaluates the potential effectiveness of these and other solutions for countering disaster mythology. Las investigaciones sociológicas realizadas tras los desastres naturales han hecho evidentes una serie de “mitos del desastre”, conceptos erróneos ampliamente compartidos sobre el comportamiento humano típico tras un desastre. Este artículo analiza la posibilidad de que la perpetuación de los mitos del desastre refleje una “cascada de disponibilidad”, definida en estudios anteriores como un “proceso de auto-refuerzo de la formación de una creencia colectiva, a través del que una percepción expresada produce una reacción en cadena que hace que la percepción sea cada vez más verosímil, a través de una mayor presencia en el discurso público” (Kuran y Sunstein 1999. Enmarcar la propagación de los mitos del desastre como una cascada de disponibilidad sugiere que ciertas herramientas pueden ser

  17. WHISTLER TURBULENCE FORWARD CASCADE VERSUS INVERSE CASCADE: THREE-DIMENSIONAL PARTICLE-IN-CELL SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ouliang [Oracle Corporation, Redwood Shores, CA (United States); Gary, S. Peter [Space Science Institute, Boulder, CO (United States); Wang, Joseph, E-mail: ouliang@usc.edu, E-mail: pgary@lanl.gov, E-mail: josephjw@usc.edu [University of Southern California, Los Angeles, CA (United States)

    2015-02-20

    We present the results of the first fully three-dimensional particle-in-cell simulations of decaying whistler turbulence in a magnetized, homogeneous, collisionless plasma in which both forward cascades to shorter wavelengths, and inverse cascades to longer wavelengths are allowed to proceed. For the electron beta β {sub e} = 0.10 initial value considered here, the early-time rate of inverse cascade is very much smaller than the rate of forward cascade, so that at late times the fluctuation energy in the regime of the inverse cascade is much weaker than that in the forward cascade regime. Similarly, the wavevector anisotropy in the inverse cascade regime is much weaker than that in the forward cascade regime.

  18. Inverse cascades and resonant triads in rotating and stratified turbulence

    Science.gov (United States)

    Oks, D.; Mininni, P. D.; Marino, R.; Pouquet, A.

    2017-11-01

    Kraichnan's seminal ideas on inverse cascades yielded new tools to study common phenomena in geophysical turbulent flows. In the atmosphere and the oceans, rotation and stratification result in a flow that can be approximated as two-dimensional at very large scales but which requires considering three-dimensional effects to fully describe turbulent transport processes and non-linear phenomena. Motions can thus be classified into two classes: fast modes consisting of inertia-gravity waves and slow quasi-geostrophic modes for which the Coriolis force and horizontal pressure gradients are close to balance. In this paper, we review previous results on the strength of the inverse cascade in rotating and stratified flows and then present new results on the effect of varying the strength of rotation and stratification (measured by the inverse Prandtl ratio N/f, of the Coriolis frequency to the Brunt-Väisäla frequency) on the amplitude of the waves and on the flow quasi-geostrophic behavior. We show that the inverse cascade is more efficient in the range of N/f for which resonant triads do not exist, 1 /2 ≤N /f ≤2 . We then use the spatio-temporal spectrum to show that in this range slow modes dominate the dynamics, while the strength of the waves (and their relevance in the flow dynamics) is weaker.

  19. 2-D imaging with cascaded GEM/MHSP multipliers

    CERN Document Server

    Maia, J M; Breskin, Amos; Chechik, R; Veloso, J F C A; Dos Santos, J M F

    2007-01-01

    The imaging properties of cascaded-GEM (Gas Electron Multiplier) and cascaded-GEM/MHSP (Micro-Hole and Strip Plate) gaseous electron multipliers, equipped with 2-D Wedge & Strip (W&S) readout electrodes, are presented. The W&S electrode was capacitively coupled to the electron multiplier through a resistive electrode, to adapt the charge-cloud size to the 1.6 mm readout pitch. The studies were carried out with soft X-rays and single UV-photons in Ar/5%CH4 gas mixture at atmospheric pressure. Spatial resolutions of ~225μm and ~250μm (FWHM) were reached, with 5.9 keV X-rays, in 3-GEM and 2-GEM/MHSP based detectors, respectively. Single photoelectrons, emitted from a CsI photocathode deposited on the top electrode of the first GEM in the cascade, were localized with resolution of ~ 170μm (FWHM) in a 4-GEM gaseous photomultiplier.

  20. Contingency Analysis of Cascading Line Outage Events

    Energy Technology Data Exchange (ETDEWEB)

    Thomas L Baldwin; Magdy S Tawfik; Miles McQueen

    2011-03-01

    As the US power systems continue to increase in size and complexity, including the growth of smart grids, larger blackouts due to cascading outages become more likely. Grid congestion is often associated with a cascading collapse leading to a major blackout. Such a collapse is characterized by a self-sustaining sequence of line outages followed by a topology breakup of the network. This paper addresses the implementation and testing of a process for N-k contingency analysis and sequential cascading outage simulation in order to identify potential cascading modes. A modeling approach described in this paper offers a unique capability to identify initiating events that may lead to cascading outages. It predicts the development of cascading events by identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 328-bus simplified SERC power system network. The results of the study indicate that initiating events and possible cascading chains may be identified, ranked and visualized. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

  1. Physics of interband cascade lasers

    Science.gov (United States)

    Vurgaftman, I.; Bewley, W. W.; Merritt, C. D.; Canedy, C. L.; Kim, C. S.; Abell, J.; Meyer, J. R.; Kim, M.

    2012-01-01

    The interband cascade laser (ICL) is a unique device concept that combines the effective parallel connection of its multiple-quantum-well active regions, interband active transitions, and internal generation of electrons and holes at a semimetallic interface within each stage of the device. The internal generation of carriers becomes effective under bias, and the role of electrical injection is to replenish the carriers consumed by recombination processes. Major strides have been made toward fundamentally understanding the rich and intricate ICL physics, which has in turn led to dramatic improvements in the device performance. In this article, we review the physical principles of the ICL operation and designs of the active region, electron and hole injectors, and optical waveguide. The results for state-of- the-art ICLs spanning the 3-6 μm wavelength range are also briefly reviewed. The cw threshold input powers at room temperature are more than an order of magnitude lower than those for quantum cascade lasers throughout the mid-IR spectral range. This will lengthen battery lifetimes and greatly relax packaging and size/weight requirements for fielded sensing systems.

  2. Lifespans of Cascade Arc volcanoes

    Science.gov (United States)

    Calvert, A. T.

    2015-12-01

    Compiled argon ages reveal inception, eruptive episodes, ages, and durations of Cascade stratovolcanoes and their ancestral predecessors. Geologic mapping and geochronology show that most Cascade volcanoes grew episodically on multiple scales with periods of elevated behavior lasting hundreds of years to ca. 100 kyr. Notable examples include the paleomag-constrained, few-hundred-year-long building of the entire 15-20 km3 Shastina edifice at Mt. Shasta, the 100 kyr-long episode that produced half of Mt. Rainier's output, and the 30 kyr-long episode responsible for all of South and Middle Sister. Despite significant differences in timing and rates of construction, total durations of active and ancestral volcanoes at discrete central-vent locations are similar. Glacier Peak, Mt. Rainier, Mt. Adams, Mt. Hood, and Mt. Mazama all have inception ages of 400-600 ka. Mt. St. Helens, Mt. Jefferson, Newberry Volcano, Mt. Shasta and Lassen Domefield have more recent inception ages of 200-300 ka. Only the Sisters cluster and Mt. Baker have established eruptive histories spanning less than 50 kyr. Ancestral volcanoes centered 5-20 km from active stratocones appear to have similar total durations (200-600 kyr), but are less well exposed and dated. The underlying mechanisms governing volcano lifecycles are cryptic, presumably involving tectonic and plumbing changes and perhaps circulation cycles in the mantle wedge, but are remarkably consistent along the arc.

  3. A Semisupervised Cascade Classification Algorithm

    Directory of Open Access Journals (Sweden)

    Stamatis Karlos

    2016-01-01

    Full Text Available Classification is one of the most important tasks of data mining techniques, which have been adopted by several modern applications. The shortage of enough labeled data in the majority of these applications has shifted the interest towards using semisupervised methods. Under such schemes, the use of collected unlabeled data combined with a clearly smaller set of labeled examples leads to similar or even better classification accuracy against supervised algorithms, which use labeled examples exclusively during the training phase. A novel approach for increasing semisupervised classification using Cascade Classifier technique is presented in this paper. The main characteristic of Cascade Classifier strategy is the use of a base classifier for increasing the feature space by adding either the predicted class or the probability class distribution of the initial data. The classifier of the second level is supplied with the new dataset and extracts the decision for each instance. In this work, a self-trained NB∇C4.5 classifier algorithm is presented, which combines the characteristics of Naive Bayes as a base classifier and the speed of C4.5 for final classification. We performed an in-depth comparison with other well-known semisupervised classification methods on standard benchmark datasets and we finally reached to the point that the presented technique has better accuracy in most cases.

  4. Cascading rainfall uncertainty into flood inundation impact models

    Science.gov (United States)

    Souvignet, Maxime; Freer, Jim E.; de Almeida, Gustavo A. M.; Coxon, Gemma; Neal, Jeffrey C.; Champion, Adrian J.; Cloke, Hannah L.; Bates, Paul D.

    2014-05-01

    Observed and numerical weather prediction (NWP) simulated precipitation products typically show differences in their spatial and temporal distribution. These differences can considerably influence the ability to predict hydrological responses. For flood inundation impact studies, as in forecast situations, an atmospheric-hydrologic-hydraulic model chain is needed to quantify the extent of flood risk. Uncertainties cascaded through the model chain are seldom explored, and more importantly, how potential input uncertainties propagate through this cascade, and how best to approach this, is still poorly understood. This requires a combination of modelling capabilities, the non-linear transformation of rainfall to river flow using rainfall-runoff models, and finally the hydraulic flood wave propagation based on the runoff predictions. Improving the characterisation of uncertainty, and what is important to include, in each component is important for quantifying impacts and understanding flood risk for different return periods. In this paper, we propose to address this issue by i) exploring the effects of errors in rainfall on inundation predictive capacity within an uncertainty framework by testing inundation uncertainty against different comparable meteorological conditions (i.e. using different rainfall products) and ii) testing different techniques to cascade uncertainties (e.g. bootstrapping, PPU envelope) within the GLUE (generalised likelihood uncertainty estimation) framework. Our method cascades rainfall uncertainties into multiple rainfall-runoff model structures using the Framework for Understanding Structural Errors (FUSE). The resultant prediction uncertainties in upstream discharge provide uncertain boundary conditions that are cascaded into a simplified shallow water hydraulic model (LISFLOOD-FP). Rainfall data captured by three different measurement techniques - rain gauges, gridded radar data and numerical weather predictions (NWP) models are evaluated

  5. Double-Cascade Events from New Physics in Icecube

    Science.gov (United States)

    Coloma, Pilar; Machado, Pedro A. N.; Martinez-Soler, Ivan; Shoemaker, Ian M.

    2017-11-01

    A variety of new physics models allows for neutrinos to up-scatter into heavier states. If the incident neutrino is energetic enough, the heavy neutrino may travel some distance before decaying. In this work, we consider the atmospheric neutrino flux as a source of such events. At IceCube, this would lead to a "double-bang" (DB) event topology, similar to what is predicted to occur for tau neutrinos at ultrahigh energies. The DB event topology has an extremely low background rate from coincident atmospheric cascades, making this a distinctive signature of new physics. Our results indicate that IceCube should already be able to derive new competitive constraints on models with GeV-scale sterile neutrinos using existing data.

  6. Double-Cascade Events from New Physics in Icecube.

    Science.gov (United States)

    Coloma, Pilar; Machado, Pedro A N; Martinez-Soler, Ivan; Shoemaker, Ian M

    2017-11-17

    A variety of new physics models allows for neutrinos to up-scatter into heavier states. If the incident neutrino is energetic enough, the heavy neutrino may travel some distance before decaying. In this work, we consider the atmospheric neutrino flux as a source of such events. At IceCube, this would lead to a "double-bang" (DB) event topology, similar to what is predicted to occur for tau neutrinos at ultrahigh energies. The DB event topology has an extremely low background rate from coincident atmospheric cascades, making this a distinctive signature of new physics. Our results indicate that IceCube should already be able to derive new competitive constraints on models with GeV-scale sterile neutrinos using existing data.

  7. Power quality enhancement using cascaded multilevel inverter ...

    African Journals Online (AJOL)

    This paper investigates mitigation of current harmonics using different configuration of cascaded multilevel inverter based shunt hybrid active power filter (SHAPF) and to improve power quality of the system. The main objective of this paper is to develop and analyze the compensation characteristics of cascaded multilevel ...

  8. Cascading disaster models in postburn flash flood

    Science.gov (United States)

    Fred May

    2007-01-01

    A useful method of modeling threats from hazards and documenting their disaster causation sequences is called “cascading threat modeling.” This type of modeling enables emergency planners to address hazard and risk assessments systematically. This paper describes a cascading threat modeling and analysis process. Wildfire and an associated postburn flash flood disaster...

  9. Cascade Harvest’ red raspberry

    Science.gov (United States)

    Cascade Harvest’ is a new floricane fruiting raspberry cultivar (Rubus idaeus L.) jointly released by Washington State University (WSU), Oregon State University (OSU) and the U.S. Department of Agriculture (USDA). ‘Cascade Harvest’ produces a high yield of large, firm fruit suited to machine harves...

  10. Suppressing cascades of load in interdependent networks

    CERN Document Server

    Brummitt, Charles D; Leicht, E A

    2011-01-01

    Understanding how interdependence among systems affects cascading behaviors is increasingly important across many fields of science and engineering. Inspired by cascades of load shedding in coupled electric grids and other infrastructure, we study the Bak-Tang-Wiesenfeld sandpile model on modular random graphs and on graphs based on actual, interdependent power grids. Starting from two isolated networks, adding some connectivity between them is beneficial, for it suppresses the largest cascades in each system. Too much interconnectivity, however, becomes detrimental for two reasons. First, interconnections open pathways for neighboring networks to inflict large cascades. Second, as in real infrastructure, new interconnections increase capacity and total possible load, which fuels even larger cascades. Using a multi-type branching process and simulations we show these effects and estimate the optimal level of interconnectivity that balances their tradeoffs. Such equilibria could allow, for example, power grid ...

  11. MAPK cascades in guard cell signal transduction

    Directory of Open Access Journals (Sweden)

    Yuree eLee

    2016-02-01

    Full Text Available Guard cells form stomata on the epidermis and continuously respond to endogenous and environmental stimuli to fine-tune the gas exchange and transpirational water loss, processes which involve mitogen-activated protein kinase (MAPK cascades. MAPKs form three-tiered kinase cascades with MAPK kinases and MAPK kinase kinases, by which signals are transduced to the target proteins. MAPK cascade genes are highly conserved in all eukaryotes, and they play crucial roles in myriad developmental and physiological processes. MAPK cascades function during biotic and abiotic stress responses by linking extracellular signals received by receptors to cytosolic events and gene expression. In this review, we highlight recent findings and insights into MAPK-mediated guard cell signaling, including the specificity of MAPK cascades and the remaining questions.

  12. Experimental study of flow through compressor Cascade

    Directory of Open Access Journals (Sweden)

    Satyam Panchal

    2017-09-01

    Full Text Available The objective of this research work is to study the behaviour of flow at the inlet, within the blade passage and at the exit of a compressor cascade. For this purpose, a cascade with six numbers of aerofoil blades was designed and constructed. The cascade was fitted on the cascade test tunnel. Out of six blades two were instrumented for measuring the pressure distribution on the pressure and suction surface. The blades had a parabolic camber line, with a maximum camber position at 40% of the chord from the leading edge of the blade. The profile of the blade was C4, height of the blade was 160 mm, chord length was 80 mm, camber angle was 45° and stagger angle was 30°. Similarly, the length of the cascade was 300 mm, span was 160 mm, pitch was 60 mm, the actual chord of the cascade was 80 mm, the axial chord of the cascade was 70 mm, the stagger angle of the cascade was 30° and the pitch-chord ratio was 0.75. The data was taken and analyzed at −500% of the axial chord before the cascade, −25% of the axial chord before the leading edge, 25%, 50%, 75% and 150% of the axial chord from the leading edge of the blade. The readings were taken from the cascade wall to the mid span position along the pitch wise direction. The angle of incidence was also changed during the experiment and varied from i=−50°, −30°, −10° to 5°.

  13. Multi-elemental analysis of atmospheric pollutants and determination of particle size using the PIXE method, a cascade impactor and a filter unit constructed in Mexico; Analisis multielemental de contaminantes atmosfericos y determinacion de tamano de particula utilizando el metodo PIXE, un impactor de cascada y una unidad de filtro construidos en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Aldape U, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1989-01-15

    This work presents: 1) The methodology and the experimental conditions of the PIXE technique so that it is used as a better option inside the analytical methods in aerosols studies, 2) The development, tests and applications of a cascade impactor of the Batelle type built to determine particle size to use it jointly with the mentioned technique in the determination of the elements concentration according to its size.By this way is fulfilled with the first goal of this extensive project. (Author)

  14. Atmospheric Dispositifs

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2015-01-01

    Through the coupling of dispositif with atmosphere this paper engages in a discussion of the atmospherics as both a form of knowledge and a material practice. In doing so the objective is to provide an inventory of tools and methodologies deployed in the construction of atmosphere understood......, the conceptual foundations and protocols for the production of atmosphere in architecture might be found beneath the surface of contemporary debates. In this context, the notion of atmospheric dispositif – illustrated through an oeuvre of the German architect Werner Ruhnau and its theoretical and historical...

  15. SLAC T-510: Radio emission from particle cascades in the presence of a magnetic field

    Science.gov (United States)

    Mulrey, Katharine

    2017-03-01

    Cosmic ray induced particle cascades radiate in radio frequencies in the Earth's atmosphere. Geomagnetic and Askaryan emission provide an effective way to detect ultra-high energy cosmic rays. The SLAC T-510 experiment was the first to measure magnetically induced radiation from particle cascades in a controlled laboratory setting. An electron beam incident upon a dense dielectric target produced a particle cascade in the presence of a variable magnetic field. Antennas covering a band of 30-3000 MHz sampled RF emission in vertical and horizontal polarizations. Results from T-510 are compared to particle-level RF-emission simulations which are critical for reconstructing the energy and composition of detected ultra-high energy cosmic ray air showers. We discuss the experimental set up, the data processing, the systematic errors and the main results of the experiment, which we found in a good agreement with the simulations.

  16. Power scaling of high-efficiency 1.5 μm cascaded Raman fiber lasers.

    Science.gov (United States)

    Supradeepa, V R; Nicholson, Jeffrey W

    2013-07-15

    High-power fiber lasers operating at the 1.5 μm wavelength region have attractive features, such as eye safety and atmospheric transparency, and cascaded Raman fiber lasers offer a convenient method to obtain high-power sources at these wavelengths. A limitation to power scaling, however, has been the lower conversion efficiency of these lasers. We recently introduced a high-efficiency architecture for high-power cascaded Raman fiber lasers applicable for 1.5 μm fiber lasers. Here we demonstrate further power scaling using this new architecture. Using numerical simulations, we identify the ideal operating conditions for the new architecture. We demonstrate a high-efficiency 1480 nm cascaded Raman fiber laser with an output power of 301 W, comparable to record power levels achieved with rare-earth-doped fiber lasers in the 1.5 μm wavelength region.

  17. MAPK cascade signalling networks in plant defence.

    Science.gov (United States)

    Pitzschke, Andrea; Schikora, Adam; Hirt, Heribert

    2009-08-01

    The sensing of stress signals and their transduction into appropriate responses is crucial for the adaptation and survival of plants. Kinase cascades of the mitogen-activated protein kinase (MAPK) class play a remarkably important role in plant signalling of a variety of abiotic and biotic stresses. MAPK cascade-mediated signalling is an essential step in the establishment of resistance to pathogens. Here, we describe the most recent insights into MAPK-mediated pathogen defence response regulation with a particular focus on the cascades involving MPK3, MPK4 and MPK6. We also discuss the strategies developed by plant pathogens to circumvent, inactivate or even 'hijack' MAPK-mediated defence responses.

  18. Mount Rainier active cascade volcano

    Science.gov (United States)

    1994-01-01

    Mount Rainier is one of about two dozen active or recently active volcanoes in the Cascade Range, an arc of volcanoes in the northwestern United States and Canada. The volcano is located about 35 kilometers southeast of the Seattle-Tacoma metropolitan area, which has a population of more than 2.5 million. This metropolitan area is the high technology industrial center of the Pacific Northwest and one of the commercial aircraft manufacturing centers of the United States. The rivers draining the volcano empty into Puget Sound, which has two major shipping ports, and into the Columbia River, a major shipping lane and home to approximately a million people in southwestern Washington and northwestern Oregon. Mount Rainier is an active volcano. It last erupted approximately 150 years ago, and numerous large floods and debris flows have been generated on its slopes during this century. More than 100,000 people live on the extensive mudflow deposits that have filled the rivers and valleys draining the volcano during the past 10,000 years. A major volcanic eruption or debris flow could kill thousands of residents and cripple the economy of the Pacific Northwest. Despite the potential for such danger, Mount Rainier has received little study. Most of the geologic work on Mount Rainier was done more than two decades ago. Fundamental topics such as the development, history, and stability of the volcano are poorly understood.

  19. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily exper......” implications and qualities of the approach are identified through concrete examples of a design case, which also investigates the qualities and implications of addressing atmospheres both as design concern and user experience.......This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...... experience in space, presented as middle ground experience. In the field of HCI, middle ground experiences complete the unarticulated spectrum between designing for foreground of attention or background awareness. When “Articulating Atmospheres through Middle Ground Experiences in Interaction Design...

  20. Resilience and Regime Shifts: Assessing Cascading Effects

    National Research Council Canada - National Science Library

    Kinzig, Ann P; Ryan, Paul; Etienne, Michel; Allison, Helen; Elmqvist, Thomas; Walker, Brian H

    2006-01-01

    .... "Cascading thresholds," i.e., the tendency of the crossing of one threshold to induce the crossing of other thresholds, often lead to very resilient, although often less desirable, alternative states.

  1. Substrate-emitting ring interband cascade lasers

    Science.gov (United States)

    Holzbauer, Martin; Szedlak, Rolf; Detz, Hermann; Weih, Robert; Höfling, Sven; Schrenk, Werner; Koeth, Johannes; Strasser, Gottfried

    2017-10-01

    We demonstrate interband cascade lasers fabricated into ring-shaped cavities with vertical light emission through the substrate at a wavelength of λ ≈ 3.7 μm. The out-coupling mechanism is based on a metallized second-order distributed feedback grating. At room-temperature, a pulsed threshold current-density of 0.75 kA/cm2 and a temperature-tuning rate of 0.3 nm/°C are measured. In contrast to the azimuthal polarization of ring quantum cascade lasers, we observe a radial polarization of the projected nearfield of ring interband cascade lasers. These findings underline the fundamental physical difference between light generation in interband and intersubband cascade lasers, offering new perspectives for device integration.

  2. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  3. Atmospheric Neutrinos

    Directory of Open Access Journals (Sweden)

    Takaaki Kajita

    2012-01-01

    Full Text Available Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses atmospheric neutrino experiments and the neutrino oscillation studies with these neutrinos.

  4. Compression limits in cascaded quadratic soliton compression

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Krolikowski, Wieslaw

    2008-01-01

    Cascaded quadratic soliton compressors generate under optimal conditions few-cycle pulses. Using theory and numerical simulations in a nonlinear crystal suitable for high-energy pulse compression, we address the limits to the compression quality and efficiency.......Cascaded quadratic soliton compressors generate under optimal conditions few-cycle pulses. Using theory and numerical simulations in a nonlinear crystal suitable for high-energy pulse compression, we address the limits to the compression quality and efficiency....

  5. Cascade of links in complex networks

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yeqian; Sun, Bihui [Department of Management Science, School of Government, Beijing Normal University, 100875 Beijing (China); Zeng, An, E-mail: anzeng@bnu.edu.cn [School of Systems Science, Beijing Normal University, 100875 Beijing (China)

    2017-01-30

    Cascading failure is an important process which has been widely used to model catastrophic events such as blackouts and financial crisis in real systems. However, so far most of the studies in the literature focus on the cascading process on nodes, leaving the possibility of link cascade overlooked. In many real cases, the catastrophic events are actually formed by the successive disappearance of links. Examples exist in the financial systems where the firms and banks (i.e. nodes) still exist but many financial trades (i.e. links) are gone during the crisis, and the air transportation systems where the airports (i.e. nodes) are still functional but many airlines (i.e. links) stop operating during bad weather. In this letter, we develop a link cascade model in complex networks. With this model, we find that both artificial and real networks tend to collapse even if a few links are initially attacked. However, the link cascading process can be effectively terminated by setting a few strong nodes in the network which do not respond to any link reduction. Finally, a simulated annealing algorithm is used to optimize the location of these strong nodes, which significantly improves the robustness of the networks against the link cascade. - Highlights: • We propose a link cascade model in complex networks. • Both artificial and real networks tend to collapse even if a few links are initially attacked. • The link cascading process can be effectively terminated by setting a few strong nodes. • A simulated annealing algorithm is used to optimize the location of these strong nodes.

  6. Urban atmospheres.

    Science.gov (United States)

    Gandy, Matthew

    2017-07-01

    What is an urban atmosphere? How can we differentiate an 'atmosphere' from other facets of urban consciousness and experience? This essay explores some of the wider cultural, political, and philosophical connotations of atmospheres as a focal point for critical reflections on space and subjectivity. The idea of an 'affective atmosphere' as a distinctive kind of mood or shared corporeal phenomenon is considered in relation to recent developments in phenomenology, extended conceptions of agency, and new understandings of materialism. The essay draws in particular on the changing characteristics of air and light to reflect on different forms of sensory experience and their wider cultural and political connotations. The argument highlights some of the tensions and anomalies that permeate contemporary understandings of urban atmospheres.

  7. Robustness of localized DNA strand displacement cascades.

    Science.gov (United States)

    Teichmann, Mario; Kopperger, Enzo; Simmel, Friedrich C

    2014-08-26

    Colocalization can strongly alter the kinetics and efficiency of chemical processes. For instance, in DNA-templated synthesis unfavorable reactions are sped up by placing reactants into close proximity onto a DNA scaffold. In biochemistry, clustering of enzymes has been demonstrated to enhance the reaction flux through some enzymatic cascades. Here we investigate the effect of colocalization on the performance of DNA strand displacement (DSD) reactions, an important class of reactions utilized in dynamic DNA nanotechnology. We study colocalization by immobilizing a two-stage DSD reaction cascade comprised of a “sender” and a “receiver” gate onto a DNA origami platform. The addition of a DNA (or RNA) input strand displaces a signal strand from the sender gate, which can then transfer to the receiver gate. The performance of the cascade is found to vary strongly with the distance between the gates. A cascade with an intermediate gate distance of ≈20 nm exhibits faster kinetics than those with larger distances, whereas a cascade with smaller distance is corrupted by excessive intraorigami leak reactions. The 20 nm cascade is found to be considerably more robust with respect to a competing reaction, and implementation of multiple receiver gates further increases this robustness. Our results indicate that for the 20 nm distance a fraction of signal strands is transferred locally to a receiver gate on the same platform, probably involving direct physical contact between the gates. The performance of the cascade is consistent with a simple model that takes “local” and “global” transfer processes into account.

  8. Atmospheric Infancy

    DEFF Research Database (Denmark)

    Roald, Tone; Pedersen, Ida Egmose; Levin, Kasper

    2017-01-01

    In this article we establish intersubjective meaning-making in infancy as atmospheric. Through qualitative descriptions of five mother–infant dyads in a video-recorded, experimental setting when the infant is 4, 7, 10, and 13 months, we discovered atmospheric appearances with a developmental...... pattern of atmospheric variations. These appearances, we argue, are contextual and intersubjective monologues. The monologues are similar to what Daniel Stern describes with his concept of “vitality affects,” but they arise as a unified force that envelops the mother and child. As such, we present a new...

  9. MAP kinase cascades in Arabidopsis innate immunity

    DEFF Research Database (Denmark)

    Rasmussen, Magnus Wohlfahrt; Roux, Milena Edna; Petersen, Morten

    2012-01-01

    Plant mitogen-activated protein kinase (MAPK) cascades generally transduce extracellular stimuli into cellular responses. These stimuli include the perception of pathogen-associated molecular patterns (PAMPs) by host transmembrane pattern recognition receptors which trigger MAPK-dependent innate...... immune responses. In the model Arabidopsis, molecular genetic evidence implicates a number of MAPK cascade components in PAMP signaling, and in responses to immunity-related phytohormones such as ethylene, jasmonate, and salicylate. In a few cases, cascade components have been directly linked...... to the transcription of target genes or to the regulation of phytohormone synthesis. Thus MAPKs are obvious targets for bacterial effector proteins and are likely guardees of resistance proteins, which mediate defense signaling in response to the action of effectors, or effector-triggered immunity. This mini...

  10. Bifurcations analysis of turbulent energy cascade

    Energy Technology Data Exchange (ETDEWEB)

    Divitiis, Nicola de, E-mail: n.dedivitiis@gmail.com

    2015-03-15

    This note studies the mechanism of turbulent energy cascade through an opportune bifurcations analysis of the Navier–Stokes equations, and furnishes explanations on the more significant characteristics of the turbulence. A statistical bifurcations property of the Navier–Stokes equations in fully developed turbulence is proposed, and a spatial representation of the bifurcations is presented, which is based on a proper definition of the fixed points of the velocity field. The analysis first shows that the local deformation can be much more rapid than the fluid state variables, then explains the mechanism of energy cascade through the aforementioned property of the bifurcations, and gives reasonable argumentation of the fact that the bifurcations cascade can be expressed in terms of length scales. Furthermore, the study analyzes the characteristic length scales at the transition through global properties of the bifurcations, and estimates the order of magnitude of the critical Taylor-scale Reynolds number and the number of bifurcations at the onset of turbulence.

  11. Seeded QED cascades in counterpropagating laser pulses.

    Science.gov (United States)

    Grismayer, T; Vranic, M; Martins, J L; Fonseca, R A; Silva, L O

    2017-02-01

    The growth rates of seeded QED cascades in counterpropagating lasers are calculated with first-principles two- and three-dimensional QED-PIC (particle-in-cell) simulations. The dependence of the growth rate on the laser polarization and intensity is compared with analytical models that support the findings of the simulations. The models provide insight regarding the qualitative trend of the cascade growth when the intensity of the laser field is varied. A discussion about the cascade's threshold is included, based on the analytical and numerical results. These results show that relativistic pair plasmas and efficient conversion from laser photons to γ rays can be observed with the typical intensities planned to operate on future ultraintense laser facilities such as ELI or Vulcan.

  12. Emergence of event cascades in inhomogeneous networks

    CERN Document Server

    Onaga, Tomokatsu

    2016-01-01

    There is a commonality among contagious diseases, tweets, urban crimes, nuclear reactions, and neuronal firings that past events facilitate the future occurrence of events. The spread of events has been extensively studied such that the systems exhibit catastrophic chain reactions if the interaction represented by the ratio of reproduction exceeds unity; however, their subthreshold states for the case of the weaker interaction are not fully understood. Here, we report that these systems are possessed by nonstationary cascades of event-occurrences already in the subthreshold regime. Event cascades can be harmful in some contexts, when the peak-demand causes vaccine shortages, heavy traffic on communication lines, frequent crimes, or large fluctuations in nuclear reactions, but may be beneficial in other contexts, such that spontaneous activity in neural networks may be used to generate motion or store memory. Thus it is important to comprehend the mechanism by which such cascades appear, and consider controlli...

  13. Epidemic and Cascading Survivability of Complex Networks

    DEFF Research Database (Denmark)

    Manzano, Marc; Calle, Eusebi; Ripoll, Jordi

    2014-01-01

    Our society nowadays is governed by complex networks, examples being the power grids, telecommunication networks, biological networks, and social networks. It has become of paramount importance to understand and characterize the dynamic events (e.g. failures) that might happen in these complex...... networks. For this reason, in this paper, we propose two measures to evaluate the vulnerability of complex networks in two different dynamic multiple failure scenarios: epidemic-like and cascading failures. Firstly, we present epidemic survivability ( ES ), a new network measure that describes...... the vulnerability of each node of a network under a specific epidemic intensity. Secondly, we propose cascading survivability ( CS ), which characterizes how potentially injurious a node is according to a cascading failure scenario. Then, we show that by using the distribution of values obtained from ES and CS...

  14. Epidemic and Cascading Survivability of Complex Networks

    CERN Document Server

    Manzano, Marc; Ripoll, Jordi; Fagertun, Anna Manolova; Torres-Padrosa, Victor; Pahwa, Sakshi; Scoglio, Caterina

    2014-01-01

    Our society nowadays is governed by complex networks, examples being the power grids, telecommunication networks, biological networks, and social networks. It has become of paramount importance to understand and characterize the dynamic events (e.g. failures) that might happen in these complex networks. For this reason, in this paper, we propose two measures to evaluate the vulnerability of complex networks in two different dynamic multiple failure scenarios: epidemic-like and cascading failures. Firstly, we present \\emph{epidemic survivability} ($ES$), a new network measure that describes the vulnerability of each node of a network under a specific epidemic intensity. Secondly, we propose \\emph{cascading survivability} ($CS$), which characterizes how potentially injurious a node is according to a cascading failure scenario. Then, we show that by using the distribution of values obtained from $ES$ and $CS$ it is possible to describe the vulnerability of a given network. We consider a set of 17 different compl...

  15. Piscivores, Trophic Cascades, and Lake Management

    Directory of Open Access Journals (Sweden)

    Ray W. Drenner

    2002-01-01

    Full Text Available The concept of cascading trophic interactions predicts that an increase in piscivore biomass in lakes will result in decreased planktivorous fish biomass, increased herbivorous zooplankton biomass, and decreased phytoplankton biomass. Though often accepted as a paradigm in the ecological literature and adopted by lake managers as a basis for lake management strategies, the trophic cascading interactions hypothesis has not received the unequivocal support (in the form of rigorous experimental testing that might be expected of a paradigm. Here we review field experiments and surveys, testing the hypothesis that effects of increasing piscivore biomass will cascade down through the food web yielding a decline in phytoplankton biomass. We found 39 studies in the scientific literature examining piscivore effects on phytoplankton biomass. Of the studies, 22 were confounded by supplemental manipulations (e.g., simultaneous reduction of nutrients or removal of planktivores and could not be used to assess piscivore effects. Of the 17 nonconfounded studies, most did not find piscivore effects on phytoplankton biomass and therefore did not support the trophic cascading interactions hypothesis. However, the trophic cascading interactions hypothesis also predicts that lake systems containing piscivores will have lower phytoplankton biomass for any given phosphorus concentration. Based on regression analyses of chlorophyll�total phosphorus relationships in the 17 nonconfounded piscivore studies, this aspect of the trophic cascading interactions hypothesis was supported. The slope of the chlorophyll vs. total phosphorus regression was lower in lakes with planktivores and piscivores compared with lakes containing only planktivores but no piscivores. We hypothesize that this slope can be used as an indicator of “functional piscivory” and that communities with extremes of functional piscivory (zero and very high represent classical 3- and 4-trophic level

  16. Volcano geodesy in the Cascade arc, USA

    Science.gov (United States)

    Poland, Michael; Lisowski, Michael; Dzurisin, Daniel; Kramer, Rebecca; McLay, Megan; Pauk, Benjamin

    2017-01-01

    Experience during historical time throughout the Cascade arc and the lack of deep-seated deformation prior to the two most recent eruptions of Mount St. Helens might lead one to infer that Cascade volcanoes are generally quiescent and, specifically, show no signs of geodetic change until they are about to erupt. Several decades of geodetic data, however, tell a different story. Ground- and space-based deformation studies have identified surface displacements at five of the 13 major Cascade arc volcanoes that lie in the USA (Mount Baker, Mount St. Helens, South Sister, Medicine Lake, and Lassen volcanic center). No deformation has been detected at five volcanoes (Mount Rainier, Mount Hood, Newberry Volcano, Crater Lake, and Mount Shasta), and there are not sufficient data at the remaining three (Glacier Peak, Mount Adams, and Mount Jefferson) for a rigorous assessment. In addition, gravity change has been measured at two of the three locations where surveys have been repeated (Mount St. Helens and Mount Baker show changes, while South Sister does not). Broad deformation patterns associated with heavily forested and ice-clad Cascade volcanoes are generally characterized by low displacement rates, in the range of millimeters to a few centimeters per year, and are overprinted by larger tectonic motions of several centimeters per year. Continuous GPS is therefore the best means of tracking temporal changes in deformation of Cascade volcanoes and also for characterizing tectonic signals so that they may be distinguished from volcanic sources. Better spatial resolution of volcano deformation can be obtained through the use of campaign GPS, semipermanent GPS, and interferometric synthetic aperture radar observations, which leverage the accumulation of displacements over time to improve signal to noise. Deformation source mechanisms in the Cascades are diverse and include magma accumulation and withdrawal, post-emplacement cooling of recent volcanic deposits, magmatic

  17. Cascade morphology transition in bcc metals.

    Science.gov (United States)

    Setyawan, Wahyu; Selby, Aaron P; Juslin, Niklas; Stoller, Roger E; Wirth, Brian D; Kurtz, Richard J

    2015-06-10

    Energetic atom collisions in solids induce shockwaves with complex morphologies. In this paper, we establish the existence of a morphological transition in such cascades. The order parameter of the morphology is defined as the exponent, b, in the defect production curve as a function of cascade energy (N(F) ~ E(MD)(b)). Response of different bcc metals can be compared in a consistent energy domain when the energy is normalized by the transition energy, μ, between the high- and the low-energy regime. Using Cr, Fe, Mo and W data, an empirical formula of μ as a function of displacement threshold energy, E(d), is presented for bcc metals.

  18. Cascade morphology transition in bcc metals

    OpenAIRE

    Setyawan, Wahyu; Selby, Aaron P.; Juslin, Niklas; Stoller, Roger E; Wirth, Brian D.; Kurtz, Richard J.

    2014-01-01

    Energetic atom collisions in solids induce shockwaves with complex morphologies. In this paper, we establish the existence of a morphological transition in such cascades. The order parameter of the morphology is defined as the exponent, $b$, in the defect production curve as a function of cascade energy ($N_F \\sim E_{MD}^b$). Response of different bcc metals can be compared in a consistent energy domain when the energy is normalized by the transition energy, $\\mu$, between the high- and the l...

  19. Robustness of networks against cascading failures

    Science.gov (United States)

    Dou, Bing-Lin; Wang, Xue-Guang; Zhang, Shi-Yong

    2010-06-01

    Inspired by other related works, this paper proposes a non-linear load-capacity model against cascading failures, which is more suitable for real networks. The simulation was executed on the B-A scale-free network, E-R random network, Internet AS level network, and the power grid of the western United States. The results show that the model is feasible and effective. By studying the relationship between network cost and robustness, we find that the model can defend against cascading failures better and requires a lower investment cost when higher robustness is required.

  20. Robustness of network controllability in cascading failure

    Science.gov (United States)

    Chen, Shi-Ming; Xu, Yun-Fei; Nie, Sen

    2017-04-01

    It is demonstrated that controlling complex networks in practice needs more inputs than that predicted by the structural controllability framework. Besides, considering the networks usually faces to the external or internal failure, we define parameters to evaluate the control cost and the variation of controllability after cascades, exploring the effect of number of control inputs on the controllability for random networks and scale-free networks in the process of cascading failure. For different topological networks, the results show that the robustness of controllability will be stronger through allocating different control inputs and edge capacity.

  1. Volcano geodesy in the Cascade arc, USA

    Science.gov (United States)

    Poland, Michael P.; Lisowski, Michael; Dzurisin, Daniel; Kramer, Rebecca; McLay, Megan; Pauk, Ben

    2017-08-01

    Experience during historical time throughout the Cascade arc and the lack of deep-seated deformation prior to the two most recent eruptions of Mount St. Helens might lead one to infer that Cascade volcanoes are generally quiescent and, specifically, show no signs of geodetic change until they are about to erupt. Several decades of geodetic data, however, tell a different story. Ground- and space-based deformation studies have identified surface displacements at five of the 13 major Cascade arc volcanoes that lie in the USA (Mount Baker, Mount St. Helens, South Sister, Medicine Lake, and Lassen volcanic center). No deformation has been detected at five volcanoes (Mount Rainier, Mount Hood, Newberry Volcano, Crater Lake, and Mount Shasta), and there are not sufficient data at the remaining three (Glacier Peak, Mount Adams, and Mount Jefferson) for a rigorous assessment. In addition, gravity change has been measured at two of the three locations where surveys have been repeated (Mount St. Helens and Mount Baker show changes, while South Sister does not). Broad deformation patterns associated with heavily forested and ice-clad Cascade volcanoes are generally characterized by low displacement rates, in the range of millimeters to a few centimeters per year, and are overprinted by larger tectonic motions of several centimeters per year. Continuous GPS is therefore the best means of tracking temporal changes in deformation of Cascade volcanoes and also for characterizing tectonic signals so that they may be distinguished from volcanic sources. Better spatial resolution of volcano deformation can be obtained through the use of campaign GPS, semipermanent GPS, and interferometric synthetic aperture radar observations, which leverage the accumulation of displacements over time to improve signal to noise. Deformation source mechanisms in the Cascades are diverse and include magma accumulation and withdrawal, post-emplacement cooling of recent volcanic deposits, magmatic

  2. Atmospheric neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kajita, Takaaki [Research Center for Cosmic Neutrinos, Institute for Cosmic Ray Research, University of Tokyo, Kashiwa-no-ha 5-1-5, Kashiwa, Chiba 277-8582 (Japan)

    2004-12-01

    Neutrino oscillation was discovered through the study of atmospheric neutrinos. Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron neutrinos and muon neutrinos are produced mainly by the decay chain of charged pions to muons and electrons. Depending on the energy of the neutrinos, atmospheric neutrinos are observed as fully contained events, partially contained events and upward-going muon events. The energy range covered by these events is from a few hundred MeV to >1 TeV. Data from various experiments showed zenith angle- and energy-dependent deficit of {nu}{sub {mu}} events, while {nu}{sub e} events did not show any such effect. It was also shown that the {nu}{sub {mu}} survival probability obeys the sinusoidal function as predicted by neutrino oscillations. Two-flavour {nu}{sub {mu}} {r_reversible} {nu}{sub {tau}} oscillations, with sin{sup 2} 2{theta} > 0.90 and {delta}m{sup 2} in the region of 1.9 x 10{sup -3} to 3.0 x 10{sup -3} eV{sup 2}, explain all these data. Various detailed studies using high statistics atmospheric neutrino data excluded the alternative hypotheses that were proposed to explain the {nu}{sub {mu}} deficit.

  3. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  4. Gene regulation by MAP kinase cascades

    DEFF Research Database (Denmark)

    Fiil, Berthe Katrine; Petersen, Klaus; Petersen, Morten

    2009-01-01

    Mitogen-activated protein kinase (MAPK) cascades are signaling modules that transduce extracellular stimuli to a range of cellular responses. Research in yeast and metazoans has shown that MAPK-mediated phosphorylation directly or indirectly regulates the activity of transcription factors. Plant ...... gene expression....

  5. Multilevel Inverter by Cascading Industrial VSI

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede; Pedersen, John Kim

    2002-01-01

    by a standard triphase IGBT inverter module. Thus, a high fault tolerance is being achieved and the output transformer requirement is eliminated. A staggered space-vector modulation technique applicable to three-phase cascaded voltage-source inverter topologies is also demonstrated. Both computer simulations...

  6. Criticality in a cascading failure blackout model

    Energy Technology Data Exchange (ETDEWEB)

    Nedic, Dusko P.; Kirschen, Daniel S. [University of Manchester (United Kingdom). School of Electrical and Electronic Engineering; Dobson, Ian [University of Wisconsin, Madison, WI (United States). ECE Department; Carreras, Benjamin A.; Lynch, Vickie E. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2006-11-15

    We verify and examine criticality in a 1000 bus network with an AC blackout model that represents many of the interactions that occur in cascading failure. At the critical loading there is a sharp rise in the mean blackout size and a power law probability distribution of blackout size that indicates a significant risk of large blackouts. (author)

  7. Geothermal research, Oregon Cascades: Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Priest, G.R.; Black, G.L.

    1988-10-27

    Previous USDOE-funded geothermal studies have produced an extensive temperature gradient and heat flow data base for the State of Oregon. One of the important features identified as a result of these studies is a rapid transition from heat flow values on the order of 40 mW/m/sup 2/ in the Willamette Valley and Western Cascades to values of greater than or equal to100 mW/m/sup 2/ in the High Cascades and the eastern portion of the Western Cascades. These data indicate that the Cascade Range in Oregon has potential as a major geothermal province and stimulated much of the later work completed by government agencies and private industry. Additional data generated as a result of this grant and published in DOGAMI Open-File Report 0-86-2 further define the location and magnitude of this transition zone. In addition, abundant data collected from the vicinity of Breitenbush and Austin Hot Springs have permitted the formulation of relatively detailed models of these hydrothermal systems. These models are published in DOGAMI Open-File Report 0-88-5. Task 1.2 of the Deliverables section of Amendment M001 is fulfilled by DOGAMI publication GMS-48, Geologic map of the McKenzie Bridge quadrangle, Lane County, Oregon. This map was printed in October, 1988, and is part of the final submission to USDOE. 8 refs.

  8. The Attention Cascade Model and Attentional Blink

    Science.gov (United States)

    Shih, Shui-I

    2008-01-01

    An attention cascade model is proposed to account for attentional blinks in rapid serial visual presentation (RSVP) of stimuli. Data were collected using single characters in a single RSVP stream at 10 Hz [Shih, S., & Reeves, A. (2007). "Attentional capture in rapid serial visual presentation." "Spatial Vision", 20(4), 301-315], and single words,…

  9. Quantum Cascade Lasers in Biomedical Infrared Imaging.

    Science.gov (United States)

    Bird, Benjamin; Baker, Matthew J

    2015-10-01

    Technological advances, namely the integration of quantum cascade lasers (QCLs) within an infrared (IR) microscope, are enabling the development of valuable label-free biomedical-imaging tools capable of targeting and detecting salient chemical species within practical clinical timeframes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Nonconforming finite elements and the Cascade iteration

    NARCIS (Netherlands)

    Stevenson, R.

    1999-01-01

    We derive sucient conditions under which the Cascade iteration applied to nonconforming nite element discretizations yields an optimal solver. Key ingredients are optimal error estimates of such discretizations, which we therefore study in detail. We derive a new, ecient modied Morley nite element

  11. Cascade Training and Teachers' Professional Development.

    Science.gov (United States)

    Hayes, David

    2000-01-01

    Examines the experience of a nationwide inservice teacher development project in Sri Lanka that aims to remedy the potential deficiencies of cascade models of teacher development. Shows how project training and development strategies that are context sensitive, collaborative, and reflexive seek to involve teachers in managing their own…

  12. Cascading effects of overfishing marine systems

    NARCIS (Netherlands)

    Scheffer, M.; Carpenter, S.; Young, de B.

    2005-01-01

    Profound indirect ecosystem effects of overfishing have been shown for coastal systems such as coral reefs and kelp forests. A new study from the ecosystem off the Canadian east coast now reveals that the elimination of large predatory fish can also cause marked cascading effects on the pelagic food

  13. Modeling and simulation of cascading contingencies

    Science.gov (United States)

    Zhang, Jianfeng

    This dissertation proposes a new approach to model and study cascading contingencies in large power systems. The most important contribution of the work involves the development and validation of a heuristic analytic model to assess the likelihood of cascading contingencies, and the development and validation of a uniform search strategy. We model the probability of cascading contingencies as a function of power flow and power flow changes. Utilizing logistic regression, the proposed model is calibrated using real industry data. This dissertation analyzes random search strategies for Monte Carlo simulations and proposes a new uniform search strategy based on the Metropolis-Hastings Algorithm. The proposed search strategy is capable of selecting the most significant cascading contingencies, and it is capable of constructing an unbiased estimator to provide a measure of system security. This dissertation makes it possible to reasonably quantify system security and justify security operations when economic concerns conflict with reliability concerns in the new competitive power market environment. It can also provide guidance to system operators about actions that may be taken to reduce the risk of major system blackouts. Various applications can be developed to take advantage of the quantitative security measures provided in this dissertation.

  14. Source Tracking of Nitrous Oxide using A Quantum Cascade ...

    Science.gov (United States)

    Nitrous oxide is an important greenhouse gas and ozone depleting substance. Nitrification and denitrification are two major biological pathways that are responsible for soil emissions of N2O. However, source tracking of in-situ or laboratory N2O production is still challenging to soil scientists. The objective of this study was to introduce the use of a new technology, quantum cascade laser (QCL) spectroscopy, which allows for significantly improved accuracy and precision to continuously measure real-time N2O for source tracking. This data provides important emission inventory information to air quality and atmospheric chemistry models. The task demonstrated that QCL spectroscopy can measure the flux of nitrous oxide at ambient and well as elevated concentrations in real time. The fractionation of the nitrous oxide produced by microbial processing of nitrate can be measured and characterized as isotopic signatures related to the nitrifying or denitrifying state of the microbial communities. This has important implications for monitoring trace gases in the atmosphere. The data produced by this system will provide clients including the air quality and climate change communities with needed information on the sources and strengths of N2O emissions for modeling and research into mitigation strategies to reduce overall GHG emissions in agricultural systems.

  15. Cascade theory in isotopic separation processes; Theorie des cascades en separation isotopique

    Energy Technology Data Exchange (ETDEWEB)

    Agostini, J.P.

    1994-06-01

    Three main areas are developed within the scope of this work: - the first one is devoted to fundamentals: separative power, value function, ideal cascade and square cascade. Applications to two main cases are carried out, namely: Study of binary isotopic mix, Study of processes with a small enrichment coefficient. - The second one is devoted to cascade coupling -high-flux coupling (more widely used and better known) as well as low-flux coupling are presented and compared to one another. - The third one is an outlook on problems linked to cascade transients. Those problem are somewhat intricate and their interest lies mainly into two areas: economics where the start-up time may have a large influence on the interests paid during the construction and start-up period, military productions where the start-up time has a direct bearing on the production schedule. (author). 50 figs. 3 annexes. 12 refs. 6 tabs.

  16. Higher-order Kerr effect and harmonic cascading in gases

    OpenAIRE

    Bache, Morten; Eilenberger, Falk; Minardi, Stefano

    2012-01-01

    The higher-order Kerr effect (HOKE) has recently been advocated to explain measurements of the saturation of the nonlinear refractive index in gases. Here we show that cascaded third-harmonic generation results in an effective fifth-order nonlinearity that is negative and significant. Higher-order harmonic cascading will also occur from the HOKE, and the cascading contributions may significantly modify the observed nonlinear index change. At lower wavelengths, cascading increases the HOKE sat...

  17. A Modeling Framework for System Restoration from Cascading Failures

    OpenAIRE

    Chaoran Liu; Daqing Li; Enrico Zio; Rui Kang

    2014-01-01

    System restoration from cascading failures is an integral part of the overall defense against catastrophic breakdown in networked critical infrastructures. From the outbreak of cascading failures to the system complete breakdown, actions can be taken to prevent failure propagation through the entire network. While most analysis efforts have been carried out before or after cascading failures, restoration during cascading failures has been rarely studied. In this paper, we present a modeling f...

  18. Exploring cascading outages and weather via processing historic data

    OpenAIRE

    Dobson, Ian; Carrington, NichelleLe K.; Zhou, Kai; Wang, Zhaoyu; Carreras, Benjamin A.; Reynolds-Barredo, Jose M.

    2017-01-01

    We describe some bulk statistics of historical initial line outages and the implications for forming contingency lists and understanding which initial outages are likely to lead to further cascading. We use historical outage data to estimate the effect of weather on cascading via cause codes and via NOAA storm data. Bad weather significantly increases outage rates and interacts with cascading effects, and should be accounted for in cascading models and simulations. We suggest how weather effe...

  19. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    Nurses working in the Neuro-Intensive Care Unit at Aarhus University Hospital lack the tools to prepare children for the alarming atmosphere they will enter when visiting a hospitalised relative. The complex soundscape dominated by alarms and sounds from equipment is mentioned as the main stressor...

  20. Atmospheric humidity

    Science.gov (United States)

    Water vapor plays a critical role in earth's atmosphere. It helps to maintain a habitable surface temperature through absorption of outgoing longwave radiation, and it transfers trmendous amounts of energy from the tropics toward the poles by absorbing latent heat during evaporation and subsequently...

  1. Calculation of transonic flow in radial turbine blade cascade

    Science.gov (United States)

    Petr, Straka

    2017-09-01

    Numerical modeling of transonic centripetal turbulent flow in radial blade cascade is described in this paper. Attention is paid to effect of the outlet confusor on flow through the radial blade cascade. Parameters of presented radial blade cascade are compared with its linear representation

  2. Hollow Anode Cascading Plasma Focus | Alabraba | Journal of the ...

    African Journals Online (AJOL)

    Journal of the Nigerian Association of Mathematical Physics ... Using the 3-phase model for each focus event, the 9-phase, two solid disc auxiliary anode cascading plasma focus has been extended to include holes at the center of each cascade anode (hereafter referred to as hollow anode cascading focus) with a view of ...

  3. Higher-order Kerr effect and harmonic cascading in gases

    DEFF Research Database (Denmark)

    Bache, Morten; Eilenberger, Falk; Minardi, Stefano

    2012-01-01

    The higher-order Kerr effect (HOKE) has recently been advocated to explain measurements of the saturation of the nonlinear refractive index in gases. Here we show that cascaded third-harmonic generation results in an effective fifth-order nonlinearity that is negative and significant. Higher......-order harmonic cascading will also occur from the HOKE, and the cascading contributions may significantly modify the observed nonlinear index change. At lower wavelengths, cascading increases the HOKE saturation intensity, while for longer wavelengths cascading will decrease the HOKE saturation intensity....

  4. Higher-order Kerr effect and harmonic cascading in gases.

    Science.gov (United States)

    Bache, Morten; Eilenberger, Falk; Minardi, Stefano

    2012-11-15

    The higher-order Kerr effect (HOKE) has recently been advocated to explain measurements of the saturation of the nonlinear refractive index in gases. Here we show that cascaded third-harmonic generation results in an effective fifth-order nonlinearity that is negative and significant. Higher-order harmonic cascading will also occur from the HOKE, and the cascading contributions may significantly modify the observed nonlinear index change. At lower wavelengths, cascading increases the HOKE saturation intensity, while for longer wavelengths cascading will decrease the HOKE saturation intensity.

  5. Atmospheric materiality

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2016-01-01

    A disjunction between the material and the immaterial has been at the heart of the architectural debate for decades. In this dialectic tension, the notion of atmosphere which increasingly claims attention in architectural discourse seems to be parallactic, leading to the re-evaluation of perceptual...... experience and, consequently, to the conceptual and methodological shifts in the production of space, and hence in the way we think about materiality. In this context, architectural space is understood as a contingent construction – a space of engagement that appears to us as a result of continuous...... and complex interferences revealed through our perception; ‘the atmospheric’ is explored as a spatial and affective quality as well as a sensory background, and materiality as a powerful and almost magical agency in shaping of atmosphere. Challenging existing dichotomies and unraveling intrinsic...

  6. A sulfur hexafluoride sensor using quantum cascade and CO2 laser-based photoacoustic spectroscopy.

    Science.gov (United States)

    Rocha, Mila; Sthel, Marcelo; Lima, Guilherme; da Silva, Marcelo; Schramm, Delson; Miklós, András; Vargas, Helion

    2010-01-01

    The increase in greenhouse gas emissions is a serious environmental problem and has stimulated the scientific community to pay attention to the need for detection and monitoring of gases released into the atmosphere. In this regard, the development of sensitive and selective gas sensors has been the subject of several research programs. An important greenhouse gas is sulphur hexafluoride, an almost non-reactive gas widely employed in industrial processes worldwide. Indeed it is estimated that it has a radiative forcing of 0.52 W/m(2). This work compares two photoacoustic spectrometers, one coupled to a CO(2) laser and another one coupled to a Quantum Cascade (QC) laser, for the detection of SF(6). The laser photoacoustic spectrometers described in this work have been developed for gas detection at small concentrations. Detection limits of 20 ppbv for CO(2) laser and 50 ppbv for quantum cascade laser were obtained.

  7. Cascade morphology transition in bcc metals

    Energy Technology Data Exchange (ETDEWEB)

    Setyawan, Wahyu; Selby, A.; Juslin, Niklas; Stoller, Roger E.; Wirth, Brian D.; Kurtz, Richard J.

    2015-06-10

    Energetic atom collisions in solids induce shockwaves with complex morphologies. In this paper, we establish the existence of a morphological transition in such cascades. The order parameter of the morphology is defined as the exponent, $b$, in the defect production curve as a function of cascade energy ($N_F$$ \\sim$$E_{MD}^b$). Response of different bcc metals can be compared in a consistent energy domain when the energy is normalized by the transition energy, $\\mu$, between the high- and the low-energy regime. Using Cr, Fe, Mo and W data, an empirical formula of $\\mu$ as a function of displacement threshold energy, $E_d$, is presented for bcc metals.

  8. Cascade Apartments: Deep Energy Multifamily Retrofit

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, A. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mattheis, L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kunkle, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Howard, L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lubliner, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions : 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  9. Cascade Apartments: Deep Energy Multifamily Retrofit

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, A. [Washington State Univ. Energy Program, Olympia, WA (United States); Mattheis, L. [Washington State Univ. Energy Program, Olympia, WA (United States); Kunkle, R. [Washington State Univ. Energy Program, Olympia, WA (United States); Howard, L. [Washington State Univ. Energy Program, Olympia, WA (United States); Lubliner, M. [Washington State Univ. Energy Program, Olympia, WA (United States)

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions: 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  10. Regimes of turbulence without an energy cascade

    CERN Document Server

    Barenghi, C F; Baggaley, A W

    2016-01-01

    Experiments and numerical simulations of turbulent $^4$He and $^3$He-B have established that, at hydrodynamic length scales larger than the average distance between quantum vortices, the energy spectrum obeys the same 5/3 Kolmogorov law which is observed in the homogeneous isotropic turbulence of ordinary fluids. The importance of the 5/3 law is that it points to the existence of a Richardson energy cascade from large eddies to small eddies. However, there is also evidence of quantum turbulent regimes without Kolmogorov scaling. This raises the important questions of why, in such regimes, the Kolmogorov spectrum fails to form, what is the physical nature of turbulence without energy cascade, and whether hydrodynamical models can account for the unusual behaviour of turbulent superfluid helium. In this work we describe simple physical mechanisms which prevent the formation of Kolmogorov scaling in the thermal counterflow, and analyze the conditions necessary for emergence of quasiclassical regime in quantum tu...

  11. Cascaded Multicell Trans-Z-Source Inverters

    DEFF Research Database (Denmark)

    Li, Ding; Chiang Loh, Poh; Zhu, Miao

    2013-01-01

    strictly be small to prevent overvoltages caused by switching of their winding currents. To avoid these related problems, cascaded trans-Z-source inverters are proposed. They use multiple magnetic cells in an alternately cascading pattern rather than a single magnetic cell with large turns ratio....... Simulation and experimental results have shown that the multicell inverters can produce the same high-voltage gain, while keeping currents and voltages of the components low. The inverters can also step down their output voltages like a traditional voltage-source inverter without compromising waveform......Inverters with high-output voltage gain usually face the problem of high-input current flowing through their components. The problem might further be exaggerated if the inverters use high-frequency magnetic devices like transformers or coupled inductors. Leakage inductances of these devices must...

  12. Cascaded impedance networks for NPC inverter

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang

    2010-01-01

    Multilevel inverters are getting more and more attracted because they have better output waveform quality and lower semiconductor voltage stress. The Z-source NPC is a kind of single stage multilevel inverter which has the ability of voltage boost. But the boost capability is relatively low when...... they are subject to the renewable sources. To date, three distinct types of impedance networks can be summarized for implementing a hybrid source impedance network, which can in principle be combined and cascaded before connected to a NPC inverter by proposed two ways. The resulting cascaded impedance network NPC...... would have a higher output voltage gain. It is anticipated that it would help the formed inverters find applications in photovoltaic and other renewable systems, where a high voltage gain is usually requested. Experimental testing has already been conducted and verifies the theory....

  13. Cascaded trans-z-source inverters

    DEFF Research Database (Denmark)

    Li, Ding; Loh, Poh Chiang; Zhu, Miao

    2011-01-01

    Z-source inverter is a recently proposed single-stage inverter with added voltage-boost capability for complementing the usual voltage-buck operation of a traditional voltage-source inverter. As long as the transformer element added in to the z-source concept, a trans-z-source inverter with one...... transformer and one capacitor is reported recently. This paper has adapted the cascaded concept into the trans-z-source and trans-quasi-z-source inverters to extend each to the cascaded topologies before combination is made with allowing more sources embedded which reduces the capacitor voltage and enhanced...... the compatibility for distributed sources. Unlike existing techniques, voltage stresses within the proposed inverters are better distributed among the passive components. Theoretical analysis for explaining these operating features has already been discussed before simulation were performed and an experimental...

  14. Supersonic Chordwise Bending Flutter in Cascades

    Science.gov (United States)

    1975-05-31

    bonding agent was injected via hypodermic needles after the blade tabs were properly inserted, The integrity and repeatability of the mounting of the indi...in conjunction with NASTRAN predictions and supersonic cascade aerodynamic computa- tions. Comparisons between theory and experiment are discussed. DD...explored by using the theory of .ieferences 3 and 4 to calculate the aero- dynamic damping for a typical chordwise blade deformation (Reference 6 and

  15. How do cilia organize signalling cascades?

    Science.gov (United States)

    Nachury, Maxence V

    2014-09-05

    Cilia and flagella are closely related centriole-nucleated protrusions of the cell with roles in motility and signal transduction. Two of the best-studied signalling pathways organized by cilia are the transduction cascade for the morphogen Hedgehog in vertebrates and the mating pathway that initiates gamete fusion in the unicellular green alga Chlamydomonas reinhardtii. What is the role of cilia in these signalling transduction cascades? In both Hedgehog and mating pathways, all signalling intermediates have been found to localize to cilia, and, for some signalling factors, ciliary localization is regulated by pathway activation. Given a concentration factor of three orders of magnitude provided by translocating a protein into the cilium, the compartment model proposes that cilia act as miniaturized reaction tubes bringing signalling factors and processing enzymes in close proximity. On the other hand, the scaffolding model views the intraflagellar transport machinery, whose primary function is to build cilia and flagella, as a molecular scaffold for the mating transduction cascade at the flagellar membrane. While these models may coexist, it is hoped that a precise understanding of the mechanisms that govern signalling inside cilia will provide a satisfying answer to the question 'how do cilia organize signalling?'. This review covers the evidence supporting each model of signalling and outlines future directions that may address which model applies in given biological settings. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  16. Cascade laser applications: trends and challenges

    Science.gov (United States)

    d'Humières, B.; Margoto, Éric; Fazilleau, Yves

    2016-03-01

    When analyses need rapid measurements, cost effective monitoring and miniaturization, tunable semiconductor lasers can be very good sources. Indeed, applications like on-field environmental gas analysis or in-line industrial process control are becoming available thanks to the advantage of tunable semiconductor lasers. Advances in cascade lasers (CL) are revolutionizing Mid-IR spectroscopy with two alternatives: interband cascade lasers (ICL) in the 3-6μm spectrum and quantum cascade lasers (QCL), with more power from 3 to 300μm. The market is getting mature with strong players for driving applications like industry, environment, life science or transports. CL are not the only Mid-IR laser source. In fact, a strong competition is now taking place with other technologies like: OPO, VCSEL, Solid State lasers, Gas, SC Infrared or fiber lasers. In other words, CL have to conquer a share of the Mid-IR application market. Our study is a market analysis of CL technologies and their applications. It shows that improvements of components performance, along with the progress of infrared laser spectroscopy will drive the CL market growth. We compare CL technologies with other Mid-IR sources and estimate their share in each application market.

  17. Analysis of cascading failure in gene networks

    Directory of Open Access Journals (Sweden)

    Shudong eWang

    2012-12-01

    Full Text Available It is an important subject to research the functional mechanism of cancer-related genes make in formation and development of cancers. The modern methodology of data analysis plays a very important role for deducing the relationship between cancers and cancer-related genes and analyzing functional mechanism of genome. In this research, we construct mutual information networks using gene expression profiles of glioblast and renal in normal condition and cancer conditions. We investigate the relationship between structure and robustness in gene networks of the two tissues using a cascading failure model based on betweenness centrality. Define some important parameters such as the percentage of failure nodes of the network, the average size-ratio of cascading failure and the cumulative probability of size-ratio of cascading failure to measure the robustness of the networks. By comparing control group and experiment groups, we find that the networks of experiment groups are more robust than that of control group. The gene that can cause large scale failure is called structural key gene (SKG. Some of them have been confirmed to be closely related to the formation and development of glioma and renal cancer respectively. Most of them are predicted to play important roles during the formation of glioma and renal cancer, maybe the oncogenes, suppressor genes, and other cancer candidate genes in the glioma and renal cancer cells. However, these studies provide little information about the detailed roles of identified cancer genes.

  18. EXPOSURE OF AMPHIBIANS TO SEMI-VOLATILE ORGANIC COMPOUNDS IN THE SIERRA NEVADA MOUNTAINS AND CALIFORNIA CASCADES: RELATIONSHIP BETWEEN TADPOLE TISSUE AND SEDIMENT CONCENTRATIONS

    Science.gov (United States)

    Pesticides and other semi-volatile organic compounds (SOCs) undergo regional and longrange atmospheric transport. One such example is the transport of current-use pesticides from the intensely cultivated Central Valley of California into the adjacent Sierra Nevada and Cascade Mou...

  19. Faraday rotation spectroscopy of nitrogen dioxide based on a widely tunable external cavity quantum cascade laser

    Science.gov (United States)

    Zaugg, Christian A.; Lewicki, Rafal; Day, Tim; Curl, Robert F.; Tittel, Frank K.

    2011-01-01

    Faraday Rotation Spectroscopy (FRS) is a technique for the sensitive and selective detection of paramagnetic molecules or radicals such as NO, NO2, O2 or OH-. Moreover FRS is suitable for atmospheric measurements due to the insensitivity to non-paramagnetic interfering molecules such as H2O and CO2. Experimental results of an FRS sensor for the NO2detection employing an external-cavity quantum cascade laser (EC-QCL) are reported. The CW EC-QCL exhibits modehop free (MHF) tuning between 1600 cm-1 and 1650 cm-1. This allows targeting the optimum 441constant (TC).

  20. Heat cascading regenerative sorption heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1995-01-01

    A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

  1. The identification of a cascade hypernucleus

    CERN Document Server

    Mondal, A S; Husain, A; Kasim, M M

    1979-01-01

    In a systematic search for rare hypernuclear species in nuclear emulsion exposed to 3.0 GeV/c K/sup -/-mesons at the CERN PS, an event with three connecting stars has been observed. The two secondary stars are most probably due to the decay of a cascade hypernucleus according to the following channel: /sub Xi //sup -13/-C to /sub Lambda //sup 8 /Be+/sub Lambda //sup 5/He+Q. The binding energy of the Xi - hypernucleus is B/sub Xi /-(/sub Xi //sup 13/-C)=(18.1+or-3.2) MeV. (11 refs).

  2. Chronic traumatic encephalopathy and the availability cascade.

    Science.gov (United States)

    Solomon, Gary S; Sills, Allen

    2014-09-01

    Chronic traumatic encephalopathy (CTE) in sports has been known for > 85 years, and has experienced a resurgence of interest over the past decade, both in the media and in the scientific community. However, there appears to be a disconnection between the public's perception of CTE and the currently available scientific data. The cognitive bias known as the "availability cascade" has been suggested as a reason to explain this rift in knowledge. This review summarizes and updates the history of CTE in sports, discusses recent epidemiological and autopsy studies, summarizes the evidence base related to CTE in sports, and offers recommendations for future directions.

  3. The Cascade of Non-Stationarity

    Science.gov (United States)

    Belmont, P.; Kumarasamy, K.; Kelly, S. A.; Schaffrath, K. R.; Beach, T. J.

    2014-12-01

    Landscapes and channel networks are dynamic systems, often characterized by immense variability in time and space. Systematic shifts in hydrologic, geomorphic, or ecologic drivers can cause a cascade of changes within the system, which may fundamentally alter the way the system itself functions. Due to variability in resilience and resisting forces throughout the landscape, this cascade of changes may manifest in different ways within any given system. Humans may also exert considerable influence, often amplifying or damping system response. We illustrate the cascading effects of non-stationary hydrology and geomorphology in the Minnesota River Basin (MRB), a 44,000 km2 natural laboratory in which pervasive landscape disturbance has been triggered by several well-documented events. Rapid base-level lowering 13,400 YBP along the mainstem Minnesota River created a wave of incision, which continues to propagate up tributary channel networks. Temperature and precipitation have changed significantly in the MRB over the past century with rising temperatures, shifting precipitation patterns and an increase in heavy rainfall events. Streamflow has changed drastically and variably throughout the basin with 5% exceedance flows increasing 60-100% in recent decades, as increases in precipitation have been amplified by land management and artificial drainage. Increases in channel width and depth have occurred variably in the mainstem Minnesota River, the actively incising lower (knick zone) reaches of tributaries, and the low gradient, passively meandering reaches above the knick zones. Altered hydrologic regimes and channel morphologies, combined with increased sedimentation and nutrient loading have adversely affected aquatic biota via disruption of life cycles and habitat degradation. Existing landscape, water quality, and flood risk models are poorly equipped to deal with the cascading effects of non-stationarity and therefore may grossly over- or under

  4. Tracking Control for Switched Cascade Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Dong

    2015-01-01

    Full Text Available The issue of H∞ output tracking for switched cascade nonlinear systems is discussed in this paper, where not all the linear parts of subsystems are stabilizable. The conditions of the solvability for the issue are given by virtue of the structural characteristics of the systems and the average dwell time method, in which the total activation time for stabilizable subsystems is longer than that for the unstabilizable subsystems. At last, a simulation example is used to demonstrate the validity and advantages of the proposed approach.

  5. Cascaded recompression closed brayton cycle system

    Energy Technology Data Exchange (ETDEWEB)

    Pasch, James J.

    2018-01-02

    The present disclosure is directed to a cascaded recompression closed Brayton cycle (CRCBC) system and method of operation thereof, where the CRCBC system includes a compressor for compressing the system fluid, a separator for generating fluid feed streams for each of the system's turbines, and separate segments of a heater that heat the fluid feed streams to different feed temperatures for the system's turbines. Fluid exiting each turbine is used to preheat the fluid to the turbine. In an embodiment, the amount of heat extracted is determined by operational costs.

  6. Long-Haul TCP vs. Cascaded TCP

    OpenAIRE

    Feng, Wu-chun

    2006-01-01

    In this work, we investigate the bandwidth and transfer time of long-haul TCP versus cascaded TCP [5]. First, we discuss the models for TCP throughput. For TCP flows in support of bulk data transfer (i.e., long-lived TCP flows), the TCP throughput models have been derived [2, 3]. These models rely on the congestion-avoidance algorithm of TCP. Though these models cannot be applied with short-lived TCP connections, our interest relative to logistical networking is in longer-li...

  7. Plant MAPK cascades: Just rapid signaling modules?

    KAUST Repository

    Boudsocq, Marie

    2015-08-27

    © 2015 Taylor & Francis Group, LLC. Abscisic acid (ABA) is a major phytohormone mediating important stress-related processes. We recently unveiled an ABA-activated MAPK signaling module constituted of MAP3K17/18-MKK3-MPK1/2/7/14. Unlike classical rapid MAPK activation, we showed that the activation of the new MAPK module is delayed and relies on the MAP3K protein synthesis. In this addendum, we discuss the role of this original and unexpected activation mechanism of MAPK cascades which suggests that MAPKs can regulate both early and longterm plant stress responses.

  8. The impact of a network split on cascading failure processes

    OpenAIRE

    Sloothaak, Fiona; Borst, Sem C.; Zwart, Bert

    2017-01-01

    Cascading failure models are typically used to capture the phenomenon where failures possibly trigger further failures in succession, causing knock-on effects. In many networks this ultimately leads to a disintegrated network where the failure propagation continues independently across the various components. In order to gain insight in the impact of network splitting on cascading failure processes, we extend a well-established cascading failure model for which the number of failures obeys a ...

  9. Large phase shift via polarization-coupling cascading.

    Science.gov (United States)

    Huo, Juan; Chen, Xianfeng

    2012-06-04

    Herein, we propose a phenomenon of "polarization-coupling (PC) cascading" generated in MgO doped periodically poled lithium niobate crystal (PPMgLN). PC cascading contributes to the effective electro-optical (EO) Kerr effect that is several orders of magnitude stronger than the classical ones. Experiment of Newton's rings demonstrates the large phase accumulation during the PC cascaded processes, and the experimental data is identical with the theoretical simulation.

  10. Estimating Failure Propagation in Models of Cascading Blackouts

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, Ian [University of Wisconsin, Madison; Carreras, Benjamin A [ORNL; Lynch, Vickie E [ORNL; Nkei, Bertrand [ORNL; Newman, David E [University of Alaska

    2005-09-01

    We compare and test statistical estimates of failure propagation in data from versions of a probabilistic model of loading-dependent cascading failure and a power systems blackout model of cascading transmission line overloads. The comparisons suggest mechanisms affecting failure propagation and are an initial step towards monitoring failure propagation from practical system data. Approximations to the probabilistic model describe the forms of probability distributions of cascade sizes.

  11. Unlimited Damage Accumulation in Metallic Materials Under Cascade-Damage Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Barashev, Aleksandr [University of Liverpool; Golubov, Stanislav I [ORNL

    2008-09-01

    Most experiments on neutron or heavy-ion cascade-produced irradiation of pure metals and metallic alloys demonstrate unlimited void growth as well as development of the dislocation structure. In contrast, the theory of radiation damage predicts saturation of void swelling at sufficiently high irradiation doses and, accordingly, termination of accumulation of interstitial-type defects. It is shown in the present paper that, under conditions of steady production of one-dimensionally (1-D) mobile clusters of self-interstitial atoms (SIAs) in displacement cascades, any one of the following three conditions can result in indefinite damage accumulation. First, if the fraction of SIAs generated in the clustered form is smaller than some finite value of the order of the dislocation bias factor. Second, if solute, impurity or transmuted atoms form atmospheres around voids and repel the SIA clusters. Third, if spatial correlations between voids and other defects, such as second-phase precipitates and dislocations, exist that provide shadowing of voids from the SIA clusters. The driving force for the development of such correlations is the same as for void lattice formation and is argued to be always present under cascade-damage conditions. It is emphasised that the mean-free path of 1-D migrating SIA clusters is typically at least an order of magnitude longer than the average distance between microstructural defects; hence spatial correlations on the same scale should be taken into consideration. A way of developing a predictive theory is discussed. An interpretation

  12. All passive architecture for high efficiency cascaded Raman conversion

    Science.gov (United States)

    Balaswamy, V.; Arun, S.; Chayran, G.; Supradeepa, V. R.

    2018-02-01

    Cascaded Raman fiber lasers have offered a convenient method to obtain scalable, high-power sources at various wavelength regions inaccessible with rare-earth doped fiber lasers. A limitation previously was the reduced efficiency of these lasers. Recently, new architectures have been proposed to enhance efficiency, but this came at the cost of enhanced complexity, requiring an additional low-power, cascaded Raman laser. In this work, we overcome this with a new, all-passive architecture for high-efficiency cascaded Raman conversion. We demonstrate our architecture with a fifth-order cascaded Raman converter from 1117nm to 1480nm with output power of ~64W and efficiency of 60%.

  13. Cascading walks model for human mobility patterns.

    Science.gov (United States)

    Han, Xiao-Pu; Wang, Xiang-Wen; Yan, Xiao-Yong; Wang, Bing-Hong

    2015-01-01

    Uncovering the mechanism behind the scaling laws and series of anomalies in human trajectories is of fundamental significance in understanding many spatio-temporal phenomena. Recently, several models, e.g. the explorations-returns model (Song et al., 2010) and the radiation model for intercity travels (Simini et al., 2012), have been proposed to study the origin of these anomalies and the prediction of human movements. However, an agent-based model that could reproduce most of empirical observations without priori is still lacking. In this paper, considering the empirical findings on the correlations of move-lengths and staying time in human trips, we propose a simple model which is mainly based on the cascading processes to capture the human mobility patterns. In this model, each long-range movement activates series of shorter movements that are organized by the law of localized explorations and preferential returns in prescribed region. Based on the numerical simulations and analytical studies, we show more than five statistical characters that are well consistent with the empirical observations, including several types of scaling anomalies and the ultraslow diffusion properties, implying the cascading processes associated with the localized exploration and preferential returns are indeed a key in the understanding of human mobility activities. Moreover, the model shows both of the diverse individual mobility and aggregated scaling displacements, bridging the micro and macro patterns in human mobility. In summary, our model successfully explains most of empirical findings and provides deeper understandings on the emergence of human mobility patterns.

  14. Quaternary Magmatism in the Cascades - Geologic Perspectives

    Science.gov (United States)

    Hildreth, Wes

    2007-01-01

    Foreward The Cascade magmatic arc is a belt of Quaternary volcanoes that extends 1,250 km from Lassen Peak in northern California to Meager Mountain in Canada, above the subduction zone where the Juan de Fuca Plate plunges beneath the North American Plate. This Professional Paper presents a synthesis of the entire volcanic arc, addressing all 2,300 known Quaternary volcanoes, not just the 30 or so visually prominent peaks that comprise the volcanic skyline. Study of Cascade volcanoes goes back to the geological explorers of the late 19th century and the seminal investigations of Howel Williams in the 1920s and 1930s. However, major progress and application of modern scientific methods and instrumentation began only in the 1970s with the advent of systematic geological, geophysical, and geochemical studies of the entire arc. Initial stimulus from the USGS Geothermal Research Program was enhanced by the USGS Volcano Hazards Program following the 1980 eruption of Mount St. Helens. Together, these two USGS Programs have provided more than three decades of stable funding, staffing, and analytical support. This Professional Paper summarizes the resultant USGS data sets and integrates them with the parallel contributions of other investigators. The product is based upon an all-encompassing and definitive geological database, including chemical and isotopic analyses to characterize the rocks and geochronology to provide the critical time constraints. Until now, this massive amount of data has not been summarized, and a systematic and uniform interpretation firmly grounded in geological fact has been lacking. Herein lies the primary utility of this Cascade volume. It not only will be the mandatory starting point for new workers, but also will provide essential geological context to broaden the perspectives of current investigators of specific Cascade volcanoes. Wes Hildreth's insightful understanding of volcanic processes and his uncompromising scientific integrity make him

  15. Terahertz Quantum Cascade Laser Local Oscillator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has a need for airborne or space-based observatories and remote sensors in order to penetrate the opaque atmosphere between 1 and 10 THz. For observations >2...

  16. Spectral Energy Budget of High Resolution General Circulation Models: Simulation of the Direct Energy Cascade

    Science.gov (United States)

    Augier, P.; Lindborg, E.

    2012-12-01

    Nastrom and Gage (1985) showed that the atmospheric kinetic energy and potential temperature spectra measured in the upper troposphere and lower stratosphere present two inertial ranges. At the mesoscales, the spectra have a kh-5/3 power law dependence. At larger scales, there is a narrow range where the spectra show a kh-3 dependence. Recently, there has been considerable progress in simulating the observed spectra with some high resolution General Circulation Models (GCMs) (see e.g.~Hamilton et al., 2008). Our aim is to understand fundamental mechanisms of energy transfer between different scales and how well these mechanisms are described by different GCMs. In particular, we wish to test the hypothesis recently proposed by Vallgren, Deusebio & Lindborg (2011), that the atmospheric kinetic and potential energy spectra can be explained by assuming that there are two cascade processes emanating from the same large-scale energy source at scales of thousands of kilometers. In order to do this, we calculate the spectral budgets of energy using data from different GCMs, including data from the T639L24 AFES model and the T1279L91 ECMWF Integrated Forecast System. The concept of available potential energy (APE, Lorenz, 1955) has been used to formulate the spectral budgets of the so-called ``primitive equations'' in pressure coordinates, with spherical harmonics as the base functions, and taking into account the topography. The ratio of the total APE over the total kinetic energy (KE) is large, of the order of 3. This is due to a larger magnitude of the APE spectrum at the very large scales of the atmosphere (total wavenumber l ≤slant 3). At the other scales, APE and KE spectra are of the same order of magnitude. For the ECMWF model and at the synoptic scales, the APE spectrum is half the KE spectrum as predicted by Charney (1971). The main terms of the spectral energy budget are computed, which allows us to present a spectral representation of the Lorenz energy cycle

  17. Measurement of Neutrino Induced, Charged Current, Charged Pion Production

    Energy Technology Data Exchange (ETDEWEB)

    Wilking, Michael Joseph [Univ. of Colorado, Boulder, CO (United States)

    2009-05-01

    Neutrinos are among the least understood particles in the standard model of particle physics. At neutrino energies in the 1 GeV range, neutrino properties are typically determined by observing the outgoing charged lepton produced in a charged current quasi-elastic interactions. The largest charged current background to these measurements comes from charged current pion production interactions, for which there is very little available data.

  18. Neutrino induced showers from gamma-ray bursts

    NARCIS (Netherlands)

    Presani, E.

    2011-01-01

    Neutrino’s (ongeladen, elementaire deeltjes) komen voor in drie gedaantes. Elk van dit soort neutrino’s interageert op zijn eigen manier op de materie. Bij de interactie kan een geladen zwak boson worden uitgewisseld. De neutrino’s veranderen daarbij in hun geladen partner (muon-neutrino naar muon,

  19. Reconstruction of neutrino-induced showers with ANTARES

    NARCIS (Netherlands)

    Dorosti Hasankiadeh, Qader

    2013-01-01

    Op aarde zijn kosmische deeltjes gemeten met extreem hoge energieën. De bijbehorende bronnen we kennen niet, we weten zelfs niet of die misschien binnen ons melkwegstelsel liggen. Wel weten we dat in uitbarstingen van kosmische energie ook neutrino's worden geproduceerd. Boven alle andere deeltjes

  20. Neutrino induced vorticity, Alfven waves and the normal modes

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, Jitesh R. [Theory Division, Physical Research Laboratory, Ahmedabad (India); George, Manu [Theory Division, Physical Research Laboratory, Ahmedabad (India); Indian Institute of Technology, Department of Physics, Ahmedabad (India)

    2017-08-15

    We consider a plasma consisting of electrons and ions in the presence of a background neutrino gas and develop the magnetohydrodynamic equations for the system. We show that the electron neutrino interaction can induce vorticity in the plasma even in the absence of any electromagnetic perturbations if the background neutrino density is left-right asymmetric. This induced vorticity supports a new kind of Alfven wave whose velocity depends on both the external magnetic field and on the neutrino asymmetry. The normal mode analysis show that in the presence of neutrino background the Alfven waves can have different velocities. We also discuss our results in the context of dense astrophysical plasma such as magnetars and show that the difference in the Alfven velocities can be used to explain the observed pulsar kick. We discuss also the relativistic generalisation of the electron fluid in presence of an asymmetric neutrino background. (orig.)

  1. Neutrino-induced Neucleosynthesis in Supernova Helium Shells

    Science.gov (United States)

    Banerjee, Projjwal

    We re-examine a neutrino-driven r-process mechanism in the helium shell of a core-collapse supernova. We analyze the pre-shock evolution in detail using recent stellar models. In addition we perform full hydrodynamic simulations including the effect of shock, finding that the outer helium shells can be the site for an r-process. We find that this mechanism could succeed in early stars of metallicity ≲ 10-3 the solar value, at relatively low temperatures and neutron densities, producing A ˜ 130 and 195 abundance peaks over ˜ 50--60 s. The mechanism is extremely sensitive to the neutrino emission model and to neutrino oscillations. While this mechanism is not very sensitive to the explosion energy, mixing of the ejecta can be different for different explosion energies. We discuss the implications of an r-process that could alter interpretations of abundance data from metal-poor stars.

  2. Eruptive history of South Sister, Oregon Cascades

    Science.gov (United States)

    Fierstein, J.; Hildreth, W.; Calvert, A.T.

    2011-01-01

    South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50ka to 2ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic ~50ka. By ~37ka, rhyolitic lava flows and domes (72-74% SiO2) began alternating with radially emplaced dacite (63-68% SiO2) and andesite (59-63% SiO2) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO2) culminated ~30ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200m thick. This was followed at ~27ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO2) and formation of a summit crater ~800m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by >150m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO2) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO2) - the most mafic product of South Sister - erupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until ~22ka. A 20kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO2) and (2) the Devils Chain of ~20 domes and short coulees (72.3-72.8% SiO2) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the

  3. Temporal switching induced by cascaded third order nonlinearity

    DEFF Research Database (Denmark)

    Eilenberger, Falk; Bache, Morten; Minardi, Stefano

    2012-01-01

    We investigate the impact of cascaded third harmonic generation and the intrinsic n4 material nonlinearity on the propagation of ultrashort pulses in noble-gas filled Kagome fibers. We show that the pressure tunability of the cascade allows for the implementation of temporal switching. We also...... investigate the relative strengths of both effects and show their ratio to be pressure tunable....

  4. Cascade vulnerability for risk analysis of water infrastructure.

    Science.gov (United States)

    Sitzenfrei, R; Mair, M; Möderl, M; Rauch, W

    2011-01-01

    One of the major tasks in urban water management is failure-free operation for at least most of the time. Accordingly, the reliability of the network systems in urban water management has a crucial role. The failure of a component in these systems impacts potable water distribution and urban drainage. Therefore, water distribution and urban drainage systems are categorized as critical infrastructure. Vulnerability is the degree to which a system is likely to experience harm induced by perturbation or stress. However, for risk assessment, we usually assume that events and failures are singular and independent, i.e. several simultaneous events and cascading events are unconsidered. Although failures can be causally linked, a simultaneous consideration in risk analysis is hardly considered. To close this gap, this work introduces the term cascade vulnerability for water infrastructure. Cascade vulnerability accounts for cascading and simultaneous events. Following this definition, cascade risk maps are a merger of hazard and cascade vulnerability maps. In this work cascade vulnerability maps for water distribution systems and urban drainage systems based on the 'Achilles-Approach' are introduced and discussed. It is shown, that neglecting cascading effects results in significant underestimation of risk scenarios.

  5. A nine-level hybrid symmetric cascaded multilevel converter for ...

    Indian Academy of Sciences (India)

    Bridge (TCHB) power cell and one three-level H-bridge power cell with equal dc link voltages, and they are connected in cascade. Due to cascade connection and equal dc link voltage, the power shared by each power cell is nearly equal.

  6. Hybrid Modulation Scheme for Cascaded H-Bridge Inverter Cells ...

    African Journals Online (AJOL)

    This work proposes a switching technique for cascaded H-Bridge (CHB) cells. Single carrier Sinusoidal PWM (SCSPWM) scheme is employed in the generation of the gating signals. A sequential switching and base PWM circulation schemes are presented for this fundamental cascaded multilevel inverter topology.

  7. Influence of blood flow on the coagulation cascade

    DEFF Research Database (Denmark)

    The influence of diffusion and convetive flows on the blood coagulation cascade is investigated for a controlled perfusion experiment. We present a cartoon model and reaction schemes for parts of the coagulation cascade with sunsequent set up of a mathematical model in two space dimensions plus one...

  8. Seeking the northern boundary of the Cascade strawberry

    Science.gov (United States)

    Fragaria cascadensis K.E. Hummer, an endemic decaploid strawberry species, was described from the Oregon Cascade Mountains in the Pacific North-western United States. Its range occurs near Mt. Hood, the highest peak in the northern Oregon Cascades, in a band of higher elevation sites southwards to n...

  9. 36 CFR 7.66 - North Cascades National Park.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false North Cascades National Park. 7.66 Section 7.66 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.66 North Cascades National Park. (a...

  10. Intermittent Flow Regimes in a Transonic Fan Airfoil Cascade

    Directory of Open Access Journals (Sweden)

    J. Lepicovsky

    2004-01-01

    velocity.To date, this flow behavior has only been observed in a linear transonic cascade. Further research is necessary to confirm this phenomenon occurs in actual transonic fans and is not the by-product of an endwall restricted linear cascade.

  11. A modeling framework for system restoration from cascading failures.

    Science.gov (United States)

    Liu, Chaoran; Li, Daqing; Zio, Enrico; Kang, Rui

    2014-01-01

    System restoration from cascading failures is an integral part of the overall defense against catastrophic breakdown in networked critical infrastructures. From the outbreak of cascading failures to the system complete breakdown, actions can be taken to prevent failure propagation through the entire network. While most analysis efforts have been carried out before or after cascading failures, restoration during cascading failures has been rarely studied. In this paper, we present a modeling framework to investigate the effects of in-process restoration, which depends strongly on the timing and strength of the restoration actions. Furthermore, in the model we also consider additional disturbances to the system due to restoration actions themselves. We demonstrate that the effect of restoration is also influenced by the combination of system loading level and restoration disturbance. Our modeling framework will help to provide insights on practical restoration from cascading failures and guide improvements of reliability and resilience of actual network systems.

  12. Impedance Coordinative Control for Cascaded Converter in Bidirectional Application

    DEFF Research Database (Denmark)

    Tian, Yanjun; Deng, Fujin; Chen, Zhe

    2015-01-01

    Two stage cascaded converters are widely used in bidirectional applications, but the negative impedance may cause system instability. Actually the impedance interaction is much different between forward power flow and reversed power flow, which will introduce more uncertainty to the system...... stability. This paper proposes a control method for the constant power controlled converter in cascaded system, and consequently it can change the negative impedance of constant power converter into resistive impedance, which will improve the cascaded system stability, as well as merge the impedance...... difference between forward and reversed power flow. This paper addresses the analysis with the topology of cascaded dual-active-bridge converter (DAB) with inverter, and the proposed control method can also be implemented in unidirectional applications and other general cascaded converter system...

  13. A modeling framework for system restoration from cascading failures.

    Directory of Open Access Journals (Sweden)

    Chaoran Liu

    Full Text Available System restoration from cascading failures is an integral part of the overall defense against catastrophic breakdown in networked critical infrastructures. From the outbreak of cascading failures to the system complete breakdown, actions can be taken to prevent failure propagation through the entire network. While most analysis efforts have been carried out before or after cascading failures, restoration during cascading failures has been rarely studied. In this paper, we present a modeling framework to investigate the effects of in-process restoration, which depends strongly on the timing and strength of the restoration actions. Furthermore, in the model we also consider additional disturbances to the system due to restoration actions themselves. We demonstrate that the effect of restoration is also influenced by the combination of system loading level and restoration disturbance. Our modeling framework will help to provide insights on practical restoration from cascading failures and guide improvements of reliability and resilience of actual network systems.

  14. Modelling of Attenuation and Crosstalk of Cascaded Transmission Lines

    Directory of Open Access Journals (Sweden)

    Pavel Lafata

    2011-01-01

    Full Text Available This paper deals with the measurements and modelling of attenuation and near-end (NEXT and far-end (FEXT crosstalk for cascaded metallic transmission lines. The transmission parameters of homogenous metallic line can be easily described by telegraph equations or cascade matrix; there are also several models for NEXT and FEXT frequency dependence. But these models and equations could not be applied in the situation of two or more different cascaded transmission lines, because these cascaded lines do not meet the essential condition of overall homogenous transmission line. However in such case, it is still possible to estimate the overall transmission characteristics of the whole combination thanks to the characteristics of each separate element. This paper brings the description of complex measurements performed for the combination of three different metallic cables and based on these measurements, several conclusions about the possibilities of modelling the attenuation and NEXT and FEXT crosstalk for cascaded transmission lines are presented.

  15. Quantum cascade laser FM spectroscopy of explosives

    Science.gov (United States)

    Gutmann, Zach; Clasp, Trocia; Lue, Chris; Johnson, Tiffani; Ingle, Taylor; Jamison, Janet; Buchanan, Roger; Reeve, Scott

    2013-05-01

    Polyisobutylene is an industrial polymer that is widely used in a number of applications including the manufacture of military grade explosives. We have examined the vapor emanating from a series of different molecular weight samples of polyisobutylene using high resolution Quantum Cascade Laser FM spectroscopy. The vapor phase spectra all exhibit a rovibrational structure similar to that for the gas phase isobutylene molecule. We have assigned the structure in the 890 cm-1 and 1380 cm-1 regions to the isobutylene ν28 and ν7 fundamental bands respectively. These spectroscopic signatures may prove useful for infrared sensing applications. Here we will present the infrared signatures along with recent GCMS data from a sample of C4, utilizing solid-phase microextraction vapor collection fibers, which confirm the presence of isobutylene as one of the volatile bouquet species in RDX-based explosives.

  16. Control of cascaded induction generator systems

    Science.gov (United States)

    Ortmeyer, T. H.

    1984-12-01

    This report documents an investigation of the stability and control of cascaded doubly fed machines (CDFM). These machines are brushless variable speed constant frequency electric power generators with potential for application in aircraft. A previous analytical study indicated the CDFM system would be controllable in the subsynchronous operating mode with a passive RL load. The present study contains two steps. First is an investigation of the machine operation in the supersynchronous mode. The second step is an investigation of machine operation with output capacitors providing excitation VARs for the machine and load. Step 1 results show that the machines exhibit stability characteristics in the supersynchronous mode similar to those observed in the subsynchronous mode. Step 2 results show that output capacitors degrade the system performance, particularly at light loads. The results show that output current feedback can be employed to improve the system performance.

  17. Cascaded face alignment via intimacy definition feature

    Science.gov (United States)

    Li, Hailiang; Lam, Kin-Man; Chiu, Man-Yau; Wu, Kangheng; Lei, Zhibin

    2017-09-01

    Recent years have witnessed the emerging popularity of regression-based face aligners, which directly learn mappings between facial appearance and shape-increment manifolds. We propose a random-forest based, cascaded regression model for face alignment by using a locally lightweight feature, namely intimacy definition feature. This feature is more discriminative than the pose-indexed feature, more efficient than the histogram of oriented gradients feature and the scale-invariant feature transform feature, and more compact than the local binary feature (LBF). Experimental validation of our algorithm shows that our approach achieves state-of-the-art performance when testing on some challenging datasets. Compared with the LBF-based algorithm, our method achieves about twice the speed, 20% improvement in terms of alignment accuracy and saves an order of magnitude on memory requirement.

  18. Cascaded Amplitude Modulations in Sound Texture Perception

    DEFF Research Database (Denmark)

    McWalter, Richard Ian; Dau, Torsten

    2017-01-01

    Sound textures, such as crackling fire or chirping crickets, represent a broad class of sounds defined by their homogeneous temporal structure. It has been suggested that the perception of texture is mediated by time-averaged summary statistics measured from early auditory representations....... In this study, we investigated the perception of sound textures that contain rhythmic structure, specifically second-order amplitude modulations that arise from the interaction of different modulation rates, previously described as "beating" in the envelope-frequency domain. We developed an auditory texture...... model that utilizes a cascade of modulation filterbanks that capture the structure of simple rhythmic patterns. The model was examined in a series of psychophysical listening experiments using synthetic sound textures-stimuli generated using time-averaged statistics measured from real-world textures...

  19. Cascaded Quadratic Soliton Compression in Waveguide Structures

    DEFF Research Database (Denmark)

    Guo, Hairun

    between the Kerr nonlinear effects and the dispersive effects in the medium. A Kerr-like nonlinearity is produced through the cascaded phase mismatched quadratic process, e.g. the second harmonic generation process, which can be flexibly tuned in both the sign and the amplitude, making possible a strong...... and self-defocusing Kerr effect so that the soliton is created and the soliton self-compression happens in the normal dispersion region. Meanwhile, the chromatic dispersion in the waveguide is also tunable, understood as the dispersion engineering with structural designs. Therefore, compared to commonly......-focusing Kerr effects when under the self-defocusing regime. On the other hand, CQSC in quadratic waveguides seems highly complementary to that in quadratic bulk crystals. With bulk crystals dealing with high-energy, low-repetition-rate and large-beam-size pulses, quadratic waveguides could operate low...

  20. Information propagation in a noisy gene cascade

    Science.gov (United States)

    Monteoliva, D.; Diambra, L.

    2017-07-01

    We use information theory to study the information transmission through a simple gene cascade where the product of an unregulated gene regulates the expression activity of a cooperative genetic switch. While the input signal is provided by the upstream gene with two states, we consider that the expression of downstream gene is controlled by a cis-regulatory system with three binding sites for the regulator product, which can bind cooperatively. By computing exactly the associated probability distributions, we estimate information transmission thought the mutual information measure. We found that the mutual information associated with unimodal input signal is lower than the associated with bimodal inputs. We also observe that mutual information presents a maximum in the cooperativity intensity, and the position of this maximum depends on the kinetic rates of the promoter. Furthermore, we found that the bursting dynamics of the input signal can enhance the information transmission capacity.

  1. Fluctuation sensitivity of a transcriptional signaling cascade

    Science.gov (United States)

    Pilkiewicz, Kevin R.; Mayo, Michael L.

    2016-09-01

    The internal biochemical state of a cell is regulated by a vast transcriptional network that kinetically correlates the concentrations of numerous proteins. Fluctuations in protein concentration that encode crucial information about this changing state must compete with fluctuations caused by the noisy cellular environment in order to successfully transmit information across the network. Oftentimes, one protein must regulate another through a sequence of intermediaries, and conventional wisdom, derived from the data processing inequality of information theory, leads us to expect that longer sequences should lose more information to noise. Using the metric of mutual information to characterize the fluctuation sensitivity of transcriptional signaling cascades, we find, counter to this expectation, that longer chains of regulatory interactions can instead lead to enhanced informational efficiency. We derive an analytic expression for the mutual information from a generalized chemical kinetics model that we reduce to simple, mass-action kinetics by linearizing for small fluctuations about the basal biological steady state, and we find that at long times this expression depends only on a simple ratio of protein production to destruction rates and the length of the cascade. We place bounds on the values of these parameters by requiring that the mutual information be at least one bit—otherwise, any received signal would be indistinguishable from noise—and we find not only that nature has devised a way to circumvent the data processing inequality, but that it must be circumvented to attain this one-bit threshold. We demonstrate how this result places informational and biochemical efficiency at odds with one another by correlating high transcription factor binding affinities with low informational output, and we conclude with an analysis of the validity of our assumptions and propose how they might be tested experimentally.

  2. Cascading walks model for human mobility patterns.

    Directory of Open Access Journals (Sweden)

    Xiao-Pu Han

    Full Text Available Uncovering the mechanism behind the scaling laws and series of anomalies in human trajectories is of fundamental significance in understanding many spatio-temporal phenomena. Recently, several models, e.g. the explorations-returns model (Song et al., 2010 and the radiation model for intercity travels (Simini et al., 2012, have been proposed to study the origin of these anomalies and the prediction of human movements. However, an agent-based model that could reproduce most of empirical observations without priori is still lacking.In this paper, considering the empirical findings on the correlations of move-lengths and staying time in human trips, we propose a simple model which is mainly based on the cascading processes to capture the human mobility patterns. In this model, each long-range movement activates series of shorter movements that are organized by the law of localized explorations and preferential returns in prescribed region.Based on the numerical simulations and analytical studies, we show more than five statistical characters that are well consistent with the empirical observations, including several types of scaling anomalies and the ultraslow diffusion properties, implying the cascading processes associated with the localized exploration and preferential returns are indeed a key in the understanding of human mobility activities. Moreover, the model shows both of the diverse individual mobility and aggregated scaling displacements, bridging the micro and macro patterns in human mobility. In summary, our model successfully explains most of empirical findings and provides deeper understandings on the emergence of human mobility patterns.

  3. Orexin/hypocretin receptor signalling cascades.

    Science.gov (United States)

    Kukkonen, J P; Leonard, C S

    2014-01-01

    Orexin (hypocretin) peptides and their two known G-protein-coupled receptors play essential roles in sleep-wake control and powerfully influence other systems regulating appetite/metabolism, stress and reward. Consequently, drugs that influence signalling by these receptors may provide novel therapeutic opportunities for treating sleep disorders, obesity and addiction. It is therefore critical to understand how these receptors operate, the nature of the signalling cascades they engage and their physiological targets. In this review, we evaluate what is currently known about orexin receptor signalling cascades, while a sister review (Leonard & Kukkonen, this issue) focuses on tissue-specific responses. The evidence suggests that orexin receptor signalling is multifaceted and is substantially more diverse than originally thought. Indeed, orexin receptors are able to couple to members of at least three G-protein families and possibly other proteins, through which they regulate non-selective cation channels, phospholipases, adenylyl cyclase, and protein and lipid kinases. In the central nervous system, orexin receptors produce neuroexcitation by postsynaptic depolarization via activation of non-selective cation channels, inhibition of K⁺ channels and activation of Na⁺/Ca²⁺ exchange, but they also can stimulate the release of neurotransmitters by presynaptic actions and modulate synaptic plasticity. Ca²⁺ signalling is also prominently influenced by these receptors, both via the classical phospholipase C-Ca²⁺ release pathway and via Ca²⁺ influx, mediated by several pathways. Upon longer-lasting stimulation, plastic effects are observed in some cell types, while others, especially cancer cells, are stimulated to die. Thus, orexin receptor signals appear highly tunable, depending on the milieu in which they are operating. © 2013 The British Pharmacological Society.

  4. Normalized-Mutual-Information-Based Mining Method for Cascading Patterns

    Directory of Open Access Journals (Sweden)

    Cunjin Xue

    2016-09-01

    Full Text Available A cascading pattern is a sequential pattern characterized by an item following another item in order. Recent research has investigated a challenge of dealing with cascading patterns, namely, the exponential time dependence of database scanning with respect to the number of items involved. We propose a normalized-mutual-information-based mining method for cascading patterns (M3Cap to address this challenge. M3Cap embeds mutual information to reduce database-scanning time. First, M3Cap calculates the asymmetrical mutual information between items with one database scan and extracts pair-wise related items according to a user-specified information threshold. Second, a one-level cascading pattern is generated by scanning the database once for each pair-wise related item at the quantitative level. Third, a recursive linking–pruning–generating loop generates an (m + 1-level-candidate cascading pattern from m-dimensional patterns on the basis of antimonotonicity and non-additivity, repeating this step until no further candidate cascading patterns are generated. Fourth, meaningful cascading patterns are generated according to user-specified minimum evaluation indicators. Finally, experiments with remote sensing image datasets covering the Pacific Ocean demonstrate that the computation time of recursive linking and pruning is significantly less than that of database scanning; thus, M3Cap improves performance by reducing database scanning while increasing intensive computing.

  5. Out of control: Fluctuation of cascading dynamics in networks

    Science.gov (United States)

    Wang, Jianwei; Cai, Lin; Xu, Bo; Li, Peng; Sun, Enhui; Zhu, Zhiguo

    2016-11-01

    Applying two preferential selection mechanisms of flow destination, we develop two new methods to quantify the initial load of a node, where the flow is transported along the shortest path between two nodes. We propose a simple cascading model and study cascading dynamics induced by attacking the node with the highest load in some synthetic and actual networks. Surprisingly, we observe the abnormal fluctuation of cascading dynamics, i.e., more damage can be triggered if we spend significantly higher cost to protect a network. In particular, this phenomenon is independent of the initial flow distribution and the preferential selection mechanisms of flow destination. However, it remains unclear which specific structural patterns may affect the fluctuation of cascading dynamics. In this paper, we examine the local evolution of the cascading propagation by constructing some special networks. We show that revivals of some nodes in the double ring structure facilitate the transportation of the flow between two unconnected sub-networks, cause more damage and subsequently lead to the abnormal fluctuation of cascading dynamics. Compared with the traditional definition of the betweenness, we adopt two new proposed methods to further evaluate the resilience of several actual networks. We find that some real world networks reach the strongest resilience level against cascading failures in our preferential selection mechanisms of flow destination. Moreover, we explore how to use the minimum cost to maximize the resilience of the studied networks.

  6. MAGNETOHYDRODYNAMIC KINK WAVES IN NONUNIFORM SOLAR FLUX TUBES: PHASE MIXING AND ENERGY CASCADE TO SMALL SCALES

    Energy Technology Data Exchange (ETDEWEB)

    Soler, Roberto; Terradas, Jaume, E-mail: roberto.soler@uib.es [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain)

    2015-04-10

    Magnetohydrodynamic (MHD) kink waves are ubiquitously observed in the solar atmosphere. The propagation and damping of these waves may play relevant roles in the transport and dissipation of energy in the solar atmospheric medium. However, in the atmospheric plasma dissipation of transverse MHD wave energy by viscosity or resistivity needs very small spatial scales to be efficient. Here, we theoretically investigate the generation of small scales in nonuniform solar magnetic flux tubes due to phase mixing of MHD kink waves. We go beyond the usual approach based on the existence of a global quasi-mode that is damped in time due to resonant absorption. Instead, we use a modal expansion to express the MHD kink wave as a superposition of Alfvén continuum modes that are phase mixed as time evolves. The comparison of the two techniques evidences that the modal analysis is more physically transparent and describes both the damping of global kink motions and the building up of small scales due to phase mixing. In addition, we discuss that the processes of resonant absorption and phase mixing are closely linked. They represent two aspects of the same underlying physical mechanism: the energy cascade from large scales to small scales due to naturally occurring plasma and/or magnetic field inhomogeneities. This process may provide the necessary scenario for efficient dissipation of transverse MHD wave energy in the solar atmospheric plasma.

  7. Active control of light based on polarization-coupling cascading

    Science.gov (United States)

    Huo, Juan; Zheng, Yuanlin; Chen, Xianfeng

    2014-10-01

    In this letter, we proposed a novel method for optical manipulation based on polarization-coupling cascading in MgO-doped periodically poled lithium niobate crystal. Polarization-coupling cascading, a series of energy exchanges between two orthogonally polarized beams close to phase matching condition, can also lead to phase shifts, in analogy with that in cascaded second-order nonlinearities. In addition, the parameters of light such as phase, amplitude, and group velocity can be modulated by changing the relative power ratio of the incident continuous wave beams. The phase control was demonstrated by Newton's rings experiment, which was in good agreement with the theoretical prediction.

  8. An Improved Phase Disposition SPWM Strategy for Cascaded Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    Jinbang Xu

    2014-01-01

    Full Text Available The Carrier Phase Shifted (CPS strategy is conventional for cascaded multilevel inverter, because it can naturally ensure all cascaded cells to output balanced power. However, in point of spectra of the output line voltage, CPS is suboptimal to Phase Disposition (PD strategy, because the latter can not naturally ensure power balance. This paper presents an improved PD strategy, inspiration from the disposition of CPS strategy triangle carriers. Just reconstructing the triangle carriers of PD strategy, it can not only reserve the waveform quality of the line voltage to be optimal, but also naturally ensure the output power of each cascaded cells to be balanced.

  9. Revised tephra volumes for Cascade Range volcanoes

    Science.gov (United States)

    Nathenson, Manuel

    2017-01-01

    Isopach maps from tephra eruptions from Mount St. Helens were reported in Carey et al. (1995) and for tephra eruptions from Glacier Peak in Gardner et al. (1998). For exponential thinning, the isopach data only define a single slope on a log thickness versus square root of area plot. Carey et al. (1995) proposed a model that was used to estimate a second slope, and volumes were presented in both studies using this model. A study by Sulpizio (2005) for estimating the second slope and square root of area where the lines intersect involves a systematic analysis of many eruptions to provide correlation equations. The purpose of this paper is to recalculate the volumes of Cascades eruptions and compare results from the two methods. In order to gain some perspective on the methods for estimating the second slope, we use data for thickness versus distance beyond the last isopach that are available for some of the larger eruptions in the Cascades. The thickness versus square root of area method is extended to thickness versus distance by developing an approximate relation between the two assuming elliptical isopachs with the source at one of the foci. Based on the comparisons made between the Carey et al. (1995) and Sulpizio (2005) methods, it is felt that the later method provides a better estimate of the second slope. For Mount St. Helens, the estimates of total volume using the Sulpizio (2005) method are generally smaller than those using the Carey et al. (1995) method. For the volume estimates of Carey et al. (1995), the volume of the May 18, 1980, eruption of Mount St. Helens is smaller than six of the eight previous eruptions. With the new volumes using the Sulpizio (2005) method, the 1980 eruption is smaller in volume than the upper end of the range for only three of the layers (Wn, Ye, and Yn) and is the same size as layer We. Thus the 1980 eruption becomes representative of the mid-range of volumes rather than being in the lower range.

  10. Atmosphere: Power, Critique, Politics

    DEFF Research Database (Denmark)

    Albertsen, Niels

    2016-01-01

    This paper hans three interrelated parts. First, atmosphere is approached through the concept of power. Atmospheres 'grip' us directly or mediate power indirectly by manipulating moods and evoking emotions. How does atmosphere relate to different conceptions of power? Second, atmospheric powers may...

  11. Herbivore release through cascading risk effects.

    Science.gov (United States)

    Schmidt-Entling, Martin H; Siegenthaler, Eva

    2009-12-23

    Predators influence prey through consumption, and through trait-mediated effects such as emigration in response to predation risk (risk effects). We studied top-down effects of (sub-) adult wolf spiders (Lycosidae) on arthropods in a meadow. We compared risk effects with the overall top-down effect (including consumption) by gluing the chelicers of wolf spiders to prevent them from killing the prey. In a field experiment, we created three treatments that included either: (i) intact ('predation') wolf spiders; (ii) wolf spiders with glued chelicers ('risk spiders'); or (iii) no (sub-) adult wolf spiders. Young wolf spiders were reduced by their (sub-) adult congeners. Densities of sheetweb spiders (Linyphiidae), a known intraguild prey of wolf spiders, were equally reduced by the presence of risk and predation wolf spiders. Plant- and leafhoppers (Auchenorrhyncha) showed the inverse pattern of higher densities in the presence of both risk and predation wolf spiders. We conclude that (sub-) adult wolf spiders acted as top predators, which reduced densities of intermediate predators and thereby enhanced herbivores. Complementary to earlier studies that found trait-mediated herbivore suppression, our results demonstrate that herbivores can be enhanced through cascading risk effects by top predators.

  12. Particle energy cascade in the intergalactic medium

    Science.gov (United States)

    Valdés, M.; Evoli, C.; Ferrara, A.

    2010-05-01

    We study the development of high-energy (Ein new code MEDEA (Monte Carlo Energy Deposition Analysis) which includes Bremsstrahlung and inverse Compton (IC) processes, along with H/He collisional ionizations and excitations, and electron-electron collisions. The cascade energy partition into heating, excitations and ionizations depends primarily not only on the IGM ionized fraction, xe, but also on redshift, z, due to IC on cosmic microwave background (CMB) photons. While Bremsstrahlung is unimportant under most conditions, IC becomes largely dominant at energies Ein >= 1 MeV. The main effect of IC at injection energies Ein = 1 GeV CMB photons are preferentially upscattered within the X-ray spectrum (hν > 104 eV) and can free stream to the observer. Complete tables of the fractional energy depositions as a function of redshift, Ein and ionized fraction are given. Our results can be used in many astrophysical contexts, with an obvious application related to the study of decaying/annihilating dark matter (DM) candidates in the high-z Universe.

  13. Cascaded Amplitude Modulations in Sound Texture Perception

    Directory of Open Access Journals (Sweden)

    Richard McWalter

    2017-09-01

    Full Text Available Sound textures, such as crackling fire or chirping crickets, represent a broad class of sounds defined by their homogeneous temporal structure. It has been suggested that the perception of texture is mediated by time-averaged summary statistics measured from early auditory representations. In this study, we investigated the perception of sound textures that contain rhythmic structure, specifically second-order amplitude modulations that arise from the interaction of different modulation rates, previously described as “beating” in the envelope-frequency domain. We developed an auditory texture model that utilizes a cascade of modulation filterbanks that capture the structure of simple rhythmic patterns. The model was examined in a series of psychophysical listening experiments using synthetic sound textures—stimuli generated using time-averaged statistics measured from real-world textures. In a texture identification task, our results indicated that second-order amplitude modulation sensitivity enhanced recognition. Next, we examined the contribution of the second-order modulation analysis in a preference task, where the proposed auditory texture model was preferred over a range of model deviants that lacked second-order modulation rate sensitivity. Lastly, the discriminability of textures that included second-order amplitude modulations appeared to be perceived using a time-averaging process. Overall, our results demonstrate that the inclusion of second-order modulation analysis generates improvements in the perceived quality of synthetic textures compared to the first-order modulation analysis considered in previous approaches.

  14. MCDF calculations of Auger cascade processes

    Science.gov (United States)

    Beerwerth, Randolf; Fritzsche, Stephan

    2017-10-01

    We model the multiple ionization of near-neutral core-excited atoms where a cascade of Auger processes leads to the emission of several electrons. We utilize the multiconfiguration Dirac-Fock (MCDF) method to generate approximate wave functions for all fine-structure levels and to account for all decays between them. This approach allows to compute electron spectra, the population of final-states and ion yields, that are accessible in many experiments. Furthermore, our approach is based on the configuration interaction method. A careful treatment of correlation between electronic configurations enables one to model three-electron processes such as an Auger decay that is accompanied by an additional shake-up transition. Here, this model is applied to the triple ionization of atomic cadmium, where we show that the decay of inner-shell 4p holes to triply-charged final states is purely due to the shake-up transition of valence 5s electrons. Contribution to the Topical Issue "Atomic and Molecular Data and their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, Grzegorz Karwasz.

  15. Quantum cascade lasers (QCLs) in biomedical spectroscopy.

    Science.gov (United States)

    Schwaighofer, Andreas; Brandstetter, Markus; Lendl, Bernhard

    2017-10-02

    Quantum cascade lasers (QCL) are the first room temperature semiconductor laser source for the mid-IR spectral region, triggering substantial development for the advancement of mid-IR spectroscopy. Mid-IR spectroscopy in general provides rapid, label-free and objective analysis, particularly important in the field of biomedical analysis. Due to their unique properties, QCLs offer new possibilities for development of analytical methods to enable quantification of clinically relevant concentration levels and to support medical diagnostics. Compared to FTIR spectroscopy, novel and elaborated measurement techniques can be implemented that allow miniaturized and portable instrumentation. This review illustrates the characteristics of QCLs with a particular focus on their benefits for biomedical analysis. Recent applications of QCL-based spectroscopy for analysis of a variety of clinically relevant samples including breath, urine, blood, interstitial fluid, and biopsy samples are summarized. Further potential for technical advancements is discussed in combination with future prospects for employment of QCL-based devices in routine and point-of-care diagnostics.

  16. Quantum cascade lasers for defense and security

    Science.gov (United States)

    Day, Timothy; Pushkarsky, Michael; Caffey, Dave; Cecchetti, Kristen; Arp, Ron; Whitmore, Alex; Henson, Michael; Takeuchi, Eric B.

    2013-10-01

    Quantum cascade laser (QCL) systems are mature and at the vanguard of a new generation of products that support military applications such as Infrared Countermeasures (IRCM) and targeting. The demanding product requirements for aircraft platforms that include reduced size, weight, power consumption and cost (SWaP-C) extends to portable, battery powered handheld products. QCL technology operates throughout the mid-wave (MWIR) and long-wave (LWIR) infrared to provide new capabilities that leverage existing thermal imaging cameras. In addition to their suitability for aircraft platforms, QCL products are a natural fit to meet operator demands for small, lightweight pointer and beacon capabilities. Field-testing of high power, lightweight, battery operated devices has demonstrated their utility across a range of air and ground applications. This talk will present an overview of QCL technology and the Defense and Security products and capabilities that are enabled by it. This talk will also provide an overview of the extensive environmental and performance testing associated with products based on QCL technology.

  17. Cascading reminiscence bumps in popular music.

    Science.gov (United States)

    Krumhansl, Carol Lynne; Zupnick, Justin Adam

    2013-10-01

    Autobiographical memories are disproportionately recalled for events in late adolescence and early adulthood, a phenomenon called the reminiscence bump. Previous studies on music have found autobiographical memories and life-long preferences for music from this period. In the present study, we probed young adults' personal memories associated with top hits over 5-and-a-half decades, as well as the context of their memories and their recognition of, preference for, quality judgments of, and emotional reactions to that music. All these measures showed the typical increase for music released during the two decades of their lives. Unexpectedly, we found that the same measures peaked for the music of participants' parents' generation. This finding points to the impact of music in childhood and suggests that these results reflect the prevalence of music in the home environment. An earlier peak occurred for 1960s music, which may be explained by its quality or by its transmission through two generations. We refer to this pattern of musical cultural transmission over generations as cascading reminiscence bumps.

  18. Enhanced performance of quantum cascade Raman laser

    Science.gov (United States)

    Yousefvand, Hossein Reza; Aahmadi, Vahid

    2015-05-01

    We present a self-consistent numerical approach for quantum cascade Raman laser (QC-RL) with a modified design to improve the device performance. Our modeling approach is based on monolithic integration of stimulated Raman scattering (SRS) and electrically pumped QC laser. The laser band structure utilizing techniques with both material-dependent effective mass and band nonparabolicity is calculated by solving the Schrodinger-Poisson equations self-consistently. A detailed analysis of output characteristics of the obtained structure is carried out within a simplified 4-level rate equations model taking into account the SRS process. The model accurately explains the operating characteristics found in QCLs, such as damping transient response and non-resonant behavior of modulation frequency response. Furthermore, modification of the structure is focused on improving the SRS in the QC-RL. This leads to an enhancement of the device performance such as threshold current, external quantum efficiency, conversion efficiency, turn-on delay and modulation response. The excellent agreement of the experimental data with the simulated light output-current characteristics confirms the validity of the model.

  19. A screening cascade to identify ERβ ligands.

    Science.gov (United States)

    Filgueira, Carly S; Benod, Cindy; Lou, Xiaohua; Gunamalai, Prem S; Villagomez, Rosa A; Strom, Anders; Gustafsson, Jan-Åke; Berkenstam, Anders L; Webb, Paul

    2014-01-01

    The establishment of effective high throughput screening cascades to identify nuclear receptor (NR) ligands that will trigger defined, therapeutically useful sets of NR activities is of considerable importance. Repositioning of existing approved drugs with known side effect profiles can provide advantages because de novo drug design suffers from high developmental failure rates and undesirable side effects which have dramatically increased costs. Ligands that target estrogen receptor β (ERβ) could be useful in a variety of diseases ranging from cancer to neurological to cardiovascular disorders. In this context, it is important to minimize cross-reactivity with ERα, which has been shown to trigger increased rates of several types of cancer. Because of high sequence similarities between the ligand binding domains of ERα and ERβ, preferentially targeting one subtype can prove challenging. Here, we describe a sequential ligand screening approach comprised of complementary in-house assays to identify small molecules that are selective for ERβ. Methods include differential scanning fluorimetry, fluorescence polarization and a GAL4 transactivation assay. We used this strategy to screen several commercially-available chemical libraries, identifying thirty ERβ binders that were examined for their selectivity for ERβ versus ERα, and tested the effects of selected ligands in a prostate cancer cell proliferation assay. We suggest that this approach could be used to rapidly identify candidates for drug repurposing.

  20. Evaluating the Spatial Distribution of Toxic Air Contaminants in Multiple Ecosystem Indicators in the Sierra Nevada-Southern Cascades

    Science.gov (United States)

    Nanus, L.; Simonich, S. L.; Rocchio, J.; Flanagan, C.

    2013-12-01

    Toxic air contaminants originating from agricultural areas of the Central Valley in California threaten vulnerable sensitive receptors including surface water, vegetation, snow, sediments, fish, and amphibians in the Sierra Nevada-Southern Cascades region. The spatial distribution of toxic air contaminants in different ecosystem indicators depends on variation in atmospheric concentrations and deposition, and variation in air toxics accumulation in ecosystems. The spatial distribution of organic air toxics and mercury at over 330 unique sampling locations and sample types over two decades (1990-2009) in the Sierra Nevada-Southern Cascades region were compiled and maps were developed to further understand spatial patterns and linkages between air toxics deposition and ecological effects. Potential ecosystem impacts in the Sierra Nevada-Southern Cascades region include bioaccumulation of air toxics in both aquatic and terrestrial ecosystems, reproductive disruption, and immune suppression. The most sensitive ecological end points in the region that are affected by bioaccumulation of toxic air contaminants are fish. Mercury was detected in all fish and approximately 6% exceeded human consumption thresholds. Organic air toxics were also detected in fish yielding variable spatial patterns. For amphibians, which are sensitive to pesticide exposure and potential immune suppression, increasing trends in current and historic use pesticides are observed from north to south across the region. In other indicators, such as vegetation, pesticide concentrations in lichen increase with increasing elevation. Current and historic use pesticides and mercury were also observed in snowpack at high elevations in the study area. This study shows spatial patterns in toxic air contaminants, evaluates associated risks to sensitive receptors, and identifies data gaps. Future research on atmospheric modeling and information on sources is needed in order to predict which ecosystems are the

  1. Optimization of quantum cascade laser operation by geometric design of cascade active band in open and closed models

    Directory of Open Access Journals (Sweden)

    M.V. Tkach

    2013-01-01

    Full Text Available Using the effective mass and rectangular potential approximations, the theory of electron dynamic conductivity is developed for the plane multilayer resonance tunnel structure placed into a constant electric field within the model of open nanosystem, and oscillator forces of quantum transitions within the model of closed nanosystem. For the experimentally produced quantum cascade laser with four-barrier active band of separate cascade, it is proven that just the theory of dynamic conductivity in the model of open cascade most adequately describes the radiation of high frequency electromagnetic field while the electrons transport through the resonance tunnel structure driven by a constant electric field.

  2. Terahertz quantum-cascade lasers based on an interlaced photon-phonon cascade

    Science.gov (United States)

    Köhler, Rüdeger; Tredicucci, Alessandro; Mauro, Cosimo; Beltram, Fabio; Beere, Harvey E.; Linfield, Edmund H.; Davies, A. Giles; Ritchie, David A.

    2004-02-01

    A THz (λ˜80 μm) quantum-cascade laser utilizing alternating photon- and phonon-emitting stages has been developed to achieve efficient extraction of electrons from the lower laser level. Thermal backfilling of electrons is drastically reduced leading to an operation up to 95 K and a weak temperature dependence of the power versus current slope efficiency. The threshold current density is 280 A cm-2 at 6 K and increases to 580 A cm-2 at 90 K. Peak output powers of 10 mW at 30 K and 4 mW at 80 K are obtained.

  3. On periodic orbits in discrete-time cascade systems

    Directory of Open Access Journals (Sweden)

    Huimin Li

    2006-01-01

    Full Text Available We present some results on existence, minimum period, number of periodic orbits, and stability of periodic orbits in discrete-time cascade systems. Some examples are presented to illustrate these results.

  4. Quantum cascade laser infrared spectroscopy of single cancer cells

    KAUST Repository

    Patel, Imran

    2017-03-27

    Quantum cascade laser infrared spectroscopy is a next generation novel imaging technique allowing high resolution spectral imaging of cells. We show after spectral pre-processing, identification of different cancer cell populations within minutes.

  5. Critical Boundary of Cascaded Quadratic Soliton Compression in PPLN

    OpenAIRE

    Guo, Hairun; Zeng, Xianglong; Zhou, Binbin; Bache, Morten

    2012-01-01

    Cascaded quadratic soliton compression in PPLN is investigated and a general critical soliton number is found as the compression boundary. An optimal-parameter diagram for compression at 1550 nm is presented.

  6. Terahertz Quantum Cascade Laser Based 3D Imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — LongWave Photonics proposes a terahertz quantum-cascade laser based swept-source optical coherence tomography (THz SS-OCT) system for single-sided, 3D,...

  7. Multicompartment Artificial Organelles Conducting Enzymatic Cascade Reactions inside Cells

    DEFF Research Database (Denmark)

    Gallardo, Maria Godoy; Labay, Cédric Pierre; Trikalitis, Vasileios

    2017-01-01

    capsosome system, which consists of multiple liposomes and fluorescent gold nanoclusters embedded within a polymer carrier capsule. We subsequently demonstrate that encapsulated enzymes preserve their activity intracellularly, allowing for controlled enzymatic cascade reaction within a host cell....

  8. Cascaded spintronic logic with low-dimensional carbon

    Science.gov (United States)

    Friedman, Joseph S.; Girdhar, Anuj; Gelfand, Ryan M.; Memik, Gokhan; Mohseni, Hooman; Taflove, Allen; Wessels, Bruce W.; Leburton, Jean-Pierre; Sahakian, Alan V.

    2017-06-01

    Remarkable breakthroughs have established the functionality of graphene and carbon nanotube transistors as replacements to silicon in conventional computing structures, and numerous spintronic logic gates have been presented. However, an efficient cascaded logic structure that exploits electron spin has not yet been demonstrated. In this work, we introduce and analyse a cascaded spintronic computing system composed solely of low-dimensional carbon materials. We propose a spintronic switch based on the recent discovery of negative magnetoresistance in graphene nanoribbons, and demonstrate its feasibility through tight-binding calculations of the band structure. Covalently connected carbon nanotubes create magnetic fields through graphene nanoribbons, cascading logic gates through incoherent spintronic switching. The exceptional material properties of carbon materials permit Terahertz operation and two orders of magnitude decrease in power-delay product compared to cutting-edge microprocessors. We hope to inspire the fabrication of these cascaded logic circuits to stimulate a transformative generation of energy-efficient computing.

  9. Mutually independent cascades in anisotropic soap-film turbulence

    Science.gov (United States)

    Liu, Chien-Chia; Gioia, Gustavo; Chakraborty, Pinaki

    2015-03-01

    Computational, experimental and field data amassed to date indicate that in 2D turbulence the spectrum of longitudinal velocity fluctuations, E11 (k1) , and the spectrum of transverse velocity fluctuations, E22 (k1) , correspond always to the same cascade, consistent with isotropy, so that E11 (k1) ~k-α and E22 (k1) ~k-α , where the ``spectral exponent'' α is either 5/3 (for the inverse-energy cascade) or 3 (for the enstrophy cascade). Here, we carry out experiments on turbulent 2D soap-film flows in which E11 (k1) ~k - 5 / 3 and E22 (k1) ~k-3 , as if two mutually independent cascades were concurrently active within the same flow. To our knowledge, this species of spectrum has never been observed or predicted theoretically. Our finding might open up new vistas in the understanding of turbulence.

  10. Cascade Structure of Digital Predistorter for Power Amplifier Linearization

    Directory of Open Access Journals (Sweden)

    E. B. Solovyeva

    2015-12-01

    Full Text Available In this paper, a cascade structure of nonlinear digital predistorter (DPD synthesized by the direct learning adaptive algorithm is represented. DPD is used for linearization of power amplifier (PA characteristic, namely for compensation of PA nonlinear distortion. Blocks of the cascade DPD are described by different models: the functional link artificial neural network (FLANN, the polynomial perceptron network (PPN and the radially pruned Volterra model (RPVM. At synthesis of the cascade DPD there is possibility to overcome the ill conditionality problem due to reducing the dimension of DPD nonlinear operator approximation. Results of compensating nonlinear distortion in Wiener–Hammerstein model of PA at the GSM–signal with four carriers are shown. The highest accuracy of PA linearization is produced by the cascade DPD containing PPN and RPVM.

  11. PULSE MODULATION POWER AMPLIFIER WITH ENHANCED CASCADE CONTROL METHOD

    DEFF Research Database (Denmark)

    1998-01-01

    A digital switching power amplifier with Multivariable Enhanced Cascade Controlled (MECC) includes a modulator, a switching power stage and a low pass filter. In the first preferred embodiment an enhanced cascade control structure local to the switching power stage is added, characterised by havi...... and feedback path A to determine stable self-oscillating conditions. An implemented 250W example MECC digital power amplifier has proven superior performance in terms of audio performance (0.005 % distortion, 115 dB dynamic range) and efficiency (92 %).......A digital switching power amplifier with Multivariable Enhanced Cascade Controlled (MECC) includes a modulator, a switching power stage and a low pass filter. In the first preferred embodiment an enhanced cascade control structure local to the switching power stage is added, characterised by having...

  12. Vortex merging and spectral cascade in two-dimensional flows

    DEFF Research Database (Denmark)

    Nielsen, A.H.; He, X.; Juul Rasmussen, J.

    1996-01-01

    The merging of two identical vortices is studied numerically using a spectral code. It is noted that the enstrophy cascade is most active on the distorted vortex boundaries, with a Kolmogorov-like spectrum E(k) approximate to k(-alpha), alpha less than or equal to 4, developed at high wave numbers....... The inverse energy cascade is completed when the vortices merge into one of larger size. (C) 1996 American Institute of Physics....

  13. The importance of sensory integration processes for action cascading

    OpenAIRE

    Krutika Gohil; Ann-Kathrin Stock; Christian Beste

    2015-01-01

    Dual tasking or action cascading is essential in everyday life and often investigated using tasks presenting stimuli in different sensory modalities. Findings obtained with multimodal tasks are often broadly generalized, but until today, it has remained unclear whether multimodal integration affects performance in action cascading or the underlying neurophysiology. To bridge this gap, we asked healthy young adults to complete a stop-change paradigm which presented different stimuli in either ...

  14. Noise properties and cascadability of SOA-EA regenerators

    DEFF Research Database (Denmark)

    Öhman, Filip; Bischoff, Svend; Tromborg, Bjarne

    2002-01-01

    We suggest and analyse a new device containing concatenated pairs of semiconductor optical amplifiers (SOAs) and electroabsorption modulators (EAs). The device has regenerative properties and improves the cascadability of optical fibre links.......We suggest and analyse a new device containing concatenated pairs of semiconductor optical amplifiers (SOAs) and electroabsorption modulators (EAs). The device has regenerative properties and improves the cascadability of optical fibre links....

  15. Climate Change and Baleen Whale Trophic Cascades in Greenland

    Science.gov (United States)

    2009-09-30

    DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. Climate Change and Baleen Whale Trophic Cascades in Greenland...SUBTITLE Climate Change And Baleen Whale Trophic Cascades In Greenland 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...2009. Polar bears in Northwest Greenland – An interview survey about the catch and the climate . Meddelelser om Grønland. [In Press, refereed] Heide

  16. Critical Boundary of Cascaded Quadratic Soliton Compression in PPLN

    DEFF Research Database (Denmark)

    Guo, Hairun; Zeng, Xianglong; Zhou, Binbin

    2012-01-01

    Cascaded quadratic soliton compression in PPLN is investigated and a general critical soliton number is found as the compression boundary. An optimal-parameter diagram for compression at 1550 nm is presented.......Cascaded quadratic soliton compression in PPLN is investigated and a general critical soliton number is found as the compression boundary. An optimal-parameter diagram for compression at 1550 nm is presented....

  17. Parton-hadron cascade approach at SPS and RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Nara, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-07-01

    A parton-hadron cascade model which is the extension of hadronic cascade model incorporating hard partonic scattering based on HIJING is presented to describe the space-time evolution of parton/hadron system produced by ultra-relativistic nuclear collisions. Hadron yield, baryon stopping and transverse momentum distribution are calculated and compared with HIJING and VNI. Baryon density, energy density and temperature for RHIC are calculated within this model. (author)

  18. Advanced Dementia Research in the Nursing Home: The CASCADE Study

    OpenAIRE

    Mitchell, Susan L.; Kiely, Dan K.; Jones, Richard N.; Prigerson, Holly; Volicer, Ladislav; Teno, Joan M.

    2006-01-01

    Despite the growing number of persons with advanced dementia, and the need to improve their end-of-life care, few studies have addressed this important topic. The objectives of this report are to present the methodology established in the CASCADE (Choices, Attitudes, and Strategies for Care of Advanced Dementia at the End-of-Life) study, and to describe how challenges specific to this research were met. The CASCADE study is an ongoing, federally funded, 5-year prospective cohort study of nurs...

  19. Power system cascading risk assessment based on complex network theory

    Science.gov (United States)

    Wang, Zhuoyang; Hill, David J.; Chen, Guo; Dong, Zhao Yang

    2017-09-01

    When a single failure occurs in a vulnerable part of a power system, this may cause a large area cascading event. Therefore, an advanced method that can assess the risks during cascading events is needed. In this paper, an improved complex network model for power system risk assessment is proposed. Risk is defined by consequence and probability of the failures in this model, which are affected by both power factors and network structure. Compared with existing risk assessment models, the proposed one can evaluate the risk of the system comprehensively during a cascading event by combining the topological and electrical information. A new cascading event simulation module is adopted to identify the power grid cascading chain from a system-level view. In addition, simulations are investigated on the IEEE 14 bus system and IEEE 39 bus system respectively to illustrate the performance of the proposed module. The simulation results demonstrate that the proposed method is effective in a power grid risk assessment during cascading event.

  20. Signal transduction in a covalent post-assembly modification cascade

    Science.gov (United States)

    Pilgrim, Ben S.; Roberts, Derrick A.; Lohr, Thorsten G.; Ronson, Tanya K.; Nitschke, Jonathan R.

    2017-12-01

    Natural reaction cascades control the movement of biomolecules between cellular compartments. Inspired by these systems, we report a synthetic reaction cascade employing post-assembly modification reactions to direct the partitioning of supramolecular complexes between phases. The system is composed of a self-assembled tetrazine-edged FeII8L12 cube and a maleimide-functionalized FeII4L6 tetrahedron. Norbornadiene (NBD) functions as the stimulus that triggers the cascade, beginning with the inverse-electron-demand Diels-Alder reaction of NBD with the tetrazine moieties of the cube. This reaction generates cyclopentadiene as a transient by-product, acting as a relay signal that subsequently undergoes a Diels-Alder reaction with the maleimide-functionalized tetrahedron. Cyclooctyne can selectively inhibit the cascade by outcompeting NBD as the initial trigger. Initiating the cascade with 2-octadecyl NBD leads to selective alkylation of the tetrahedron upon cascade completion. The increased lipophilicity of the C18-tagged tetrahedron drives this complex into a non-polar phase, allowing its isolation from the initially inseparable mixture of complexes.

  1. Cascading failures in spatially-embedded random networks.

    Science.gov (United States)

    Asztalos, Andrea; Sreenivasan, Sameet; Szymanski, Boleslaw K; Korniss, Gyorgy

    2014-01-01

    Cascading failures constitute an important vulnerability of interconnected systems. Here we focus on the study of such failures on networks in which the connectivity of nodes is constrained by geographical distance. Specifically, we use random geometric graphs as representative examples of such spatial networks, and study the properties of cascading failures on them in the presence of distributed flow. The key finding of this study is that the process of cascading failures is non-self-averaging on spatial networks, and thus, aggregate inferences made from analyzing an ensemble of such networks lead to incorrect conclusions when applied to a single network, no matter how large the network is. We demonstrate that this lack of self-averaging disappears with the introduction of a small fraction of long-range links into the network. We simulate the well studied preemptive node removal strategy for cascade mitigation and show that it is largely ineffective in the case of spatial networks. We introduce an altruistic strategy designed to limit the loss of network nodes in the event of a cascade triggering failure and show that it performs better than the preemptive strategy. Finally, we consider a real-world spatial network viz. a European power transmission network and validate that our findings from the study of random geometric graphs are also borne out by simulations of cascading failures on the empirical network.

  2. Mitigate Cascading Failures on Networks using a Memetic Algorithm.

    Science.gov (United States)

    Tang, Xianglong; Liu, Jing; Hao, Xingxing

    2016-12-09

    Research concerning cascading failures in complex networks has become a hot topic. However, most of the existing studies have focused on modelling the cascading phenomenon on networks and analysing network robustness from a theoretical point of view, which considers only the damage incurred by the failure of one or several nodes. However, such a theoretical approach may not be useful in practical situation. Thus, we first design a much more practical measure to evaluate the robustness of networks against cascading failures, termed Rcf. Then, adopting Rcf as the objective function, we propose a new memetic algorithm (MA) named MA-Rcf to enhance network the robustness against cascading failures. Moreover, we design a new local search operator that considers the characteristics of cascading failures and operates by connecting nodes with a high probability of having similar loads. In experiments, both synthetic scale-free networks and real-world networks are used to test the efficiency and effectiveness of the MA-Rcf. We systematically investigate the effects of parameters on the performance of the MA-Rcf and validate the performance of the newly designed local search operator. The results show that the local search operator is effective, that MA-Rcf can enhance network robustness against cascading failures efficiently, and that it outperforms existing algorithms.

  3. Human initiated cascading failures in societal infrastructures.

    Directory of Open Access Journals (Sweden)

    Chris Barrett

    Full Text Available In this paper, we conduct a systematic study of human-initiated cascading failures in three critical inter-dependent societal infrastructures due to behavioral adaptations in response to a crisis. We focus on three closely coupled socio-technical networks here: (i cellular and mesh networks, (ii transportation networks and (iii mobile call networks. In crises, changes in individual behaviors lead to altered travel, activity and calling patterns, which influence the transport network and the loads on wireless networks. The interaction between these systems and their co-evolution poses significant technical challenges for representing and reasoning about these systems. In contrast to system dynamics models for studying these interacting infrastructures, we develop interaction-based models in which individuals and infrastructure elements are represented in detail and are placed in a common geographic coordinate system. Using the detailed representation, we study the impact of a chemical plume that has been released in a densely populated urban region. Authorities order evacuation of the affected area, and this leads to individual behavioral adaptation wherein individuals drop their scheduled activities and drive to home or pre-specified evacuation shelters as appropriate. They also revise their calling behavior to communicate and coordinate among family members. These two behavioral adaptations cause flash-congestion in the urban transport network and the wireless network. The problem is exacerbated with a few, already occurring, road closures. We analyze how extended periods of unanticipated road congestion can result in failure of infrastructures, starting with the servicing base stations in the congested area. A sensitivity analysis on the compliance rate of evacuees shows non-intuitive effect on the spatial distribution of people and on the loading of the base stations. For example, an evacuation compliance rate of 70% results in higher number

  4. Product lifecycle approach to cascade impaction measurements.

    Science.gov (United States)

    Tougas, Terrence P; Christopher, Dave; Mitchell, Jolyon; Lyapustina, Svetlana; Van Oort, Michiel; Bauer, Richard; Glaab, Volker

    2011-03-01

    Over the lifecycle of an orally inhaled product (OIP), multi-stage cascade impactor (CI) measurements are used for different purposes and to address different questions. Full-resolution CIs can provide important information during product development and are widely used but are time- and resource-intensive, highly variable, and suboptimal for OIP quality control (QC) testing. By contrast, Efficient Data Analysis (EDA) combined with Abbreviated Impactor Measurement (AIM) systems pertinent either for QC and-possibly-for adult Human Respiratory Tract (pHRT) has been introduced for OIP performance assessment during and post-development. This article summarizes available evidence and discusses a strategy for using either abbreviated or full-resolution CI systems depending on the purpose of the measurement, such that adequate, accurate, and efficient testing of aerodynamic particle size distribution (APSD) of OIPs can be achieved throughout the lifecycle of a product. Under these proposals, a comprehensive testing program should initially be conducted by full-resolution CI in OIP development to ascertain the product's APSD. Subsequently, correlations should be established from the selected AIM CIs to the corresponding full-resolution system, ideally developing specifications common to both techniques. In the commercial phase, it should be possible to release product using AIM/EDA, keeping the full-resolution CI for investigations, change control, and trouble-shooting, thus optimizing resources for APSD characterization throughout the product lifecycle. If an in vitro-in vivo relationship is established and clinically relevant sizes are known, an AIM-pHRT could serve as a quick indicator that clinically relevant fractions have not changed and also, in the management of post-approval changes. © 2011 American Association of Pharmaceutical Scientists

  5. Cascaded processing in written compound word production

    Directory of Open Access Journals (Sweden)

    Raymond eBertram

    2015-04-01

    Full Text Available In this study we investigated the intricate interplay between central linguistic processing and peripheral motor processes during typewriting. Participants had to typewrite two-constituent (noun-noun Finnish compounds in response to picture presentation while their typing behavior was registered. As dependent measures we used writing onset time to assess what processes were completed before writing and inter-key intervals to assess what processes were going on during writing. It was found that writing onset time was determined by whole word frequency rather than constituent frequencies, indicating that compound words are retrieved as whole orthographic units before writing is initiated. In addition, we found that the length of the first syllable also affects writing onset time, indicating that the first syllable is fully prepared before writing commences. The inter-key interval results showed that linguistic planning is not fully ready before writing, but cascades into the motor execution phase. More specifically, inter-key intervals were largest at syllable and morpheme boundaries, supporting the view that additional linguistic planning takes place at these boundaries. Bigram and trigram frequency also affected inter-key intervals with shorter intervals corresponding to higher frequencies. This can be explained by stronger memory traces for frequently co-occurring letter sequences in the motor memory for typewriting. These frequency effects were even larger in the second than in the first constituent, indicating that low-level motor memory starts to become more important during the course of writing compound words. We discuss our results in the light of current models of morphological processing and written word production.

  6. Longitudinal gradients along a reservoir cascade

    Science.gov (United States)

    Miranda, L.E.; Habrat, M.D.; Miyazono, S.

    2008-01-01

    Reservoirs have traditionally been regarded as spatially independent entities rather than as longitudinal segments of a river system that are connected upstream and downstream to the river and other reservoirs. This view has frustrated advancement in reservoir science by impeding adequate organization of available information and by hindering interchanges with allied disciplines that often consider impounded rivers at the basin scale. We analyzed reservoir morphology, water quality, and fish assemblage data collected in 24 reservoirs of the Tennessee River; we wanted to describe longitudinal changes occurring at the scale of the entire reservoir series (i.e., cascade) and to test the hypothesis that fish communities and environmental factors display predictable gradients like those recognized for unimpounded rivers. We used a data set collected over a 7-year period; over 3 million fish representing 94 species were included in the data set. Characteristics such as reservoir mean depth, relative size of the limnetic zone, water retention time, oxygen stratification, thermal stratification, substrate size, and water level fluctuations increased in upstream reservoirs. Conversely, reservoir area, extent of riverine and littoral zones, access to floodplains and associated wetlands, habitat diversity, and nutrient and sediment inputs increased in downstream reservoirs. Upstream reservoirs included few, largely lacustrine, ubiquitous fish taxa that were characteristic of the lentic upper reaches of the basin. Fish species richness increased in a downstream direction from 12 to 67 species/ reservoir as riverine species became more common. Considering impoundments at a basin scale by viewing them as sections in a river or links in a chain may generate insight that is not always available when the impoundments are viewed as isolated entities. Basin-scale variables are rarely controllable but constrain the expression of processes at smaller scales and can facilitate the

  7. Measurement of the atmospheric nu (mu) energy spectrum from 100 GeV to 200 TeV with the ANTARES telescope

    NARCIS (Netherlands)

    Adrian-Martinez, S.; Albert, A.; Al Samarai, I.; Andre, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Astraatmadja, T.; Aubert, J. -J.; Baret, B.; Barrios-Marti, J.; Basa, S.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bogazzi, C.; Bouhou, B.; Bouwhuis, M.C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carloganu, C.; Carr, J.; Cecchini, S.; Charif, Z.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Classen, F.; Core, L.; Costantini, H.; Coyle, P.; Creusot, A.; Curtil, C.; Dekeyser, I.; Deschamps, A.; De Bonis, G.; Decowski, M. P.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drouhin, D.; Dumas, A.; Eberl, T.; Emanuele, U.; Enzenhoefer, A.; Ernenwein, J. -P.; Escoffier, S.; Fehn, K.; Fermani, P.; Flaminio, V.; Folger, F.; Fritsch, U.; Fusco, L. A.; Galata, S.; Gay, P.; Geisselsoeder, S.; Geyer, K.; Giacomelli, G.; Giordano, V.; Gleixner, A.; Gomez-Gonzalez, J. P.; Graf, K.; Guillard, G.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernandez-Rey, J. J.; Herold, B.; Hoessl, J.; James, C. W.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U.; Kooijman, P.; Kouchner, A.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lambard, E.; Lambard, G.; Larosa, G.; Lattuada, D.; Lefevre, D.; Leonora, E.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-Mora, J. A.; Martini, S.; Michael, T.; Montaruli, T.; Morganti, M.; Motz, H.; Mueller, C.; Neff, M.; Nezri, E.; Palioselitis, D.; Pavalas, G. E.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Racca, C.; Richter, R.; Riviere, C.; Robert, A.; Roensch, K.; Rostovtsev, A.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schmid, J.; Schnabel, J.; Schulte, S.; Schuessler, F.; Seitz, T.; Shanidze, R.; Sieger, C.; Simeone, F.; Spies, A.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Sanchez-Losa, A.; Taiuti, M.; Tamburini, C.; Tayalati, Y.; Trovato, A.; Vallage, B.; Vallee, C.; Van Elewyck, V.; Vernin, P.; Visser, E.; Wagner, S.; Wilms, J.; de Wolf, E.; Yatkin, K.; Yepes, H.; Zornoza, J. D.; Zuniga, J.

    2013-01-01

    Atmospheric neutrinos are produced during cascades initiated by the interaction of primary cosmic rays with air nuclei. In this paper, a measurement of the atmospheric energy spectrum in the energy range 0.1-200 TeV is presented, using data collected by the ANTARES underwater neutrino telescope from

  8. Atmosphere-Ionosphere Coupling via Atmospheric Waves

    Science.gov (United States)

    Koucka Knizova, Petra; Lastovicka, Jan

    2017-04-01

    The Earth atmosphere and ionosphere is complicated and highly variable system which displays oscillations on wide range scales. The most important factor influencing the ionosphere is certainly the solar and geomagnetic activity. However, the processes even in distant regions in the neutral atmosphere cannot be simply neglected. This contribution reviews aspects of ionospheric variability originating in the lower laying atmosphere. It focuses especially on the generation and propagation of the atmospheric waves from their source region up to the heights of the ionosphere. We will show the role of infrasound, gravity waves, tides and planetary waves in the atmosphere-ionosphere coupling. Particularly gravity waves are of high importance for the ionosphere. Recent theoretical and experimental results will briefly be reviewed.

  9. Deep-cascade: Cascading 3D Deep Neural Networks for Fast Anomaly Detection and Localization in Crowded Scenes.

    Science.gov (United States)

    Sabokrou, Mohammad; Fayyaz, Mohsen; Fathy, Mahmood; Klette, Reinhard

    2017-02-17

    This paper proposes a fast and reliable method for anomaly detection and localization in video data showing crowded scenes. Time-efficient anomaly localization is an ongoing challenge and subject of this paper. We propose a cubicpatch- based method, characterised by a cascade of classifiers, which makes use of an advanced feature-learning approach. Our cascade of classifiers has two main stages. First, a light but deep 3D auto-encoder is used for early identification of "many" normal cubic patches. This deep network operates on small cubic patches as being the first stage, before carefully resizing remaining candidates of interest, and evaluating those at the second stage using a more complex and deeper 3D convolutional neural network (CNN). We divide the deep autoencoder and the CNN into multiple sub-stages which operate as cascaded classifiers. Shallow layers of the cascaded deep networks (designed as Gaussian classifiers, acting as weak single-class classifiers) detect "simple" normal patches such as background patches, and more complex normal patches are detected at deeper layers. It is shown that the proposed novel technique (a cascade of two cascaded classifiers) performs comparable to current top-performing detection and localization methods on standard benchmarks, but outperforms those in general with respect to required computation time.

  10. Freedom from band-gap slavery: from diode lasers to quantum cascade lasers

    Science.gov (United States)

    Capasso, Federico

    2010-02-01

    Semiconductor heterostructure lasers, for which Alferov and Kromer received part of the Nobel Prize in Physics in 2000, are the workhorse of technologies such as optical communications, optical recording, supermarket scanners, laser printers and fax machines. They exhibit high performance in the visible and near infrared and rely for their operation on electrons and holes emitting photons across the semiconductor bandgap. This mechanism turns into a curse at longer wavelengths (mid-infrared) because as the bandgap, shrinks laser operation becomes much more sensitive to temperature, material defects and processing. Quantum Cascade Laser (QCL), invented in 1994, rely on a radically different process for light emission. QCLs are unipolar devices in which electrons undergo transitions between quantum well energy levels and are recycled through many stages emitting a cascade of photons. Thus by suitable tailoring of the layers' thickness, using the same heterostructure material, they can lase across the molecular fingerprint region from 3 to 25 microns and beyond into the far-infrared and submillimiter wave spectrum. High power cw room temperature QCLs and QCLs with large continuous single mode tuning range have found many applications (infrared countermeasures, spectroscopy, trace gas analysis and atmospheric chemistry) and are commercially available. )

  11. Forest Vegetation Monitoring Protocol for National Parks in the North Coast and Cascades Network

    Science.gov (United States)

    Woodward, Andrea; Hutten, Karen M.; Boetsch, John R.; Acker, Steven A.; Rochefort, Regina M.; Bivin, Mignonne M.; Kurth, Laurie L.

    2009-01-01

    Plant communities are the foundation for terrestrial trophic webs and animal habitat, and their structure and species composition are an integrated result of biological and physical drivers (Gates, 1993). Additionally, they have a major role in geologic, geomorphologic and soil development processes (Jenny, 1941; Stevens and Walker, 1970). Throughout most of the Pacific Northwest, environmental conditions support coniferous forests as the dominant vegetation type. In the face of anthropogenic climate change, forests have a global role as potential sinks for atmospheric carbon (Goodale and others, 2002). Consequently, knowledge of the status of forests in the three large parks of the NCCN [that is, Mount Rainier (MORA), North Cascades (NOCA), and Olympic (OLYM) National Parks] is fundamental to understanding the condition of Pacific Northwest ecosystems. Diverse climate and soil properties across the Pacific Northwest result in a variety of forest types (Franklin and Dyrness, 1973; Franklin and others, 1988; Henderson and others, 1989, 1992). The mountainous terrain of Mount Rainier, North Cascades, and Olympic National Parks create steep elevational and precipitation gradients within and among the parks: collectively, these parks span from sea level to more than 4,200 m; and include areas with precipitation from 90 to more than 500 cm. The resulting forests range from coastal rainforests with dense understories and massive trees draped with epiphytes; to areas with drought-adapted Ponderosa pines; to high-elevation subalpine fir forests interspersed with meadows just below treeline (table 1). These forests, in turn, are the foundation for other biotic communities constituting Pacific Northwest ecosystems.

  12. Aeration efficiency over stepped cascades: better predictions from flow regimes.

    Science.gov (United States)

    Khdhiri, Hatem; Potier, Olivier; Leclerc, Jean-Pierre

    2014-05-15

    Stepped cascades are recognized as high potential air-water gas exchangers. In natural rivers, these structures enhance oxygen transfer to water by creating turbulence at interface with increasing air entrainment in water and air-water surface exchange. Stepped cascades could be really useful to improve the natural self-purification process by providing oxygen to aerobic micro-organisms. The aeration performance of these structures depends on several operating and geometrical parameters. In the literature, several empirical correlations for aeration efficiency prediction on stepped cascades exist. Most of these correlations are only applicable for operating and geometrical parameters in the range of which they have been developed. In this paper, 398 experimental sets of data (from our experiments and collected from literature) were used to develop a correlation for aeration prediction over stepped cascades derived from dimensional analysis and parameterized for each individual flow regime in order to consider change in flow regime effect on oxygen transfer. This new correlation allowed calculating the whole set of data obtained for cascades with steps heights between 0.05 m and 0.254 m, cascade total height between 0.25 m and 2.5 m, for discharges per unit of width ranging from 0.28 10(-3) m(2)/s to 600 10(-3) m(2)/s and for cascade steps number between 3 and 25. In these ranges of parameters, standard deviation for aeration efficiency estimation was found to be less than 17%. Finally, advices were proposed to help and improve the structure design in order to improve aeration. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Quantum cascade laser-based multipass absorption system for hydrogen peroxide detection

    Science.gov (United States)

    Cao, Yingchun; Sanchez, Nancy P.; Jiang, Wenzhe; Ren, Wei; Lewicki, Rafal; Jiang, Dongfang; Griffin, Robert J.; Tittel, Frank K.

    2015-01-01

    Hydrogen peroxide (H2O2) is a relevant molecular trace gas species, that is related to the oxidative capacity of the atmosphere, the production of radical species such as OH, the generation of sulfate aerosol via oxidation of S(IV) to S(VI), and the formation of acid rain. The detection of atmospheric H2O2 involves specific challenges due to its high reactivity and low concentration (ppbv to sub-ppbv level). Traditional methods for measuring atmospheric H2O2 concentration are often based on wet-chemistry methods that require a transfer from the gas- to liquid-phase for a subsequent determination by techniques such as fluorescence spectroscopy, which can lead to problems such as sampling artifacts and interference by other atmospheric constituents. A quartz-enhanced photoacoustic spectroscopy-based system for the measurement of atmospheric H2O2 with a detection limit of 75 ppb for 1-s integration time was previously reported. In this paper, an updated H2O2 detection system based on long-optical-path-length absorption spectroscopy by using a distributed feedback quantum cascade laser (DFB-QCL) will be described. A 7.73-μm CW-DFB-QCL and a thermoelectrically cooled infrared detector, optimized for a wavelength of 8 μm, are employed for theH2O2 sensor system. A commercial astigmatic Herriott multi-pass cell with an effective optical path-length of 76 m is utilized for the reported QCL multipass absorption system. Wavelength modulation spectroscopy (WMS) with second harmonic detection is used for enhancing the signal-to-noise-ratio. A minimum detection limit of 13.4 ppb is achieved with a 2 s sampling time. Based on an Allan-Werle deviation analysis the minimum detection limit can be improved to 1.5 ppb when using an averaging time of 300 s.

  14. Quantum cascade semiconductor infrared and far-infrared lasers: from trace gas sensing to non-linear optics.

    Science.gov (United States)

    Duxbury, Geoffrey; Langford, Nigel; McCulloch, Michael T; Wright, Stephen

    2005-11-01

    The Quantum cascade (QC) laser is an entirely new type of semiconductor device in which the laser wavelength depends on the band-gap engineering. It can be made to operate over a much larger range than lead salt lasers, covering significant parts of both the infrared and submillimetre regions, and with higher output power. In this tutorial review we survey some of the applications of these new lasers, which range from trace gas detection for atmospheric or medical purposes to sub-Doppler and time dependent non-linear spectroscopy.

  15. Intracavity laser absorption spectroscopy using mid-IR quantum cascade laser

    Science.gov (United States)

    Medhi, G.; Muravjov, A. V.; Saxena, H.; Fredricksen, C. J.; Brusentsova, T.; Peale, R. E.; Edwards, O.

    2011-06-01

    Intracavity Laser Absorption Spectroscopy (ICLAS) at IR wavelengths offers an opportunity for spectral sensing with sufficient sensitivity to detect vapors of low vapor pressure compounds such as explosives. Reported here are key enabling technologies for this approach, including multi-mode external-cavity quantum cascade lasers and a scanning Fabry-Perot spectrometer to analyze the laser mode spectrum in the presence of a molecular intracavity absorber. Reported also is the design of a compact integrated data acquisition and control system. Applications include military and commercial sensing for threat compounds, chemical gases, biological aerosols, drugs, and banned or invasive plants or animals, bio-medical breath analysis, and terrestrial or planetary atmosphere science.

  16. Atmospheric structure from Phoenix atmospheric entry data

    Science.gov (United States)

    Catling, D. C.

    2008-12-01

    The atmospheric structure at the time of landing of NASA's Phoenix probe has been derived from measurements of the aerodynamic drag of the spacecraft during atmospheric entry and descent. The result provides the first atmospheric structure in Mars' polar environment obtained from in situ measurements. Phoenix was equipped with an inertial measurement unit (IMU) that used accelerometers for linear acceleration measurement in three Cartesian axes and ring-laser gyroscopes to measure the three- dimensional orientation of the probe (Taylor et al., 2008). The temperature structure of the atmosphere along the flight path was calculated via a four-step process: (i) integrating forward the IMU data to obtain the time history of the spacecraft velocity vector relative to the atmosphere as a function of altitude; (ii) calculating atmospheric density from drag, with iteration for aerodynamic coefficient dependence on density; (iii) integrating the hydrostatic equation to derive the vertical pressure; and (iv) calculating atmospheric temperature from the equation of state. Initial profile reconstruction shows reasonable agreement with predictions in the middle atmosphere for the given season and time of day (landing occurred at 16h 33min 37sec in local solar time expressed as a 24-hour clock). However, the derived lower atmospheric structure below ~0.1 mbar is generally warmer than predicted. A possible explanation could be a shallower vertical distribution of dust that usually assumed. References: P. A. Taylor, D. C. Catling, M. Daly, C. S. Dickinson, H. O. Gunnlaugsson, A-M. Harri, C. F. Lange, Temperature, pressure and wind instrumentation on the Phoenix meteorological package, J. Geophys. Res., 113, EA0A10, doi:10.1029/2007JE003015, 2008.

  17. Measuring turbulent cascades in Jupiter's weather layer

    Science.gov (United States)

    Young, Roland M. B.; Read, Peter L.

    2017-10-01

    Jupiter's atmosphere has often been compared with a classical quasi-two-dimensional, geostrophically turbulent fluid, in which kinetic energy is transferred upscale, with zonal jets emerging due to the spherical curvature of the planet. In a new analysis of 2D wind fields obtained from Cassini cloud images taken during closest approach to Jupiter at the time of the December 2000 fly-by, we have determined 2nd and 3rd order structure functions and spectral transfers of kinetic energy and enstrophy (squared vorticity) across scales ranging from ~1000 km to the scale of the planet itself. These confirm the upscale transfer of kinetic energy from eddies on scales ≥ 3000 km up to the scales of the zonal jets, with ~90% of the energy being transferred into the jets themselves, accompanied by downscale transfer of enstrophy from all scales. For scales ≤ 3000 km or so, however, kinetic energy is transferred downscale, indicating a strong source of kinetic energy at a scale ~2000-3000 km, comparable with the internal Rossby deformation radius. This suggests an important role for baroclinic instability in energising Jupiter's turbulent atmosphere.

  18. Planetary Atmospheric Electricity

    CERN Document Server

    Leblanc, F; Yair, Y; Harrison, R. G; Lebreton, J. P; Blanc, M

    2008-01-01

    This volume presents our contemporary understanding of atmospheric electricity at Earth and in other solar system atmospheres. It is written by experts in terrestrial atmospheric electricity and planetary scientists. Many of the key issues related to planetary atmospheric electricity are discussed. The physics presented in this book includes ionisation processes in planetary atmospheres, charge generation and separation, and a discussion of electromagnetic signatures of atmospheric discharges. The measurement of thunderstorms and lightning, including its effects and hazards, is highlighted by articles on ground and space based instrumentation, and new missions.Theory and modelling of planetary atmospheric electricity complete this review of the research that is undertaken in this exciting field of space science. This book is an essential research tool for space scientists and geoscientists interested in electrical effects in atmospheres and planetary systems. Graduate students and researchers who are new to t...

  19. Mirador - Atmospheric Composition

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. Atmospheric Composition is focused on the composition of Earth's atmosphere in relation to climate prediction, solar effects,...

  20. Cascaded systems analysis of photon counting detectors.

    Science.gov (United States)

    Xu, J; Zbijewski, W; Gang, G; Stayman, J W; Taguchi, K; Lundqvist, M; Fredenberg, E; Carrino, J A; Siewerdsen, J H

    2014-10-01

    Photon counting detectors (PCDs) are an emerging technology with applications in spectral and low-dose radiographic and tomographic imaging. This paper develops an analytical model of PCD imaging performance, including the system gain, modulation transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). A cascaded systems analysis model describing the propagation of quanta through the imaging chain was developed. The model was validated in comparison to the physical performance of a silicon-strip PCD implemented on an experimental imaging bench. The signal response, MTF, and NPS were measured and compared to theory as a function of exposure conditions (70 kVp, 1-7 mA), detector threshold, and readout mode (i.e., the option for coincidence detection). The model sheds new light on the dependence of spatial resolution, charge sharing, and additive noise effects on threshold selection and was used to investigate the factors governing PCD performance, including the fundamental advantages and limitations of PCDs in comparison to energy-integrating detectors (EIDs) in the linear regime for which pulse pileup can be ignored. The detector exhibited highly linear mean signal response across the system operating range and agreed well with theoretical prediction, as did the system MTF and NPS. The DQE analyzed as a function of kilovolt (peak), exposure, detector threshold, and readout mode revealed important considerations for system optimization. The model also demonstrated the important implications of false counts from both additive electronic noise and charge sharing and highlighted the system design and operational parameters that most affect detector performance in the presence of such factors: for example, increasing the detector threshold from 0 to 100 (arbitrary units of pulse height threshold roughly equivalent to 0.5 and 6 keV energy threshold, respectively), increased the f50 (spatial-frequency at which the MTF falls to a value of

  1. The HIV care cascade: Japanese perspectives.

    Directory of Open Access Journals (Sweden)

    Aikichi Iwamoto

    Full Text Available Japan has been known as a low HIV-prevalence country with a concentrated epidemic among high-risk groups. However, it has not been determined whether Japan meets the 90-90-90 goals set by the Joint United Nations Programme on HIV/AIDS (UNAIDS/World Health Organization (WHO. Moreover, to date, the HIV care cascade has not been examined. We estimated the total number of diagnosed people living with HIV/AIDS (PLWHA (n = 22,840 based on legal reports to the Ministry of Health, Labour and Welfare by subtracting the number of foreigners who left Japan (n = 2,273 and deaths (n = 2,321 from the cumulative diagnosis report (n = 27,434. The number of total undiagnosed PLWHA was estimated by age and sex specific HIV-positive rates observed among first-time blood donors between 2011-2015 in Japan. Our estimates show that 14.4% (n = 3,830 of all PLWHA (n = 26,670 were undiagnosed in Japan at the end of 2015. The number of patients retained in care (n = 20,615: 77.3% of PLWHA, the percentage of those on antiretroviral therapy (n = 18,921: 70.9% of PLWHA and those with suppressed viral loads (<200 copies/mL; n = 18,756: 70.3% of PLWHA were obtained through a questionnaire survey conducted in the AIDS Core Hospitals throughout the country. According to these estimates, Japan failed to achieve the first two of the three UNAIDS/WHO targets (22,840/26,670 = 85.6% of HIV-positive cases were diagnosed; 18,921/22,840 = 82.8% of those diagnosed were treated; 18,756/18,921 = 99.1% of those treated experienced viral suppression. Although the antiretroviral treatment uptake and success after retention in medical care appears to be excellent in Japan, there are unmet needs, mainly at the surveillance level before patients are retained in care. The promotion of HIV testing and treatment programs among the key affected populations (especially men who have sex with men may contribute to further decreasing the HIV epidemic and achieving the UNAIDS/WHO targets in Japan.

  2. Atmospheric refraction : a history

    NARCIS (Netherlands)

    Lehn, WH; van der Werf, S

    2005-01-01

    We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of

  3. Cascades and Dissipative Anomalies in Compressible Fluid Turbulence

    Science.gov (United States)

    Eyink, Gregory L.; Drivas, Theodore D.

    2018-02-01

    We investigate dissipative anomalies in a turbulent fluid governed by the compressible Navier-Stokes equation. We follow an exact approach pioneered by Onsager, which we explain as a nonperturbative application of the principle of renormalization-group invariance. In the limit of high Reynolds and Péclet numbers, the flow realizations are found to be described as distributional or "coarse-grained" solutions of the compressible Euler equations, with standard conservation laws broken by turbulent anomalies. The anomalous dissipation of kinetic energy is shown to be due not only to local cascade but also to a distinct mechanism called pressure-work defect. Irreversible heating in stationary, planar shocks with an ideal-gas equation of state exemplifies the second mechanism. Entropy conservation anomalies are also found to occur via two mechanisms: an anomalous input of negative entropy (negentropy) by pressure work and a cascade of negentropy to small scales. We derive "4 /5 th-law"-type expressions for the anomalies, which allow us to characterize the singularities (structure-function scaling exponents) required to sustain the cascades. We compare our approach with alternative theories and empirical evidence. It is argued that the "Big Power Law in the Sky" observed in electron density scintillations in the interstellar medium is a manifestation of a forward negentropy cascade or an inverse cascade of usual thermodynamic entropy.

  4. Trend-driven information cascades on random networks.

    Science.gov (United States)

    Kobayashi, Teruyoshi

    2015-12-01

    Threshold models of global cascades have been extensively used to model real-world collective behavior, such as the contagious spread of fads and the adoption of new technologies. A common property of those cascade models is that a vanishingly small seed fraction can spread to a finite fraction of an infinitely large network through local infections. In social and economic networks, however, individuals' behavior is often influenced not only by what their direct neighbors are doing, but also by what the majority of people are doing as a trend. A trend affects individuals' behavior while individuals' behavior creates a trend. To analyze such a complex interplay between local- and global-scale phenomena, I generalize the standard threshold model by introducing a type of node called global nodes (or trend followers), whose activation probability depends on a global-scale trend, specifically the percentage of activated nodes in the population. The model shows that global nodes play a role as accelerating cascades once a trend emerges while reducing the probability of a trend emerging. Global nodes thus either facilitate or inhibit cascades, suggesting that a moderate share of trend followers may maximize the average size of cascades.

  5. Gradients in Catostomid assemblages along a reservoir cascade

    Science.gov (United States)

    Miranda, Leandro E.; Keretz, Kevin R.; Gilliland, Chelsea R.

    2017-01-01

    Serial impoundment of major rivers leads to alterations of natural flow dynamics and disrupts longitudinal connectivity. Catostomid fishes (suckers, family Catostomidae) are typically found in riverine or backwater habitats yet are able to persist in impounded river systems. To the detriment of conservation, there is limited information about distribution of catostomid fishes in impounded rivers. We examined the longitudinal distribution of catostomid fishes over 23 reservoirs of the Tennessee River reservoir cascade, encompassing approximately 1600 km. Our goal was to develop a basin-scale perspective to guide conservation efforts. Catostomid species composition and assemblage structure changed longitudinally along the reservoir cascade. Catostomid species biodiversity was greatest in reservoirs lower in the cascade. Assemblage composition shifted from dominance by spotted sucker Minytrema melanops and buffalos Ictiobus spp. in the lower reservoirs to carpsuckers Carpiodes spp. midway through the cascade and redhorses Moxostoma spp. in the upper reservoirs. Most species did not extend the length of the cascade, and some species were rare, found in low numbers and in few reservoirs. The observed gradients in catostomid assemblages suggest the need for basin-scale conservation measures focusing on three broad areas: (1) conservation and management of the up-lake riverine reaches of the lower reservoirs, (2) maintenance of the access to quality habitat in tributaries to the upper reservoirs and (3) reintroductions into currently unoccupied habitat within species' historic distributions

  6. INCAS: an analytical model to describe displacement cascades

    Science.gov (United States)

    Jumel, Stéphanie; Claude Van-Duysen, Jean

    2004-07-01

    REVE (REactor for Virtual Experiments) is an international project aimed at developing tools to simulate neutron irradiation effects in Light Water Reactor materials (Fe, Ni or Zr-based alloys). One of the important steps of the project is to characterise the displacement cascades induced by neutrons. Accordingly, the Department of Material Studies of Electricité de France developed an analytical model based on the binary collision approximation. This model, called INCAS (INtegration of CAScades), was devised to be applied on pure elements; however, it can also be used on diluted alloys (reactor pressure vessel steels, etc.) or alloys composed of atoms with close atomic numbers (stainless steels, etc.). INCAS describes displacement cascades by taking into account the nuclear collisions and electronic interactions undergone by the moving atoms. In particular, it enables to determine the mean number of sub-cascades induced by a PKA (depending on its energy) as well as the mean energy dissipated in each of them. The experimental validation of INCAS requires a large effort and could not be carried out in the framework of the study. However, it was verified that INCAS results are in conformity with those obtained from other approaches. As a first application, INCAS was applied to determine the sub-cascade spectrum induced in iron by the neutron spectrum corresponding to the central channel of the High Flux Irradiation Reactor of Oak Ridge National Laboratory.

  7. INCAS: an analytical model to describe displacement cascades

    Energy Technology Data Exchange (ETDEWEB)

    Jumel, Stephanie E-mail: stephanie.jumel@edf.fr; Claude Van-Duysen, Jean E-mail: jean-claude.van-duysen@edf.fr

    2004-07-01

    REVE (REactor for Virtual Experiments) is an international project aimed at developing tools to simulate neutron irradiation effects in Light Water Reactor materials (Fe, Ni or Zr-based alloys). One of the important steps of the project is to characterise the displacement cascades induced by neutrons. Accordingly, the Department of Material Studies of Electricite de France developed an analytical model based on the binary collision approximation. This model, called INCAS (INtegration of CAScades), was devised to be applied on pure elements; however, it can also be used on diluted alloys (reactor pressure vessel steels, etc.) or alloys composed of atoms with close atomic numbers (stainless steels, etc.). INCAS describes displacement cascades by taking into account the nuclear collisions and electronic interactions undergone by the moving atoms. In particular, it enables to determine the mean number of sub-cascades induced by a PKA (depending on its energy) as well as the mean energy dissipated in each of them. The experimental validation of INCAS requires a large effort and could not be carried out in the framework of the study. However, it was verified that INCAS results are in conformity with those obtained from other approaches. As a first application, INCAS was applied to determine the sub-cascade spectrum induced in iron by the neutron spectrum corresponding to the central channel of the High Flux Irradiation Reactor of Oak Ridge National Laboratory.

  8. Reducing Cascading Failure Risk by Increasing Infrastructure Network Interdependence

    Science.gov (United States)

    Korkali, Mert; Veneman, Jason G.; Tivnan, Brian F.; Bagrow, James P.; Hines, Paul D. H.

    2017-01-01

    Increased interconnection between critical infrastructure networks, such as electric power and communications systems, has important implications for infrastructure reliability and security. Others have shown that increased coupling between networks that are vulnerable to internetwork cascading failures can increase vulnerability. However, the mechanisms of cascading in these models differ from those in real systems and such models disregard new functions enabled by coupling, such as intelligent control during a cascade. This paper compares the robustness of simple topological network models to models that more accurately reflect the dynamics of cascading in a particular case of coupled infrastructures. First, we compare a topological contagion model to a power grid model. Second, we compare a percolation model of internetwork cascading to three models of interdependent power-communication systems. In both comparisons, the more detailed models suggest substantially different conclusions, relative to the simpler topological models. In all but the most extreme case, our model of a “smart” power network coupled to a communication system suggests that increased power-communication coupling decreases vulnerability, in contrast to the percolation model. Together, these results suggest that robustness can be enhanced by interconnecting networks with complementary capabilities if modes of internetwork failure propagation are constrained. PMID:28317835

  9. Long-term change of the atmospheric energy cycles and weather disturbances

    Science.gov (United States)

    Kim, WonMoo; Choi, Yong-Sang

    2017-11-01

    Weather disturbances are the manifestation of mean atmospheric energy cascading into eddies, thus identifying atmospheric energy structure is of fundamental importance to understand the weather variability in a changing climate. The question is whether our observational data can lead to a consistent diagnosis on the energy conversion characteristics. Here we investigate the atmospheric energy cascades by a simple framework of Lorenz energy cycle, and analyze the energy distribution in mean and eddy fields as forms of potential and kinetic energy. It is found that even the widely utilized independent reanalysis datasets, NCEP-DOE AMIP-II Reanalysis (NCEP2) and ERA-Interim (ERA-INT), draw different conclusions on the change of weather variability measured by eddy-related kinetic energy. NCEP2 shows an increased mean-to-eddy energy conversion and enhanced eddy activity due to efficient baroclinic energy cascade, but ERA-INT shows relatively constant energy cascading structure between the 1980s and the 2000s. The source of discrepancy mainly originates from the uncertainties in hydrological variables in the mid-troposphere. Therefore, much efforts should be made to improve mid-tropospheric observations for more reliable diagnosis of the weather disturbances as a consequence of man-made greenhouse effect.

  10. Atmospheric Habitable Zones in Y Dwarf Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Yates, Jack S.; Palmer, Paul I. [School of GeoSciences, University of Edinburgh (United Kingdom); Biller, Beth; Cockell, Charles S., E-mail: j.s.yates@ed.ac.uk [Centre for Exoplanet Science, University of Edinburgh (United Kingdom)

    2017-02-20

    We use a simple organism lifecycle model to explore the viability of an atmospheric habitable zone (AHZ), with temperatures that could support Earth-centric life, which sits above an environment that does not support life. To illustrate our model, we use a cool Y dwarf atmosphere, such as WISE J085510.83–0714442.5, whose 4.5–5.2 μ m spectrum shows absorption features consistent with water vapor and clouds. We allow organisms to adapt to their atmospheric environment (described by temperature, convection, and gravity) by adopting different growth strategies that maximize their chance of survival and proliferation. We assume a constant upward vertical velocity through the AHZ. We found that the organism growth strategy is most sensitive to the magnitude of the atmospheric convection. Stronger convection supports the evolution of more massive organisms. For a purely radiative environment, we find that evolved organisms have a mass that is an order of magnitude smaller than terrestrial microbes, thereby defining a dynamical constraint on the dimensions of life that an AHZ can support. Based on a previously defined statistical approach, we infer that there are of the order of 10{sup 9} cool Y brown dwarfs in the Milky Way, and likely a few tens of these objects are within 10 pc from Earth. Our work also has implications for exploring life in the atmospheres of temperate gas giants. Consideration of the habitable volumes in planetary atmospheres significantly increases the volume of habitable space in the galaxy.

  11. Cascaded VLSI Chips Help Neural Network To Learn

    Science.gov (United States)

    Duong, Tuan A.; Daud, Taher; Thakoor, Anilkumar P.

    1993-01-01

    Cascading provides 12-bit resolution needed for learning. Using conventional silicon chip fabrication technology of VLSI, fully connected architecture consisting of 32 wide-range, variable gain, sigmoidal neurons along one diagonal and 7-bit resolution, electrically programmable, synaptic 32 x 31 weight matrix implemented on neuron-synapse chip. To increase weight nominally from 7 to 13 bits, synapses on chip individually cascaded with respective synapses on another 32 x 32 matrix chip with 7-bit resolution synapses only (without neurons). Cascade correlation algorithm varies number of layers effectively connected into network; adds hidden layers one at a time during learning process in such way as to optimize overall number of neurons and complexity and configuration of network.

  12. A Cascade-Based Emergency Model for Water Distribution Network

    Directory of Open Access Journals (Sweden)

    Qing Shuang

    2015-01-01

    Full Text Available Water distribution network is important in the critical physical infrastructure systems. The paper studies the emergency resource strategies on water distribution network with the approach of complex network and cascading failures. The model of cascade-based emergency for water distribution network is built. The cascade-based model considers the network topology analysis and hydraulic analysis to provide a more realistic result. A load redistribution function with emergency recovery mechanisms is established. From the aspects of uniform distribution, node betweenness, and node pressure, six recovery strategies are given to reflect the network topology and the failure information, respectively. The recovery strategies are evaluated with the complex network indicators to describe the failure scale and failure velocity. The proposed method is applied by an illustrative example. The results showed that the recovery strategy considering the node pressure can enhance the network robustness effectively. Besides, this strategy can reduce the failure nodes and generate the least failure nodes per time.

  13. Bearing-Only Formation Control for Cascade Multirobots

    Directory of Open Access Journals (Sweden)

    Qing Han

    2016-01-01

    Full Text Available A new formation control method is proposed, which is used to queue multirobots in a single-direction cascade structure. In the cascade formation, each robot is a follower for the previous robot and a leader for the next robot, and the robots in the middle act as both leader and follower. The follower robot can only observe the bearing information of the leader robot. The observability of the cascade leader-follower formation is studied, which shows that the bearing-only observation meets the observability conditions required for the nonlinear system. Based on the bearing-only observations, the unscented Kalman filter (UKF is employed for the state estimation of the leader and the follower robots at all levels, which enables the real-time movement control of the follower robots via the input-output feedback control. Simulation results demonstrate that the proposed approach can efficiently control the formation of multirobots as desired.

  14. Performance validation of a cascade control system through

    Directory of Open Access Journals (Sweden)

    A. Lakshmi Sangeetha

    2016-11-01

    Full Text Available The work analyzes the performance characteristics of a cascade control system when interconnected with various network architectures, such as Internet, mobile and wireless networks. The cascade control system consists of level and flow as primary and secondary variables, respectively. The web-enabled monitoring and control are realized using three techniques namely remote client–server, ActiveX-data socket and web publishing tool. Mobile network is established by interfacing the control system with a GSM modem which enables the monitoring of process parameters through mobile phones. The cascade control system is also monitored wirelessly from remote locations with advent of an indigenous wireless sensor node. The performance analysis proved that wireless monitoring may be considered as an effective alternate technique to the Internet-based communication especially for shorter distances.

  15. The Alzheimer's Disease Mitochondrial Cascade Hypothesis: Progress and Perspectives

    Science.gov (United States)

    Swerdlow, Russell H.; Burns, Jeffrey M.; Khan, Shaharyar M.

    2013-01-01

    Ten years ago we first proposed the Alzheimer's disease (AD) mitochondrial cascade hypothesis. This hypothesis maintains gene inheritance defines an individual's baseline mitochondrial function; inherited and environmental factors determine rates at which mitochondrial function changes over time; and baseline mitochondrial function and mitochondrial change rates influence AD chronology. Our hypothesis unequivocally states in sporadic, late-onset AD, mitochondrial function affects amyloid precursor protein (APP) expression, APP processing, or beta amyloid (Aβ) accumulation and argues if an amyloid cascade truly exists, mitochondrial function triggers it. We now review the state of the mitochondrial cascade hypothesis, and discuss it in the context of recent AD biomarker studies, diagnostic criteria, and clinical trials. Our hypothesis predicts biomarker changes reflect brain aging, new AD definitions clinically stage brain aging, and removing brain Aβ at any point will marginally impact cognitive trajectories. Our hypothesis, therefore, offers unique perspective into what sporadic, late-onset AD is and how to best treat it. PMID:24071439

  16. The Alzheimer's disease mitochondrial cascade hypothesis: progress and perspectives.

    Science.gov (United States)

    Swerdlow, Russell H; Burns, Jeffrey M; Khan, Shaharyar M

    2014-08-01

    Ten years ago we first proposed the Alzheimer's disease (AD) mitochondrial cascade hypothesis. This hypothesis maintains that gene inheritance defines an individual's baseline mitochondrial function; inherited and environmental factors determine rates at which mitochondrial function changes over time; and baseline mitochondrial function and mitochondrial change rates influence AD chronology. Our hypothesis unequivocally states in sporadic, late-onset AD, mitochondrial function affects amyloid precursor protein (APP) expression, APP processing, or beta amyloid (Aβ) accumulation and argues if an amyloid cascade truly exists, mitochondrial function triggers it. We now review the state of the mitochondrial cascade hypothesis, and discuss it in the context of recent AD biomarker studies, diagnostic criteria, and clinical trials. Our hypothesis predicts that biomarker changes reflect brain aging, new AD definitions clinically stage brain aging, and removing brain Aβ at any point will marginally impact cognitive trajectories. Our hypothesis, therefore, offers unique perspective into what sporadic, late-onset AD is and how to best treat it. © 2013.

  17. Progress in high-performance quantum cascade lasers

    Science.gov (United States)

    Lyakh, Arkadiy; Maulini, Richard; Tsekoun, Alexei G.; Patel, C. Kumar N.

    2010-11-01

    Because of their compact size, reliability, tunability, and convenience of direct electrical pumping, quantum cascade lasers have found a number of important civilian and defense applications in the midwave infrared and long-wave-infrared spectral range. Most of these applications would benefit from higher laser optical power and higher wall-plug efficiency. We describe some of the most important features of high-efficiency quantum cascade laser design and realization of high-power quantum cascade laser systems. Specifically, optimization of the active region and waveguide, thermal management on the chip level, and impact of the laser facet coating on laser efficiency and scaling of optical power with cavity length are discussed. Also, we present experimental results demonstrating multiwatt operation with reliability of at least several thousands of hours on a system level.

  18. Analysis and synthesis of cascaded metasurfaces using wave matrices

    Science.gov (United States)

    Ranjbar, Amin; Grbic, Anthony

    2017-05-01

    Various matrix representations are used to analyze the propagation of electromagnetic waves through stratified (layered) media or cascaded circuit networks. These include ABCD matrices, scattering matrices, impedance matrices, and hybrid matrices. A less known network representation is the wave matrix. In this paper, a brief review of wave matrices is presented and their relation to other network representations derived. Wave matrices are found for common interfaces such as boundaries between dielectric media, dielectric slabs, as well as electric, magnetic, and magneto-electric sheet boundaries (generalized sheet transition conditions). These results are then used to develop an analytical synthesis approach for cascaded metasurfaces: metasurfaces consisting of a cascade of sheets separated by dielectric spacers. This is in contrast to earlier works which relied on numerical solvers or optimization methods to design such structures. A few design examples are presented to demonstrate the utility of the synthesis approach.

  19. Substrate-driven chemotactic assembly in an enzyme cascade

    Science.gov (United States)

    Zhao, Xi; Palacci, Henri; Yadav, Vinita; Spiering, Michelle M.; Gilson, Michael K.; Butler, Peter J.; Hess, Henry; Benkovic, Stephen J.; Sen, Ayusman

    2018-03-01

    Enzymatic catalysis is essential to cell survival. In many instances, enzymes that participate in reaction cascades have been shown to assemble into metabolons in response to the presence of the substrate for the first enzyme. However, what triggers metabolon formation has remained an open question. Through a combination of theory and experiments, we show that enzymes in a cascade can assemble via chemotaxis. We apply microfluidic and fluorescent spectroscopy techniques to study the coordinated movement of the first four enzymes of the glycolysis cascade: hexokinase, phosphoglucose isomerase, phosphofructokinase and aldolase. We show that each enzyme independently follows its own specific substrate gradient, which in turn is produced by the preceding enzymatic reaction. Furthermore, we find that the chemotactic assembly of enzymes occurs even under cytosolic crowding conditions.

  20. Cascading Failures in Networks: Inference, Intervention and Robustness to WMDs

    Science.gov (United States)

    2016-08-01

    8725 John J. Kingman Road, MS 6201 Fort Belvoir, VA 22060-6201 T E C H N IC A L R E P O R T DTRA-TR-16-83 Cascading Failures in Networks...Austin   Project  Title:  Cascading   Failures  in  Networks:  Inference,  Intervention  and  Robustness  to   WMDs   What  are  the  major  goals  of...networks  are  prone  to  creating  cascading   failures :  events  where  the   initial  destruction/compromising  of  a  few  nodes  results  in  the

  1. Slash fire atmospheric pollution.

    Science.gov (United States)

    Leo Fritschen; Harley Bovee; Konrad Buettner; Robert Charlson; Lee Monteith; Stewart Pickford; James. Murphy

    1970-01-01

    In the Pacific Northwest, as in many other parts of the country, burning is the standard method for disposal of undesirable waste including logging debris and agricultural residue. About 81,000 hectares (200,000 acres) of logging slash are burned annually west of the Cascade Range in the States of Washington and Oregon. In addition, 101,000 hectares (250,000 acres) of...

  2. Special Issue ;Sediment cascades in cold climate geosystems;

    Science.gov (United States)

    Morche, David; Krautblatter, Michael; Beylich, Achim A.

    2017-06-01

    This Editorial introduces the Special Issue on sediment cascades in cold climate geosystems that evolved from the eighth I.A.G./A.I.G. SEDIBUD (Sediment Budgets in Cold Environments; http://www.geomorph.org/sedibud-working-group/) workshop. The workshop was held from 1st to 4th September 2014 at the Environmental Research Station ;Schneefernerhaus; (http://www.schneefernerhaus.de/en/home.html) located at Mt. Zugspitze, the highest peak of Germany, (2962 m asl). Paper and poster presentations focused on observations, measurements and modeling of geomorphological processes in sediment cascades in cold climate geosystems. This resulting Special Issue brings together ten selected contributions from arctic and alpine environments.

  3. Cascade Control of Magnetic Levitation with Sliding Modes

    Directory of Open Access Journals (Sweden)

    Eroğlu Yakup

    2016-01-01

    Full Text Available The effectiveness and applicability of magnetic levitation systems need precise feedback control designs. A cascade control approach consisting of sliding mode control plus sliding mode control (SMC plus SMC is designed to solve position control problem and to provide a high control performance and robustness to the magnetic levitation plant. It is shown that the SMC plus SMC cascade controller is able to eliminate the effects of the inductance related uncertainties of the electromagnetic coil of the plant and achieve a robust and precise position control. Experimental and numerical results are provided to validate the effectiveness and feasibility of the method.

  4. Process Evaluation Tools for Enzymatic Cascades Welcome Message

    DEFF Research Database (Denmark)

    Abu, Rohana

    limited reactions are not only via application of enzyme coupling reactions (coupling the unfavourable reaction with an energetically favourable reaction) but also by matching the relative reaction rates between the interconnecting enzymes. When the reaction steps are independent in a cascade......, the kinetics can be controlled in a highly efficient way to achieve a sufficiently favourable conversion to a given target product. This is exemplified in the second case study, in the kinetic modelling of the formation of 2-ketoglutarate from glucoronate, the second case study. This cascade consists of 4...

  5. Limits to compression with cascaded quadratic soliton compressors

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Krolikowski, Wieslaw

    2008-01-01

    We study cascaded quadratic soliton compressors and address the physical mechanisms that limit the compression. A nonlocal model is derived, and the nonlocal response is shown to have an additional oscillatory component in the nonstationary regime when the group-velocity mismatch (GVM) is strong....... This inhibits efficient compression. Raman-like perturbations from the cascaded nonlinearity, competing cubic nonlinearities, higher-order dispersion, and soliton energy may also limit compression, and through realistic numerical simulations we point out when each factor becomes important. We find...

  6. Fast perceptual image hash based on cascade algorithm

    Science.gov (United States)

    Ruchay, Alexey; Kober, Vitaly; Yavtushenko, Evgeniya

    2017-09-01

    In this paper, we propose a perceptual image hash algorithm based on cascade algorithm, which can be applied in image authentication, retrieval, and indexing. Image perceptual hash uses for image retrieval in sense of human perception against distortions caused by compression, noise, common signal processing and geometrical modifications. The main disadvantage of perceptual hash is high time expenses. In the proposed cascade algorithm of image retrieval initializes with short hashes, and then a full hash is applied to the processed results. Computer simulation results show that the proposed hash algorithm yields a good performance in terms of robustness, discriminability, and time expenses.

  7. On the turbulent energy cascade in anisotropic magnetohydrodynamic turbulence

    CERN Document Server

    Carbone, V; Marino, R

    2010-01-01

    The problem of the occurrence of an energy cascade for Alfv\\'enic turbulence in solar wind plasmas was hystorically addressed by using phenomenological arguments based to the weakness of nonlinear interactions and the anisotropy of the cascade in wave vectors space. Here, this paradox is reviewed through the formal derivation of a Yaglom relation from anisotropic Magnetohydrodynamic equation. The Yaglom relation involves a third-order moment calculated from velocity and magnetic fields and involving both Els\\"asser vector fields, and is particularly useful to be used as far as spacecraft observations of turbulence are concerned.

  8. Interrelation of structure and operational states in cascading failure of overloading lines in power grids

    Science.gov (United States)

    Xue, Fei; Bompard, Ettore; Huang, Tao; Jiang, Lin; Lu, Shaofeng; Zhu, Huaiying

    2017-09-01

    As the modern power system is expected to develop to a more intelligent and efficient version, i.e. the smart grid, or to be the central backbone of energy internet for free energy interactions, security concerns related to cascading failures have been raised with consideration of catastrophic results. The researches of topological analysis based on complex networks have made great contributions in revealing structural vulnerabilities of power grids including cascading failure analysis. However, existing literature with inappropriate assumptions in modeling still cannot distinguish the effects between the structure and operational state to give meaningful guidance for system operation. This paper is to reveal the interrelation between network structure and operational states in cascading failure and give quantitative evaluation by integrating both perspectives. For structure analysis, cascading paths will be identified by extended betweenness and quantitatively described by cascading drop and cascading gradient. Furthermore, the operational state for cascading paths will be described by loading level. Then, the risk of cascading failure along a specific cascading path can be quantitatively evaluated considering these two factors. The maximum cascading gradient of all possible cascading paths can be used as an overall metric to evaluate the entire power grid for its features related to cascading failure. The proposed method is tested and verified on IEEE30-bus system and IEEE118-bus system, simulation evidences presented in this paper suggests that the proposed model can identify the structural causes for cascading failure and is promising to give meaningful guidance for the protection of system operation in the future.

  9. Atmospheric Circulation of Exoplanets

    OpenAIRE

    Showman, Adam P.; Cho, James Y-K.; Menou, Kristen

    2009-01-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-wate...

  10. Cascade Screening in Families with Inherited Cardiac Diseases Driven by Cardiologists

    DEFF Research Database (Denmark)

    Theilade, Juliane; Kanters, Jørgen; Henriksen, Finn Lund

    2013-01-01

    We assessed the outcome of cascade screening of families with congenital long QT syndrome (LQTS) in Danish heart centers.......We assessed the outcome of cascade screening of families with congenital long QT syndrome (LQTS) in Danish heart centers....

  11. Cascading Constrained 2-D Arrays using Periodic Merging Arrays

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Laursen, Torben Vaarby

    2003-01-01

    We consider a method for designing 2-D constrained codes by cascading finite width arrays using predefined finite width periodic merging arrays. This provides a constructive lower bound on the capacity of the 2-D constrained code. Examples include symmetric RLL and density constrained codes...

  12. Energy Cascade Analysis: from Subscale Eddies to Mean Flow

    Science.gov (United States)

    Cheikh, Mohamad Ibrahim; Wonnell, Louis; Chen, James

    2017-11-01

    Understanding the energy transfer between eddies and mean flow can provide insights into the energy cascade process. Much work has been done to investigate the energy cascade at the level of the smallest eddies using different numerical techniques derived from the Navier-Stokes equations. These methodologies, however, prove to be computationally inefficient when producing energy spectra for a wide range of length scales. In this regard, Morphing Continuum Theory (MCT) resolves the length-scales issues by assuming the fluid continuum to be composed of inner structures that play the role of subscale eddies. The current study show- cases the capabilities of MCT in capturing the dynamics of energy cascade at the level of subscale eddies, through a supersonic turbulent flow of Mach 2.93 over an 8× compression ramp. Analysis of the results using statistical averaging procedure shows the existence of a statistical coupling of the internal and translational kinetic energy fluctuations with the corresponding rotational kinetic energy of the subscale eddies, indicating a multiscale transfer of energy. The results show that MCT gives a new characterization of the energy cascade within compressible turbulence without the use of excessive computational resources. This material is based upon work supported by the Air Force Office of Scientific Research under Award Number FA9550-17-1-0154.

  13. A nine-level hybrid symmetric cascaded multilevel converter for ...

    Indian Academy of Sciences (India)

    Indrajit Sarkar

    Therefore, due to this limitation of asymmetric or hybrid cascaded converters on input power quality, the use of these converters is popular for electric vehicle applications, and have limited industrial use [20]. Several attempts have been made to increase the number of output voltage levels of symmetric CHB–MLCs as well.

  14. Successful Treatment Of Homozygous Familial Hypercholesterolemia Using Cascade Filtration Plasmapheresis

    Directory of Open Access Journals (Sweden)

    Fatih Kardas

    2012-12-01

    Full Text Available OBJECTIVE: The aim of our study is to discuss the efficacy of low-density lipoprotein-cholesterol (LDL-C apheresis procedure using the cascade filtration system for pediatric patients with homozygous familial hypercholesterolemia (FH, and to clarify the adverse effects and difficulties. METHODS: LDL apheresis using the cascade filtration system was performed in 3 pediatric patients with homozygous FH. In total, 120 apheresis sessions were performed for all patients. RESULTS: Cascade filtration therapy significantly reduced the mean LDL-C values from 418 ± 62 mg/dl to 145 ± 43 mg/dl (p<0.05. We determined an acute mean reduction in the plasma levels of total cholesterol (57.9%, LDL cholesterol (70.8%, and high-density lipoprotein (HDL cholesterol (40.7%. Treatments were well tolerated. The most frequent clinical adverse effects were hypotension in 3 sessions (2.5%, chills/feeling cold (1.7% in 2 sessions, and nausea and vomiting in 3 sessions (2.5%. CONCLUSION: Our experience with three patients using the cascade filtration system were, good clinical outcomes, laboratory findings, safety of usage, minor adverse effects and technical problems.

  15. Thresholds and Complex Dynamics of Interdependent Cascading Infrastructure Systems

    Science.gov (United States)

    Carreras, B. A.; Newman, D. E.; Dobson, I.; Lynch, V. E.; Gradney, Paul

    Critical infrastructures have a number of the characteristic properties of complex systems. Among these are infrequent large failures through cascading events. These events, though infrequent, often obey a power law distribution in their probability versus size which suggests that conventional risk analysis does not apply to these systems. Real infrastructure systems typically have an additional layer of complexity, namely the heterogeneous coupling to other infrastructure systems that can allow a failure in one system to propagate to the other system. Here, we model the infrastructure systems through a network with complex system dynamics. We use both mean field theory to get analytic results and a numerical complex systems model, Demon, for computational results. An isolated system has bifurcated fixed points and a cascading threshold which is the same as the bifurcation point. When systems are coupled, this is no longer true and the cascading threshold is different from the bifurcation point of the fixed point solutions. This change in the cascading threshold caused by the interdependence of the system can have an impact on the "safe operation" of interdependent infrastructure systems by changing the critical point and even the power law exponent.

  16. Numerical optimization of a transcritical CO2/propylene cascaded ...

    Indian Academy of Sciences (India)

    application. Parallel compression economization is one of the promising cycle mod- ifications to improve the COP of transcritical CO2 cascaded systems. In this paper, ... liquefaction of petroleum vapors and natural gas, manufacturing of dry ice, precipitation hard- ening of special ..... first and second laws of thermodynamics.

  17. Reliable Broadcast under Cascading Failures in Interdependent Networks

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Sisi [ORNL; Lee, Sangkeun (Matt) [ORNL; Chinthavali, Supriya [ORNL; Shankar, Mallikarjun (Arjun) [ORNL

    2017-01-01

    Reliable broadcast is an essential tool to disseminate information among a set of nodes in the presence of failures. We present a novel study of reliable broadcast in interdependent networks, in which the failures in one network may cascade to another network. In particular, we focus on the interdependency between the communication network and power grid network, where the power grid depends on the signals from the communication network for control and the communication network depends on the grid for power. In this paper, we build a resilient solution to handle crash failures in the communication network that may cause cascading failures and may even partition the network. In order to guarantee that all the correct nodes deliver the messages, we use soft links, which are inactive backup links to non-neighboring nodes that are only active when failures occur. At the core of our work is a fully distributed algorithm for the nodes to predict and collect the information of cascading failures so that soft links can be maintained to correct nodes prior to the failures. In the presence of failures, soft links are activated to guarantee message delivery and new soft links are built accordingly for long term robustness. Our evaluation results show that the algorithm achieves low packet drop rate and handles cascading failures with little overhead.

  18. Probing supersymmetry with third-generation cascade decays

    Energy Technology Data Exchange (ETDEWEB)

    Graesser, Michael [Los Alamos National Laboratory; Shelton, Jessie [RUTGERS UNIV

    2008-01-01

    The chiral structure of supersymmetric particle couplings involving third generation Standard Model fermions depends on left-right squark and slepton mixings as well as gaugino-higgsino mixings. The shapes and intercorrelations of invariant mass distributions of a first or second generation lepton with bottoms and taus arising from adjacent branches of SUSY cascade decays are shown to be a sensitive probe of this chiral structure. All possible cascade decays that can give rise to such correlations within the MSSM are considered. For bottom-lepton correlations the distinctive structure of the invariant mass distributions distinguishes between decays originating from stop or sbottom squarks through either an intermediate chargino or neutralino. For decay through a chargino the spins of the stop and chargino are established by the form of the distribution. When the bottom charge is signed through soft muon tagging, the structure of the same-sign and opposite-sign invariant mass distributions depends on a set function of left-right and gaugino-higgsino mixings, as well as establishes the spins of all the superpartners in the sequential two-body cascade decay. Tau-lepton and tau-tau invariant mass distributions arising from MSSM cascade decays are likewise systematically considered with particular attention to their dependence on tau polarization. All possible tau-lepton and tau-tau distributions are plotted using a semi-analytic model for hadronic one-prong taus. Algorithms for fitting tau-tau and tau-lepton distributions to data are suggested.

  19. Numerical optimization of a transcritical CO2/propylene cascaded ...

    Indian Academy of Sciences (India)

    Use of organic refrigerants such as Hydrochlorofluorocarbons and Chlorofluorocarbons have been criticized for their adverse impact on the Earth's protective ozone layer and for their significant global warming potential (GWP). CO2 has been receiving great concern as an alternative refrigerant. Cascade refrigeration ...

  20. Fire severity in intermittent stream drainages, Western Cascade Range, Oregon.

    Science.gov (United States)

    Jennifer E. Tollefson; Frederick J. Swanson; John H. Cissel

    2004-01-01

    We quantified fire severity patterns within intermittent stream drainages in a recently burned area of the central western Cascades, Oregon. Aerial photographs were used to estimate post fire live canopy cover within streamside and upland zones on the southeast and southwest-facing slopes of 33 watersheds. Live canopy cover did not differ significantly between...

  1. DISPLACEMENT CASCADE SIMULATION IN TUNGSTEN AT 1025 K

    Energy Technology Data Exchange (ETDEWEB)

    Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Kurtz, Richard J.; Wirth, Brian D.

    2013-09-30

    Molecular dynamics simulation was employed to investigate the irradiation damage properties of bulk tungsten at 1025 K (0.25 melting temperature). A comprehensive data set of primary cascade damage was generated up to primary knock-on atom (PKA) energies 100 keV. The dependence of the number of surviving Frenkel pairs (NFP) on the PKA energy (E) exhibits three different characteristic domains presumably related to the different cascade morphologies that form. The low-energy regime < 0.2 keV is characterized by a hit-or-miss type of Frenkel pair (FP) production near the displacement threshold energy of 128 eV. The middle regime 0.3 – 30 keV exhibits a sublinear dependence of log(NFP) vs log(E) associated with compact cascade morphology with a slope of 0.73. Above 30 keV, the cascade morphology consists of complex branches or interconnected damage regions. In this extended morphology, large interstitial clusters form from superposition of interstitials from nearby damage regions. Strong clustering above 30 keV results in a superlinear dependence of log(NFP) vs log(E) with a slope of 1.365. At 100 keV, an interstitial cluster of size 92 and a vacancy cluster of size 114 were observed.

  2. Gamma irradiation of Fabry–Perot interband cascade lasers

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Tanya L. [Pacific Northwest National Laboratory, Richland, Washington; Cannon, Bret D. [Pacific Northwest National Laboratory, Richland, Washington; Brauer, Carolyn S. [Pacific Northwest National Laboratory, Richland, Washington; Canedy, Chadwick L. [Naval Research Laboratory, Washington, DC; Kim, Chul Soo [Naval Research Laboratory, Washington, DC; Kim, Mijin [Sotera Defense Solutions, Inc., Columbia, Maryland; Merritt, Charles D. [Naval Research Laboratory, Washington, DC; Bewley, William W. [Naval Research Laboratory, Washington, DC; Vurgaftman, Igor [Naval Research Laboratory, Washington, DC; Meyer, Jerry R. [Naval Research Laboratory, Washington, DC

    2017-09-20

    Two Fabry-Perot interband cascade lasers (ICLs) were exposed to Cobalt-60 gamma rays for a dosage of 500 krad(Si) each, which is higher than is typically encountered in space applications. The ICLs do not show any significant changes in threshold current or slope efficiency, suggesting the suitability of ICLs for use in radiation environments.

  3. ECG classification and abnormality detection using cascade forward ...

    African Journals Online (AJOL)

    user

    different networks and different algorithms are compared, it is found that to identify whether the ECG beat is normal or abnormal, cascade forward back network algorithm has shown 99.9 % correct classification. These results are compared with previous neural network techniques and found that method proposed in this ...

  4. Effect of field quantization on Rabi oscillation of equidistant cascade ...

    Indian Academy of Sciences (India)

    We have exactly solved a model of equidistant cascade four-level system interacting with a single-mode radiation field both semiclassically and quantum mechanically by exploiting its similarity with Jaynes-Cummings model. For the classical field, it is shown that the Rabi oscillation of the system initially in the first level ...

  5. Effect of field quantization on Rabi oscillation of equidistant cascade ...

    Indian Academy of Sciences (India)

    Abstract. We have exactly solved a model of equidistant cascade four-level system inter- acting with a single-mode radiation field both semiclassically and quantum mechanically by exploiting its similarity with Jaynes–Cummings model. For the classical field, it is shown that the Rabi oscillation of the system initially in the first ...

  6. Low crosstalk Arrayed Waveguide Grating with Cascaded Waveguide Grating Filter

    Energy Technology Data Exchange (ETDEWEB)

    Deng Yang; Liu Yuan; Gao Dingshan, E-mail: dsgao@mail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-02-01

    We propose a highly compact and low crosstalk arrayed waveguide grating (AWG) with cascaded waveguide grating (CWGF). The side lobes of the silicon nanowire AWG, which are normally introduced by fabrication errors, can be effectively suppressed by the CWGF. And the crosstalk can be improved about 15dB.

  7. Cascade reactions in an all-enzyme nanoreactor

    NARCIS (Netherlands)

    Delaittre, Guillaume; Reynhout, Irene C.; Cornelissen, Jeroen Johannes Lambertus Maria; Nolte, Roeland J.M.

    2009-01-01

    Good things come in small packages! Giant amphiphiles, consisting of a polymeric hydrophobic tail and a horseradish peroxidase head, were simultaneously synthesized and self-assembled into vesicles. During the self-assembly process, glucose oxidase was encapsulated to create enzymatic cascade

  8. Mitogen-activated protein kinase cascades in Vitis vinifera.

    Science.gov (United States)

    Çakır, Birsen; Kılıçkaya, Ozan

    2015-01-01

    Protein phosphorylation is one of the most important mechanisms to control cellular functions in response to external and endogenous signals. Mitogen-activated protein kinases (MAPK) are universal signaling molecules in eukaryotes that mediate the intracellular transmission of extracellular signals resulting in the induction of appropriate cellular responses. MAPK cascades are composed of four protein kinase modules: MAPKKK kinases (MAPKKKKs), MAPKK kinases (MAPKKKs), MAPK kinases (MAPKKs), and MAPKs. In plants, MAPKs are activated in response to abiotic stresses, wounding, and hormones, and during plant pathogen interactions and cell division. In this report, we performed a complete inventory of MAPK cascades genes in Vitis vinifera, the whole genome of which has been sequenced. By comparison with MAPK, MAPK kinases, MAPK kinase kinases and MAPK kinase kinase kinase kinase members of Arabidopsis thaliana, we revealed the existence of 14 MAPKs, 5 MAPKKs, 62 MAPKKKs, and 7 MAPKKKKs in Vitis vinifera. We identified orthologs of V. vinifera putative MAPKs in different species, and ESTs corresponding to members of MAPK cascades in various tissues. This work represents the first complete inventory of MAPK cascades in V. vinifera and could help elucidate the biological and physiological functions of these proteins in V. vinifera.

  9. Separation of an inulin mixture using cascaded nanofiltration

    NARCIS (Netherlands)

    Patil, N.V.; Feng, Xiaoxia; Sewalt, J.J.W.; Boom, R.M.; Janssen, A.E.M.

    2015-01-01

    This paper examines the use of a pilot-scale spiral wound nanofiltration cascade with regard to separation of mono- and disaccharides from a mixture of inulin of different polymer sizes. The choices of the membrane and operational conditions were based on single stage experiments. Two 3-stage

  10. Checklist of vertebrate animals of the Cascade Head Experimental Forest.

    Science.gov (United States)

    Chris Maser; Jerry F. Franklin

    1974-01-01

    Three months, April and August 1971 and August 1972, were spent studying the vertebrate fauna of Cascade Head Experimental Forest. The resulting annotated checklist includes 9 amphibians, 2 reptiles, 35 birds, and 40 mammals. A standardized animal habitat classification is presented in an effort to correlate the vertebrates in some meaningful way to their environment...

  11. Aspects of microstructure evolution under cascade damage conditions

    DEFF Research Database (Denmark)

    Singh, B.N.; Golubov, S.I.; Trinkaus, H.

    1997-01-01

    The conventional theoretical models describing the damage accumulation, particularly void swelling, under cascade damage conditions do not include treatments of important features such as intracascade clustering of self-interstitial atoms (SIAs) and one-dimensional glide of SIA clusters produced...

  12. Intensity correlations and anticorrelations in a three-level cascade ...

    Indian Academy of Sciences (India)

    Intensity correlations; two-photon coherence; non-classical light; three-level cascade system; incoherent pumping. ... Further, we show that by applying even a very weak incoherent pump, the nature of the emitted radiation can be switched from classical to non-classicalwithout significantly affecting the probe transparency ...

  13. Optical Cherenkov radiation in ultrafast cascaded second-harmonic generation

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin

    2010-01-01

    We show through theory and numerics that when few-cycle femtosecond solitons are generated through cascaded (phase-mismatched) second-harmonic generation, these broadband solitons can emit optical Cherenkov radiation in the form of linear dispersive waves located in the red part of the spectrum. ...

  14. Advanced Dementia Research in the Nursing Home: The CASCADE Study

    Science.gov (United States)

    Mitchell, Susan L.; Kiely, Dan K.; Jones, Richard N.; Prigerson, Holly; Volicer, Ladislav; Teno, Joan M.

    2009-01-01

    Despite the growing number of persons with advanced dementia, and the need to improve their end-of-life care, few studies have addressed this important topic. The objectives of this report are to present the methodology established in the CASCADE (Choices, Attitudes, and Strategies for Care of Advanced Dementia at the End-of-Life) study, and to describe how challenges specific to this research were met. The CASCADE study is an ongoing, federally funded, 5-year prospective cohort study of nursing [nursing home (NH)] residents with advanced dementia and their health care proxies (HCPs) initiated in February 2003. Subjects were recruited from 15 facilities around Boston. The recruitment and data collection protocols are described. The demographic features, ownership, staffing, and quality of care of participant facilities are presented and compared to NHs nationwide. To date, 189 resident/HCP dyads have been enrolled. Baseline data are presented, demonstrating the success of the protocol in recruiting and repeatedly assessing NH residents with advanced dementia and their HCPs. Factors challenging and enabling implementation of the protocol are described. The CASCADE experience establishes the feasibility of conducting rigorous, multisite dementia NH research, and the described methodology serves as a detailed reference for subsequent CASCADE publications as results from the study emerge. PMID:16917187

  15. Extension of CASCADE.04 to estimate neutron fluence and dose ...

    Indian Academy of Sciences (India)

    neutron source situated at the centre of the paraffin cylinder as described above and obtained neutron fluences at different radial distances from both the codes. The results of fluence per unit incident neutron are compared in figure 3. The cal- culated values from CASCADE.04.d code are close to that of the values obtained.

  16. A network approach for power grid robustness against cascading failures

    NARCIS (Netherlands)

    Wang, X.; Koç, Y.; Kooij, R.E.; Mieghem, P. van

    2015-01-01

    Cascading failures are one of the main reasons for blackouts in electrical power grids. Stable power supply requires a robust design of the power grid topology. Currently, the impact of the grid structure on the grid robustness is mainly assessed by purely topological metrics, that fail to capture

  17. Learning from a role model: A cascade or whirlpool effect?

    NARCIS (Netherlands)

    Jochemsen-van der Leeuw, H. G. A. Ria; Buwalda, Nienke; Wieringa-de Waard, Margreet; van Dijk, Nynke

    2015-01-01

    Continuing Professional Development (CPD) and Faculty Development (FD) courses have been designed in the expectation that a cascade effect will occur, consisting of a conveyance of information from the courses to clinical trainers to daily practice and/or to trainees by means of role modeling. The

  18. Cascading pressure reactor and method for solar-thermochemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Ermanoski, Ivan

    2017-11-14

    Reactors and methods for solar thermochemical reactions are disclosed. The reactors and methods include a cascade of reduction chambers at successively lower pressures that leads to over an order of magnitude pressure decrease compared to a single-chambered design. The resulting efficiency gains are substantial, and represent an important step toward practical and efficient solar fuel production on a large scale.

  19. Experiments on Cascaded Quadratic Soliton Compression in Unpoled LN Waveguide

    DEFF Research Database (Denmark)

    Guo, Hairun; Zhou, Binbin; Zeng, Xianglong

    2014-01-01

    Experiments on cascaded quadratic soliton compression in unpoled phasemismatched lithium niobate waveguides are presented. Pulse self-phasemodulation dominated by an overall self-defocusing nonlinearity is observed, with an variation of pump wavelength and waveguide core width. © 2014 Optical...... Society of America...

  20. Network protection against worms and cascading failures using modularity partitioning

    NARCIS (Netherlands)

    Omic, J.; Hernandez, J.M.; Van Mieghem, P.

    2010-01-01

    Communication networks are prone to virus and worms spreading and cascading failures. Recently, a number of social networking worms have spread over public Web sites. Another example is error propagation in routing tables, such as in BGP tables. The immunization and error curing applied to these

  1. Mitogen-activated protein kinase cascades in Vitis vinifera

    Science.gov (United States)

    Çakır, Birsen; Kılıçkaya, Ozan

    2015-01-01

    Protein phosphorylation is one of the most important mechanisms to control cellular functions in response to external and endogenous signals. Mitogen-activated protein kinases (MAPK) are universal signaling molecules in eukaryotes that mediate the intracellular transmission of extracellular signals resulting in the induction of appropriate cellular responses. MAPK cascades are composed of four protein kinase modules: MAPKKK kinases (MAPKKKKs), MAPKK kinases (MAPKKKs), MAPK kinases (MAPKKs), and MAPKs. In plants, MAPKs are activated in response to abiotic stresses, wounding, and hormones, and during plant pathogen interactions and cell division. In this report, we performed a complete inventory of MAPK cascades genes in Vitis vinifera, the whole genome of which has been sequenced. By comparison with MAPK, MAPK kinases, MAPK kinase kinases and MAPK kinase kinase kinase kinase members of Arabidopsis thaliana, we revealed the existence of 14 MAPKs, 5 MAPKKs, 62 MAPKKKs, and 7 MAPKKKKs in Vitis vinifera. We identified orthologs of V. vinifera putative MAPKs in different species, and ESTs corresponding to members of MAPK cascades in various tissues. This work represents the first complete inventory of MAPK cascades in V. vinifera and could help elucidate the biological and physiological functions of these proteins in V. vinifera. PMID:26257761

  2. Errata Field theoretic calculation of energy cascade rates in non ...

    Indian Academy of Sciences (India)

    Errata. Field theoretic calculation of energy cascade rates in non-helical magnetohydrodynamic turbulence. MAHENDRA K VERMA. (Pramana – J. Phys., Vol. 61, No. 3, pp. 577–594 (2003)). In our paper we committed some typographical errors. We are correcting them here. 1. In eqs (25) and (26), 〈Sub(k |p|q)〉 and 〈Sbu(k ...

  3. A comparative study on dual colour soft aperture cascaded second ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... A comparative study in terms of optimized output power and stability is made on cascaded second-order nonlinear optical mode-locking with KTP, BBO and LBO crystals for both 1064 nm and 532 nm. Large nonlinear optical phase shift achieved in a non-phase-matched second harmonic generating crystal ...

  4. Neutron spallation source and the Dubna Cascade Code

    Indian Academy of Sciences (India)

    into a stationary state sometimes emitting several nucleons. At the third and the last stage the excited residual nucleus decays by competitive successive evaporation of nucleons, fission and emission of γ-quanta. Dubna Cascade Code [4] developed for the purpose of mathematical modeling of ADSS allows one to estimate ...

  5. A cascaded online uninterruptible power supply using reduced semiconductor

    DEFF Research Database (Denmark)

    Zhang, Lei; Loh, Poh Chiang; Gao, Feng

    2011-01-01

    are experienced by the presented UPS, as guaranteed through proper topological and control design. Advantages of the cascaded UPS can therefore be summarized as reduced system cost, improved redundancy, better waveform quality and the same reliable protection expected from an online system. The only disadvantage...

  6. An Algebraic Approach to Signaling Cascades with n Layers

    DEFF Research Database (Denmark)

    Feliu, Elisenda; Knudsen, Michael; Andersen, Lars Nørvang

    2011-01-01

    Posttranslational modification of proteins is key in transmission of signals in cells. Many signaling pathways contain several layers of modification cycles that mediate and change the signal through the pathway. Here, we study a simple signaling cascade consisting of n layers of modification...

  7. Cascade: an RNA-seq visualization tool for cancer genomics.

    Science.gov (United States)

    Shifman, Aaron R; Johnson, Radia M; Wilhelm, Brian T

    2016-01-25

    Cancer genomics projects are producing ever-increasing amounts of rich and diverse data from patient samples. The ability to easily visualize this data in an integrated an intuitive way is currently limited by the current software available. As a result, users typically must use several different tools to view the different data types for their cohort, making it difficult to have a simple unified view of their data. Here we present Cascade, a novel web based tool for the intuitive 3D visualization of RNA-seq data from cancer genomics experiments. The Cascade viewer allows multiple data types (e.g. mutation, gene expression, alternative splicing frequency) to be simultaneously displayed, allowing a simplified view of the data in a way that is tuneable based on user specified parameters. The main webpage of Cascade provides a primary view of user data which is overlaid onto known biological pathways that are either predefined or added by users. A space-saving menu for data selection and parameter adjustment allows users to access an underlying MySQL database and customize the features presented in the main view. There is currently a pressing need for new software tools to allow researchers to easily explore large cancer genomics datasets and generate hypotheses. Cascade represents a simple yet intuitive interface for data visualization that is both scalable and customizable.

  8. Emergence of a turbulent cascade in a quantum gas

    Science.gov (United States)

    Navon, Nir; Gaunt, Alexander L.; Smith, Robert P.; Hadzibabic, Zoran

    2016-11-01

    A central concept in the modern understanding of turbulence is the existence of cascades of excitations from large to small length scales, or vice versa. This concept was introduced in 1941 by Kolmogorov and Obukhov, and such cascades have since been observed in various systems, including interplanetary plasmas, supernovae, ocean waves and financial markets. Despite much progress, a quantitative understanding of turbulence remains a challenge, owing to the interplay between many length scales that makes theoretical simulations of realistic experimental conditions difficult. Here we observe the emergence of a turbulent cascade in a weakly interacting homogeneous Bose gas—a quantum fluid that can be theoretically described on all relevant length scales. We prepare a Bose-Einstein condensate in an optical box, drive it out of equilibrium with an oscillating force that pumps energy into the system at the largest length scale, study its nonlinear response to the periodic drive, and observe a gradual development of a cascade characterized by an isotropic power-law distribution in momentum space. We numerically model our experiments using the Gross-Pitaevskii equation and find excellent agreement with the measurements. Our experiments establish the uniform Bose gas as a promising new medium for investigating many aspects of turbulence, including the interplay between vortex and wave turbulence, and the relative importance of quantum and classical effects.

  9. Neutron spallation source and the Dubna Cascade Code

    Indian Academy of Sciences (India)

    Neutron multiplicity per incident proton, /, in collision of high energy proton beam with voluminous Pb and W targets has been estimated from the Dubna Cascade Code and compared with the available experimental data for the purpose of benchmarking of the code. Contributions of various atomic and nuclear processes ...

  10. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie; Højlund, Marie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful,....... The potentials and implica-­‐ tions are presented through a design case, Kidkit, highlighting temporality as design parametre within interaction design.......This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful...

  11. Atmospheric Measurements Laboratory (AML)

    Data.gov (United States)

    Federal Laboratory Consortium — The Atmospheric Measurements Laboratory (AML) is one of the nation's leading research facilities for understanding aerosols, clouds, and their interactions. The AML...

  12. A New Perspective on Trapped Radiation Belts in Planetary Atmospheres

    Science.gov (United States)

    Diaz, A.; Lodhi, M. A. K.; Wilson, T. L.

    2005-01-01

    The charged particle fluxes trapped in the magnetic dipole fields of certain planets in our Solar System are interesting signatures of planetary properties in space physics. They also represent a source of potentially hazardous radiation to spacecraft during planetary and interplanetary exploration. The Earth s trapped radiation belts have been studied for years and the physical mechanisms by which primary radiation from the Sun and Galaxy is captured is well understood. The higher-energy particles collide with molecules in the planetary atmosphere and initiate large cascades of secondary radiation which itself becomes trapped by the magnetic dipole field of the planet. Some of it is even backscattered as albedo neutrons.

  13. Development of a New Cascade Voltage-Doubler for Voltage Multiplication

    Directory of Open Access Journals (Sweden)

    Arash Toudeshki

    2014-01-01

    Full Text Available For more than eight decades, cascade voltage-doubler circuits are used as a method to produce DC output voltage higher than the input voltage. In this paper, the topological developments of cascade voltage-doublers are reviewed. A new circuit configuration for cascade voltage-doubler is presented. This circuit can produce a higher value of the DC output voltage and better output quality compared to the conventional cascade voltage-doubler circuits, with the same number of stages.

  14. Development of a New Cascade Voltage-Doubler for Voltage Multiplication

    OpenAIRE

    Toudeshki, Arash; Mariun, Norman; Hizam, Hashim; Abdul Wahab, Noor Izzri

    2014-01-01

    For more than eight decades, cascade voltage-doubler circuits are used as a method to produce DC output voltage higher than the input voltage. In this paper, the topological developments of cascade voltage-doublers are reviewed. A new circuit configuration for cascade voltage-doubler is presented. This circuit can produce a higher value of the DC output voltage and better output quality compared to the conventional cascade voltage-doubler circuits, with the same number of stages.

  15. Can salinity trigger cascade effects on streams? A mesocosm approach.

    Science.gov (United States)

    Cañedo-Argüelles, Miguel; Sala, Miquel; Peixoto, Gabriela; Prat, Narcís; Faria, Melissa; Soares, Amadeu M V M; Barata, Carlos; Kefford, Ben

    2016-01-01

    Human activities have greatly increased the salt concentration of the world's rivers, and this might be amplified by water scarcity in the future. While the lethal effects of salinity have been documented for a wide variety of stream invertebrates, the sub-lethal effects (i.e. changes in biological condition without mortality) are not deeply understood yet. One important sub-lethal effect that has yet to be investigated is changes in predation efficiency, which could trigger cascade effects associated to the abundance of herbivorous invertebrates that control algae biomass. In this study we combined the use of biomarkers with community-level data in a stream mesocosm to evaluate the potential cascade effect of increased salinity on the trophic food web. Both predation and salt treatments had an effect on the aquatic invertebrate abundance, richness and community composition. The presence of predators had a clear cascade effect, it reduced herbivorous invertebrate abundance and richness leading to higher chlorophyll a concentrations. The salt treatment significantly reduced taxa richness, but only in the gravel bed. The predators were significantly stressed by salt addition, as shown by the different analyzed biomarkers. Concordantly, in the presence of predators, Tanytarsini registered higher abundances and chlorophyll a showed a lower concentration when salt was added. However, none of these changes was significant. Therefore, although salt addition significantly stressed Dina lineata, our results suggest that a longer exposure time is needed to fully capture cascading effects (e.g. a decrease in chlorophyll a due to a relaxation of predation on herbivorous invertebrates). We suggest that the potential cascade effects of salinization need to be evaluated when addressing the impacts of water scarcity (as caused by climate change and increasing water demand) on river ecosystems, since flow reductions will lead to higher salt concentrations. Copyright © 2015

  16. Hydrothermal heat discharge in the Cascade Range, northwestern United States

    Science.gov (United States)

    Ingebritsen, S.E.; Mariner, R.H.

    2010-01-01

    Hydrothermal heat discharge in the Cascade Range includes the heat discharged by thermal springs, by "slightly thermal" springs that are only a few degrees warmer than ambient temperature, and by fumaroles. Thermal-spring heat discharge is calculated on the basis of chloride-flux measurements and geothermometer temperatures and totals ~ 240 MW in the U.S. part of the Cascade Range, excluding the transient post-1980 discharge at Mount St. Helens (~80 MW as of 2004-5). Heat discharge from "slightly thermal" springs is based on the degree of geothermal warming (after correction for gravitational potential energy effects) and totals ~. 660. MW. Fumarolic heat discharge is calculated by a variety of indirect and direct methods and totals ~160 MW, excluding the transient mid-1970s discharge at Mount Baker (~80 MW) and transient post-1980 discharge at Mount St. Helens (>. 230. MW as of 2005). Other than the pronounced transients at Mount St. Helens and Mount Baker, hydrothermal heat discharge in the Cascade Range appears to be fairly steady over a ~25-year period of measurement. Of the total of ~. 1050. MW of "steady" hydrothermal heat discharge identified in the U.S. part of the Cascade Range, less than 50. MW occurs north of latitude 45??15' N (~0.1 MW per km arc length from 45??15' to 49??N). Much greater rates of hydrothermal heat discharge south of 45??15'N (~1.7 MW per km arc length from 40?? to 45??15'N) may reflect the influence of Basin and Range-style extensional tectonics (faulting) that impinges on the Cascades as far north as Mount Jefferson but is not evident farther north. ?? 2010.

  17. Experimental investigation of gas turbine airfoil aerodynamic performance without and with film cooling in an annular sector cascade

    Energy Technology Data Exchange (ETDEWEB)

    Wiers, S.H.

    2002-02-01

    The steady growing of industrialization, the densification of the anthroposphere, the increasing concern over the effects of gas turbine cruise emissions on the atmosphere threaten the growth of air transportation, and the perception about the possible climatic impact of CO{sub 2} emissions causes a public distinctive sense of responsibility. The conventional energy production techniques, which are based on fossil fuel, will keep its central importance within the global energy production. Forecasts about the increasing air transportation give duplication in the next 10-15 years. The optimization of the specific fuel consumption is necessary to decrease the running costs and the pollution emissions in the atmosphere, which makes an increased process efficiency of stationary turbines as well as of jet engines essential. This leads to the necessity of an increased thermodynamic efficiency of the overall process and the optimization of the aerodynamic components. Due to the necessity of more detailed three-dimensional data on the behavior of film cooled blades an annular sector cascade turbine test facility has gone into service. The annular sector cascade facility is a relative cost efficient solution compared to a full annular facility to investigate three-dimensional effects on a non cooled and cooled turbine blade. The aerodynamic investigations on the annular sector cascade facility are part of a broad perspective where experimental data from a hot annular sector cascade facility and the cold annular sector facility are used to verify, calibrate and understand the physics for both internal and external calculation methods for flow and heat transfer prediction. The objective of the present study is the design and validation of a cold flow annular sector cascade facility, which meets the flow conditions in a modem turbine as close as possible, with emphasis on achieving periodic flow conditions. The first part of this study gives the necessary background on this

  18. Photochemistry of planetary atmospheres. [Mars atmospheric composition

    Science.gov (United States)

    Stief, L. J.

    1973-01-01

    The atmospheric composition of Mars is presented, and the applicability of laboratory data on CO2 absorption cross sections and quantum yields of dissociation is discussed. A summary and critical evaluation are presented on the various mechanisms proposed for converting the photodissociation products CO and O2 back to CO2.

  19. 77 FR 73651 - Cascade Energy Storage, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Science.gov (United States)

    2012-12-11

    ... No. 14464-000] Cascade Energy Storage, LLC; Notice of Preliminary Permit Application Accepted for..., Cascade Energy Storage, LLC, filed an application for a preliminary permit, pursuant to section 4(f) of... Executive Officer, Cascade Energy Storage, LLC, 1210 W. Franklin Street, Ste. 2, Boise, Idaho 83702; phone...

  20. DECREASING OF WATER TROPHY IN CASCADE SYSTEMS, ON EXAMPLE OF THE SOŁA RIVER DAM CASCADE (SOUTHERN POLAND

    Directory of Open Access Journals (Sweden)

    Ewa Jachniak

    2014-10-01

    Full Text Available In this thesis the subject of water self-purification in cascade systems of water reservoirs was engaged. The results of hydrobiological research of three dam reservoirs (Tresna, Porąbka and Czaniec, creating the Soła river dam cascade were presented. The trophic status of these reservoirs was defined on the grounds of the concentration of chlorophyll a, biomass of phytoplankton and occurrence of indicating species of planktonic algae. The results of research indicated on decreasing of water trophy in the layout from the highest into the lowest reservoir of the cascade. The average concentrations of chlorophyll a amounted appropriately 19,99 μg·dm-3, 8,74 μg·dm-3 and 4,29 μg·dm-3, instead the average biomass of phytoplankton amounted appropriately 4,1 mg·dm-3, 3,4 mg·dm-3 and 0,1 mg·dm-3. The observed species of algae confirmed occurrence of differences between reservoirs. In Tresna reservoir more species of phytoplankton indicating for eutrophy were thrived, instead in Porąbka and Czaniec reservoirs the species occurring in oligomesotrophic water thrived. Water self-purification in the Soła river dam cascade expressed decreasing of their fertility is important for water management of the region, because the Czaniec reservoir fulfill a function of water-supply reservoir.

  1. Controlled Atmosphere Stunning

    NARCIS (Netherlands)

    Lambooij, E.; Gerritzen, M.A.

    2009-01-01

    Controlled atmosphere (CAS) stunning includes several variations of gaseous mixtures given to induce an anaesthetic state before slaughter poultry. One method of multi phase CAS is to unload the birds out of the crate on a conveyor belt and subject the birds to an atmosphere of 30% O2, 40% CO2 and

  2. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...

  3. The Power of Atmosphere

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2014-01-01

    composed of bubbles of affects – that is, the particles that are charged with power and normativity. References Grtiffero, T. (2014 (2010)). Atmospheres: Aesthetics of Emotional Spaces. Ashgate Philippopoulos-Mihalopoulos, A. (2013). Atmospheres of law: Senses, affects, lawscapes, in Emotion, Space...

  4. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful....... The potentials and implications are presented through a design case, Kidkit, highlighting temporality as design parametre within interaction design....

  5. Atmosphere Impact Losses

    Science.gov (United States)

    Schlichting, Hilke E.; Mukhopadhyay, Sujoy

    2018-02-01

    Determining the origin of volatiles on terrestrial planets and quantifying atmospheric loss during planet formation is crucial for understanding the history and evolution of planetary atmospheres. Using geochemical observations of noble gases and major volatiles we determine what the present day inventory of volatiles tells us about the sources, the accretion process and the early differentiation of the Earth. We further quantify the key volatile loss mechanisms and the atmospheric loss history during Earth's formation. Volatiles were accreted throughout the Earth's formation, but Earth's early accretion history was volatile poor. Although nebular Ne and possible H in the deep mantle might be a fingerprint of this early accretion, most of the mantle does not remember this signature implying that volatile loss occurred during accretion. Present day geochemistry of volatiles shows no evidence of hydrodynamic escape as the isotopic compositions of most volatiles are chondritic. This suggests that atmospheric loss generated by impacts played a major role during Earth's formation. While many of the volatiles have chondritic isotopic ratios, their relative abundances are certainly not chondritic again suggesting volatile loss tied to impacts. Geochemical evidence of atmospheric loss comes from the {}3He/{}^{22}Ne, halogen ratios (e.g., F/Cl) and low H/N ratios. In addition, the geochemical ratios indicate that most of the water could have been delivered prior to the Moon forming impact and that the Moon forming impact did not drive off the ocean. Given the importance of impacts in determining the volatile budget of the Earth we examine the contributions to atmospheric loss from both small and large impacts. We find that atmospheric mass loss due to impacts can be characterized into three different regimes: 1) Giant Impacts, that create a strong shock transversing the whole planet and that can lead to atmospheric loss globally. 2) Large enough impactors (m_{cap} ≳ √{2

  6. Multi-species trace gas analysis with dual-wavelength quantum cascade laser

    Science.gov (United States)

    Jágerská, Jana; Tuzson, Béla; Looser, Herbert; Jouy, Pierre; Hugi, Andreas; Mangold, Markus; Soltic, Patrik; Faist, Jérôme; Emmenegger, Lukas

    2015-04-01

    Simultaneous detection of multiple gas species using mid-IR laser spectroscopy is highly appealing for a large variety of applications ranging from air quality monitoring, medical breath analysis to industrial process control. However, state-of-the-art distributed-feedback (DFB) mid-IR lasers are usually tunable only within a narrow spectral range, which generally leads to one-laser-one-compound measurement strategy. Thus, multi-species detection involves several lasers and elaborate beam combining solutions [1]. This makes them bulky, costly, and highly sensitive to optical alignment, which limits their field deployment. In this paper, we explore an alternative measurement concept based on a dual-wavelength quantum cascade laser (DW-QCL) [2]. Such a laser can emit at two spectrally distinct wavelengths using a succession of two DFB gratings with different periodicities and a common waveguide to produce one output beam. The laser design was optimized for NOx measurements and correspondingly emits single-mode at 5.26 and 6.25 μm. Electrical separation of the respective laser sections makes it possible to address each wavelength independently. Thereby, it is possible to detect NO and NO2 species with one laser using the same optical path, without any beam combining optics, i.e. in a compact and cost-efficient single-path optical setup. Operated in a time-division multiplexed mode, the spectrometer reaches detection limits at 100 s averaging of 0.5 and 1.5 ppb for NO2 and NO, respectively. The performance of the system was validated against the well-established chemiluminescence detection while measuring the NOx emissions on an automotive test-bench, as well as monitoring the pollution at a suburban site. [1] B. Tuzson, K. Zeyer, M. Steinbacher, J. B. McManus, D. D. Nelson, M. S. Zahniser, and L. Emmenegger, 'Selective measurements of NO, NO2 and NOy in the free troposphere using quantum cascade laser spectroscopy,' Atmospheric Measurement Techniques 6, 927-936 (2013

  7. Neutron Transport Associated with the Galactic Cosmic Ray Cascade

    Science.gov (United States)

    Singleterry, Robert Clay, Jr.

    Transport of low energy neutrons associated with the galactic cosmic ray cascade is analyzed in this dissertation. A benchmark quality analytical algorithm is demonstrated for use with B scRYNTRN, a computer program written by the High Energy Physics Division of N scASA Langley Research Center, which is used to design and analyze shielding against the radiation created by the cascade. B scRYNTRN uses numerical methods to solve the integral transport equations for baryons with the straight-ahead approximation, and numerical and empirical methods to generate the interaction probabilities. The straight-ahead approximation is adequate for charged particles, but not for neutrons. As N scASA Langley improves B scRYNTRN to include low energy neutrons, a benchmark quality solution is needed for comparison. The neutron transport algorithm demonstrated in this dissertation uses the closed-form Green's function solution to the galactic cosmic ray cascade transport equations to generate a source of neutrons. A basis function expansion for finite heterogeneous and semi-infinite homogeneous slabs with multiple energy groups and isotropic scattering is used to generate neutron fluxes resulting from the cascade. This method, called the F_{rm N} method, is used to solve the neutral particle linear Boltzmann transport equation. As a demonstration of the algorithm coded in the programs M scGSLAB and M scGSEMI, neutron and ion fluxes are shown for a beam of fluorine ions at 1000 MeV per nucleon incident on semi-infinite and finite aluminum slabs. Also, to demonstrate that the shielding effectiveness against the radiation from the galactic cosmic ray cascade is not directly proportional to shield thickness, a graph of transmitted total neutron scalar flux versus slab thickness is shown. A simple model based on the nuclear liquid drop assumption is used to generate cross sections for the galactic cosmic ray cascade. The E scNDF/B V database is used to generate the total and scattering

  8. Development of a Quantum Cascade Laser-Based Detector for Ammonia and Nitric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Zahniser, Mark S.; Nelson, David D.; McManus, J. Barry; Shorter, Joanne H.; Herndon, Scott C.; Jimenez, Rodrigo

    2005-12-31

    We have developed a compact, robust, atmospheric trace gas detector based on mid-infrared absorption spectroscopy using pulsed quantum cascade (QC) lasers. The spectrometer is suitable for airborne measurements of ammonia, nitric acid, formaldehyde, formic acid, methane, nitrous oxide, carbon monoxide, nitrogen dioxide and other gases that have line-resolved absorption spectra in the mid-infrared spectral region. The QC laser light source operates near room temperature with thermal electric cooling instead of liquid nitrogen which has been previously required for semiconductor lasers in the mid-infrared spectral region. The QC lasers have sufficient output power so that thermal electric cooled detectors may be used in many applications with lower precision requirements. The instrument developed in this program has been used in several field campaigns from both the Aerodyne Mobile Laboratory and from the NOAA WP3 aircraft. The Phase II program has resulted in more than 10 archival publications describing the technology and its applications. Over 12 instruments based on this design have been sold to research groups in Europe and the United States making the program both a commercial as well as a technological success. Anticipated Benefits The development of a sensitive, cryogen-free, mid-infrared absorption method for atmospheric trace gas detection will have wide benefits for atmospheric and environmental research and broader potential commercial applications in areas such as medical diagnostic and industrial process monitoring of gaseous compounds. Examples include air pollution monitoring, breath analysis, combustion exhaust diagnostics, and plasma diagnostics for semi-conductor fabrication. The substitution of near-room temperature QC lasers for cryogenic lead salt TDLs and the resulting simplifications in instrument design and operation will greatly expand the range of applications.

  9. Atmospheric composition change: Ecosystems–Atmosphere interactions

    DEFF Research Database (Denmark)

    Fowler, D.; Pilegaard, Kim; Sutton, M.A.

    2009-01-01

    in the size range 1 nm–10 μm including organic and inorganic chemical species. The main focus of the review is on the exchange between terrestrial ecosystems, both managed and natural and the atmosphere, although some new developments in ocean–atmosphere exchange are included. The material presented is biased...... and techniques in micrometeorology. For some of the compounds there have been paradigm shifts in approach and application of both techniques and assessment. These include flux measurements over marine surfaces and urban areas using micrometeorological methods and the up-scaling of flux measurements using...... aircraft and satellite remote sensing. The application of a flux-based approach in assessment of O3 effects on vegetation at regional scales is an important policy linked development secured through improved quantification of fluxes. The coupling of monitoring, modelling and intensive flux measurement...

  10. Dynamics of Massive Atmospheres

    Science.gov (United States)

    Chemke, Rei; Kaspi, Yohai

    2017-10-01

    The many recently discovered terrestrial exoplanets are expected to hold a wide range of atmospheric masses. Here the dynamic-thermodynamic effects of atmospheric mass on atmospheric circulation are studied using an idealized global circulation model by systematically varying the atmospheric surface pressure. On an Earth analog planet, an increase in atmospheric mass weakens the Hadley circulation and decreases its latitudinal extent. These changes are found to be related to the reduction of the convective fluxes and net radiative cooling (due to the higher atmospheric heat capacity), which, respectively, cool the upper troposphere at mid-low latitudes and warm the troposphere at high latitudes. These together decrease the meridional temperature gradient, tropopause height and static stability. The reduction of these parameters, which play a key role in affecting the flow properties of the tropical circulation, weakens and contracts the Hadley circulation. The reduction of the meridional temperature gradient also decreases the extraction of mean potential energy to the eddy fields and the mean kinetic energy, which weakens the extratropical circulation. The decrease of the eddy kinetic energy decreases the Rhines wavelength, which is found to follow the meridional jet scale. The contraction of the jet scale in the extratropics results in multiple jets and meridional circulation cells as the atmospheric mass increases.

  11. Atmospheric refraction: a history

    Science.gov (United States)

    Lehn, Waldemar H.; van der Werf, Siebren

    2005-09-01

    We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of uniform density up to a sharp upper transition to the ether, at which the refraction occurred. Alhazen and Witelo transmitted his knowledge to medieval Europe. The first accurate measurements were made by Tycho Brahe in the 16th century. Finally, Kepler, who was aware of unusually strong refractions, used the Ptolemaic model to explain the first documented and recognized mirage (the Novaya Zemlya effect).

  12. New atmospheric program

    Science.gov (United States)

    The National Science Foundation's Division of Atmospheric Sciences has established an Upper Atmospheric Facilities program within its Centers and Facilities section. The program will support the operation of and the scientific research that uses the longitudinal chain of incoherent scatter radars. The program also will ensure that the chain is maintained as a state-of-the-art research tool available to all interested and qualified scientists.For additional information, contact Richard A. Behnke, Division of Atmospheric Sciences, National Science Foundation, 1800 G Street, N.W., Washington, DC 20550 (telephone: 202-357-7390).

  13. Discovery of atmospheric neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Kajita, Takaaki [Tokyo Univ., Inst. for Cosmic Ray Research, Kashiwa, Chiba (Japan)

    2003-05-01

    Cosmic ray particles entering the atmosphere interact with the air nuclei produce neutrinos. These neutrinos are called atmospheric neutrinos. The atmospheric neutrino anomaly observed in Kamiokande is now understood as due to neutrino oscillations by high statistics measurements of the atmospheric neutrinos in Super-Kamiokande. The studies of the atmospheric neutrinos have matured into detailed studies of neutrino masses and mixings. (author)

  14. Effects of structural coupling on mistuned cascade flutter and response

    Science.gov (United States)

    Kielb, R. E.; Kaza, K. R. V.

    1983-01-01

    The effects of structural coupling on mistuned cascade flutter and response are analytically investigated using an extended typical section model. This model includes both structural and aerodynamic coupling between the blades. The model assumes that the structurally coupled system natural modes were determined and are represented in the form of N bending and N torsional uncoupled modes for each blade, where N is the number of blades and, hence, is only valid for blade dominated motion. The aerodynamic loads are calculated by using two dimensional unsteady cascade theories in the subsonic and supersonic flow regimes. The results show that the addition of structural coupling can affect both the aeroelastic stability and frequency. The stability is significantly affected only when the system is mistuned. The resonant frequencies can be significantly changed by structural coupling in both tuned and mistuned systems, however, the peak response is significantly affected only in the latter.

  15. Impedance coordinative control for cascaded converter in bidirectional application

    DEFF Research Database (Denmark)

    Tian, Yanjun; Loh, Poh Chiang; Deng, Fujin

    2016-01-01

    A two-stage cascaded converter is formed by connecting two sub-converters in series. Output impedance of one sub-converter will therefore interact with input impedance of the other sub-converter. Such interaction may affect the system dynamics and stability, especially when one sub-converter is c......A two-stage cascaded converter is formed by connecting two sub-converters in series. Output impedance of one sub-converter will therefore interact with input impedance of the other sub-converter. Such interaction may affect the system dynamics and stability, especially when one sub......-converter is constant-power-controlled, and hence has different impedance characteristics when its power reverses. To lessen such constant-power effects, a control scheme that can coordinate impedance behaviors of the two sub-converters is proposed. The idea is to reshape the lowfrequency negative impedance...

  16. Hybrid-source impedance network and its generalized cascading concepts

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang

    2009-01-01

    for current-type inverters. These impedance networks can in principle be combined into a single generic network entity, before generalized cascading concepts are proposed for connecting multiple of them together to form energy converters with a higher output voltage gain and other unique advantages....... It is anticipated that these concepts and their formed inverters can find applications in photovoltaic and other renewable systems, which in turn motivate the investigation initiated here on two-level and three-level generalized cascading concepts. In addition to their theoretical performance merits, practical...... shortcomings and relevant transient phenomena exhibited by the generalized concepts are discussed to provide a comprehensive knowledge base needed for weighing relevant tradeoffs before deciding on a particular application....

  17. SCC: Semantic Context Cascade for Efficient Action Detection

    KAUST Repository

    Heilbron, Fabian Caba

    2017-11-09

    Despite the recent advances in large-scale video analysis, action detection remains as one of the most challenging unsolved problems in computer vision. This snag is in part due to the large volume of data that needs to be analyzed to detect actions in videos. Existing approaches have mitigated the computational cost, but still, these methods lack rich high-level semantics that helps them to localize the actions quickly. In this paper, we introduce a Semantic Cascade Context (SCC) model that aims to detect action in long video sequences. By embracing semantic priors associated with human activities, SCC produces high-quality class-specific action proposals and prune unrelated activities in a cascade fashion. Experimental results in ActivityNet unveils that SCC achieves state-of-the-art performance for action detection while operating at real time.

  18. Multi Agent System Based Wide Area Protection against Cascading Events

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Liu, Leo

    2012-01-01

    In this paper, a multi-agent system based wide area protection scheme is proposed in order to prevent long term voltage instability induced cascading events. The distributed relays and controllers work as a device agent which not only executes the normal function automatically but also can...... be modified to fulfill the extra function according to external requirements. The control center is designed as a highest level agent in MAS to coordinate all the lower agents to prevent the system wide voltage disturbance. A hybrid simulation platform with MATLAB and RTDS is set up to demonstrate...... the effectiveness of proposed protection strategy. The simulation results indicate that the proposed multi agent control system can effectively coordinate the distributed relays and controllers to prevent the long term voltage instability induced cascading events....

  19. Extending the cascading gravity model to lower dimensions

    Science.gov (United States)

    Hao, Peng; Stojkovic, Dejan

    2014-07-01

    The cascading gravity model was proposed to eliminate instabilities of the original Dvali, Gabadadze, Porrati model by embedding our 4D (where D refers to the number of space-time dimensions) Universe into a 5D brane, which is itself embedded in a 6D bulk. Thus gravity cascades from 6D down to 4D as we decrease the length scales. We show that it is possible to extend this setup to lower dimensions as well, i.e. there is a self-consistent embedding of a 3D brane into a 4D brane, which is itself embedded in a 5D bulk and so on. This extension fits well into the "vanishing dimensions" framework in which dimensions open up as we increase the length scales.

  20. Continuous Emission Monitoring of Tetrafluoromethane Using Quantum Cascade Lasers

    Directory of Open Access Journals (Sweden)

    Peter Geiser

    2016-04-01

    Full Text Available Recent developments in quantum cascade lasers have enabled the development of new sensors for in-situ applications that have so far only been possible with extractive systems. In this work, a sensor is presented using a unique Wavelength Modulation Spectroscopy approach to measure tetrafluoromethane, a strong greenhouse gas. The sensor was characterized in a laboratory environment indicating a long-term detection limit of 20 ppb·m and a short-term value of well below 10 ppb·m. To demonstrate the feasibility of the sensor in a real-world environment, it was installed at an Alcoa aluminum smelter. A co-located Fourier Transform Infrared Spectrometer allowed direct comparison measurements of both systems. General agreement between the two methods was observed, leading to the conclusion that the developed in-situ quantum cascade laser based sensor has the potential to continuously measure tetrafluoromethane at aluminum smelters.

  1. Cascade Apartments - Deep Energy Multifamily Retrofit , Kent, Washington (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2014-02-01

    In December of 2009-10, King County Housing Authority (KCHA) implemented energy retrofit improvements in the Cascade multifamily community, located in Kent, Washington (marine climate.)This research effort involved significant coordination from stakeholders KCHA, WA State Department of Commerce, utility Puget Sound Energy, and Cascade tenants. This report focuses on the following three primary BA research questions : 1. What are the modeled energy savings using DOE low income weatherization approved TREAT software? 2. How did the modeled energy savings compare with measured energy savings from aggregate utility billing analysis? 3. What is the Savings to Investment Ratio (SIR) of the retrofit package after considering utility window incentives and KCHA capitol improvement funding.

  2. 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...

  3. CO{sub 2} degassing in the Oregon Cascades

    Energy Technology Data Exchange (ETDEWEB)

    James, E.R.; Manga, M. [Univ. of Oregon, Eugene, OR (United States). Dept. of Geological Sciences; Rose, T.P. [Lawrence Livermore National Lab., CA (United States). Isotope Sciences Div.

    1999-09-01

    The carbon isotope content of dissolved inorganic carbon was measured for large cold springs in the central Oregon Cascades. Low {sup 14}C activities in some of the springs are interpreted to result from the dissolution of diffuse emissions of magmatic CO{sub 2}, even though volcanic activity has not occurred in this area for more than 1300 yr. On the basis of dissolved magmatic carbon concentrations in the springs, the authors infer a diffuse magmatic CO{sub 2} degassing rate of 3.4 {times} 10{sup 5} kg/yr per kilometer of arc for the central Oregon Cascades. The CO{sub 2} flux calculated from estimates of the mean magmatic intrusion rate and experimentally determined values of CO{sub 2} content in melts is consistent with that determined from their measurements of the dissolved CO{sub 2} flux at springs.

  4. CO[sub 2] degassing in the Oregon Cascades

    Energy Technology Data Exchange (ETDEWEB)

    James, E.R.; Manga, M. (Univ. of Oregon, Eugene, OR (United States). Dept. of Geological Sciences); Rose, T.P. (Lawrence Livermore National Lab., CA (United States). Isotope Sciences Div.)

    1999-09-01

    The carbon isotope content of dissolved inorganic carbon was measured for large cold springs in the central Oregon Cascades. Low [sup 14]C activities in some of the springs are interpreted to result from the dissolution of diffuse emissions of magmatic CO[sub 2], even though volcanic activity has not occurred in this area for more than 1300 yr. On the basis of dissolved magmatic carbon concentrations in the springs, the authors infer a diffuse magmatic CO[sub 2] degassing rate of 3.4 [times] 10[sup 5] kg/yr per kilometer of arc for the central Oregon Cascades. The CO[sub 2] flux calculated from estimates of the mean magmatic intrusion rate and experimentally determined values of CO[sub 2] content in melts is consistent with that determined from their measurements of the dissolved CO[sub 2] flux at springs.

  5. Cascading quantum light-matter interfaces with minimal interconnection losses

    Science.gov (United States)

    Namazi, Mehdi; Mittiga, Thomas; Kupchak, Connor; Figueroa, Eden

    2015-09-01

    The ability to interface multiple optical quantum devices is a key milestone towards the development of future quantum information processors and networks. One of the requirements for any of their constituent elements will be cascadability, i.e., the ability to drive the input of a device using the output of another one. Here, we report the cascading of quantum light-matter interfaces by storing few-photon level pulses of light in warm vapor followed by the subsequent storage of the retrieved field onto a second ensemble. We demonstrate that by using built-in purification mechanisms in the sequential storage, the final signal-to-background ratio can remain greater than one for weak pulses containing eight input photons on average.

  6. Exploring percolative landscapes: Infinite cascades of geometric phase transitions.

    Science.gov (United States)

    Timonin, P N; Chitov, Gennady Y

    2016-01-01

    The evolution of many kinetic processes in 1+1 (space-time) dimensions results in 2D directed percolative landscapes. The active phases of these models possess numerous hidden geometric orders characterized by various types of large-scale and/or coarse-grained percolative backbones that we define. For the patterns originated in the classical directed percolation (DP) and contact process we show from the Monte Carlo simulation data that these percolative backbones emerge at specific critical points as a result of continuous phase transitions. These geometric transitions belong to the DP universality class and their nonlocal order parameters are the capacities of corresponding backbones. The multitude of conceivable percolative backbones implies the existence of infinite cascades of such geometric transitions in the kinetic processes considered. We present simple arguments to support the conjecture that such cascades of transitions are a generic feature of percolation as well as of many other transitions with nonlocal order parameters.

  7. Experimental Investigation of Hot Carriers in Terahertz Quantum Cascade Lasers

    Science.gov (United States)

    Scamarcio, G.; Vitiello, M. S.; Spagnolo, V.

    2008-03-01

    The nature of the electron distribution and the electron-lattice energy relaxation phenomena in all classes of quantum cascade lasers operating in the THz range, namely, resonant-phonon, bound-to-continuum, and interlaced photon-phonon designs are reviewed. Thermalized hot-electron distributions are found in all cases. However, electronic temperatures of individual conduction subband are strongly influenced by the specific quantum design and the actual electron-lattice energy relaxation channels. A wealth of information was obtained both below and above laser threshold from the analysis of micro-probe band-to-band photoluminescence spectra recorded with a spatial resolution of ≈ 2 μm. The influence of the detailed knowledge of the hot electron distributions on the design of improved THz quantum cascade lasers aiming at high temperature operation will be discussed.

  8. Delay time calculation for dual-wavelength quantum cascade lasers

    Energy Technology Data Exchange (ETDEWEB)

    Hamadou, A., E-mail: abd-hamado@yahoo.fr [Département des Sciences et Techniques, Faculté des Sciences et de la Technologie, Université de Bordj Bou Arreridj 34000 (Algeria); Laboratoire d’étude des surfaces et interfaces des matériaux solides (LESIMS), Sétif 19000 (Algeria); Lamari, S. [Laboratoire d’étude des surfaces et interfaces des matériaux solides (LESIMS), Sétif 19000 (Algeria); Département de Physique, Faculté des Sciences, Université Sétif 1, 19000 (Algeria); Thobel, J.-L. [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR 8520, Université Lille1, Avenue Poincaré, BP 60069, 59652 Villeneuve d' Ascq Cédex (France)

    2013-11-28

    In this paper, we calculate the turn-on delay (t{sub th}) and buildup (Δt) times of a midinfrared quantum cascade laser operating simultaneously on two laser lines having a common upper level. The approach is based on the four-level rate equations model describing the variation of the electron number in the states and the photon number present within the cavity. We obtain simple analytical formulae for the turn-on delay and buildup times that determine the delay times and numerically apply our results to both the single and bimode states of a quantum cascade laser, in addition the effects of current injection on t{sub th} and Δt are explored.

  9. Forward design of a complex enzyme cascade reaction

    Science.gov (United States)

    Hold, Christoph; Billerbeck, Sonja; Panke, Sven

    2016-09-01

    Enzymatic reaction networks are unique in that one can operate a large number of reactions under the same set of conditions concomitantly in one pot, but the nonlinear kinetics of the enzymes and the resulting system complexity have so far defeated rational design processes for the construction of such complex cascade reactions. Here we demonstrate the forward design of an in vitro 10-membered system using enzymes from highly regulated biological processes such as glycolysis. For this, we adapt the characterization of the biochemical system to the needs of classical engineering systems theory: we combine online mass spectrometry and continuous system operation to apply standard system theory input functions and to use the detailed dynamic system responses to parameterize a model of sufficient quality for forward design. This allows the facile optimization of a 10-enzyme cascade reaction for fine chemical production purposes.

  10. Analysis and improvement of face detection based on surf cascade

    Science.gov (United States)

    Hu, Siquan; Zhang, Caihong; Liu, Lei

    2017-08-01

    This paper aims to study limitations of the commonly employed boosting cascade framework. We focus on the factors like data, feature, weak classifier and stages. A set of novel experiments were done to show the relationship. The model contains three key points: SURF feature, weak classifier based on logistic regression and AUC-based cascade learning algorithm. This paper adds cross validation in logistic regression creatively which improves accuracy and speeds up convergence greatly. Eventually only five stages and about 100 weak classifiers are needed. The frontal face detector improves reject rate to 99% for the first three stages, decreases number of false positive greatly and achieves comparable performance among non-CNN techniques on FDDB dataset.

  11. Preliminary Results of the CASCADE Hidden Sector Photon Search

    CERN Document Server

    Woollett, Nathan; Burt, Graeme; Chattopadhyay, Swapan; Dainton, John; Dexter, Amos; Goudket, Phillipe; Jenkins, Michael; Kalliokoski, Matti; Moss, Andrew; Pattalwar, Shrikant; Thakker, Trina; Williams, Peter

    2015-01-01

    Light shining through a wall experiments can be used to make measurements of photon-WISP couplings. The first stage of the CASCADE experiment at the Cockcroft Institute of Accelerator Science and Technology is intended to be a proof-of-principle experiment utilising standard microwave technologies to make a modular, cryogenic HSP detector to take advantage of future high-power superconducting cavity tests. In these proceedings we will be presenting the preliminary results of the CASCADE LSW experiment showing a peak expected exclusion of $1.10 \\times 10^{-8}$ in the mass range from 1.96$\\mu$eV to 5.38$\\mu$eV, exceeding current limits.

  12. Joint Face Detection and Alignment Using Multitask Cascaded Convolutional Networks

    Science.gov (United States)

    Zhang, Kaipeng; Zhang, Zhanpeng; Li, Zhifeng; Qiao, Yu

    2016-10-01

    Face detection and alignment in unconstrained environment are challenging due to various poses, illuminations and occlusions. Recent studies show that deep learning approaches can achieve impressive performance on these two tasks. In this paper, we propose a deep cascaded multi-task framework which exploits the inherent correlation between them to boost up their performance. In particular, our framework adopts a cascaded structure with three stages of carefully designed deep convolutional networks that predict face and landmark location in a coarse-to-fine manner. In addition, in the learning process, we propose a new online hard sample mining strategy that can improve the performance automatically without manual sample selection. Our method achieves superior accuracy over the state-of-the-art techniques on the challenging FDDB and WIDER FACE benchmark for face detection, and AFLW benchmark for face alignment, while keeps real time performance.

  13. Molecular dynamics simulation of radiation damage cascades in diamond

    Energy Technology Data Exchange (ETDEWEB)

    Buchan, J. T. [Department of Physics and Astronomy, Curtin University, Perth, Western Australia 6845 (Australia); Robinson, M. [Nanochemistry Research Institute, Curtin University, Perth, Western Australia 6845 (Australia); Christie, H. J.; Roach, D. L.; Ross, D. K. [Physics and Materials Research Centre, School of Computing, Science and Engineering, University of Salford, Salford, Greater Manchester M5 4WT (United Kingdom); Marks, N. A. [Department of Physics and Astronomy, Curtin University, Perth, Western Australia 6845 (Australia); Nanochemistry Research Institute, Curtin University, Perth, Western Australia 6845 (Australia)

    2015-06-28

    Radiation damage cascades in diamond are studied by molecular dynamics simulations employing the Environment Dependent Interaction Potential for carbon. Primary knock-on atom (PKA) energies up to 2.5 keV are considered and a uniformly distributed set of 25 initial PKA directions provide robust statistics. The simulations reveal the atomistic origins of radiation-resistance in diamond and provide a comprehensive computational analysis of cascade evolution and dynamics. As for the case of graphite, the atomic trajectories are found to have a fractal-like character, thermal spikes are absent and only isolated point defects are generated. Quantitative analysis shows that the instantaneous maximum kinetic energy decays exponentially with time, and that the timescale of the ballistic phase has a power-law dependence on PKA energy. Defect recombination is efficient and independent of PKA energy, with only 50% of displacements resulting in defects, superior to graphite where the same quantity is nearly 75%.

  14. Spatial correlation analysis of cascading failures: congestions and blackouts.

    Science.gov (United States)

    Daqing, Li; Yinan, Jiang; Rui, Kang; Havlin, Shlomo

    2014-06-20

    Cascading failures have become major threats to network robustness due to their potential catastrophic consequences, where local perturbations can induce global propagation of failures. Unlike failures spreading via direct contacts due to structural interdependencies, overload failures usually propagate through collective interactions among system components. Despite the critical need in developing protection or mitigation strategies in networks such as power grids and transportation, the propagation behavior of cascading failures is essentially unknown. Here we find by analyzing our collected data that jams in city traffic and faults in power grid are spatially long-range correlated with correlations decaying slowly with distance. Moreover, we find in the daily traffic, that the correlation length increases dramatically and reaches maximum, when morning or evening rush hour is approaching. Our study can impact all efforts towards improving actively system resilience ranging from evaluation of design schemes, development of protection strategies to implementation of mitigation programs.

  15. Distributed flow optimization and cascading effects in weighted complex networks

    OpenAIRE

    Asztalos, Andrea; Sreenivasan, Sameet; Szymanski, Boleslaw K.; Korniss, G.

    2011-01-01

    We investigate the effect of a specific edge weighting scheme $\\sim (k_i k_j)^{\\beta}$ on distributed flow efficiency and robustness to cascading failures in scale-free networks. In particular, we analyze a simple, yet fundamental distributed flow model: current flow in random resistor networks. By the tuning of control parameter $\\beta$ and by considering two general cases of relative node processing capabilities as well as the effect of bandwidth, we show the dependence of transport efficie...

  16. Cascading Events, Technology and the Floods Directive: future challenges

    OpenAIRE

    Pescaroli Gianluca; Nones Michael

    2016-01-01

    Cascading events can be referred to multidimensional disasters, where a primary trigger generates a nonlinear series of secondary emergencies that escalate in time, becoming eventually the priority to tackle. In this process, critical infrastructure can be handled as roots of vulnerabilities, because they accumulate both physical attributes and functional nodes. When compromised, they produce widespread breakdowns of society, but also orient emergency responses and long-term recovery. Althoug...

  17. Understanding and preventing cascading breakdown in complex clustered networks.

    Science.gov (United States)

    Huang, Liang; Lai, Ying-Cheng; Chen, Guanrong

    2008-09-01

    Complex clustered networks are ubiquitous in natural and technological systems. Understanding the physics of the security of such networks in response to attacks is of significant value. We develop a model, based on physical analysis and numerical computations, for the key ingredients of load dynamics in typical clustered networks. With this understanding, an effective strategy is proposed for preventing cascading breakdown, one of the most disastrous events that can happen to a complex networked system.

  18. Cascade upgrading of γ-valerolactone to biofuels.

    Science.gov (United States)

    Yan, Kai; Lafleur, Todd; Wu, Xu; Chai, Jiajue; Wu, Guosheng; Xie, Xianmei

    2015-04-25

    Cascade upgrading of γ-valerolactone (GVL), produced from renewable cellulosic biomass, with selective conversion to biofuels pentyl valerate (PV) and pentane in one pot using a bifunctional Pd/HY catalyst is described. Excellent catalytic performance (over 99% conversion of GVL, 60.6% yield of PV and 22.9% yield of pentane) was achieved in one step. These biofuels can be targeted for gasoline and jet fuel applications.

  19. Cascade of complexity in evolving predator-prey dynamics.

    Science.gov (United States)

    Guttenberg, Nicholas; Goldenfeld, Nigel

    2008-02-08

    We simulate an individual-based model that represents both the phenotype and genome of digital organisms with predator-prey interactions. We show how open-ended growth of complexity arises from the invariance of genetic evolution operators with respect to changes in the complexity, and that the dynamics which emerges shows scaling indicative of a nonequilibrium critical point. The mechanism is analogous to the development of the cascade in fluid turbulence.

  20. Quantifying efficient information transduction of biochemical signaling cascades

    OpenAIRE

    Tsuruyama, Tatsuaki

    2016-01-01

    Cells can be considered as systems that utilize changes in thermodynamic entropy as information. Therefore, they serve as useful models for investigating the relationships between entropy production and information transmission, i.e., signal transduction. Based on the hypothesis that cells apply a chemical reaction cascade for the most efficient transduction of information, we adopted a coding design that minimizes the number of bits per concentration of molecules that are employed for inform...

  1. A cascade computer model for mocrobicide diffusivity from mucoadhesive formulations

    OpenAIRE

    Lee, Yugyung; Khemka, Alok; Acharya, Gayathri; Giri, Namita; Lee, Chi H.

    2015-01-01

    Background The cascade computer model (CCM) was designed as a machine-learning feature platform for prediction of drug diffusivity from the mucoadhesive formulations. Three basic models (the statistical regression model, the K nearest neighbor model and the modified version of the back propagation neural network) in CCM operate sequentially in close collaboration with each other, employing the estimated value obtained from the afore-positioned base model as an input value to the next-position...

  2. Null controllability of a cascade system of Schrodinger equations

    Directory of Open Access Journals (Sweden)

    Marcos Lopez-Garcia

    2016-03-01

    Full Text Available This article presents a control problem for a cascade system of two linear N-dimensional Schrodinger equations. We address the problem of null controllability by means of a control supported in a region not satisfying the classical geometrical control condition. The proof is based on the application of a Carleman estimate with degenerate weights to each one of the equations and a careful analysis of the system in order to prove null controllability with only one control force.

  3. Novel aspects in the regulation of the leukocyte adhesion cascade

    OpenAIRE

    Chavakis, Emmanouil; Choi, Eun Young; Chavakis, Triantafyllos

    2009-01-01

    Leukocyte recruitment plays a major role in the immune response to infectious pathogens and during inflammatory and autoimmune disorders. The process of leukocyte extravasation from the blood into the inflamed tissue requires a complex cascade of adhesive events between the leukocytes and the endothelium including leukocyte rolling, adhesion and transendothelial migration. Leukocyte-endothelial interactions are mediated by tightly regulated binding interactions between adhesion receptors on b...

  4. Optimization Model of the Váh Cascade Operation

    OpenAIRE

    Šulek, Peter

    2009-01-01

    The optimal operation of an electrical power supply subsystem results from respect for the effectiveness criterion for the control of an industrial enterprise. It is essential for the operation of the Váh cascade hydro power plants - a significant Slovak hydro-energy system. The fundamental principle of this operation is the potential hydropower utilization of water courses in addition to planning the control of the whole electrical system.

  5. Evidence of intermittent cascades from discrete hierarchical dissipation in turbulence

    Science.gov (United States)

    Zhou, Wei-Xing; Sornette, Didier

    2002-05-01

    We present the results of a search of log-periodic corrections to scaling in the moments of the square of velocity increments taken as proxies of the energy dissipation rate in experiments at high Reynolds number (≈2500) of three-dimensional fully developed turbulence. A simple dynamical representation of the Richardson-Kolmogorov cartoon of a cascade shows that standard averaging techniques erase by their very construction the possible existence of log-periodic corrections to scaling associated with a discrete hierarchy. To remedy this drawback, we introduce a novel “canonical” averaging that we test extensively on synthetic examples constructed to mimic the interplay between a weak log-periodic component and rather strong multiplicative and phase noises. Tests are also presented on 1/ f5/3 random-phase noise, on the multifractal random walk model, and on lattice and non-lattice multifractal models. Our extensive tests confirm the remarkable observation of statistically significant log-periodic corrections to scaling, with a preferred scaling ratio for length scales compatible with the value γ=2. A strong confirmation of this result is provided by the identification of up to five harmonics of the fundamental log-periodic undulations, associated with up to five levels of the underlying hierarchical dynamical structure. A natural interpretation of our results is that the Richardson-Kolmogorov mental picture of a cascade becomes a realistic description if one allows for intermittent births and deaths of discrete cascades at varying scales.

  6. The importance of sensory integration processes for action cascading.

    Science.gov (United States)

    Gohil, Krutika; Stock, Ann-Kathrin; Beste, Christian

    2015-03-30

    Dual tasking or action cascading is essential in everyday life and often investigated using tasks presenting stimuli in different sensory modalities. Findings obtained with multimodal tasks are often broadly generalized, but until today, it has remained unclear whether multimodal integration affects performance in action cascading or the underlying neurophysiology. To bridge this gap, we asked healthy young adults to complete a stop-change paradigm which presented different stimuli in either one or two modalities while recording behavioral and neurophysiological data. Bimodal stimulus presentation prolonged response times and affected bottom-up and top-down guided attentional processes as reflected by the P1 and N1, respectively. However, the most important effect was the modulation of response selection processes reflected by the P3 suggesting that a potentially different way of forming task goals operates during action cascading in bimodal vs. unimodal tasks. When two modalities are involved, separate task goals need to be formed while a conjoint task goal may be generated when all stimuli are presented in the same modality. On a systems level, these processes seem to be related to the modulation of activity in fronto-polar regions (BA10) as well as Broca's area (BA44).

  7. Intermittent Flow Regimes in a Transonic Fan Airfoil Cascade

    Science.gov (United States)

    Lepicovsky, J.; McFarland, E. R.; Chima, R. V.; Capece, V. R.; Hayden, J.

    2002-01-01

    A study was conducted in the NASA Glenn Research Center linear cascade on the intermittent flow on the suction surface of an airfoil section from the tip region of a modern low aspect ratio fan blade. Experimental results revealed that, at a large incidence angle, a range of transonic inlet Mach numbers exist where the leading-edge shock-wave pattern was unstable. Flush mounted high frequency response pressure transducers indicated large local jumps in the pressure in the leading edge area, which generates large intermittent loading on the blade leading edge. These measurements suggest that for an inlet Mach number between 0.9 and 1.0 the flow is bi-stable, randomly switching between subsonic and supersonic flows. Hence, it appears that the change in overall flow conditions in the transonic region is based on the frequency of switching between two stable flow states rather than on the continuous increase of the flow velocity. To date, this flow behavior has only been observed in a linear transonic cascade. Further research is necessary to confirm this phenomenon occurs in actual transonic fans and is not the byproduct of an endwall restricted linear cascade.

  8. Cascading Events, Technology and the Floods Directive: future challenges

    Directory of Open Access Journals (Sweden)

    Pescaroli Gianluca

    2016-01-01

    Full Text Available Cascading events can be referred to multidimensional disasters, where a primary trigger generates a nonlinear series of secondary emergencies that escalate in time, becoming eventually the priority to tackle. In this process, critical infrastructure can be handled as roots of vulnerabilities, because they accumulate both physical attributes and functional nodes. When compromised, they produce widespread breakdowns of society, but also orient emergency responses and long-term recovery. Although floods have been widely associated to the failure of vulnerable equipments or to the disruption of strategic sectors such as energy, communication and transportation, their integration with the emerging concept of cascading has been limited. This open topic presents many challenges for scholars, researchers and practitioners, in particular when the implementation of the EU Floods Directive is considered. The paper presents an overview of the Floods Directive and its relation with the cascading events, using case studies and examples from the existing literature to point out missing links and gaps in the legislation. Conclusions argue that the Directive considers only local geographical scales and limited temporal horizons, which can be result inadequate to limit the escalation of events.

  9. Photoproduction of the Cascade Baryons at GlueX

    Science.gov (United States)

    Ernst, Ashley; GlueX Collaboration

    2017-09-01

    Multi-strange baryons play an important role in understanding the strong interaction and despite their importance, little is known about such hyperons. Almost all knowledge of the Cascades today stems from Kaon-nucleon interactions in bubble chamber experiments performed in the 1960s and 1970s, of which only the octet and decuplet ground states, Ξ (1320) and Ξ (1530) respectively, are well established. This research uses the GlueX experiment at Jefferson Laboratory to map out the spectrum of doubly-strange Cascade resonances, as well as to measure the spin-parity for each of the detected resonances. The first physics run for GlueX has recently been completed and a clear signature of the Ξ (1320) is observed. The systematics of the Cascade spectrum will be presented motivated by prior discoveries in the N* program. This work was supported by the U.S. Department of Energy Grant DE-FG02-92ER40735 and National Science Foundation Grant 1449440.

  10. THz quantum cascade lasers for standoff molecule detection.

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Weng Wah; Wanke, Michael Clement; Lerttamrab, Maytee; Waldmueller, Ines

    2007-10-01

    Remote optical detection of molecules, agents, and energetic materials has many applications to national security interests. Currently there is significant interest in determining under what circumstances THz frequency coverage will aid in a complete sensing package. Sources of coherent THz frequency (i.e. 0.1 to 10 THz) electromagnetic radiation with requisite power levels, frequency agility, compactness and reliability represent the single greatest obstacle in establishing a THz technology base, but recent advances in semiconductor-based quantum cascade lasers (QCLs) offer huge improvements towards the ultimate THz source goals. This project advanced the development of narrow-linewidth THz quantum cascade lasers. We developed theoretical tools to guide the improvement of standard THz quantum cascade lasers, the investigation of nonlinear optics employing infrared QCLs, and the exploration of quantum coherence to improve QCL performance. The latter was aimed especially towards achieving high temperature operation. In addition we developed a computer algorithm capable of shifting the frequencies of an existing THz QCL to a different frequency and invented a new type of laser that may enable room temperature THz generation in a electrically driven solid-state source.

  11. Process Evaluation Tools for Enzymatic Cascades Welcome Message

    DEFF Research Database (Denmark)

    Abu, Rohana

    Biocatalysis is attracting significant attention from both academic and industrial scientists due to the excellent capability of enzyme to catalyse selective reactions. Recently, much interest has been shown in the application of enzymatic cascades as a useful tool in organic synthesis to synthes......Biocatalysis is attracting significant attention from both academic and industrial scientists due to the excellent capability of enzyme to catalyse selective reactions. Recently, much interest has been shown in the application of enzymatic cascades as a useful tool in organic synthesis...... to synthesize valuable compounds (e.g. chiral molecules) especially as pharmaceutical intermediates and to assist complex reactions that otherwise has problems as single step system. Despite this interest, process evaluation of many enzymatic cascades has only rarely been reported in the search for process...... the equilibrium positions in the main syntheses. In principle, this strategy could successfully achieve high conversion, using ammonia as the sole reagent used in excess to drive the conversion. The findings herein indicate that quantitatively the possibilities for improving the conversion of thermodynamically...

  12. Synthetic cascades are enabled by combining biocatalysts with artificial metalloenzymes

    Science.gov (United States)

    Köhler, V.; Wilson, Y. M.; Dürrenberger, M.; Ghislieri, D.; Churakova, E.; Quinto, T.; Knörr, L.; Häussinger, D.; Hollmann, F.; Turner, N. J.; Ward, T. R.

    2013-02-01

    Enzymatic catalysis and homogeneous catalysis offer complementary means to address synthetic challenges, both in chemistry and in biology. Despite its attractiveness, the implementation of concurrent cascade reactions that combine an organometallic catalyst with an enzyme has proven challenging because of the mutual inactivation of both catalysts. To address this, we show that incorporation of a d6-piano stool complex within a host protein affords an artificial transfer hydrogenase (ATHase) that is fully compatible with and complementary to natural enzymes, thus enabling efficient concurrent tandem catalysis. To illustrate the generality of the approach, the ATHase was combined with various NADH-, FAD- and haem-dependent enzymes, resulting in orthogonal redox cascades. Up to three enzymes were integrated in the cascade and combined with the ATHase with a view to achieving (i) a double stereoselective amine deracemization, (ii) a horseradish peroxidase-coupled readout of the transfer hydrogenase activity towards its genetic optimization, (iii) the formation of L-pipecolic acid from L-lysine and (iv) regeneration of NADH to promote a monooxygenase-catalysed oxyfunctionalization reaction.

  13. US geothermal database and Oregon cascade thermal studies: (Final report)

    Energy Technology Data Exchange (ETDEWEB)

    Blackwell, D.D.; Steele, J.L.; Carter, L.

    1988-05-01

    This report describes two tasks of different nature. The first of these tasks was the preparation of a data base for heat flow and associated ancillary information for the United States. This data base is being used as the basis for preparation of the United States portion of a geothermal map of North America. The ''Geothermal Map of North America'' will be published as part of the Decade of North American Geology (DNAG) series of the Geological Society of America. The second of these tasks was to make a geothermal evaluation of holes drilled in the Cascade Range as part of a Department of Energy (DOE)/Industry co-sponsored deep drilling project. This second task involved field work, making temperature logs in the holes, and laboratory work, measuring thermal conductivity measurements on an extensive set of samples from these holes. The culmination of this task was an interpretation of heat flow values in terms of the regional thermal conditions; implications for geothermal systems in the Cascade Range; evaluation of the effect of groundwater flow on the depths that need to be drilled for successful measurements in the Cascade Range; and investigation of the nature of the surface groundwater effects on the temperature-depth curves. 40 refs., 7 figs., 7 tabs.

  14. Atmospheric Transport Modeling Resources

    Energy Technology Data Exchange (ETDEWEB)

    Mazzola, Carl A. [Stone and Webster Engineering Corporation, Aiken, SC (United States); Addis, Robert P. [Westinghouse Savannah River Company, Aiken, SC (United States)

    1995-03-01

    The purpose of this publication is to provide DOE and other federal agency emergency managers with an in-depth compilation and description of atmospheric dispersion models available to DOE and other Federal sites.

  15. Atmospheric Heavy Metal Pollution

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 4. Atmospheric Heavy Metal Pollution - Development of Chronological Records and Geochemical Monitoring. Rohit Shrivastav. General Article Volume 6 Issue 4 April 2001 pp 62-68 ...

  16. Students 'Weigh' Atmospheric Pollution.

    Science.gov (United States)

    Caporaloni, Marina

    1998-01-01

    Describes a procedure developed by students that measures the mass concentration of particles in a polluted urban atmosphere. Uses a portable fan and filters of various materials. Compares students' data with official data. (DDR)

  17. Our Changing Atmosphere.

    Science.gov (United States)

    Clearing, 1988

    1988-01-01

    Summarizes what is known about two major variables involved in certain types of chemical pollution that seem to be changing the structure of the Earth's atmosphere. Discusses the greenhouse effect and the ozone layer. (TW)

  18. Global atmospheric changes.

    OpenAIRE

    Piver, W T

    1991-01-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the proces...

  19. Dynamics in Atmospheric Physics

    Science.gov (United States)

    Lindzen, Richard A.

    2005-08-01

    Motion is manifest in the atmosphere in an almost infinite variety of ways. In Dynamics in Atmospheric Physics, Dr. Richard Lindzen describes the nature of motion in the atmosphere, develops fluid dynamics relevant to the atmosphere, and explores the role of motion in determining the climate and atmospheric composition. The author presents the material in a lecture note style, and the emphasis throughout is on describing phenomena that are at the frontiers of current research, but due attention is given to the methodology of research and to the historical background of these topics. The author's treatment and choice of topics is didactic. Problems at the end of each chapter will help students assimilate the material. In general the discussions emphasize physical concepts, and throughout Dr. Lindzen makes a concerted effort to avoid the notion that dynamic meteorology is simply the derivation of equations and their subsequent solution. His desire is that interested students will delve further into solution details. The book is intended as a text for first year graduate students in the atmospheric sciences. Although the material in the book is self contained, a familiarity with differential equations is assumed; some background in fluid mechanics is helpful.

  20. Atmospheric Circulation of Exoplanets

    Science.gov (United States)

    Showman, A. P.; Cho, J. Y.-K.; Menou, K.

    2010-12-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from solar system studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and simple scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric dynamics are given particular attention, as these close-in planets have been the subject of most of the concrete developments in the study of exoplanetary atmospheres. We then turn to the basic elements of circulation on terrestrial planets as inferred from solar system studies, including Hadley cells, jet streams, processes that govern the large-scale horizontal temperature contrasts, and climate, and we discuss how these insights may apply to terrestrial exoplanets. Although exoplanets surely possess a greater diversity of circulation regimes than seen on the planets in our solar system, our guiding philosophy is that the multidecade study of solar system planets reviewed here provides a foundation upon which our understanding of more exotic exoplanetary meteorology must build.

  1. Atmospheric Change on Pluto

    Science.gov (United States)

    Person, Michael

    2013-10-01

    We propose to use SOFIA with HIPO and FLITECAM (FLIPO) to measure the parameters of Pluto's atmosphere (temperature, pressure, possible particulate haze) by observing a stellar occultation by Pluto on 15 November 2014. Due to its highly elliptical orbit and seasonally variable obliquity, Pluto's atmosphere is predicted to condense onto its surface within the next ~10 years and possibly within the next few years and thus frequent observations are critical. Detection of the occultation central flash will allow measurement of the structure of Pluto's lower atmosphere and atmospheric oblateness. We will use FLIPO to measure the refracted starlight contemporaneously at visible and infrared wavelengths; this approach is needed to differentiate between two competing explanations for the deficiency in the observed light refracted from Pluto's lower atmosphere (strong thermal gradients versus variable particulate extinction). Only an airborne platform such as SOFIA has the flexibility to place a large telescope in the center of the shadow path of this brief event while at the same time nearly eliminating the possibility of missing time-critical observations due to unfortunate weather systems. Occultation predictions will be updated throughout the period preceding the observations with the goal of achieving sufficient prediction accuracy at the event time to place SOFIA directly in the path of Pluto's central flash. This SOFIA observation will be combined with our ongoing ground-based observing program whose goal is to measure the temporal variability of Pluto's atmosphere in response to its changing seasonal obliquity (and resulting ice migration) and recession from the sun. For the NASA New Horizons mission to Pluto and the Kuiper Belt, this Pluto occultation event represents the last chance, prior to the spacecraft closest approach to the Pluto/Charon system (July 2015), to provide input to the mission for encounter planning, as well as context and supporting atmospheric

  2. Prediction of hydrogen concentration in nuclear power plant containment under severe accidents using cascaded fuzzy neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Geon Pil; Kim, Dong Yeong; Yoo, Kwae Hwan; Na, Man Gyun, E-mail: magyna@chosun.ac.kr

    2016-04-15

    Highlights: • We present a hydrogen-concentration prediction method in an NPP containment. • The cascaded fuzzy neural network (CFNN) is used in this prediction model. • The CFNN model is much better than the existing FNN model. • This prediction can help prevent severe accidents in NPP due to hydrogen explosion. - Abstract: Recently, severe accidents in nuclear power plants (NPPs) have attracted worldwide interest since the Fukushima accident. If the hydrogen concentration in an NPP containment is increased above 4% in atmospheric pressure, hydrogen combustion will likely occur. Therefore, the hydrogen concentration must be kept below 4%. This study presents the prediction of hydrogen concentration using cascaded fuzzy neural network (CFNN). The CFNN model repeatedly applies FNN modules that are serially connected. The CFNN model was developed using data on severe accidents in NPPs. The data were obtained by numerically simulating the accident scenarios using the MAAP4 code for optimized power reactor 1000 (OPR1000) because real severe accident data cannot be obtained from actual NPP accidents. The root-mean-square error level predicted by the CFNN model is below approximately 5%. It was confirmed that the CFNN model could accurately predict the hydrogen concentration in the containment. If NPP operators can predict the hydrogen concentration in the containment using the CFNN model, this prediction can assist them in preventing a hydrogen explosion.

  3. Experimental and numerical investigation on compressor cascade flows with tip clearance at a low Reynolds number condition

    Science.gov (United States)

    Kato, Hiromasa; Taniguchi, Hideo; Matsuda, Kazunari; Funazaki, Ken-Ichi; Kato, Dai; Pallot, Guillaume

    2011-12-01

    High flow rate aeroengines typically employ axial flow compressors, where aerodynamic loss is predominantly due to secondary flow features such as tip leakage and corner vortices. In very high altitude missions, turbomachinery operates at low density ambient atmosphere, and the recent trend toward more compact engine core inevitably leads to the reduction of blade size, which in turn increases the relative height of the blade tip clearance. Low Reynolds number flowfield as a result of these two factors amplifies the relative importance of secondary flow effects. This paper focuses on the behavior of tip leakage flow, investigating by use of both experimental and numerical approaches. In order to understand the complex secondary flow behavior, cascade tests are usually conducted using intrusive probes to determine the loss. However relatively few experimental studies are published on tip leakage flows which take into account the interaction between a rotating blade row and its casing wall. Hence a new linear cascade facility has been designed with a moving belt casing in order to reproduce more realistic flowfield as encountered by a rotating compressor row. Numerical simulations were also performed to aid in the understanding of the complex flow features. The experimental results indicate a significant difference in the flowfield when the moving belt casing is present. The numerical simulations reveal that the leakage vortex is pulled by the shearing motion of the endwall toward the pressure side of the adjacent blade. The results highlight the importance of casing wall relative motion in analyzing leakage flow effects.

  4. Fundamentals of Atmospheric Radiation

    Science.gov (United States)

    Bohren, Craig F.; Clothiaux, Eugene E.

    2006-02-01

    This textbook fills a gap in the literature for teaching material suitable for students of atmospheric science and courses on atmospheric radiation. It covers the fundamentals of emission, absorption, and scattering of electromagnetic radiation from ultraviolet to infrared and beyond. Much of the book applies to planetary atmosphere. The authors are physicists and teach at the largest meteorology department of the US at Penn State. Craig T. Bohren has taught the atmospheric radiation course there for the past 20 years with no book. Eugene Clothiaux has taken over and added to the course notes. Problems given in the text come from students, colleagues, and correspondents. The design of the figures especially for this book is meant to ease comprehension. Discussions have a graded approach with a thorough treatment of subjects, such as single scattering by particles, at different levels of complexity. The discussion of the multiple scattering theory begins with piles of plates. This simple theory introduces concepts in more advanced theories, i.e. optical thickness, single-scattering albedo, asymmetry parameter. The more complicated theory, the two-stream theory, then takes the reader beyond the pile-of-plates theory. Ideal for advanced undergraduate and graduate students of atmospheric science.

  5. Atmospheric pollution in Lisbon urban atmosphere

    Science.gov (United States)

    Oliveira, C.

    2009-04-01

    Lisbon is the capital city of Portugal with about 565,000 residents in 2008 and a population density of 6,600 inhabitants per square kilometre. Like several other major metropolis, the town is surrounded by satellite cities, forming together a region known as "Lisbon Metropolitan Area" with about 3 million inhabitants, a quarter of the overall Portuguese population. Besides their local residents, it is estimated that more than one million citizens come into the Lisbon area every day from the outskirts, leading to elevated traffic densities and intense traffic jams, with important consequences on air pollution levels and obvious negative impacts on human health. Airborne particulate matter limit values are frequently exceeded, making urgent the existence of consistent programs to monitor and help taking measures to control them. Within the Portuguese project PAHLIS (Polycyclic Aromatic Hydrocarbons Contamination in Lisbon Urban Atmosphere) financed by the Portuguese Science Foundation ("Fundação para a Ciência e a Tecnologia"), an aerosol and vapour phase sampling program is being implemented in the city of Lisbon at two selected contrasting zones, namely a typically busy area with intense road traffic and frequent exceedences of the particulate matter standard for the maximum allowable concentration, and a residential quieter area, thus with a cleaner atmosphere characterised as an urban background site. An one month-long sampling campaign was performed during the summer of 2008, where particulate matter was collected in two fractions (coarse 2.5µmcommunication, the results of both organic and inorganic analyses of aerosol samples from these two sites will be presented, compared and discussed. Results of this work are expected to cover a lack of reliable information regarding sources of atmospheric pollutants in Portugal and present, for the first time, systematic data of PAHs levels in Lisbon. Acknowledgement: This work was performed under Project PAHLIS (PTDC

  6. Phenomenology of atmospheric neutrinos

    Directory of Open Access Journals (Sweden)

    Fedynitch Anatoli

    2016-01-01

    Full Text Available The detection of astrophysical neutrinos, certainly a break-through result, introduced new experimental challenges and fundamental questions about acceleration mechanisms of cosmic rays. On one hand IceCube succeeded in finding an unambiguous proof for the existence of a diffuse astrophysical neutrino flux, on the other hand the precise determination of its spectral index and normalization requires a better knowledge about the atmospheric background at hundreds of TeV and PeV energies. Atmospheric neutrinos in this energy range originate mostly from decays of heavy-flavor mesons, which production in the phase space relevant for prompt leptons is uncertain. Current accelerator-based experiments are limited by detector acceptance and not so much by the collision energy. This paper recaps phenomenological aspects of atmospheric leptons and calculation methods, linking recent progress in flux predictions with particle physics at colliders, in particular the Large Hadron Collider.

  7. Intensifying the Atmospheric

    DEFF Research Database (Denmark)

    Liebst, Lasse Suonperä

    2012-01-01

    The phenomenological concept of urban atmospheres is more often applied as an aesthetic description of the metropolitan space as such. This conceptualization is supported in this paper; however, I strive to give the concept a post-phenomenological axial turn. While phenomenology, due to its under...... sufficiently intense. All things considered, the paper should be read as a sociological contribution to theoretically reconstruct the concept of urban atmospheres in the light of spatial morphology.......The phenomenological concept of urban atmospheres is more often applied as an aesthetic description of the metropolitan space as such. This conceptualization is supported in this paper; however, I strive to give the concept a post-phenomenological axial turn. While phenomenology, due to its...

  8. Atmospheric pollution; Pollution atmospherique

    Energy Technology Data Exchange (ETDEWEB)

    Lambrozo, J.; Guillossou, G. [EDF-Gas de France, Service des Etudes Medicales, 75 - Paris (France)

    2008-10-15

    The atmosphere is the reservoir of numerous pollutants (nitrogen oxides, sulfur oxides, carbon oxides, particulates, volatile organic compounds, polycyclic aromatic hydrocarbons) from natural origin or anthropogenic origin ( industry, transport, agriculture, district heating). With epidemiologic studies the atmospheric pollution is associated with an increase of respiratory and cardiovascular diseases. At the european level, the technological progress, the legislation have allowed a reduction of pollutant emissions, however these efforts have to be continued because the sanitary impact of atmospheric pollution must not be underestimated, even if the risks appear less important that these ones in relation with tobacco, inside pollution or others factors of cardiovascular risks. Indeed, on these last factors an individual action is possible for the exposure to air pollution people have no control. (N.C.)

  9. Atmosphere and Ambient Space

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Atmosphere and Ambient Space This paper explores the relation between atmosphere and ambient space. Atmosphere and ambient space share many salient properties. They are both ontologically indeterminate, constantly varying and formally diffuse and they are both experienced as a subtle, non......-signifying property of a given space. But from a certain point of view, the two concepts also designate quite dissimilar experiences of space. To be ’ambient’ means to surround. Accordingly, ambient space is that space, which surrounds something or somebody. (Gibson 1987: 65) Since space is essentially...... of a surrounding character, all space can thus be described as having a fundamentally ambient character. So what precisely is an ambient space, then? As I will argue in my presentation, ambient space is a sensory effect of spatiality when a space is experienced as being particularly surrounding: a ‘space effect...

  10. Design, construction and performance tests of a cascade impactor and an integral impactor; Diseno, construccion y pruebas de funcionamiento de un impactor de cascada y un impactor integral

    Energy Technology Data Exchange (ETDEWEB)

    Aldape U, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1987-06-15

    The analysis of samples of atmospheric aerosols collected by means of cascade impactores or differential it is facilitated in many aspects by means of the use of technical analytic based on faces of ions. The targets obtained with these apparatuses are those but suitable for their contained first floor of collected matter (1 mg/cm2 what allows the direct use of the samples in technical analytic as PIXE for their high sensibility and in their best interval of applicability. The objective of this work has been the design, construction and the first tests of operation of an impactor of the type Batelle, as well as of another of integral type. (Author)

  11. Near-infrared induced optical quenching effects on mid-infrared quantum cascade lasers

    Science.gov (United States)

    Guo, Dingkai; Cai, Hong; Talukder, Muhammad Anisuzzaman; Chen, Xing; Johnson, Anthony M.; Khurgin, Jacob B.; Choa, Fow-Sen

    2014-06-01

    In space communications, atmospheric absorption and Rayleigh scattering are the dominant channel impairments. Transmission using mid-infrared (MIR) wavelengths offers the benefits of lower loss and less scintillation effects. In this work, we report the telecom wavelengths (1.55 μm and 1.3 μm) induced optical quenching effects on MIR quantum cascade lasers (QCLs), when QCLs are operated well above their thresholds. The QCL output power can be near 100% quenched using 20 mW of near-infrared (NIR) power, and the quenching effect depends on the input NIR intensity as well as wavelength. Time resolved measurement was conducted to explore the quenching mechanism. The measured recovery time is around 14 ns, which indicates that NIR generated electron-hole pairs may play a key role in the quenching process. The photocarrier created local field and band bending can effectively deteriorate the dipole transition matrix element and quench the QCL. As a result, MIR QCLs can be used as an optical modulator and switch controlled by NIR lasers. They can also be used as "converters" to convert telecom optical signals into MIR optical signals.

  12. CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory

    Science.gov (United States)

    Keillor, M. E.; Aalseth, C. E.; Day, A. R.; Erikson, L. E.; Fast, J. E.; Glasgow, B. D.; Hoppe, E. W.; Hossbach, T. W.; Hyronimus, B. J.; Miley, H. S.; Myers, A. W.; Seifert, A.; Stavenger, T. J.

    2011-12-01

    State-of-the-art treaty verification techniques, environmental surveillance, and physics experiments require increased sensitivity for detecting and quantifying radionuclides of interest. This can be accomplished with new detector designs that establish high detection efficiency and reduced instrument backgrounds. Current research is producing an intrinsic germanium (HPGe) array designed for high detection efficiency, ultra-low-background performance, and sensitive γ—γ coincidence detection. The system design is optimized to accommodate filter paper samples, e.g. samples collected by the Radionuclide Aerosol Sampler/Analyzer. The system will provide high sensitivity for weak collections on atmospheric filter samples (e.g.fissions) as well as offering the potential to gather additional information from higher activity filters using gamma cascade coincidence detection. The first of two HPGe crystal arrays in ultra-low-background vacuum cryostats has been assembled, with the second in progress. Traditional methods for constructing ultra-low-background detectors were followed, including use of materials known to be low in radioactive contaminants, use of ultra-pure reagents, and clean room assembly. The cryostat is constructed mainly from copper electroformed into near-final geometry at Pacific Northwest National Laboratory. Details of the detector assembly and initial background and spectroscopic measurement results are presented; also a description of the custom analysis package used by this project is given.

  13. Portable open-path chemical sensor using a quantum cascade laser

    Science.gov (United States)

    Corrigan, Paul; Lwin, Maung; Huntley, Reuven; Chhabra, Amandeep; Moshary, Fred; Gross, Barry; Ahmed, Samir

    2009-05-01

    Remote sensing of enemy installations or their movements by trace gas detection is a critical but challenging military objective. Open path measurements over ranges of a few meters to many kilometers with sensitivity in the parts per million or billion regime are crucial in anticipating the presence of a threat. Previous approaches to detect ground level chemical plumes, explosive constituents, or combustion have relied on low-resolution, short range Fourier transform infrared spectrometer (FTIR), or low-sensitivity near-infrared differential optical absorption spectroscopy (DOAS). As mid-infrared quantum cascade laser (QCL) sources have improved in cost and performance, systems based on QCL's that can be tailored to monitor multiple chemical species in real time are becoming a viable alternative. We present the design of a portable, high-resolution, multi-kilometer open path trace gas sensor based on QCL technology. Using a tunable (1045-1047cm-1) QCL, a modeled atmosphere and link-budget analysis with commercial component specifications, we show that with this approach, accuracy in parts per billion ozone or ammonia can be obtained in seconds at path lengths up to 10 km. We have assembled an open-path QCL sensor based on this theoretical approach at City College of New York, and we present preliminary results demonstrating the potential of QCLs in open-path sensing applications.

  14. Standoff detection of turbulent chemical mixture plumes using a swept external cavity quantum cascade laser

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C. [Pacific Northwest National Laboratory, Richland, Washington; Brumfield, Brian E. [Pacific Northwest National Laboratory, Richland, Washington

    2017-08-21

    We demonstrate standoff detection of turbulent mixed-chemical plumes using a broadly-tunable external cavity quantum cascade laser (ECQCL). The ECQCL was directed through plumes of mixed methanol/ethanol vapor to a partially-reflective surface located 10 m away. The reflected power was measured as the ECQCL was swept over its tuning range of 930-1065 cm-1 (9.4-10.8 µm) at rates up to 200 Hz. Analysis of the transmission spectra though the plume was performed to determine chemical concentrations with time resolution of 0.005 s. Comparison of multiple spectral sweep rates of 2 Hz, 20 Hz, and 200 Hz shows that higher sweep rates reduce effects of atmospheric and source turbulence, resulting in lower detection noise and more accurate measurement of the rapidly-changing chemical concentrations. Detection sensitivities of 0.13 ppm*m for MeOH and 1.2 ppm*m for EtOH are demonstrated for a 200 Hz spectral sweep rate, normalized to 1 s detection time.

  15. Design of the improved cascade ADRC and its application in photoelectric tracking system

    Science.gov (United States)

    Zuo, Dan; Tang, Tao; Huang, Yongmei; Cai, Huaxiang

    2015-10-01

    According to the larger error when reversing in photoelectric tracking control system, the improved cascade Active Disturbance Rejection Controller (ADRC) is put forward to improve the system position tracking performance and tracking precision. First of all, this essay analyses the controlled object model and system control strategy; Then, it gives design method of the improved cascade ADRC; Finally, in order to analyses the improved cascade's better control performance, in the condition of the same input signal ,the improved cascade ADRC, conventional ADRC-ADRC and traditional PI-PI controller are used in photoelectric tracking control system to do comparative experiment. The experiment results show that the improved cascade ADRC's performance is better than other two algorithms, the tracking error and the steady state mean square error are significantly reduced, tracking accuracy is significantly improved. The improved cascade ADRC is an appealing solution in dealing with industrial control system problems where uncertainties and interference abound.

  16. Excitation and diagnosis of cascading Langmuir waves in ionospheric plasmas at Gakona, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Burton, L M; Cohen, J A; Pradipta, R; Labno, A; Lee, M C; Batishchev, O; Rokusek, D L [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Kuo, S P [Polytechnic University, Brooklyn, NY 11201 (United States); Watkins, B J; Oyama, S [University of Alaska Fairbanks, Fairbanks, AK 99775 (United States)], E-mail: mclee@mit.edu

    2008-12-15

    Ionospheric plasma heating experiments were conducted at Gakona, Alaska to investigate cascading spectra of Langmuir wave turbulence, excited by parametric instabilities diagnosed by Modular UHF Ionospheric Radar (MUIR). This work is aimed at testing the recent theory of Kuo and Lee (2005 J. Geophys. Res. 110 A01309) that addresses how the cascade of Langmuir waves can distribute spatially via the resonant and non-resonant decay processes. The non-resonant cascade proceeds at the location where parametric decay instability (PDI) or oscillating two-stream instability (OTSI) is excited and severely hampered by the frequency mismatch effect. By contrast, the resonant cascade, which takes place at lower matching heights, has to overcome the propagation loss of the Langmuir pump waves in each cascade step. Our experimental results have corroborated these predictions about the generation of cascading Langmuir waves by the HAARP heater.

  17. Atmospheric Infrared Radiance Variability.

    Science.gov (United States)

    1981-05-27

    ATMOSPHERIC VARIABILITY ON INFRARED RADIANCE PREDICTIONS - T. C. Degges 53 5. ATMOSPHERIC STRUCTURE - C.H. HLmphrey, C.R. Philbrick, S.M. Silverman , T.F. Tuan...variations similar to those shown in Figure 2. In arctic and subarctic regions, sudden warmings and coolings of the winter stratosphere and mesosphere... Silverman \\Jr I",rre. (;.L~~sIalmratorN Hanscom Air Force Base, Manss. T.F. Tuan Universitv of Cincinnati Cincinnati, (tio M. Anapol S.S.G.. Inc. Waltham

  18. Atmosphere and Heritage

    DEFF Research Database (Denmark)

    Ventzel Riis, Nina

    2012-01-01

    -between of the materials. This is what we identify as atmosphere, an enveloping phenomenon that surrounds and affects our sensuous system and well-being when we approach, enter, stay or move in a building. When we leave the building again we carry this atmospheric multi-sensory experience with us without adequate methods...... to describe and document it. In this paper I will introduce both new and traditional approaches to document the architectural heritage with the final conclusion to describe both tangible and intangible values, it requires an objective and geometrical approach as well as a subjective and phenomenological...

  19. Lack of plasma kallikrein-kinin system cascade in teleosts.

    Directory of Open Access Journals (Sweden)

    Marty Kwok-Shing Wong

    Full Text Available The kallikrein-kinin system (KKS consists of two major cascades in mammals: "plasma KKS" consisting of high molecular-weight (HMW kininogen (KNG, plasma kallikrein (KLKB1, and bradykinin (BK; and "tissue KKS" consisting of low molecular-weight (LMW KNG, tissue kallikreins (KLKs, and [Lys(0]-BK. Some components of the KKS have been identified in the fishes, but systematic analyses have not been performed, thus this study aims to define the KKS components in teleosts and pave a way for future physiological and evolutionary studies. Through a combination of genomics, molecular, and biochemical methods, we showed that the entire plasma KKS cascade is absent in teleosts. Instead of two KNGs as found in mammals, a single molecular weight KNG was found in various teleosts, which is homologous to the mammalian LMW KNG. Results of molecular phylogenetic and synteny analyses indicated that the all current teleost genomes lack KLKB1, and its unique protein structure, four apple domains and one trypsin domain, could not be identified in any genome or nucleotide databases. We identified some KLK-like proteins in teleost genomes by synteny and conserved domain analyses, which could be the orthologs of tetrapod KLKs. A radioimmunoassay system was established to measure the teleost BK and we found that [Arg(0]-BK is the major circulating form instead of BK, which supports that the teleost KKS is similar to the mammalian tissue KKS. Coincidently, coelacanths are the earliest vertebrate that possess both HMW KNG and KLKB1, which implies that the plasma KKS could have evolved in the early lobe-finned fish and descended to the tetrapod lineage. The co-evolution of HMW KNG and KLKB1 in lobe-finned fish and early tetrapods may mark the emergence of the plasma KKS and a contact activation system in blood coagulation, while teleosts may have retained a single KKS cascade.

  20. Potential trophic cascades triggered by the barred owl range expansion

    Science.gov (United States)

    Holm, Samantha R.; Noon, Barry R.; Wiens, David; Ripple, William J.

    2016-01-01

    Recently, the barred owl (Strix varia) has expanded its range into the Pacific Northwest of the United States resulting in pronounced effects on the demography and behavior of the northern spotted owl (S. occidentalis caurina). The range expansion has brought together historically allopatric species, creating the potential for significant changes in the avian predator community with possible cascading effects on food-web dynamics. The adverse effects of the barred owl on the behavior and demography of the northern spotted owl are well-documented, but little is known about the immediate and long-term effects changes in the predator community may have on native species composition and ecosystem processes. Based on northern spotted owl and barred owl selection for diet and habitat resources, there is a potential for trophic cascades within the region's predator and prey communities, differing responses by their shared and unique prey species, and possible direct and indirect effects on ecosystem processes. We explored the possible ecological consequences of the barred owl range expansion to wildlife communities of the Pacific Northwest based on the theoretical underpinnings of predator–prey relationships, interspecific competition, intraguild predation, and potential cascading trophic interactions. Negative effects on fitness of northern spotted owls because of interspecific competition with barred owls are strong selection forces that may contribute to the regional extinction of the northern spotted owl. In addition, we posit that shared prey species and those uniquely consumed by barred owls, along with other competing native predators, may experience changes in behavior, abundance, and distribution as a result of increased rates of predation by rapidly expanding populations of barred owls.

  1. Translating Volcano Hazards Research in the Cascades Into Community Preparedness

    Science.gov (United States)

    Ewert, J. W.; Driedger, C. L.

    2015-12-01

    Research by the science community into volcanic histories and physical processes at Cascade volcanoes in the states of Washington, Oregon, and California has been ongoing for over a century. Eruptions in the 20th century at Lassen Peak and Mount St. Helen demonstrated the active nature of Cascade volcanoes; the 1980 eruption of Mount St. Helens was a defining moment in modern volcanology. The first modern volcano hazards assessments were produced by the USGS for some Cascade volcanoes in the 1960s. A rich scientific literature exists, much of which addresses hazards at these active volcanoes. That said community awareness, planning, and preparation for eruptions generally do not occur as a result of a hazard analyses published in scientific papers, but by direct communication with scientists. Relative to other natural hazards, volcanic eruptions (or large earthquakes, or tsunami) are outside common experience, and the public and many public officials are often surprised to learn of the impacts volcanic eruptions could have on their communities. In the 1980s, the USGS recognized that effective hazard communication and preparedness is a multi-faceted, long-term undertaking and began working with federal, state, and local stakeholders to build awareness and foster community action about volcano hazards. Activities included forming volcano-specific workgroups to develop coordination plans for volcano emergencies; a concerted public outreach campaign; curriculum development and teacher training; technical training for emergency managers and first responders; and development of hazard information that is accessible to non-specialists. Outcomes include broader ownership of volcano hazards as evidenced by bi-national exchanges of emergency managers, community planners, and first responders; development by stakeholders of websites focused on volcano hazards mitigation; and execution of table-top and functional exercises, including evacuation drills by local communities.

  2. Solar energetic particle interactions with the Venusian atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Plainaki, Christina; Grassi, Davide [INAF-IAPS, Rome (Italy); Paschalis, Pavlos; Mavromichalaki, Helen [National and Kapodistrian Univ., Athens (Greece). Nuclear and Particle Physics Dept.; Andriopoulou, Maria [Austrian Academy of Sciences, Graz (Austria). Space Research Science Inst.

    2016-11-01

    In the context of planetary space weather, we estimate the ion production rates in the Venusian atmosphere due to the interactions of solar energetic particles (SEPs) with gas. The assumed concept for our estimations is based on two cases of SEP events, previously observed in near-Earth space: the event in October 1989 and the event in May 2012. For both cases, we assume that the directional properties of the flux and the interplanetary magnetic field configuration would have allowed the SEPs' arrival at Venus and their penetration to the planet's atmosphere. For the event in May 2012, we consider the solar particle properties (integrated flux and rigidity spectrum) obtained by the Neutron Monitor Based Anisotropic GLE Pure Power Law (NMBANGLE PPOLA) model (Plainaki et al., 2010, 2014) applied previously for the Earth case and scaled to the distance of Venus from the Sun. For the simulation of the actual cascade in the Venusian atmosphere initiated by the incoming particle fluxes, we apply the DYASTIMA code, a Monte Carlo (MC) application based on the Geant4 software (Paschalis et al., 2014). Our predictions are afterwards compared to other estimations derived from previous studies and discussed. Finally, we discuss the differences between the nominal ionization profile due to galactic cosmic-ray-atmosphere interactions and the profile during periods of intense solar activity, and we show the importance of understanding space weather conditions on Venus in the context of future mission preparation and data interpretation.

  3. Density matrix Monte Carlo modeling of quantum cascade lasers

    Science.gov (United States)

    Jirauschek, Christian

    2017-10-01

    By including elements of the density matrix formalism, the semiclassical ensemble Monte Carlo method for carrier transport is extended to incorporate incoherent tunneling, known to play an important role in quantum cascade lasers (QCLs). In particular, this effect dominates electron transport across thick injection barriers, which are frequently used in terahertz QCL designs. A self-consistent model for quantum mechanical dephasing is implemented, eliminating the need for empirical simulation parameters. Our modeling approach is validated against available experimental data for different types of terahertz QCL designs.

  4. Damped trophic cascades driven by fishing in model marine ecosystems

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Pedersen, Martin

    2010-01-01

    cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to explore how marine ecosystems might react to perturbations from different types of fishing pressure. The model explicitly resolves the whole life history of fish, from larvae to adults. The results show......The largest perturbation on upper trophic levels of many marine ecosystems stems from fishing. The reaction of the ecosystem goes beyond the trophic levels directly targeted by the fishery. This reaction has been described either as a change in slope of the overall size spectrum or as a trophic...

  5. Surface emitting ring quantum cascade lasers for chemical sensing

    Science.gov (United States)

    Szedlak, Rolf; Hayden, Jakob; Martín-Mateos, Pedro; Holzbauer, Martin; Harrer, Andreas; Schwarz, Benedikt; Hinkov, Borislav; MacFarland, Donald; Zederbauer, Tobias; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Acedo, Pablo; Lendl, Bernhard; Strasser, Gottfried

    2018-01-01

    We review recent advances in chemical sensing applications based on surface emitting ring quantum cascade lasers (QCLs). Such lasers can be implemented in monolithically integrated on-chip laser/detector devices forming compact gas sensors, which are based on direct absorption spectroscopy according to the Beer-Lambert law. Furthermore, we present experimental results on radio frequency modulation up to 150 MHz of surface emitting ring QCLs. This technique provides detailed insight into the modulation characteristics of such lasers. The gained knowledge facilitates the utilization of ring QCLs in combination with spectroscopic techniques, such as heterodyne phase-sensitive dispersion spectroscopy for gas detection and analysis.

  6. Analysis and control design of two cascaded boost converter

    Directory of Open Access Journals (Sweden)

    Moutabir A.

    2014-01-01

    Full Text Available This work aims to study a cascade of two BOOST converters. First, a non- linear model of the whole controlled system is developed. Then, a robust non-linear controller of currents is synthesized using a backstepping design technique. A formal analysis based on Lyapunov stability and average theory is developed to describe the control currents loops performances. A classical PI controller is used for the voltages loops. The study of the stability of the system will also be discussed. Simulated results are displayed to validate the feasibility and the effectiveness of the proposed strategy.

  7. Subsurface Microbial Ecosystems: A Photon Flux and a Metabolic Cascade

    Science.gov (United States)

    Petroff, Alexander P.; Tejera, Frank; Libchaber, Albert

    2017-05-01

    Mud is a porous medium containing a high density of diverse microorganisms. It is out of equilibrium as the energy from a photon flux is dissipated by a cascade of biochemical reactions, mediated by the metabolisms of the constituent organisms. Despite its complexity, microbes in nature self-organize into simple reproducible patterns. We present two experiments in which the dynamics of natural mud coming to steady state are observed and modeled. In the first, the oxygen gradient produced by cyanobacteria in an imposed light gradient is measured. In the second, a thin front of oxygen-consuming microbes forms at the penetration depth of oxygen and moves with the changing oxygen gradient.

  8. Resonant metamaterial detectors based on THz quantum-cascade structures

    Science.gov (United States)

    Benz, A.; Krall, M.; Schwarz, S.; Dietze, D.; Detz, H.; Andrews, A. M.; Schrenk, W.; Strasser, G.; Unterrainer, K.

    2014-01-01

    We present the design, fabrication and characterisation of an intersubband detector employing a resonant metamaterial coupling structure. The semiconductor heterostructure relies on a conventional THz quantum-cascade laser design and is operated at zero bias for the detector operation. The same active region can be used to generate or detect light depending on the bias conditions and the vertical confinement. The metamaterial is processed directly into the top metal contact and is used to couple normal incidence radiation resonantly to the intersubband transitions. The device is capable of detecting light below and above the reststrahlenband of gallium-arsenide corresponding to the mid-infrared and THz spectral region. PMID:24608677

  9. A Time Domain Analysis of Gust-Cascade Interaction Noise

    Science.gov (United States)

    Nallasamy, M.; Hixon, R.; Sawyer, S. D.; Dyson, R. W.

    2003-01-01

    The gust response of a 2 D cascade is studied by solving the full nonlinear Euler equations employing higher order accurate spatial differencing and time stepping techniques. The solutions exhibit the exponential decay of the two circumferential mode orders of the cutoff blade passing frequency (BPF) tone and propagation of one circumferential mode order at 2BPF, as would be expected for the flow configuration considered. Two frequency excitations indicate that the interaction between the frequencies and the self interaction contribute to the amplitude of the propagating mode.

  10. New quantum cascade laser sources for sensing applications (Conference Presentation)

    Science.gov (United States)

    Troccoli, Mariano

    2017-05-01

    In this presentation we will review our most recent results on development of Quantum Cascade Lasers (QCLs) for analytical and industrial applications. QCLs have demonstrated the capability to cover the entire range of Mid-IR, Far-IR, and THz wavelengths by skillful tuning of the material design and composition and by use of intrinsic material properties via a set of techniques collectively called "bandgap engineering". The use of MOCVD, pioneered on industrial scale by AdTech Optics, has enabled the deployment of QCL devices into a diverse range of environments and applications. QCLs can be tailored to the specific application requirements due to their unprecedented flexibility in design and thanks to the leveraging of well-known III-V fabrication technologies inherited from the NIR domain. Nevertheless, several applications and new frontiers in R and D need the constant support of new developments in device features, capabilities, and performances. We have developed a wide range of devices, from high power, high efficiency multi-mode sources, to narrow-band, single mode devices with low-power consumption, and from non-linear, multi-wavelength generating devices to broadband sources and multi-emitter arrays. All our devices are grown and processed using MOCVD technology and allow us to attain competitive performances across the whole mid-IR spectral range. This talk will present an overview of our current achievements. References 1. M. Troccoli, "High power emission and single mode operation of quantum cascade lasers for industrial applications", J. Sel. Topics in Quantum Electron., 21 (6), 1-7 (2015). Invited Review. 2. Seungyong Jung, Aiting Jiang, Yifan Jiang, Karun Vijayraghavan, Xiaojun Wang, Mariano Troccoli, and Mikhail A. Belkin, "Broadly Tunable Monolithic Terahertz Quantum Cascade Laser Sources", Nature Comm. 5, 4267 (2014).. 3. Mariano Troccoli, Arkadiy Lyakh, Jenyu Fan, Xiaojun Wang, Richard Maulini, Alexei G Tsekoun, Rowel Go, C Kumar N Patel, "Long

  11. Predator transitory spillover induces trophic cascades in ecological sinks

    DEFF Research Database (Denmark)

    Casini, Michele; Blenckner, Thorsten; Möllmann, Christian

    2012-01-01

    Understanding the effects of cross-system fluxes is fundamental in ecosystem ecology and biological conservation. Source-sink dynamics and spillover processes may link adjacent ecosystems by movement of organisms across system boundaries. However, effects of temporal variability in these cross......-system fluxes on a whole marine ecosystem structure have not yet been presented. Here we show, using 35 y of multitrophic data series from the Baltic Sea, that transitory spillover of the top-predator cod from its main distribution area produces cascading effects in the whole food web of an adjacent and semi...

  12. Signaling Cascades of Pasteurella multocida Toxin in Immune Evasion

    Science.gov (United States)

    Kubatzky, Katharina F.; Kloos, Bianca; Hildebrand, Dagmar

    2013-01-01

    Pasteurella multocida toxin (PMT) is a protein toxin found in toxigenic strains of Pasteurella multocida. PMT is the causative agent for atrophic rhinitis in pigs, a disease characterized by loss of nasal turbinate bones due to an inhibition of osteoblast function and an increase in osteoclast activity and numbers. Apart from this, PMT acts as a strong mitogen, protects from apoptosis and has an impact on the differentiation and function of immune cells. Many signaling pathways have been elucidated, however, the effect of these signaling cascades as a means to subvert the host’s immune system are just beginning to unravel. PMID:24064721

  13. Atomic-cascade experiment with detection of the recoil atom

    Energy Technology Data Exchange (ETDEWEB)

    Huelga, S.F. (Dept. de Fisica, Univ. de Oviedo (Spain)); Ferrero, M. (Dept. de Fisica, Univ. de Oviedo (Spain)); Santos, E. (Dept. de Fisica Moderna, Univ. de Cantabria (Spain))

    1994-07-20

    Bell's inequalities cannot be violated in atomic-cascade experiments, even with ideal apparatus, due to the three-body character of the atomic decay. Here we propose a new experiment that would block this loophole by means of a suitable selection of an ensemble of photon pairs. A threshold value for the quantum efficiency is found which may allow the discrimination between quantum mechanics and local-hidden-variables theories. Experimental requirements for performing such a test are discussed. (orig.).

  14. Neutron spallation source and the Dubna cascade code

    CERN Document Server

    Kumar, V; Goel, U; Barashenkov, V S

    2003-01-01

    Neutron multiplicity per incident proton, n/p, in collision of high energy proton beam with voluminous Pb and W targets has been estimated from the Dubna cascade code and compared with the available experimental data for the purpose of benchmarking of the code. Contributions of various atomic and nuclear processes for heat production and isotopic yield of secondary nuclei are also estimated to assess the heat and radioactivity conditions of the targets. Results obtained from the code show excellent agreement with the experimental data at beam energy, E < 1.2 GeV and differ maximum up to 25% at higher energy. (author)

  15. Manipulation of quadratic cascading processes in a locally quasi-periodic χ(²) medium.

    Science.gov (United States)

    Wang, Wenjie; Sheng, Yan; Liu, Shaoding; Niu, Xiaoying; Krolikowski, Wieslaw

    2014-03-24

    We theoretically and numerically investigate the quadratic cascading effect of third-harmonic (TH) generation in a locally quasi-periodic nonlinear photonic structure. We study the effect of structure parameters on the acceptance bandwidth and conversion efficiency of the cascading process. We demonstrate that the conversion efficiency of the cascading process can be enhanced by using a longer locally quasi-periodic nonlinear photonic crystal, without adversely affecting the acceptance bandwidth of the emitted radiation.

  16. The dynamics of dense water cascades: from laboratory scales to the Arctic Ocean

    OpenAIRE

    Wobus, Fred

    2013-01-01

    The sinking of dense shelf waters down the continental slope (or “cascading”) contributes to oceanic water mass formation and carbon cycling. Cascading is therefore of significant importance for the global overturning circulation and thus climate. The occurrence of cascades is highly intermittent in space and time and observations of the process itself (rather than its outcomes) are scarce. Global climate models do not typically resolve cascading owing to numerical challenges concerning turbu...

  17. Geologic map of upper Eocene to Holocene volcanic and related rocks in the Cascade Range, Washington

    Science.gov (United States)

    Smith, James G.

    1993-01-01

    Since 1979 the Geothermal Research Program of the U.S. Geological Survey has carried out a multidisciplinary research effort in the Cascade Range. The goal of this research is to understand the geology, tectonics, and hydrology of the Cascades in order to characterize and quantify geothermal resource potential. A major goal of the program is compilation of a comprehensive geologic map of the entire Cascade Range that incorporates modern field studies and that has a unified and internally consistent explanation.

  18. Implementing and Bounding a Cascade Heuristic for Large-Scale Optimization

    Science.gov (United States)

    2017-06-01

    BOUNDING A CASCADE HEURISTIC FOR LARGE-SCALE OPTIMIZATION by Katherine H. Guthrie June 2017 Thesis Advisor: Robert F. Dell Second Reader...AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE IMPLEMENTING AND BOUNDING A CASCADE HEURISTIC FOR LARGE-SCALE OPTIMIZATION 5. FUNDING...release. Distribution is unlimited. 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) A cascade heuristic appeals when we are faced with a

  19. Solution of Turbine Blade Cascade Flow Using an Improved Panel Method

    Directory of Open Access Journals (Sweden)

    Zong-qi Lei

    2015-01-01

    Full Text Available An improved panel method has been developed to calculate compressible inviscid flow through a turbine blade row. The method is a combination of the panel method for infinite cascade, a deviation angle model, and a compressibility correction. The resulting solution provides a fast flexible mesh-free calculation for cascade flow. A VKI turbine blade cascade is used to evaluate the method, and the comparison with experiment data is presented.

  20. A NOVEL CASCADED H- BRIDGE MULTILEVEL INVERTER BASED ON OPTIMAL PWM TECHNIQUE

    OpenAIRE

    MAHESWARI, A.; GNANAMBAL, I

    2013-01-01

    In this paper, a novel cascaded H- bridge multilevel inverter has been proposed using less number of switches. A standard cascaded multilevel inverter requires 4h number of switches for (2h + 1) levels whereas h is the number of dc sources. This proposed scheme allows less number of switches for the same level. A novel cascaded H- bridge multilevel inverter fed induction motor shows better performance due to fundamental frequency switching scheme using  optimal PWM Technique (OPWM). High qual...

  1. Mathematical Modeling of Nonstationary Separation Processes in Gas Centrifuge Cascade for Separation of Multicomponent Isotope Mixtures

    Directory of Open Access Journals (Sweden)

    Orlov Alexey

    2016-01-01

    Full Text Available This article presents results of development of the mathematical model of nonstationary separation processes occurring in gas centrifuge cascades for separation of multicomponent isotope mixtures. This model was used for the calculation parameters of gas centrifuge cascade for separation of germanium isotopes. Comparison of obtained values with results of other authors revealed that developed mathematical model is adequate to describe nonstationary separation processes in gas centrifuge cascades for separation of multicomponent isotope mixtures.

  2. Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Jia, X.; Lu, Z.

    2016-01-01

    inverter fails to reduce the leakage current is clarified. In order to solve the problem, a new cascaded H5 inverter is proposed to solve the leakage current issue. Finally, the experimental results are presented to verify the effectiveness of the proposed topology with the leakage current reduction......Leakage current reduction is one of the important issues for the transformelress PV systems. In this paper, the transformerless single-phase cascaded H-bridge PV inverter is investigated. The common mode model for the cascaded H4 inverter is analyzed. And the reason why the conventional cascade H4...

  3. Inverse cascades sustained by the transfer rate of angular momentum in a 3D turbulent flow.

    Science.gov (United States)

    López-Caballero, Miguel; Burguete, Javier

    2013-03-22

    The existence of energy cascades as signatures of conserved magnitudes is one of the universal characteristics of turbulent flows. In homogeneous 3D turbulence, the energy conservation produces a direct cascade from large to small scales, although in 2D, it produces an inverse cascade pointing towards small wave numbers. In this Letter, we present the first evidence of an inverse cascade in a fully developed 3D experimental turbulent flow where the conserved magnitude is the angular momentum. Two counterrotating flows collide in a central region where very large fluctuations are produced, generating a turbulent drag that transfers the external torque between different fluid layers.

  4. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, V. Faye [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering; Ariya, Parisa A. (ed.) [McGill Univ. Montreal, QC (Canada). Dept. of Chemistry; McGill Univ. Montreal, QC (Canada). Dept. of Atmospheric and Oceanic Sciences

    2014-09-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  5. Astronomy and Atmospheric Optics

    Science.gov (United States)

    Cowley, Les; Gaina, Alex

    2011-12-01

    The authors discusse the insuccess of the observation of the Total Eclipse of the Moon from 10 december 2011 in Romania and relate them with meteoconditions. Only a very short part of the last penumbral phase was observed, while the inital part and the totality was not observed due to very dense clouds. The change in color and brightness during this phase was signaled. Meanwhile, there is an area of science where clouds are of great use and interest. This area is Atmospheric optics, while the science which study clouds is meteorology. Clouds in combination with Solar and Moon light could give rise to a variety of strange, rare and unobvious phenomena in the atmosphere (sky), sometimes confused with Unidentified Flying Objects (UFO). The importance of meteorology for astronomy and atmospheric optics is underlined and an invitation to astronomers to use unfavourable days for athmospheric observations was sent. The web address of the site by Les Cowley, designed for atmospheric optics phenomena is contained in the text of the entry.

  6. Results from atmospheric neutrinos

    Indian Academy of Sciences (India)

    With the announcement of new evidence for muon neutrino disappearance observed by the super-Kamiokande experiment, the more than a decade old atmospheric neutrino anomaly moved from a possible indication for neutrino oscillations to an apparently inescapable fact. The evidence is reviewed, and new indications ...

  7. ESA Atmospheric Toolbox

    Science.gov (United States)

    Niemeijer, Sander

    2017-04-01

    The ESA Atmospheric Toolbox (BEAT) is one of the ESA Sentinel Toolboxes. It consists of a set of software components to read, analyze, and visualize a wide range of atmospheric data products. In addition to the upcoming Sentinel-5P mission it supports a wide range of other atmospheric data products, including those of previous ESA missions, ESA Third Party missions, Copernicus Atmosphere Monitoring Service (CAMS), ground based data, etc. The toolbox consists of three main components that are called CODA, HARP and VISAN. CODA provides interfaces for direct reading of data from earth observation data files. These interfaces consist of command line applications, libraries, direct interfaces to scientific applications (IDL and MATLAB), and direct interfaces to programming languages (C, Fortran, Python, and Java). CODA provides a single interface to access data in a wide variety of data formats, including ASCII, binary, XML, netCDF, HDF4, HDF5, CDF, GRIB, RINEX, and SP3. HARP is a toolkit for reading, processing and inter-comparing satellite remote sensing data, model data, in-situ data, and ground based remote sensing data. The main goal of HARP is to assist in the inter-comparison of datasets. By appropriately chaining calls to HARP command line tools one can pre-process datasets such that two datasets that need to be compared end up having the same temporal/spatial grid, same data format/structure, and same physical unit. The toolkit comes with its own data format conventions, the HARP format, which is based on netcdf/HDF. Ingestion routines (based on CODA) allow conversion from a wide variety of atmospheric data products to this common format. In addition, the toolbox provides a wide range of operations to perform conversions on the data such as unit conversions, quantity conversions (e.g. number density to volume mixing ratios), regridding, vertical smoothing using averaging kernels, collocation of two datasets, etc. VISAN is a cross-platform visualization and

  8. Research on complex networks' repairing characteristics due to cascading failure

    Science.gov (United States)

    Chaoqi, Fu; Ying, Wang; Xiaoyang, Wang

    2017-09-01

    In reality, most of the topological structures of complex networks are not ideal. Considering the restrictions from all aspects, we cannot timely adjust and improve network defects. Once complex networks collapse under cascading failure, an appropriate repair strategy must be implemented. This repair process is divided into 3 kinds of situations. Based on different types of opening times, we presented 2 repair modes, and researched 4 kinds of repair strategies. Results showed that network efficiency recovered faster when the repair strategies were arranged in descending order by parameters under the immediate opening condition. However, the risk of secondary failure and additional expansion capacity were large. On the contrary, when repair strategies were in ascending order, the demand for additional capacity caused by secondary failure was greatly saved, but the recovery of network efficiency was relatively slow. Compared to immediate opening, delayed opening alleviated the contradiction between network efficiency and additional expansion capacity, particularly to reduce the risk of secondary failure. Therefore, different repair methods have different repair characteristics. This paper investigates the impact of cascading effects on the network repair process, and by presenting a detailed description of the status of each repaired node, helps us understand the advantages and disadvantages of different repair strategies.

  9. Interatomic Coulombic decay cascades in multiply excited neon clusters

    Science.gov (United States)

    Nagaya, K.; Iablonskyi, D.; Golubev, N. V.; Matsunami, K.; Fukuzawa, H.; Motomura, K.; Nishiyama, T.; Sakai, T.; Tachibana, T.; Mondal, S.; Wada, S.; Prince, K. C.; Callegari, C.; Miron, C.; Saito, N.; Yabashi, M.; Demekhin, Ph. V.; Cederbaum, L. S.; Kuleff, A. I.; Yao, M.; Ueda, K.

    2016-01-01

    In high-intensity laser light, matter can be ionized by direct multiphoton absorption even at photon energies below the ionization threshold. However on tuning the laser to the lowest resonant transition, the system becomes multiply excited, and more efficient, indirect ionization pathways become operative. These mechanisms are known as interatomic Coulombic decay (ICD), where one of the species de-excites to its ground state, transferring its energy to ionize another excited species. Here we show that on tuning to a higher resonant transition, a previously unknown type of interatomic Coulombic decay, intra-Rydberg ICD occurs. In it, de-excitation of an atom to a close-lying Rydberg state leads to electron emission from another neighbouring Rydberg atom. Moreover, systems multiply excited to higher Rydberg states will decay by a cascade of such processes, producing even more ions. The intra-Rydberg ICD and cascades are expected to be ubiquitous in weakly-bound systems exposed to high-intensity resonant radiation. PMID:27917867

  10. Quantum cascade laser: Applications in chemical detection and environmental monitoring

    Directory of Open Access Journals (Sweden)

    Radovanović Jelena

    2009-01-01

    Full Text Available In this paper we consider the structural parameter optimization of the active region of a GaAs-based quantum cascade laser in order to maximize the optical gain of the laser at the characteristic wavelengths, which are best suited for detection of pollutant gasses, such as SO2, HNO3, CH4, and NH3, in the ambient air by means of direct absorption. The procedure relies on applying elaborate tools for global optimization, such as the genetic algorithm. One of the important goals is to extend the applicability of a single active region design to the detection of several compounds absorbing at close wave-lengths, and this is achieved by introducing a strong external magnetic field perpendicularly to the epitaxial layers. The field causes two-dimensional continuous energy subbands to split into the series of discrete Landau levels. Since the arrangement of Landau levels depends strongly on the magnitude of the magnetic field, this enables one to control the population inversion in the active region, and hence the optical gain. Furthermore, strong effects of band non-parabolicity result in subtle changes of the lasing wavelength at magnetic fields which maximize the gain, thus providing a path for fine-tuning of the output radiation properties and changing the target compound for detection. The numerical results are presented for quantum cascade laser structures designed to emit at specified wavelengths in the mid-infrared part of the spectrum.

  11. Robustness of Interrelated Traffic Networks to Cascading Failures

    Science.gov (United States)

    Su, Zhen; Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Xiao, Jinghua; Yang, Yixian

    2014-06-01

    The vulnerability to real-life networks against small initial attacks has been one of outstanding challenges in the study of interrelated networks. We study cascading failures in two interrelated networks S and B composed from dependency chains and connectivity links respectively. This work proposes a realistic model for cascading failures based on the redistribution of traffic flow. We study the Barabási-Albert networks (BA) and Erdős-Rényi graphs (ER) with such structure, and found that the efficiency sharply decreases with increasing percentages of the dependency nodes for removing a node randomly. Furthermore, we study the robustness of interrelated traffic networks, especially the subway and bus network in Beijing. By analyzing different attacking strategies, we uncover that the efficiency of the city traffic system has a non-equilibrium phase transition at low capacity of the networks. This explains why the pressure of the traffic overload is relaxed by singly increasing the number of small buses during rush hours. We also found that the increment of some buses may release traffic jam caused by removing a node of the bus network randomly if the damage is limited. However, the efficiencies to transfer people flow will sharper increase when the capacity of the subway network αS > α0.

  12. Observability of ``cascade mixing'' in Bo→J/ψKo

    Science.gov (United States)

    Stodolsky, L.

    2013-05-01

    In high statistics observations of Bo→J/ψKo originating from the process Υ(4S)→BoB¯o it should be possible to observe “cascade mixing,” where one mixing particle, the Bo, turns into another, the Ko. This is possible despite the difficulty that the length of the beam crossing region makes a precise definition of the primary vertex impossible. This difficulty is circumvented by using an “away side” tag to specify the initial time. We review the formalism for describing such processes, and first apply it to simple Bo mixing, noting that it gives a transparent description for CP and T asymmetries. In particular, we show that three different asymmetries of the CP and T type, with neglect of direct CP violation, are given by the same expression. For cascade mixing we present predictions for processes of the type Bi→Kj via J/ψ, where in the limit of no direct CP violation each state i or j is determined by a simple tag. There are 16 such simple measurable processes, involving 10 functions of the two time intervals involved. The coefficients of the functions are different for each of the processes and are given in terms of the mass splitting and the CP, T violating parameter of the Bo mass matrix m2. The results presented here are just consequences of the quantum mechanics of particle mixing and do not involve any particular model of CP violation.

  13. A hybrid plasmonic waveguide terahertz quantum cascade laser

    Science.gov (United States)

    Degl'Innocenti, Riccardo; Shah, Yash D.; Wallis, Robert; Klimont, Adam; Ren, Yuan; Jessop, David S.; Beere, Harvey E.; Ritchie, David A.

    2015-02-01

    We present the realization of a quantum cascade laser emitting at around 2.85 THz, based on a hybrid plasmonic waveguide with a low refractive index dielectric cladding. This hybrid waveguide design allows the performance of a double-metal waveguide to be retained, while improving the emission far-field. A set of lasers based on the same active region material were fabricated with different metal layer thicknesses. A detailed characterization of the performance of these lasers revealed that there is an optimal trade-off that yields the best far-field emission and the maximum temperature of operation. By exploiting the pure plasmonic mode of these waveguides, the standard operation conditions of a double-metal quantum cascade laser were retrieved, such that the maximum operating temperature of these devices is not affected by the process. These results pave the way to realizing a class of integrated devices working in the terahertz range which could be further exploited to fabricate terahertz on-chip circuitry.

  14. Toward Holistic Scene Understanding: Feedback Enabled Cascaded Classification Models.

    Science.gov (United States)

    Li, Congcong; Kowdle, Adarsh; Saxena, Ashutosh; Chen, Tsuhan

    2012-07-01

    Scene understanding includes many related subtasks, such as scene categorization, depth estimation, object detection, etc. Each of these subtasks is often notoriously hard, and state-of-the-art classifiers already exist for many of them. These classifiers operate on the same raw image and provide correlated outputs. It is desirable to have an algorithm that can capture such correlation without requiring any changes to the inner workings of any classifier. We propose Feedback Enabled Cascaded Classification Models (FE-CCM), that jointly optimizes all the subtasks while requiring only a "black box" interface to the original classifier for each subtask. We use a two-layer cascade of classifiers, which are repeated instantiations of the original ones, with the output of the first layer fed into the second layer as input. Our training method involves a feedback step that allows later classifiers to provide earlier classifiers information about which error modes to focus on. We show that our method significantly improves performance in all the subtasks in the domain of scene understanding, where we consider depth estimation, scene categorization, event categorization, object detection, geometric labeling, and saliency detection. Our method also improves performance in two robotic applications: an object-grasping robot and an object-finding robot.

  15. Temperature insensitive curvature sensor based on cascading photonic crystal fiber

    Science.gov (United States)

    Fu, Guangwei; Li, Yunpu; Fu, Xinghu; Jin, Wa; Bi, Weihong

    2018-03-01

    A temperature insensitive curvature sensor is proposed based on cascading photonic crystal fiber. Using the arc fusion splicing method, this sensor is fabricated by cascading together a single-mode fiber (SMF), a three layers air holes structure of photonic crystal fiber (3PCF), a five layers air holes structure of photonic crystal fiber (5PCF) and a SMF in turn. So the structure SMF-3PCF-5PCF-SMF can be obtained with a total length of 20 mm. During the process of fabrication, the splicing machine parameters and the length of each optical fiber are adjusted to obtain a high sensitivity curvature sensor. The experimental results show that the curvature sensitivity is -8.40 nm/m-1 in the curvature variation range of 0-1.09 m-1, which also show good linearity. In the range of 30-90 °C, the temperature sensitivity is only about 3.24 pm/°C, indicating that the sensor is not sensitive to temperature. The sensor not only has the advantages of easy fabricating, simple structure, high sensitivity but also can solve the problem of temperature measurement cross sensitivity, so it can be used for different areas including aerospace, large-scale bridge, architectural structure health monitoring and so on.

  16. Has spring snowpack declined in the Washington Cascades?

    Directory of Open Access Journals (Sweden)

    P. Mote

    2008-02-01

    Full Text Available Our best estimates of 1 April snow water equivalent (SWE in the Cascade Mountains of Washington State indicate a substantial (roughly 15–35% decline from mid-century to 2006, with larger declines at low elevations and smaller declines or increases at high elevations. This range of values includes estimates from observations and hydrologic modeling, reflects a range of starting points between about 1930 and 1970 and also reflects uncertainties about sampling. The most important sampling issue springs from the fact that half the 1 April SWE in the Cascades is found below about 1240 m, altitudes at which sampling was poor before 1945. Separating the influences of temperature and precipitation on 1 April SWE in several ways, it is clear that long-term trends are dominated by trends in temperature, whereas variability in precipitation adds "noise" to the time series. Consideration of spatial and temporal patterns of change rules out natural variations like the Pacific Decadal Oscillation as the sole cause of the decline. Regional warming has clearly played a role, but it is not yet possible to quantify how much of that regional warming is related to greenhouse gas emissions.

  17. Artifact removal from EEG signals using adaptive filters in cascade

    Science.gov (United States)

    Garcés Correa, A.; Laciar, E.; Patiño, H. D.; Valentinuzzi, M. E.

    2007-11-01

    Artifacts in EEG (electroencephalogram) records are caused by various factors, like line interference, EOG (electro-oculogram) and ECG (electrocardiogram). These noise sources increase the difficulty in analyzing the EEG and to obtaining clinical information. For this reason, it is necessary to design specific filters to decrease such artifacts in EEG records. In this paper, a cascade of three adaptive filters based on a least mean squares (LMS) algorithm is proposed. The first one eliminates line interference, the second adaptive filter removes the ECG artifacts and the last one cancels EOG spikes. Each stage uses a finite impulse response (FIR) filter, which adjusts its coefficients to produce an output similar to the artifacts present in the EEG. The proposed cascade adaptive filter was tested in five real EEG records acquired in polysomnographic studies. In all cases, line-frequency, ECG and EOG artifacts were attenuated. It is concluded that the proposed filter reduces the common artifacts present in EEG signals without removing significant information embedded in these records.

  18. Financial incentives to improve progression through the HIV treatment cascade.

    Science.gov (United States)

    Bassett, Ingrid V; Wilson, David; Taaffe, Jessica; Freedberg, Kenneth A

    2015-11-01

    We reviewed recent literature on conditional and unconditional financial incentives for their impact on improving movement through the HIV care cascade and HIV prevention. Concepts from behavioral economics may help improve engagement in HIV care by addressing upstream structural risk factors for HIV, such as poverty, or providing conditional rewards for immediate, measurable outcomes related to HIV care. Incentives have been shown to increase uptake of HIV testing. Yet, few studies to date focus on linkage to care: one large USA-based randomized trial failed to show an effect of incentives; and a smaller trial showed improved linkage to care among drug users, but no difference in virologic suppression. Several small USA-based studies have shown an impact of financial incentives on antiretroviral therapy adherence, but without durability beyond the incentive period. HIV prevention has the most robust evidence for decreasing HIV risk-taking behavior among adolescents and may serve as a model for research on the care cascade. Financial incentives show promise for improving engagement in HIV testing, care, and prevention. Understanding the durability, scalability, ease of implementation, and cost-effectiveness of these different approaches will be critical for maximizing the impact of incentives in curtailing the HIV epidemic.

  19. Cascades and statistical equilibrium in shell models of turbulence

    CERN Document Server

    Ditlevsen, P D

    1996-01-01

    We study the GOY shell model simulating the cascade processes of turbulent flow. The model has two inviscid invariants governing the dynamical behavior. Depending on the choice of interaction coefficients, or coupling parameters, the two invariants are either both positive definite, analogous to energy and enstrophy of 2D flow, or only one is positive definite and the other not, analogous to energy and helicity of 3D flow. In the 2D like model the dynamics depend on the spectral ratio of enstrophy to energy. That ratio depends on wave-number as $k^{\\alpha}$. The enstrophy transfer through the inertial sub-range can be described as a forward cascade for $\\alpha 2$. The $\\alpha =2$ case, corresponding to 2D turbulence, is a borderline between the two descriptions. The difference can be understood in terms of the ratio of typical timescales in the inertial sub-range and in the viscous sub-range. The multi fractality of the enstrophy dissipation also depends on the parameter $\\alpha$, and seems to be related to ...

  20. Novel cascade FPGA accelerator for support vector machines classification.

    Science.gov (United States)

    Papadonikolakis, Markos; Bouganis, Christos-Savvas

    2012-07-01

    Support vector machines (SVMs) are a powerful machine learning tool, providing state-of-the-art accuracy to many classification problems. However, SVM classification is a computationally complex task, suffering from linear dependencies on the number of the support vectors and the problem's dimensionality. This paper presents a fully scalable field programmable gate array (FPGA) architecture for the acceleration of SVM classification, which exploits the device heterogeneity and the dynamic range diversities among the dataset attributes. An adaptive and fully-customized processing unit is proposed, which utilizes the available heterogeneous resources of a modern FPGA device in efficient way with respect to the problem's characteristics. The implementation results demonstrate the efficiency of the heterogeneous architecture, presenting a speed-up factor of 2-3 orders of magnitude, compared to the CPU implementation. The proposed architecture outperforms other proposed FPGA and graphic processor unit approaches by more than seven times. Furthermore, based on the special properties of the heterogeneous architecture, this paper introduces the first FPGA-oriented cascade SVM classifier scheme, which exploits the FPGA reconfigurability and intensifies the custom-arithmetic properties of the heterogeneous architecture. The results show that the proposed cascade scheme is able to increase the heterogeneous classifier throughput even further, without introducing any penalty on the resource utilization.

  1. Regulation cascade of flagellar expression in Gram-negative bacteria.

    Science.gov (United States)

    Soutourina, Olga A; Bertin, Philippe N

    2003-10-01

    Flagellar motility helps bacteria to reach the most favourable environments and to successfully compete with other micro-organisms. These complex organelles also play an important role in adhesion to substrates, biofilm formation and virulence process. In addition, because their synthesis and functioning are very expensive for the cell (about 2% of biosynthetic energy expenditure in Escherichia coli) and may induce a strong immune response in the host organism, the expression of flagellar genes is highly regulated by environmental conditions. In the past few years, many data have been published about the regulation of motility in polarly and laterally flagellated bacteria. However, the mechanism of motility control by environmental factors and by some regulatory proteins remains largely unknown. In this respect, recent experimental data suggest that the master regulatory protein-encoding genes at the first level of the cascade are the main target for many environmental factors. This mechanism might require DNA topology alterations of their regulatory regions. Finally, despite some differences the polar and lateral flagellar cascades share many functional similarities, including a similar hierarchical organisation of flagellar systems. The remarkable parallelism in the functional organisation of flagellar systems suggests an evolutionary conservation of regulatory mechanisms in Gram-negative bacteria.

  2. Parameter estimation and forecasting for multiplicative log-normal cascades.

    Science.gov (United States)

    Leövey, Andrés E; Lux, Thomas

    2012-04-01

    We study the well-known multiplicative log-normal cascade process in which the multiplication of Gaussian and log normally distributed random variables yields time series with intermittent bursts of activity. Due to the nonstationarity of this process and the combinatorial nature of such a formalism, its parameters have been estimated mostly by fitting the numerical approximation of the associated non-Gaussian probability density function to empirical data, cf. Castaing et al. [Physica D 46, 177 (1990)]. More recently, alternative estimators based upon various moments have been proposed by Beck [Physica D 193, 195 (2004)] and Kiyono et al. [Phys. Rev. E 76, 041113 (2007)]. In this paper, we pursue this moment-based approach further and develop a more rigorous generalized method of moments (GMM) estimation procedure to cope with the documented difficulties of previous methodologies. We show that even under uncertainty about the actual number of cascade steps, our methodology yields very reliable results for the estimated intermittency parameter. Employing the Levinson-Durbin algorithm for best linear forecasts, we also show that estimated parameters can be used for forecasting the evolution of the turbulent flow. We compare forecasting results from the GMM and Kiyono et al.'s procedure via Monte Carlo simulations. We finally test the applicability of our approach by estimating the intermittency parameter and forecasting of volatility for a sample of financial data from stock and foreign exchange markets.

  3. High fishery catches through trophic cascades in China.

    Science.gov (United States)

    Szuwalski, Cody S; Burgess, Matthew G; Costello, Christopher; Gaines, Steven D

    2017-01-24

    Indiscriminate and intense fishing has occurred in many marine ecosystems around the world. Although this practice may have negative effects on biodiversity and populations of individual species, it may also increase total fishery productivity by removing predatory fish. We examine the potential for this phenomenon to explain the high reported wild catches in the East China Sea-one of the most productive ecosystems in the world that has also had its catch reporting accuracy and fishery management questioned. We show that reported catches can be approximated using an ecosystem model that allows for trophic cascades (i.e., the depletion of predators and consequent increases in production of their prey). This would be the world's largest known example of marine ecosystem "engineering" and suggests that trade-offs between conservation and food production exist. We project that fishing practices could be modified to increase total catches, revenue, and biomass in the East China Sea, but single-species management would decrease both catches and revenue by reversing the trophic cascades. Our results suggest that implementing single-species management in currently lightly managed and highly exploited multispecies fisheries (which account for a large fraction of global fish catch) may result in decreases in global catch. Efforts to reform management in these fisheries will need to consider system wide impacts of changes in management, rather than focusing only on individual species.

  4. Probability of large explosive volcanic eruptions in the Cascades

    Science.gov (United States)

    Nathenson, M.; Clynne, M. A.

    2011-12-01

    Estimating the probability of large explosive eruptions in the Cascades is problematic because they occur relatively infrequently. Although some volcanic centers have been more likely to have large eruptions than others, the calculation of the probability of large eruptions for individual volcanic centers is inappropriate. A center that has had a large eruption in the past will not necessarily have a large eruption in the future, and the occurrence for individual volcanic centers is too infrequent to have much confidence in a probability estimate. The sources of some large eruptions are ambiguous (e.g. Shevlin Park Tuff, Oregon) or unknown (Dibekulewe ash), but because the effects of large eruptions are quite widespread, the precise location of the source is less important in terms of hazards. Thus, we focus on the calculation of probability of large eruptions for the Cascade arc as a whole. To estimate the probability, we have chosen a time period for documenting eruptions of 1.15 Ma (the age of the eruption of Kulshan caldera) as a balance between the likelihood of there being good information but with a long enough time period to get a reasonable number of occurrences. We have compiled data from the literature on eruptions larger than 5 km3 in erupted volume to exclude the relatively frequent eruptions ~1-2 km3. The largest eruptions are clearly or likely to have been associated with caldera formation. For erupted volumes greater than 5 km3, 19 events have occurred in the last 1.15 Ma. A plot of event number versus age shows a high rate of occurrence since 13.5 ka and a much lower rate before then. Most of the events since 13.5 ka are 5-10 km3. Events 10 km3 and larger have occurred at a reasonably constant rate since 630 ka. The difference between the two data sets is probably the poor preservation of deposits for events between 5 and 10 km3 that occurred prior to the ending of the glaciation at about 15 ka. Before 630 ka, the only eruption > 10 km3 is Kulshan

  5. Applications of theoretical methods in atmospheric science

    DEFF Research Database (Denmark)

    Johnson, Matthew Stanley; Goodsite, Michael E.

    2008-01-01

    in addressing an issue of primary concern: understanding photochemical reaction rates at the various conditions found in the atmosphere. Atmospheric science includes both atmospheric chemistry and atmospheric physics, meteorology, climatology and the study of extraterrestrial atmospheres....

  6. Atmospheric lepton fluxes

    Directory of Open Access Journals (Sweden)

    Gaisser Thomas K.

    2015-01-01

    Full Text Available This review of atmospheric muons and neutrinos emphasizes the high energy range relevant for backgrounds to high-energy neutrinos of astrophysical origin. After a brief historical introduction, the main distinguishing features of atmospheric νμ and νe are discussed, along with the implications of the muon charge ratio for the νµ / ν̅µ ratio. Methods to account for effects of the knee in the primary cosmic-ray spectrum and the energy-dependence of hadronic interactions on the neutrino fluxes are discussed and illustrated in the context of recent results from IceCube. A simple numerical/analytic method is proposed for systematic investigation of uncertainties in neutrino fluxes arising from uncertainties in the primary cosmic-ray spectrum/composition and hadronic interactions.

  7. Habituating alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie

    This paper proposes embodied rhythmic sound habituation as a possible resource when designing contextualized technologies in critical atmospheres. The main contribution is collating the concept of rhythm as presented by Henri Lefebvre with the concept of sound habituation to help operationalize...... essential dynamic parameters when designing atmospheres. This research is based on the development of the novel research artefact Kidkit, designed for children, who are going to meet a hospitalized relative with fatal injuries in a Neuro–Intensive Care Unit. Sounds from hospital equipment have important...... functionality for the staff, but are stressful for visitors and patients, as they are designed to demand attention even though they have no direct functional meaning to them. By introducing sounds from the ward, integrated in the furniture as simple sound sample triggers, KidKit invites children to become...

  8. Atmosphere beyond Poetics

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2014-01-01

    , the notion of atmosphere is presented as parallactic for designing experience in architectural fields, since it transgresses formal and material boundaries of bodies, opening a new gap that exposes the orthodox space-body-environment relationships to questions. It leads to the dissolution...... of the architectural ‘object’ and its fixity and offers a new understanding of context and space – approached as a field of dynamic relationships. It calls for a re-evaluation of perceptual experience, offering to architecture an expanded domain in which architecture manifests itself, including qualities – besides...... poetics and beauty – that architecture has long resisted. That is, it defines space as a contingent construction, performative and intensely affective. Accordingly, the intention is to critically analyse what the term atmosphere entails in architecture, and to expand its notion in terms of affective...

  9. Contaminants in the Atmosphere

    DEFF Research Database (Denmark)

    Skov, H.; Bossi, R.; Wåhlin, P.

    This report presents the results of atmospheric monitoring in Nuuk, Greenland. A long series of heavy metals and persistent organic Pollutants (POPs) have been measured and model calculations have been carried out supporting the interpretation of the results. Financially, the Danish Environmental...... Protection Agency supported this work with means from the MIKA/DANCEA funds for Environmental Support to the Arctic Region and the work is part of the Danish contribution to Arctic Monitoring and Assessment Programme, AMAP......This report presents the results of atmospheric monitoring in Nuuk, Greenland. A long series of heavy metals and persistent organic Pollutants (POPs) have been measured and model calculations have been carried out supporting the interpretation of the results. Financially, the Danish Environmental...

  10. Haze in Pluto's atmosphere

    Science.gov (United States)

    Cheng, A. F.; Summers, M. E.; Gladstone, G. R.; Strobel, D. F.; Young, L. A.; Lavvas, P.; Kammer, J. A.; Lisse, C. M.; Parker, A. H.; Young, E. F.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Ennico, K.

    2017-07-01

    Haze in Pluto's atmosphere was detected in images by both the Long Range Reconnaissance Imager (LORRI) and the Multispectral Visible Imaging Camera (MVIC) on New Horizons. LORRI observed haze up to altitudes of at least 200 km above Pluto's surface at solar phase angles from ∼20° to ∼169°. The haze is structured with about ∼20 layers, and the extinction due to haze is greater in the northern hemisphere than at equatorial or southern latitudes. However, more haze layers are discerned at equatorial latitudes. A search for temporal variations found no evidence for motions of haze layers (temporal changes in layer altitudes) on time scales of 2 to 5 hours, but did find evidence of changes in haze scale height above 100 km altitude. An ultraviolet extinction attributable to the atmospheric haze was also detected by the ALICE ultraviolet spectrograph on New Horizons. The haze particles are strongly forward-scattering in the visible, and a microphysical model of haze is presented which reproduces the visible phase function just above the surface with 0.5 μm spherical particles, but also invokes fractal aggregate particles to fit the visible phase function at 45 km altitude and account for UV extinction. A model of haze layer generation by orographic excitation of gravity waves is presented. This model accounts for the observed layer thickness and distribution with altitude. Haze particles settle out of the atmosphere and onto Pluto's surface, at a rate sufficient to alter surface optical properties on seasonal time scales. Pluto's regional scale albedo contrasts may be preserved in the face of the haze deposition by atmospheric collapse.

  11. DREAMING OF ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Waldmann, I. P., E-mail: ingo@star.ucl.ac.uk [Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT (United Kingdom)

    2016-04-01

    Here, we introduce the RobERt (Robotic Exoplanet Recognition) algorithm for the classification of exoplanetary emission spectra. Spectral retrieval of exoplanetary atmospheres frequently requires the preselection of molecular/atomic opacities to be defined by the user. In the era of open-source, automated, and self-sufficient retrieval algorithms, manual input should be avoided. User dependent input could, in worst-case scenarios, lead to incomplete models and biases in the retrieval. The RobERt algorithm is based on deep-belief neural (DBN) networks trained to accurately recognize molecular signatures for a wide range of planets, atmospheric thermal profiles, and compositions. Reconstructions of the learned features, also referred to as the “dreams” of the network, indicate good convergence and an accurate representation of molecular features in the DBN. Using these deep neural networks, we work toward retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from current and past data, and make sensible qualitative preselections of atmospheric opacities to be used for the quantitative stage of the retrieval process.

  12. Dreaming of Atmospheres

    Science.gov (United States)

    Waldmann, I. P.

    2016-04-01

    Here, we introduce the RobERt (Robotic Exoplanet Recognition) algorithm for the classification of exoplanetary emission spectra. Spectral retrieval of exoplanetary atmospheres frequently requires the preselection of molecular/atomic opacities to be defined by the user. In the era of open-source, automated, and self-sufficient retrieval algorithms, manual input should be avoided. User dependent input could, in worst-case scenarios, lead to incomplete models and biases in the retrieval. The RobERt algorithm is based on deep-belief neural (DBN) networks trained to accurately recognize molecular signatures for a wide range of planets, atmospheric thermal profiles, and compositions. Reconstructions of the learned features, also referred to as the “dreams” of the network, indicate good convergence and an accurate representation of molecular features in the DBN. Using these deep neural networks, we work toward retrieval algorithms that themselves understand the nature of the observed spectra, are able to learn from current and past data, and make sensible qualitative preselections of atmospheric opacities to be used for the quantitative stage of the retrieval process.

  13. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T.J. (Discovery Bay Marine Laboratory, Univ. of the West Indies (JM))

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  14. Evolution of the atmosphere.

    Science.gov (United States)

    Nunn, J F

    1998-01-01

    Planetary atmospheres depend fundamentally upon their geochemical inventory, temperature and the ability of their gravitational field to retain gases. In the case of Earth and other inner planets, early outgassing released mainly carbon dioxide and water vapour. The secondary veneer of comets and meteorites added further volatiles. Photodissociation caused secondary changes, including the production of traces of oxygen from water. Earth's gravity cannot retain light gases, including hydrogen. but retains oxygen. Water vapour generally does not pass the cold trap at the stratopause. In the archaean, early evolution of life, probably in hydrothermal vents, and the subsequent development of photosynthesis in surface waters, produced oxygen, at 3500 Ma or even earlier, becoming a significant component of the atmosphere from about 2000 Ma. Thereafter banded iron formations became rare, and iron was deposited in oxidized red beds. Atmospheric levels of carbon dioxide and oxygen have varied during the Phanerozoic: major changes may have caused extinctions. particularly the Permian/Triassic. The declining greenhouse effect due to the long-term decrease in carbon dioxide has largely offset increasing solar luminosity, and changes in carbon dioxide levels relate strongly to cycles of glaciation.

  15. Determination of the Atmospheric Neutrino Fluxes from Atmospheric Neutrino Data

    NARCIS (Netherlands)

    Gonzalez-Garcia, M. C.; Maltoni, M.; Rojo, J.

    2006-01-01

    The precise knowledge of the atmospheric neutrino fluxes is a key ingredient in the interpretation of the results from any atmospheric neutrino experiment. In the standard atmospheric neutrino data analysis, these fluxes are theoretical inputs obtained from sophisticated numerical calculations based

  16. Short- and Medium-Term Induced Ionization in the Earth Atmosphere by Galactic and Solar Cosmic Rays

    Directory of Open Access Journals (Sweden)

    Alexander Mishev

    2013-01-01

    Full Text Available The galactic cosmic rays are the main source of ionization in the troposphere of the Earth. Solar energetic particles of MeV energies cause an excess of ionization in the atmosphere, specifically over polar caps. The ionization effect during the major ground level enhancement 69 on January 20, 2005 is studied at various time scales. The estimation of ion rate is based on a recent numerical model for cosmic-ray-induced ionization. The ionization effect in the Earth atmosphere is obtained on the basis of solar proton energy spectra, reconstructed from GOES 11 measurements and subsequent full Monte Carlo simulation of cosmic-ray-induced atmospheric cascade. The evolution of atmospheric cascade is performed with CORSIKA 6.990 code using FLUKA 2011 and QGSJET II hadron interaction models. The atmospheric ion rate is explicitly obtained for various latitudes, namely, 40°N, 60°N and 80°N. The time evolution of obtained ion rates is presented. The short- and medium-term ionization effect is compared with the average effect due to galactic cosmic rays. It is demonstrated that ionization effect is significant only in subpolar and polar atmosphere during the major ground level enhancement of January 20, 2005. It is negative in troposphere at midlatitude, because of the accompanying Forbush effect.

  17. Coarse-grained incompressible magnetohydrodynamics: analyzing the turbulent cascades

    Science.gov (United States)

    Aluie, Hussein

    2017-02-01

    We formulate a coarse-graining approach to the dynamics of magnetohydrodynamic (MHD) fluids at a continuum of length-scales ℓ. In this methodology, effective equations are derived for the observable velocity and magnetic fields spatially-averaged at an arbitrary scale of resolution. The microscopic equations for the ‘bare’ velocity and magnetic fields are ‘renormalized’ by coarse-graining to yield macroscopic effective equations that contain both a subscale stress and a subscale electromotive force (EMF) generated by nonlinear interaction of eliminated fields and plasma motions. Particular attention is given to the effects of these subscale terms on the balances of the quadratic invariants of ideal incompressible MHD—energy, cross-helicity and magnetic helicity. At large coarse-graining length-scales, the direct dissipation of the invariants by microscopic mechanisms (such as molecular viscosity and Spitzer resistivity) is shown to be negligible. The balance at large scales is dominated instead by the subscale nonlinear terms, which can transfer invariants across scales, and are interpreted in terms of work concepts for energy and in terms of topological flux-linkage for the two helicities. An important application of this approach is to MHD turbulence, where the coarse-graining length ℓ lies in the inertial cascade range. We show that in the case of sufficiently rough velocity and/or magnetic fields, the nonlinear inter-scale transfer need not vanish and can persist to arbitrarily small scales. Although closed expressions are not available for subscale stress and subscale EMF, we derive rigorous upper bounds on the effective dissipation they produce in terms of scaling exponents of the velocity and magnetic fields. These bounds provide exact constraints on phenomenological theories of MHD turbulence in order to allow the nonlinear cascade of energy and cross-helicity. On the other hand, we prove a very strong version of the Woltjer-Taylor conjecture

  18. Slab melting and magma formation beneath the southern Cascade arc

    Science.gov (United States)

    Walowski, Kristina J.; Wallace, Paul J.; Clynne, Michael A.; Rasmussen, D.J.; Weis, D.

    2016-01-01

    The processes that drive magma formation beneath the Cascade arc and other warm-slab subduction zones have been debated because young oceanic crust is predicted to largely dehydrate beneath the forearc during subduction. In addition, geochemical variability along strike in the Cascades has led to contrasting interpretations about the role of volatiles in magma generation. Here, we focus on the Lassen segment of the Cascade arc, where previous work has demonstrated across-arc geochemical variations related to subduction enrichment, and H-isotope data suggest that H2O in basaltic magmas is derived from the final breakdown of chlorite in the mantle portion of the slab. We use naturally glassy, olivine-hosted melt inclusions (MI) from the tephra deposits of eight primitive (MgO>7 wt%) basaltic cinder cones to quantify the pre-eruptive volatile contents of mantle-derived melts in this region. The melt inclusions have B concentrations and isotope ratios that are similar to mid-ocean ridge basalt (MORB), suggesting extensive dehydration of the downgoing plate prior to reaching sub-arc depths and little input of slab-derived B into the mantle wedge. However, correlations of volatile and trace element ratios (H2O/Ce, Cl/Nb, Sr/Nd) in the melt inclusions demonstrate that geochemical variability is the result of variable addition of a hydrous subduction component to the mantle wedge. Furthermore, correlations between subduction component tracers and radiogenic isotope ratios show that the subduction component has less radiogenic Sr and Pb than the Lassen sub-arc mantle, which can be explained by melting of subducted Gorda MORB beneath the arc. Agreement between pMELTS melting models and melt inclusion volatile, major, and trace element data suggests that hydrous slab melt addition to the mantle wedge can produce the range in primitive compositions erupted in the Lassen region. Our results provide further evidence that chlorite-derived fluids from the mantle portion of the

  19. Nitrogen Cascade: An Opportunity to Integrate Biogeochemistry and Policy

    Science.gov (United States)

    Galloway, J. N.; Moomaw, W. R.; Theis, T. L.

    2008-12-01

    It began with micro-organisms millions of years ago, was enhanced by the burning of fossil carbon in the last several hundred years, and was magnified by a patent filed one hundred years ago. Today, the combined actions of cultivation-induced biological nitrogen fixation, fossil fuel combustion and the Haber-Bosch process have exceeded natural terrestrial processes in converting N22 to nitrogen compounds that are biologically, chemically or physically reactive (reactive nitrogen, Nr). While the benefits of Nr are well understood, many of the adverse consequences of excessive Nr are invisible from a policy perspective. Over the past century, the fundamental knowledge on nitrogen processes has advanced to the point where we have a good understanding of nitrogen's biogeochemical cycle, the role of humans in altering the cycle, and the consequences of the alterations. This knowledge has collectively led us to two conclusions-the consequences of intensive human influence on the nitrogen cycle leads to a cascade of ecosystem and human effects which need to be managed. Secondly, the management is complicated by the facts that it not only has to be integrated, but it also has to take into account that the management should not lower the ability of managed ecosystems to produce food for the world's peoples. The framework of the nitrogen cascade provides us with a structure for better identifying intervention points, and more effective policies, technologies and measures to prevent or mitigate the adverse impacts of reactive nitrogen, while enhancing its beneficial uses. We can now begin to use our understanding of science to set priorities and craft new policy strategies. For many regions of the world, the science is strong enough to manage nitrogen and there are existing tools to do so. However, the tools are not integrated, critical tools are missing and most importantly, there are nitrogen-rich regions of the world where the science is lacking, and nitrogen-poor regions

  20. A robustness metric for cascading failures by targeted attacks in power networks

    NARCIS (Netherlands)

    Koc, Y.; Warnier, M.; Kooij, R.E.; Brazier, F.M.T.

    2013-01-01

    Cascading failures are the main reason blackouts occur in power networks. The economic cost of such failures is in the order of tens of billion dollars annually. In a power network, the cascading failure phenomenon is related to both topological properties (number and types of buses, density of

  1. Asymmetric Formation of Bridged Benzoxazocines through an Organocatalytic Multicomponent Dienamine-Mediated One-Pot Cascade

    DEFF Research Database (Denmark)

    Ransborg, Lars Krogager; Overgaard, Mette Kiilerich; Hejmanowska, Joanna

    2014-01-01

    An organocatalytic one-pot cascade leading to the stereoselective formation of novel bridged benzoxazocines is presented. The developed methodology is based on the first example of a γ-selective-Mannich-initiated cascade reaction and allows for direct annulation of the bridged benzoxazocines...

  2. Fire and water: volcanology, geomorphology, and hydrogeology of the Cascade Range, central Oregon

    Science.gov (United States)

    Katharine V. Cashman; Natalia I. Deligne; Marshall W. Gannett; Gordon E. Grant; Anne. Jefferson

    2009-01-01

    This field trip guide explores the interactions among the geologic evolution, hydrology, and fluvial geomorphology of the central Oregon Cascade Range. Key topics include the geologic control of hydrologic regimes on both the wet and dry sides of the Cascade Range crest, groundwater dynamics and interaction between surface and groundwater in young volcanic arcs, and...

  3. Developmental Cascade Model for Adolescent Substance Use from Infancy to Late Adolescence

    Science.gov (United States)

    Eiden, Rina D.; Lessard, Jared; Colder, Craig R.; Livingston, Jennifer; Casey, Meghan; Leonard, Kenneth E.

    2016-01-01

    A developmental cascade model for adolescent substance use beginning in infancy was examined in a sample of children with alcoholic and nonalcoholic parents. The model examined the role of parents' alcohol diagnoses, depression and antisocial behavior in a cascading process of risk via 3 major hypothesized pathways: first, via parental…

  4. Assessing wood use efficiency and greenhouse gas emissions of wood product cascading in the European Union

    NARCIS (Netherlands)

    Bais-Moleman, A.L.; Sikkema, Richard; Vis, Martijn; Reumerman, Patrick; Theurl, Michaela; Erb, Karl Heinz

    2017-01-01

    Cascading use of biomass is a recognized strategy contributing to an efficient development of the bioeconomy and for mitigating climate change. This study aims at assessing the potential of cascading use of woody biomass for reducing GHG (greenhouse gas) emissions and increasing the overall wood

  5. On the calculation of a squared-off cascade for multicomponent isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Kholpanov, L.P. [Russian Academy of Science, Moscow (Russian Federation). Inst. of New Chemical Problems; Potapov, D.V.; Sulaberidze, G.A.; Chuzhinov, V.A. [Moscow State Engineering Physics Institute (Technical Univ.), Moscow (Russian Federation)

    1998-09-01

    In this paper, a technique for calculating the stationary transfer of a multicomponent isotopic mixture in squared-off cascades is considered. The proposed method is based on quasi-linearization of the equation system describing the process of multicomponent separation. The transition to relative component concentrations is used to exclude unknown boundary conditions. The suggested method reduces the time of cascade calculation. (orig.)

  6. Differences between gas separation cascade work and the work of isobaric-isothermal mixing

    Science.gov (United States)

    Chizhkov, V. P.; Boitsov, V. N.

    2017-11-01

    The change in entropy at the nodes of the a separation cascade during the processing of a multicomponent mixture is calculated. A thermodynamic interpretation of the nature of the difference between the work of the cascade, determined from the separation potential and the thermodynamically estimated work of the isobaric-isothermal mixing of the fractions released at its ends, is presented.

  7. Multiobjective reservoir operating rules based on cascade reservoir input variable selection method

    Science.gov (United States)

    Yang, Guang; Guo, Shenglian; Liu, Pan; Li, Liping; Xu, Chongyu

    2017-04-01

    The input variable selection in multiobjective cascade reservoir operation is an important and difficult task. To address this problem, this study proposes the cascade reservoir input variable selection (CIS) method that searches for the most valuable input variables for decision making in multiple-objectivity cascade reservoir operations. From a case study of Hanjiang cascade reservoirs in China, we derive reservoir operating rules based on the combination of CIS and Gaussian radial basis functions (RBFs) methods and optimize the rules through Pareto-archived dynamically dimensioned search (PA-DDS) with two objectives: to maximize both power generation and water supply. We select the most effective input variables and evaluate their impacts on cascade reservoir operations. From the simulated trajectories of reservoir water level, power generation, and water supply, we analyze the multiobjective operating rules with several input variables. The results demonstrate that the CIS method performs well in the selection of input variables for the cascade reservoir operation, and the RBFs method can fully express the nonlinear operating rules for cascade reservoirs. We conclude that the CIS method is an effective and stable approach to identifying the most valuable information from a large number of candidate input variables. While the reservoir storage state is the most valuable information for the Hanjiang cascade reservoir multiobjective operation, the reservoir inflow is the most effective input variable for the single-objective operation of Danjiangkou.

  8. Meadow contraction and extinction debt in meadow plants and moths in the Western Cascades

    Science.gov (United States)

    Meadows in the western Cascades have contracted and fragmented by approximately 50% in the past 60 years. These habitats occupy only about 5% of the landscape of the western Cascades but are important for the preservation of biodiversity and rare species. This habitat loss and ...

  9. Methodology for Structural and Parametric Optimization of Cascade Automatic Control Systems Based on Modified Smith Predictor

    Directory of Open Access Journals (Sweden)

    G. Kulakov

    2012-01-01

    Full Text Available The paper presents methodology for structural and parametric optimization of cascade ACS   technological parameters of thermal power processes which has been developed on the basis of a modified Smith predictor. The given methodology permits significantly to improve quality of regulation in comparison with the typical cascade AСS. 

  10. Cascadability of Silicon Microring Resonators for40-Gbit/s OOK and DPSK Optical Signals

    DEFF Research Database (Denmark)

    Ozolins, Oskars; An, Yi; Lali-Dastjerdi, Zohreh

    2012-01-01

    The cascadability of a single silicon micro-ring resonator for CSRZ-OOK and CSRZ-DPSK signals is experimentally demonstrated at 40 Gbit/s for the first time. Error-free performance is obtained for both modulation formats after 5 cascaded resonators....

  11. Cascading Training down into the Classroom: The Need for Parallel Planning

    Science.gov (United States)

    Wedell, Martin

    2005-01-01

    Cascade models of in-service training are widely considered to be a cost effective means of introducing educational change to large numbers of teachers. Data from 511 teachers completing a cascade training programme that introduced current ideas about and procedures for teaching English to young learners, suggests that provision of training alone…

  12. Field theoretic calculation of energy cascade rates in non-helical ...

    Indian Academy of Sciences (India)

    Energy cascade rates and Kolmogorov's constant for non-helical steady magnetohydrodynamic turbulence have been calculated by solving the flux equations to the first order in perturbation. For zero cross helicity and space dimension d = 3 , magnetic energy cascades from large length-scales to small length-scales ...

  13. Effect of collision cascades on dislocations in tungsten: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Fu, B.Q., E-mail: bqfu@scu.edu.cn [Key Laboratory for Radiation Physics and Technology, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610065 (China); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Fitzgerald, S.P. [Department of Applied Mathematics, University of Leeds, Leeds LS2 9JT (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Hou, Q.; Wang, J.; Li, M. [Key Laboratory for Radiation Physics and Technology, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610065 (China)

    2017-02-15

    Highlights: • A cascde near a dislocation promotes climb motion. • Kinks induced by cascade facilitate the dipoles motion toward the cascade. • Shearing of dipole is dependent on PKA energy, position, direction, and dipole width. - Abstract: Tungsten (W) is the prime candidate material for the divertor and other plasma-facing components in DEMO. The point defects (i.e. vacancies and self-interstitials) produced in collision cascades caused by incident neutrons aggregate into dislocation loops (and voids), which strongly affect the mechanical properties. The point defects also interact with existing microstructural features, and understanding these processes is crucial for modelling the long term microstructural evolution of the material under fusion conditions. In this work, we performed molecular dynamics simulations of cascades interacting with initially straight edge dislocation dipoles. It was found that the residual vacancy number usually exceeds the residual interstitial number for cascades interacting with vacancy type dipoles, but for interstitial type dipoles these are close. We observed that a cascade near a dislocation promotes climb, i.e. it facilitates the movement of point defects along the climb direction. We also observed that the dislocations move easily along the glide direction, and that kinks are formed near the centre of the cascade, which then facilitate the movement of the dipoles. Some dipoles are sheared off by the cascade, and this is dependent on PKA energy, position, direction, and the width of dipole.

  14. Discrete Scale Invariance in the Cascade Heart Rate Variability Of Healthy Humans

    OpenAIRE

    Lin, Der Chyan

    2004-01-01

    Evidence of discrete scale invariance (DSI) in daytime healthy heart rate variability (HRV) is presented based on the log-periodic power law scaling of the heart beat interval increment. Our analysis suggests multiple DSI groups and a dynamic cascading process. A cascade model is presented to simulate such a property.

  15. Atmospheric Climate Experiment Plus

    Science.gov (United States)

    Lundahl, K.

    ACE+ is an atmospheric sounding mission using radio occultation techniques and is a combination of the two Earth Explorer missions ACE and WATS earlier proposed to ESA. ACE was highly rated by ESA in the Call for Earth Explorer Opportunity Missions in 1999 and was prioritised as number three and selected as a "hot-stand-by". A phase A study was carried out during 2000 and 2001. ACE will observe atmospheric parameters using radio occultations from an array of 6 micro-satellites which track the L- band signal of GPS satellites to map the detailed refractivity and thermal structure of the global atmosphere from surface to space. Water vapour and wind in Atmospheric Troposphere and Stratosphere WATS was the response to ESA's Call for Ideas for the next Earth Explorer Core Missions in 2001. WATS combines ACE GPS atmospheric occultations and LEO-LEO cross-link occultations. Cross-links strongly enhance the capability of measuring humidity relative to the ACE mission. The Earth Science Advisory Committée at ESA noted that the LEO-GNSS occultation technique is already well established through several missions in recent years and could not recommend WATS for a Phase A study as an Earth Explorer Core Mission. The ESAC was, however, deeply impressed by the LEO-LEO component of the WATS proposal and would regard it as regrettable if this science would be lost and encourages the ACE/WATS team to explore other means to achieve its scientific goal. ACE+ is therefore the response to ESA's 2nd Call for Earth Explorer Opportunity Missions in 2001 and will contribute in a significant manner to ESA's Living Planet Programme. ACE+ will considerably advance our knowledge about atmosphere physics and climate change processes. The mission will demonstrate a highly innovative approach using radio occultations for globally measuring profiles of humidity and temperature throughout the atmosphere and stratosphere. A constellation of 4 small satellites, tracking L-band GPS/GALILEO signals and

  16. The nitrogen cycle: Atmosphere interactions

    Science.gov (United States)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  17. NOAA's Tropical Atmosphere Ocean Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Realtime El Nino and La Nina data from the tropical Pacific Ocean is provided by the Tropical Atmosphere Ocean / Triangle Trans-Ocean buoy network (TAO/TRITON) of...

  18. Toward precision neutrino physics with DeepCore and beyond

    Energy Technology Data Exchange (ETDEWEB)

    DeYoung, Tyce, E-mail: deyoung@psu.edu [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States)

    2013-10-11

    DeepCore, the fully contained low energy extension to IceCube, extends IceCube's sensitivity for indirect dark matter searches and atmospheric neutrino oscillation physics as well as astrophysical neutrino sources in the southern sky. With the first year of DeepCore data we observe a significant sample of atmospheric neutrino-induced cascades, confirming the scientific potential of this approach. We discuss ideas for PINGU, a further IceCube infill array which aims for an energy threshold of around 1 GeV to support a precision IceCube neutrino physics program. In the longer term, we are exploring the feasibility of a precision neutrino physics program with a multi-megaton, sub-GeV detector in the Antarctic ice cap.

  19. Quantitative gradient of subsidies reveals a threshold in community-level trophic cascades.

    Science.gov (United States)

    Klemmer, Amanda J; Richardson, John S

    2013-09-01

    Evidence varies on how subsidies affect trophic cascades within recipient food webs. This could be due to complex nonlinearities being masked by single-level manipulations (presence/absence) of subsidies in past studies. We predicted that trophic cascade strength would increase nonlinearly across a gradient of subsidies. We set out to reveal these complex, nonlinear relationships through manipulating a quantitative gradient of detrital subsidies to lake benthic food webs along with the presence/absence of trout. Contrary to our prediction, we found that trophic cascades only occurred at low subsidy levels, disappearing as subsidies increased. This threshold in trophic cascade strength may be due to an increase in intermediate predators in the absence of top predators, as well as changes in the proportion of armored vs. un-armored primary consumers. Future studies on the effect of subsidies on trophic cascade strength need to incorporate naturally occurring gradients to reveal the complex direct and indirect interactions within food webs.

  20. Spontaneous mirror-symmetry breaking induces inverse energy cascade in 3D active fluids

    CERN Document Server

    Słomka, Jonasz

    2016-01-01

    Classical turbulence theory assumes that energy transport in a 3D turbulent flow proceeds through a Richardson cascade whereby larger vortices successively decay into smaller ones. By contrast, an additional inverse cascade characterized by vortex-mergers exists in 2D fluids and gases, with profound implications for meteorological flows and fluid mixing. The possibility of a helicity-driven inverse cascade in 3D fluids had been rejected in the 1970s based on equilibrium-thermodynamic arguments. Recently, however, it was proposed that certain symmetry breaking processes could potentially trigger a 3D inverse cascade, but no physical system exhibiting this phenomenon has been identified to date. Here, we present direct analytical and numerical evidence for the existence of a robust inverse energy cascade in an experimentally validated 3D active fluid model, describing microbial suspension flows that spontaneously break mirror-symmetry. We show analytically that self-organized scale selection, a generic feature ...