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Sample records for air holes running

  1. Running-mass inflation model and primordial black holes

    SciTech Connect

    Drees, Manuel; Erfani, Encieh E-mail: erfani@th.physik.uni-bonn.de

    2011-04-01

    We revisit the question whether the running-mass inflation model allows the formation of Primordial Black Holes (PBHs) that are sufficiently long-lived to serve as candidates for Dark Matter. We incorporate recent cosmological data, including the WMAP 7-year results. Moreover, we include ''the running of the running'' of the spectral index of the power spectrum, as well as the renormalization group ''running of the running'' of the inflaton mass term. Our analysis indicates that formation of sufficiently heavy, and hence long-lived, PBHs still remains possible in this scenario. As a by-product, we show that the additional term in the inflaton potential still does not allow significant negative running of the spectral index.

  2. Running boundary actions, Asymptotic Safety, and black hole thermodynamics

    NASA Astrophysics Data System (ADS)

    Becker, Daniel; Reuter, Martin

    2012-07-01

    theory of Black Hole Thermodynamics gets modified by quantum gravity effects and compare the new picture to older work on `RG-improved black holes' which incorporated the running of the bulk Newton constant only. We find, for instance, that the black hole's entropy vanishes and its specific heat capacity turns positive at Planckian scales.

  3. Binary Black Hole Mergers in the First Advanced LIGO Observing Run

    NASA Astrophysics Data System (ADS)

    Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Bejger, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gaebel, S.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Geng, P.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hamilton, H.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jian, L.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, N.; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nedkova, K.; Nelemans, G.; Nelson, T. J. N.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pan, Y.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Porter, E.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Setyawati, Y.; Shaddock, D. A.; Shaffer, T.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stevenson, S.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tonelli, M.; Tornasi, Z.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

    2016-10-01

    The first observational run of the Advanced LIGO detectors, from September 12, 2015 to January 19, 2016, saw the first detections of gravitational waves from binary black hole mergers. In this paper, we present full results from a search for binary black hole merger signals with total masses up to 100 M⊙ and detailed implications from our observations of these systems. Our search, based on general-relativistic models of gravitational-wave signals from binary black hole systems, unambiguously identified two signals, GW150914 and GW151226, with a significance of greater than 5 σ over the observing period. It also identified a third possible signal, LVT151012, with substantially lower significance and with an 87% probability of being of astrophysical origin. We provide detailed estimates of the parameters of the observed systems. Both GW150914 and GW151226 provide an unprecedented opportunity to study the two-body motion of a compact-object binary in the large velocity, highly nonlinear regime. We do not observe any deviations from general relativity, and we place improved empirical bounds on several high-order post-Newtonian coefficients. From our observations, we infer stellar-mass binary black hole merger rates lying in the range 9 - 240 Gpc-3 yr-1 . These observations are beginning to inform astrophysical predictions of binary black hole formation rates and indicate that future observing runs of the Advanced detector network will yield many more gravitational-wave detections.

  4. The PyCBC search for binary black hole coalescences in Advanced LIGO's first observing run

    NASA Astrophysics Data System (ADS)

    Willis, Joshua; LIGO Scientific Collaboration

    2017-01-01

    Advanced LIGO's first observing run saw the first detections of binary black hole coalescences. We describe the PyCBC matched filter analysis, and the results of that search for binary systems with total mass up to 100 solar masses. This is a matched filter search for general-relativistic signals from binary black hole systems. Two signals, GW150914 and GW151226, were identified with very high significance, and a third possible signal, LVT151012, was found, though at much lower significance. Supported by NSF award PHY-1506254.

  5. Running spectral index and formation of primordial black hole in single field inflation models

    SciTech Connect

    Drees, Manuel; Erfani, Encieh E-mail: erfani@th.physik.uni-bonn.de

    2012-01-01

    A broad range of single field models of inflation are analyzed in light of all relevant recent cosmological data, checking whether they can lead to the formation of long-lived Primordial Black Holes (PBHs). To that end we calculate the spectral index of the power spectrum of primordial perturbations as well as its first and second derivatives. PBH formation is possible only if the spectral index increases significantly at small scales, i.e. large wave number k. Since current data indicate that the first derivative α{sub S} of the spectral index n{sub S}(k{sub 0}) is negative at the pivot scale k{sub 0}, PBH formation is only possible in the presence of a sizable and positive second derivative (''running of the running'') β{sub S}. Among the three small-field and five large-field models we analyze, only one small-field model, the ''running mass'' model, allows PBH formation, for a narrow range of parameters. We also note that none of the models we analyze can accord for a large and negative value of α{sub S}, which is weakly preferred by current data.

  6. Discharge Coefficients for Combustor-liner Air-entry Holes II : Flush Rectangular Holes, Step Louvers, and Scoops

    NASA Technical Reports Server (NTRS)

    Dittrich, Ralph T

    1958-01-01

    Experimental discharge coefficients for various types of combustor-liner air-entry holes are presented as a function of a dimensionless flow parameter. In general, scoops and step louvers have higher discharge coefficients and wider flow ranges than flush holes. The effects of size or shape of a given type of hole are small. The proximity of multiple flush holes or the wall inclination of a convergent duct has a negligible effect on discharge coefficient.

  7. An experimental study of air entrainment and oxygen transfer at a water jet from a nozzle with air holes.

    PubMed

    Baylar, Ahmet; Emiroglu, M Emin

    2004-01-01

    An adequate supply of dissolved oxygen is important in natural rivers and in some water treatment processes. The dissolved oxygen concentration can be enhanced by entraining air bubbles in a receiving pool. When a water jet impinges a receiving pool at rest, air bubbles may be entrained and carried away below the pool free surface. This process is called plunging water jet entrainment and aeration. This paper describes an experimental study of the air entrainment rate and oxygen transfer efficiency of circular nozzles with and without air holes. In particular, the effect of varying the number, positions, and open/close status of the air holes is investigated. A negative pressure occurred depending on the air holes opened on the circular nozzles. This phenomenon affected the water jet expansion, water jet shape, air entrainment, and bubble penetration depth and, hence, the oxygen transfer efficiency. It was demonstrated that the air entrainment rate and the oxygen transfer efficiency of the circular nozzles with air holes were better than those of the circular nozzles without air holes. Therefore, adding air holes to a simple, circular nozzle could lead to a significantly increased air entrainment rate and oxygen transfer efficiency.

  8. Performance evaluation of household pyrolytic stove: Effect of outer air holes condition

    NASA Astrophysics Data System (ADS)

    Pradana, Yano Surya; Prasetya, Agus

    2017-03-01

    Renewable energy is the future energy for the substitution of the depleting fossil fuels. In Indonesia, biomass is one of promising renewable energy due to its abundant availability. Biomass can be converted into energy by thermochemical process, such as pyrolysis. In the implementation, pyrolysis can be applied in household cookstove, called pyrolytic stove. Pyrolytic stove will be proposed for people still cooking over an open biomass fire. This paper studied the pyrolysis of Indonesian teak using household pyrolytic stove. The effect of outer air holes on the performance of household pyrolytic stove was investigated. The increasing of cross section area of outer air holes effected on the higher of biomass combustion releasing energy for pyrolysis and cooking. Furthermore, the optimum outer air holes condition in the stove was fully open with the minimum of char product and the maximum of energy recovered for cooking.

  9. Report on the search for atmospheric holes using airs image data

    NASA Technical Reports Server (NTRS)

    Reinleitner, Lee A.

    1991-01-01

    Frank et al (1986) presented a very controversial hypothesis which states that the Earth is being bombarded by water-vapor clouds resulting from the disruption and vaporization of small comets. This hypothesis was based on single-pixel intensity decreases in the images of the earth's dayglow emissions at vacuum-ultraviolet (VUV) wavelengths using the DE-1 imager. These dark spots, or atmospheric holes, are hypothesized to be the result of VUV absorption by a water-vapor cloud between the imager and the dayglow-emitting region. Examined here is the VUV data set from the Auroral Ionospheric Remote Sensor (AIRS) instrument that was flown on the Polar BEAR satellite. AIRS was uniquely situated to test this hypothesis. Due to the altitude of the sensor, the holes should show multi-pixel intensity decreases in a scan line. A statistical estimate indicated that sufficient 130.4-nm data from AIRS existed to detect eight to nine such holes, but none was detected. The probability of this occurring is less than 1.0 x 10(exp -4). A statistical estimate indicated that sufficient 135.6-nm data from AIRS existed to detect approx. 2 holes, and two ambiguous cases are shown. In spite of the two ambiguous cases, the 135.6-nm data did not show clear support for the small-comet hypothesis. The 130.4-nm data clearly do not support the small-comet hypothesis.

  10. Heat Transfer Enhancement in Solar Air Heater Duct Fitted With Punched Hole Delta Winglets

    NASA Astrophysics Data System (ADS)

    Warrier, Hithesh. U.; Kotebavi, Vinod. M.

    2016-09-01

    This paper investigates the thermal performance of solar air heater fitted with delta winglet type vortex generators with holes punched on it by experimental and numerical analysis. Delta winglet type vortex generators having holes punched onto it are fitted in a duct of size 400*300*30mm.it is placed in duct in 3 different configurations, as an array having 5 pair in one row. Delta winglet pair has an attack angle of 30degree, with height of winglet equal to half of duct height. The study is done for Reynolds's no in the range of 9000 to 25000. Thermal performance is evaluated by analyzing both friction factor and Nussult's number using Webb's correlation for surface roughness. Numerical simulation is done using Ansys fluent. Experimental and numerical results are then compared. Results shows that heat transfer enhancement of about 20-150% can be achieved by using punched hole delta winglet.

  11. Upper Limits on the Rates of Binary Neutron Star and Neutron Star-Black Hole Mergers from Advanced LIGO’s First Observing Run

    NASA Astrophysics Data System (ADS)

    Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Bejger, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio., M., Jr.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Geng, P.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jian, L.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, N.; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nedkova, K.; Nelemans, G.; Nelson, T. J. N.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Perri, L. M.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Setyawati, Y.; Shaddock, D. A.; Shaffer, T.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tonelli, M.; Tornasi, Z.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Yvert, M.; Zadrożny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

    2016-12-01

    We report here the non-detection of gravitational waves from the merger of binary-neutron star systems and neutron star-black hole systems during the first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO). In particular, we searched for gravitational-wave signals from binary-neutron star systems with component masses \\in [1,3] {M}⊙ and component dimensionless spins <0.05. We also searched for neutron star-black hole systems with the same neutron star parameters, black hole mass \\in [2,99] {M}⊙ , and no restriction on the black hole spin magnitude. We assess the sensitivity of the two LIGO detectors to these systems and find that they could have detected the merger of binary-neutron star systems with component mass distributions of 1.35 ± 0.13 M ⊙ at a volume-weighted average distance of ˜70 Mpc, and for neutron star-black hole systems with neutron star masses of 1.4 M ⊙ and black hole masses of at least 5 M ⊙, a volume-weighted average distance of at least ˜110 Mpc. From this we constrain with 90% confidence the merger rate to be less than 12,600 Gpc-3 yr-1 for binary-neutron star systems and less than 3600 Gpc-3 yr-1 for neutron star-black hole systems. We discuss the astrophysical implications of these results, which we find to be in conflict with only the most optimistic predictions. However, we find that if no detection of neutron star-binary mergers is made in the next two Advanced LIGO and Advanced Virgo observing runs we would place significant constraints on the merger rates. Finally, assuming a rate of {10}-7+20 Gpc-3 yr-1, short gamma-ray bursts beamed toward the Earth, and assuming that all short gamma-ray bursts have binary-neutron star (neutron star-black hole) progenitors, we can use our 90% confidence rate upper limits to constrain the beaming angle of the gamma-ray burst to be greater than 2\\buildrel{\\circ}\\over{.} {3}-1.1+1.7 (4\\buildrel{\\circ}\\over{.} {3}-1.9+3.1).

  12. F-18 SRA closeup of nose cap showing new flush air data system sensor holes

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The small numbers on the nose of this F-18 aircraft at NASA's Dryden Flight Research Center, Edwards, California, show the locations of 11 tiny holes which are an integral part of a new air data system installed on the aircraft. The Real-Time Flush Air Data Sensing system measures the speed and direction of the airflow past the aircraft and its altitude, similar to standard air data systems. It incorporates flush-mounted pressure taps, miniature transducers and an advanced research computer to give pilots more accurate information than standard systems employing external probes can provide. Developed by Dryden researchers in cooperation with Honeywell's Research and Technology Center, Minneapolis, Minnesota, the system was flight tested on Dryden's Systems Research Aircraft (SRA) last year, and is now being used as a precise reference for other air data systems currently being evaluated on the modified F-18.

  13. Determination of variables for air distribution system with elastic valve for down-the-hole pneumatic hammer

    NASA Astrophysics Data System (ADS)

    Primychkin, AYu; Kondratenko, AS; Timonin, VV

    2017-02-01

    The air distribution system of down-the-hole pneumatic hammer 105 mm in diameter is updated to enhance drilling efficiency. The design model of the down-the-hole pneumatic hammer is constructed in ITI SimulationX environment. The basic variables of the air distribution system with an elastic valve are determined so that to ensure increased impact energy at the limited pre-impact velocity and the same machine size.

  14. Influence of a municipal solid waste incinerator on ambient air PCDD/F levels: a comparison of running and non-running periods.

    PubMed

    Zhang, Manwen; Zhang, Sukun; Zhang, Zhengquan; Xu, Zhengcheng; Feng, Guixian; Ren, Mingzhong

    2014-09-01

    The concentration of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the ambient air of a municipal solid waste incinerator (MSWI) during its running and non-running periods was monitored in this study to investigate the contribution of the MSWI to PCDD/F pollution in the vicinal environment. Results show that the PCDD/F levels for the normal MSWI running period and after shut-down ranged 0.156-1.44 pg I-TEQ/m(3) (0.514 pg I-TEQ/m(3)) and 0.158-0.648 pg I-TEQ/m(3) (0.345 pg I-TEQ/m(3)), respectively. Significant differences were found between the results of the two surveys in 2011 and 2012. High PCDD/F levels were observed in two of the seven study sites in 2011, and these levels directly declined in 2012. A dramatic increase in PCDD/F concentrations was observed in two sites in 2012. Comparison of congener and homologue fingerprint characteristics in the two surveys, together with principal component analysis, revealed that the PCDD/F levels in all of the samples collected in 2012 and in three of the samples collected in 2011 are mainly influenced by heavy traffic. MSWI is the primary PCDD/F emission sources of the PCDD/Fs detected in the remaining samples collected in 2011.

  15. EPA Regional Administrator to kick off Run for Clean Air as part of Philadelphia Earth Day festivities

    EPA Pesticide Factsheets

    PHILADELPHIA, Pa. (April 17, 2015) - EPA Mid-Atlantic Regional Administrator Shawn M. Garvin will get regional Earth Day festivities started Saturday morning as he opens ceremonies for the Run for Clean Air presented by Toyota Hybrids in front of th

  16. Polarization-independent waveguides in air holes photonic crystals and its slow light

    NASA Astrophysics Data System (ADS)

    Fan, Qingbin; Li, Chuanqi; Liu, Wei; Lu, Ye; Zhang, Dongchuang

    2016-12-01

    A line-defect waveguide in a triangular lattice photonic crystal (PC) made of air holes in dielectric is demonstrated to support transverse magnetic (TM) as well as transverse electric (TE) guided modes simultaneously. A group of suitable geometric parameters were found to make the guided bands overlapped by means of Genetic Algorithm. The optimized waveguide realizes a polarization-independent single-mode transmission and wide operating bandwidth which reaches 0.012 Δ ω a / (2 π c) . Moreover, the guided modes are shown to exhibit a wide-bandwidth slow light and an extremely low group velocity dispersion in most frequency range.

  17. Search for gravitational radiation from intermediate mass black hole binaries in data from the second LIGO-Virgo joint science run

    NASA Astrophysics Data System (ADS)

    Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Accadia, T.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Andersen, M.; Anderson, R.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauchrowitz, J.; Bauer, Th. S.; Bavigadda, V.; Behnke, B.; Bejger, M.; Beker, M. G.; Belczynski, C.; Bell, A. S.; Bell, C.; Bergmann, G.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bloemen, S.; Blom, M.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bosi, L.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Buchman, S.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burman, R.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Castiglia, A.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Celerier, C.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M.; Conte, A.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corpuz, A.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Canton, T. Dal; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; Debreczeni, G.; Degallaix, J.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Donath, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dossa, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Effler, A.; Eggenstein, H.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gair, J.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, C.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hooper, S.; Hopkins, P.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Huerta, E.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jaranowski, P.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karlen, J.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N. G.; Kim, N.; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Koehlenbeck, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kremin, A.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, A.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leonardi, M.; Leong, J. R.; Le Roux, A.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Litvine, V.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Luijten, E.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macarthur, J.; Macdonald, E. P.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; Mangini, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinelli, L.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Meinders, M.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyers, P.; Miao, H.; Michel, C.; Mikhailov, E. E.; Milano, L.; Milde, S.; Miller, J.; Minenkov, Y.; Mingarelli, C. M. F.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Moesta, P.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nagy, M. F.; Nanda Kumar, D.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nelemans, G.; Neri, I.; Neri, M.; Newton, G.; Nguyen, T.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Palashov, O.; Palomba, C.; Pan, H.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Poteomkin, A.; Powell, J.; Prasad, J.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Qin, J.; Quetschke, V.; Quintero, E.; Quiroga, G.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Reid, S.; Reitze, D. H.; Rhoades, E.; Ricci, F.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Scheuer, J.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Staley, A.; Stebbins, J.; Steinlechner, J.; Steinlechner, S.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Stops, D.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; ter Braack, A. P. M.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Verma, S. S.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyachanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Wang, M.; Wang, X.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Williams, K.; Williams, L.; Williams, R.; Williams, T.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yang, Z.; Yoshida, S.; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhao, C.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

    2014-06-01

    This paper reports on an unmodeled, all-sky search for gravitational waves from merging intermediate mass black hole binaries (IMBHB). The search was performed on data from the second joint science run of the LIGO and Virgo detectors (July 2009-October 2010) and was sensitive to IMBHBs with a range up to ˜200 Mpc, averaged over the possible sky positions and inclinations of the binaries with respect to the line of sight. No significant candidate was found. Upper limits on the coalescence-rate density of nonspinning IMBHBs with total masses between 100 and 450 M⊙ and mass ratios between 0.25 and 1 were placed by combining this analysis with an analogous search performed on data from the first LIGO-Virgo joint science run (November 2005-October 2007). The most stringent limit was set for systems consisting of two 88 M⊙ black holes and is equal to 0.12 Mpc-3 Myr-1 at the 90% confidence level. This paper also presents the first estimate, for the case of an unmodeled analysis, of the impact on the search range of IMBHB spin configurations: the visible volume for IMBHBs with nonspinning components is roughly doubled for a population of IMBHBs with spins aligned with the binary's orbital angular momentum and uniformly distributed in the dimensionless spin parameter up to 0.8, whereas an analogous population with antialigned spins decreases the visible volume by ˜20%.

  18. Subsurface sediment contamination during borehole drilling with an air-actuated down-hole hammer.

    PubMed

    Malard, Florian; Datry, Thibault; Gibert, Janine

    2005-10-01

    Drilling methods can severely alter physical, chemical, and biological properties of aquifers, thereby influencing the reliability of water samples collected from groundwater monitoring wells. Because of their fast drilling rate, air-actuated hammers are increasingly used for the installation of groundwater monitoring wells in unconsolidated sediments. However, oil entrained in the air stream to lubricate the hammer-actuating device can contaminate subsurface sediments. Concentrations of total hydrocarbons, heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd), and nutrients (particulate organic carbon, nitrogen, and phosphorus) were measured in continuous sediment cores recovered during the completion of a 26-m deep borehole drilled with a down-hole hammer in glaciofluvial deposits. Total hydrocarbons, Cu, Ni, Cr and particulate organic carbon (POC) were all measured at concentrations far exceeding background levels in most sediment cores. Hydrocarbon concentration averaged 124 +/- 118 mg kg(-1) dry sediment (n = 78 samples) with peaks at depths of 8, 14, and 20 m below the soil surface (maximum concentration: 606 mg kg(-1)). The concentrations of hydrocarbons, Cu, Ni, Cr, and POC were positively correlated and exhibited a highly irregular vertical pattern, that probably reflected variations in air loss within glaciofluvial deposits during drilling. Because the penetration of contaminated air into the formation is unpreventable, the representativeness of groundwater samples collected may be questioned. It is concluded that air percussion drilling has strong limitations for well installation in groundwater quality monitoring surveys.

  19. F-18 SRA closeup of nose cap showing new flush air data system sensor holes

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Small numbers on the nose cap of this F-18 Systems Research Aircraft at NASA's Dryden Flight Research Center, Edwards, California, show the locations of 11 tiny holes, which are an integral part of a new air data system installed on the aircraft. The Real-Time Flush Air Data Sensing system measures the speed and direction of the airflow past the aircraft and its altitude, similar to standard air data systems. It differs from those systems by incorporating flush-mounted pressure taps, miniature transducers and an advanced research computer to give the pilot more accurate information than systems employing external probes provide. Stephen A. Whitmore of Dryden's Aerodynamics Branch won NASA's Space Act Award for his development of the Real-Time Flush Air Data Sensing system. The award honors projects which are scientifically or technologically significant to the aeronautics and space community. The system was flight tested on the modified F-18 last year, and is now being used as a precise reference system for other air data systems currently being evaluated on the aircraft.

  20. Highly air- and moisture-stable hole-doped carbon nanotube films achieved using boron-based oxidant

    NASA Astrophysics Data System (ADS)

    Funahashi, Kazuma; Tanaka, Naoki; Shoji, Yoshiaki; Imazu, Naoki; Nakayama, Ko; Kanahashi, Kaito; Shirae, Hiroyuki; Noda, Suguru; Ohta, Hiromichi; Fukushima, Takanori; Takenobu, Taishi

    2017-03-01

    Hole doping into carbon nanotubes can be achieved. However, the doped nanotubes usually suffer from the lack of air and moisture stability, thus, they eventually lose their improved electrical properties. Here, we report that a salt of the two-coordinate boron cation Mes2B+ (Mes: 2,4,6-trimethylphenyl group) can serve as an efficient hole-doping reagent to produce nanotubes with markedly high stability in the presence of air and moisture. Upon doping, the resistances of the nanotubes decreased, and these states were maintained for one month in air. The hole-doped nanotube films showed a minimal increase in resistance even upon humidification with a relative humidity of 90%.

  1. Photonic crystal fiber interferometer composed of a long period fiber grating and one point collapsing of air holes.

    PubMed

    Choi, Hae Young; Park, Kwan Seob; Lee, Byeong Ha

    2008-04-15

    We present an all-fiber interferometer fabricated with a single piece of an endless single-mode photonic crystal fiber (PCF) by an electric arc discharge. By forming a long period grating (LPG) at a point and collapsing the air holes at another point along the PCF, the simple but effective interferometer could be implemented. The LPG made a strong wavelength selective mode coupling between the core and cladding modes in the interesting wavelength range, while the air-hole collapse induced wavelength independent mode couplings. By cascading them, we could implement the all-fiber interferometer. As a potential application of the proposed all PCF interferometer, strain sensing is experimentally demonstrated.

  2. Nonreciprocal optical transmission through a single conical air hole in an Ag film.

    PubMed

    Peng, Nan; Li, Xiaokang; She, Weilong

    2014-07-14

    In this paper, we propose a simple metal micro-nano structure having the character of nonreciprocal optical zero-order transmission. The structure is a single conical air hole (CAH) in an Ag film whose optical absorption with geometric asymmetry breaks the time reversal symmetry of the electromagnetic field. By comparing the transmissions of Ag CAH with those of ideal conductor (IC) CAH, three effects of Ag CAH, including diffraction, Fabry-Perot-like (FPL) resonance and localized surface plasmon (LSP) resonance, are analyzed and discussed. Under optimized conditions, we find that the ratio of forward transmission to backward one can be larger than 9 at a proper wavelength in visible range. This kind of Ag CAH is expected to have the potential served as all-optical diode.

  3. Effect of eggshell temperature and a hole in the air cell on the perinatal development and physiology of layer hatchlings.

    PubMed

    Molenaar, R; de Vries, S; van den Anker, I; Meijerhof, R; Kemp, B; van den Brand, H

    2010-08-01

    To investigate the effect of incubation conditions on layer hatchlings, an experiment was performed in which layer eggs were incubated at a normal (37.8 degrees C) or high (38.9 degrees C) eggshell temperature (EST) and a hole was punctured in the air cell of half of the eggs in both EST treatments from d 14 of incubation onward. Chick development, plasma metabolites, and hepatic glycogen were measured at 12 h after emergence from the eggshell. Embryo mortality was not affected by the EST or hole treatment. At the high EST, yolk-free body mass was 0.7 g lower and residual yolk weight was 0.7 g higher than at the normal EST. This may be related to the shorter incubation duration at the high EST. Relative heart, lung, stomach, liver, spleen, and intestinal weights were lower in the high EST than in the normal EST group. Yolk-free body mass did not differ between eggs with or without a hole, but residual yolk weight was slightly lower in eggs with a hole (0.3 g). Relative lung weights were higher in eggs with than without a hole, whereas no effect on other organs was found. Plasma glucose, lactate, and uric acid concentrations did not differ between the EST or hole treatments. Hepatic glycogen was lower in the high EST (7.3 mg) than in the normal EST group (11.2 mg) at 12 h after emergence from the eggshell, and this effect may be related to the shorter hatching process at the high EST. Hepatic glycogen levels were lower in eggs with a hole (8.6 mg) compared with eggs without a hole (10.0 mg), and this may be related to the longer period between external pipping and hatching in eggs with a hole. In conclusion, the EST and hole treatment did not interact, and neither treatments affected embryonic survival. High EST negatively affected hatchling development and seemed to change the carbohydrate metabolism in layer embryos. The effect of a hole in the air cell was limited.

  4. A testing machine for dental air-turbine handpiece characteristics: free-running speed, stall torque, bearing resistance.

    PubMed

    Darvell, Brain W; Dyson, J E

    2005-01-01

    The measurement of performance characteristics of dental air turbine handpieces is of interest with respect to product comparisons, standards specifications and monitoring of bearing longevity in clinical service. Previously, however, bulky and expensive laboratory equipment was required. A portable test machine is described for determining three key characteristics of dental air-turbine handpieces: free-running speed, stall torque and bearing resistance. It relies on a special circuit design for performing a hardware integration of a force signal with respect to rotational position, independent of the rate at which the turbine is allowed to turn during both stall torque and bearing resistance measurements. Free-running speed without the introduction of any imbalance can be readily monitored. From the essential linear relationship between torque and speed, dynamic torque and, hence, power, can then be calculated. In order for these measurements to be performed routinely with the necessary precision of location on the test stage, a detailed procedure for ensuring proper gripping of the handpiece is described. The machine may be used to verify performance claims, standard compliance checks should this be established as appropriate, monitor deterioration with time and usage in the clinical environment and for laboratory investigation of design development.

  5. Coherent-interference-induced transparency based on long-range air-hole assisted subwavelength waveguides

    NASA Astrophysics Data System (ADS)

    Zhou, Wen; Huang, Xu Guang; Tan, Qilong; Liang, Yao; Lao, Jieer; Chen, Zanhui

    2014-11-01

    A novel coherent-interference-induced transparency (CIT) system consisting of two coupled and detuned double-sided-branch (DSB) filters in a long-range air-hole assisted subwavelength (LR-AHAS) waveguide has been proposed and numerically demonstrated. The resonant wavelength, maximum transmittance, full width at half maximum (FWHM) and phase dispersion of the transparent window can be effectively tuned by adjusting the detuning and phase-shift between two coupled DSB filters, and FWHM can be suppressed to as small as 1.6 nm, which is much narrower than that of an individual resonator in an LR-AHAS waveguide. The FWHMs of 3.2 nm and 5.2 nm with the corresponding group refractive indices ng of 73 and 45 have been respectively demonstrated. In addition, multiple transparent peaks with an average bandwidth of 3.6 nm and high transmittance of 0.74 can be achieved by cascading more detuned DSB filters into the system. It provides a new approach to develop tunable high-channel-count bandpass filters and optical buffers based on the LR-AHAS waveguide platform for large-scale photonic integrations.

  6. A simple structure of all circular-air-holes photonic crystal fiber for achieving high birefringence and low confinement loss

    SciTech Connect

    Chou Chau, Yuan-Fong Lim, Chee Ming; Yoong, Voo Nyuk; Syafi'ie Idris, Muhammad Nur

    2015-12-28

    We propose a simple structure of photonic crystal fibers (PCFs) with high birefringence and low confinement loss based on one rectangular centric ring of smaller circular air holes (CAHs) in the fiber core, and three rings of larger CAHs in the fiber cladding. This simple geometry (using all CAHs with two different air hole sizes) is capable of achieving a flexible control of the birefringence, B = 5.501 × 10{sup −3}, and ultra-low confinement loss, 7.30 × 10{sup −5 }dB/km, at an excitation wavelength of λ = 1550 nm. The birefringence value is ∼5.0 times greater than that obtained for conventional CAH PCF. This simple structure has the added advantage from the view point of easy fabrication, robustness, and cost. A full-vector finite element method combined with anisotropic perfectly matched layers was used to analyze the various fiber structures. We have analyzed four cases of CAH PCFs, focusing on the core asymmetry design as opposed to the conventional approach of CAHs or elliptical air holes on the cladding and core. The robustness against manufacturing inaccuracies of the proposed structure has also been further investigated in this work.

  7. Light propagation characteristics in photonic crystal fibers with α-power profiles of air hole diameter distributions and their application to fiber collimator

    NASA Astrophysics Data System (ADS)

    Yokota, Hirohisa; Higuchi, Keiichi; Imai, Yoh

    2016-08-01

    Light propagation characteristics in photonic crystal fibers (PCFs) with α-power profiles of air hole diameter distributions were theoretically investigated. It was clarified that the intensity peak of the beam propagating in the PCF with Gaussian beam excitation varied periodically with little power attenuation. It was found that the envelope of the periodic intensity variation depended on α. We theoretically demonstrated that the PCF with the α-power profile of the air hole diameter distribution could be applied to a collimator for a conventional PCF with uniform air holes in Gaussian beam excitation to reduce coupling loss, where a PCF of appropriate length with the α-power air hole diameter distribution was spliced to a conventional PCF. It was also found that the coupling efficiency was higher for a larger α.

  8. Synthesis, characterization, and transistor response of semiconducting silole polymers with substantial hole mobility and air stability. Experiment and theory.

    PubMed

    Lu, Gang; Usta, Hakan; Risko, Chad; Wang, Lian; Facchetti, Antonio; Ratner, Mark A; Marks, Tobin J

    2008-06-18

    Realizing p-channel semiconducting polymers with good hole mobility, solution processibility, and air stability is an important step forward in the chemical manipulation of charge transport in polymeric solids and in the development of low-cost printed electronics. We report here the synthesis and full characterization of the dithienosilole- and dibenzosilole-based homopolymers, poly(4,4-di-n-hexyldithienosilole) (TS6) and poly(9,9-di-n-octyldibenzosilole) (BS8), and their mono- and bithiophene copolymers, poly(4,4-di-n-hexyldithienosilole-alt-(bi)thiophene) (TS6T1, TS6T2) and poly(9,9-di-n-octyldibenzosilole-alt-(bi)thiophene) (BS8T1, BS8T2), and examine in detail the consequences of introducing dithienosilole and dibenzosilole cores into a thiophene polymer backbone. We demonstrate air-stable thin-film transistors (TFTs) fabricated under ambient conditions having hole mobilities as large as 0.08 cm(2)/V x s, low turn-on voltages, and current on/off ratios > 10(6). Additionally, unencapsulated TFTs fabricated under ambient conditions are air-stable, an important advance over regioregular poly(3-hexylthiophene) (P3HT)-based devices. Density functional theory calculations provide detailed insight into the polymer physicochemical and charge transport characteristics. A direct correlation between the hole injection barrier and both TFT turn-on voltage and TFT polymer hole mobility is identified and discussed, in combination with thin-film morphological characteristics, to explain the observed OTFT performance trends.

  9. Performance of a combined three-hole conductivity probe for void fraction and velocity measurement in air-water flows

    NASA Astrophysics Data System (ADS)

    Borges, João Eduardo; Pereira, Nuno H. C.; Matos, Jorge; Frizell, Kathleen H.

    2010-01-01

    The development of a three-hole pressure probe with back-flushing combined with a conductivity probe, used for measuring simultaneously the magnitude and direction of the velocity vector in complex air-water flows, is described in this paper. The air-water flows envisaged in the current work are typically those occurring around the rotors of impulse hydraulic turbines (like the Pelton and Cross-Flow turbines), where the flow direction is not known prior to the data acquisition. The calibration of both the conductivity and three-hole pressure components of the combined probe in a rig built for the purpose, where the probe was placed in a position similar to that adopted for the flow measurements, will be reported. After concluding the calibration procedure, the probe was utilized in the outside region of a Cross-Flow turbine rotor. The experimental results obtained in the present study illustrate the satisfactory performance of the combined probe, and are encouraging toward its use for characterizing the velocity field of other complex air-water flows.

  10. Coexistence of total internal reflexion and bandgap modes in solid core photonic bandgap fibre with intersticial air holes.

    PubMed

    Perrin, Mathias; Quiquempois, Yves; Bouwmans, Géraud; Douay, Marc

    2007-10-17

    In this article, we deal with new properties of a Solid Core Photonic Bandgap (SC-PBGF) fiber with intersticial air holes (IAHs) in its transverse structure. It has been shown recently, that IAH enlarges its bandgaps (BG), compared to what is observed in a regular SC-PBGF. We shall describe the mechanisms that account for this BG opening, which has not been explained in detail yet. It is then interesting to discuss the role of air holes in the modification of the Bloch modes, at the boundaries of the BG. In particular, we will use a simple method to compute the exact BG diagrams in a faster way, than what is done usually, drawing some parallels between structured fibers and physics of photonic crystals. The very peculiar influence of IAHs on the upper/lower boundaries of the bandgaps will be explained thanks to the difference between mode profiles excited on both boundaries, and linked to the symmetry / asymmetry of the modes. We will observe a modification of the highest index band (n(FSM)) due to IAHs, that will enable us to propose a fiber design to guide by Total Internal Reflection (TIR) effect, as well as by a more common BG confinement. The transmission zone is deeply enlarged, compared to regular photonic bandgap fibers, and consists in the juxtaposition of (almost non overlapping) BG guiding zones and TIR zone.

  11. Running Away

    MedlinePlus

    ... Emergency Room? What Happens in the Operating Room? Running Away KidsHealth > For Kids > Running Away A A ... life on the streets. continue The Reality of Running Away When you think about running away, you ...

  12. Supplemental materials for the ICDP-USGS Eyreville A, B, and C core holes, Chesapeake Bay impact structure: Core-box photographs, coring-run tables, and depth-conversion files

    USGS Publications Warehouse

    Durand, C.T.; Edwards, L.E.; Malinconico, M.L.; Powars, D.S.

    2009-01-01

    During 2005-2006, the International Continental Scientific Drilling Program and the U.S. Geological Survey drilled three continuous core holes into the Chesapeake Bay impact structure to a total depth of 1766.3 m. A collection of supplemental materials that presents a record of the core recovery and measurement data for the Eyreville cores is available on CD-ROM at the end of this volume and in the GSA Data Repository. The supplemental materials on the CD-ROM include digital photographs of each core box from the three core holes, tables of the three coring-run logs, as recorded on site, and a set of depth-conversion programs. In this chapter, the contents, purposes, and basic applications of the supplemental materials are briefly described. With this information, users can quickly decide if the materials will apply to their specific research needs. ?? 2009 The Geological Society of America.

  13. Measurement of Air Flow Characteristics Using Seven-Hole Cone Probes

    NASA Technical Reports Server (NTRS)

    Takahashi, Timothy T.

    1997-01-01

    The motivation for this work has been the development of a wake survey system. A seven-hole probe can measure the distribution of static pressure, total pressure, and flow angularity in a wind tunnel environment. The author describes the development of a simple, very efficient algorithm to compute flow properties from probe tip pressures. Its accuracy and applicability to unsteady, turbulent flow are discussed.

  14. Atomic Layer Deposition of TiO2 for a High-Efficiency Hole-Blocking Layer in Hole-Conductor-Free Perovskite Solar Cells Processed in Ambient Air.

    PubMed

    Hu, Hang; Dong, Binghai; Hu, Huating; Chen, Fengxiang; Kong, Mengqin; Zhang, Qiuping; Luo, Tianyue; Zhao, Li; Guo, Zhiguang; Li, Jing; Xu, Zuxun; Wang, Shimin; Eder, Dominik; Wan, Li

    2016-07-20

    In this study we design and construct high-efficiency, low-cost, highly stable, hole-conductor-free, solid-state perovskite solar cells, with TiO2 as the electron transport layer (ETL) and carbon as the hole collection layer, in ambient air. First, uniform, pinhole-free TiO2 films of various thicknesses were deposited on fluorine-doped tin oxide (FTO) electrodes by atomic layer deposition (ALD) technology. Based on these TiO2 films, a series of hole-conductor-free perovskite solar cells (PSCs) with carbon as the counter electrode were fabricated in ambient air, and the effect of thickness of TiO2 compact film on the device performance was investigated in detail. It was found that the performance of PSCs depends on the thickness of the compact layer due to the difference in surface roughness, transmittance, charge transport resistance, electron-hole recombination rate, and the charge lifetime. The best-performance devices based on optimized TiO2 compact film (by 2000 cycles ALD) can achieve power conversion efficiencies (PCEs) of as high as 7.82%. Furthermore, they can maintain over 96% of their initial PCE after 651 h (about 1 month) storage in ambient air, thus exhibiting excellent long-term stability.

  15. Wideband and low dispersion slow-light waveguide based on a photonic crystal with crescent-shaped air holes.

    PubMed

    Meng, Bo; Wang, Ling-ling; Huang, Wei-qing; Li, Xiao-fei; Zhai, Xiang; Zhang, Hong

    2012-08-10

    We present a procedure to generate slow light with a large group index, wideband, and low dispersion in our suggested photonic crystal waveguide. By modulation of the declinations in the first two rows of air holes, the group index, the bandwidth, and the dispersion can be tuned effectively. Utilizing the two-dimensional plane wave expansion method (PWE) and the finite-difference time-domain method (FDTD), we demonstrate slow light with the group indices of 23, 35, and 45, respectively, while restricting the group-index variation within a 10% range. We accordingly attain an available bandwidth of 40.7, 23.7, and 5.1 nm, respectively. Meanwhile, the normalized delay-bandwidth product stays around 0.45, with minimal dispersion less than 0.2 (ps2/m) for all the cases.

  16. Equivalent ambipolar carrier injection of electrons and holes with Au electrodes in air-stable field effect transistors

    SciTech Connect

    Kanagasekaran, Thangavel E-mail: Shimotani@m.tohoku.ac.jp Ikeda, Susumu; Kumashiro, Ryotaro; Shimotani, Hidekazu E-mail: Shimotani@m.tohoku.ac.jp Shang, Hui; Tanigaki, Katsumi E-mail: Shimotani@m.tohoku.ac.jp

    2015-07-27

    Carrier injection from Au electrodes to organic thin-film active layers can be greatly improved for both electrons and holes by nano-structural surface control of organic semiconducting thin films using long-chain aliphatic molecules on a SiO{sub 2} gate insulator. In this paper, we demonstrate a stark contrast for a 2,5-bis(4-biphenylyl)bithiophene (BP2T) active semiconducting layer grown on a modified SiO{sub 2} dielectric gate insulator between two different modifications of tetratetracontane and poly(methyl methacrylate) thin films. Important evidence that the field effect transistor (FET) characteristics are independent of electrode metals with different work functions is given by the observation of a conversion of the metal-semiconductor contact from the Schottky limit to the Bardeen limit. An air-stable light emitting FET with an Au electrode is demonstrated.

  17. Enhanced transverse load sensitivity by using a highly birefringent photonic crystal fiber with larger air holes on one axis.

    PubMed

    Kim, Hyun-Min; Kim, Tae-Hun; Kim, Bongkyun; Chung, Youngjoo

    2010-07-10

    We report on a transverse load sensor with enhanced sensitivity through the use of a birefringent interferometer based on a highly birefringent photonic crystal fiber (HB-PCF). The transverse load sensitivity can be enhanced by using a fabricated HB-PCF having larger air holes on its fast axis. The transverse load sensitivity was measured to be high: approximately 2.17 nm/(N/cm). The temperature-induced undesirable effects can be ignored because transmission outputs of our HB-PCF were stable with the change of the temperature. The sensing probe can be compact because of its high birefringence with the order of 10(-3) and no bending loss.

  18. A novel four-air-hole multicore dual-mode large-mode-area fiber: Proposal and design

    NASA Astrophysics Data System (ADS)

    Zheng, Siwen; Ren, Guobin; Lin, Zhen; Jian, Wei; Jian, Shuisheng

    2013-10-01

    A novel four-air-hole multicore dual-mode large-mode-area optical fiber is proposed in this paper. The characteristics of the mode field distribution, the operating wavelength, the effective area Aeff and the bending loss of fundamental modes are calculated. The influence of the structural parameters on the operating wavelength, the effective index neff and the effective area of fundamental modes is also discussed. This fiber makes the second-order modes TE01 and TM01 cut-off while increasing the effective area of fundamental modes, which can realize strictly dual-mode operation. The maximum effective area of fundamental modes is approximately 4025 μm2. The single-mode operation can be also realized by adjusting the structural parameters. This fiber is simple to fabricate, and flexible to design. It can be used for large-mode-area high-power optical fiber laser and amplifier.

  19. 1×5 optical splitter for TE modes in air-hole photonic crystal based on self-collimation effect

    NASA Astrophysics Data System (ADS)

    Chen, Weijuan; Lin, Yuanyuan; Lin, Guimin; Fu, Ping; Liu, Chengkun; Qiu, Yishen; Li, Hui; Chen, Xiyao

    2016-11-01

    We propose a novel 1×5 optical splitter (OS) for TE modes based on self-collimation effect in an air-hole silicon photonic crystal. The OS consists of two cascaded resonators which is formed with eight beam splitters. The theoretical transmission spectra of the OS is derived with multiple-beam interference theory. From our analysis of transmission spectra, it is found that the transmission spectra at five drop ports will reach the maximum values while the transmission spectra at two through ports reach zero for resonant frequencies. By scanning the radius of a beam splitter, the relationship between the radius and the reflectivity is obtained. Therefore, by changing the radii of the air-hole in eight beam splitters, we can manipulate the output light-intensity ratio at five drop ports to meet requirement. Theoretically, when reflectivity of beam splitters R1=2/11, R2=8/11, R3=5/8, R4=2/5, R5=7/12, R6 =6/7, R7=1/2, R8 =2/3, the light intensity ratio at five drop ports is 1:1:1:1:1. When R1=2/7, R2=6/7, R3=1/2, R4=2/3, R5=1/7, R6=6/7, R7=2/3, R8 =1/4, the light intensity ratio at five drop ports is 2:2:1:2:3. By means of finite-difference time-domain (FDTD) simulations, the numerical transmission spectra of OS can be figured out. The simulation results are consistent with the theoretical results. Considering micro processing technology of silicon materials is already available, this OS can be used in the photonic integrated circuits because of its small size, whole-silicon material and low insertion loss.

  20. Running Away

    MedlinePlus

    ... problems of life on the streets. continue The Reality of Running Away When you think about running ... more fights. Sounds great and exciting, right? In reality, running away is anything but fun. Kids and ...

  1. Stabilized soliton self-frequency shift and 0.1- PHz sideband generation in a photonic-crystal fiber with an air-hole-modified core.

    PubMed

    Liu, Bo-Wen; Hu, Ming-Lie; Fang, Xiao-Hui; Li, Yan-Feng; Chai, Lu; Wang, Ching-Yue; Tong, Weijun; Luo, Jie; Voronin, Aleksandr A; Zheltikov, Aleksei M

    2008-09-15

    Fiber dispersion and nonlinearity management strategy based on a modification of a photonic-crystal fiber (PCF) core with an air hole is shown to facilitate optimization of PCF components for a stable soliton frequency shift and subpetahertz sideband generation through four-wave mixing. Spectral recoil of an optical soliton by a red-shifted dispersive wave, generated through a soliton instability induced by high-order fiber dispersion, is shown to stabilize the soliton self-frequency shift in a highly nonlinear PCF with an air-hole-modified core relative to pump power variations. A fiber with a 2.3-microm-diameter core modified with a 0.9-microm-diameter air hole is used to demonstrate a robust soliton self-frequency shift of unamplified 50-fs Ti: sapphire laser pulses to a central wavelength of about 960 nm, which remains insensitive to variations in the pump pulse energy within the range from 60 to at least 100 pJ. In this regime of frequency shifting, intense high- and low-frequency branches of dispersive wave radiation are simultaneously observed in the spectrum of PCF output. An air-hole-modified-core PCF with appropriate dispersion and nonlinearity parameters is shown to provide efficient four-wave mixing, giving rise to Stokes and anti-Stokes sidebands whose frequency shift relative to the pump wavelength falls within the subpetahertz range, thus offering an attractive source for nonlinear Raman microspectroscopy.

  2. An optodynamic determination of the depth of laser-drilled holes by the simultaneous detection of ultrasonic waves in the air and in the workpiece.

    PubMed

    Strgar, Simon; Mozina, Janez

    2002-05-01

    A sufficiently powerful pulsed-laser beam can be used to 'drill' a hole in a stainless-steel workpiece. Here we present a real-time method for determining the depth of such a hole produced by multi-pulse laser drilling with a Q-switched Nd:YAG laser. The developed experimental setup allowed us to detect the laser-induced ultrasonic waves in the surrounding air and in the workpiece simultaneously by means of a probe-beam-deflection method and a piezoelectric transducer. Our optodynamic approach involved an analysis of these ultrasonic waves in order to determine the depth of the hole at any stage of the process. The increasing depth of the hole and its maximum extent were estimated from changes in the propagation time of the ultrasonic waves traveling from the bottom of the hole to both detectors. Measurements of the maximum hole depth were compared with the predictions of a theoretical model and they were found to be in a good agreement.

  3. Air-permeable hole-pattern and nose-droop control improve aerodynamic performance of primary feathers.

    PubMed

    Eder, Heinrich; Fiedler, Wolfgang; Pascoe, Xaver

    2011-01-01

    Primary feathers of soaring land birds have evolved into highly specialized flight feathers characterized by morphological improvements affecting aerodynamic performance. The foremost feathers in the cascade have to bear high lift-loading with a strong bending during soaring flight. A challenge to the study of feather aerodynamics is to understand how the observed low drag and high lift values in the Reynolds (Re) regime from 1.0 to 2.0E4 can be achieved. Computed micro-tomography images show that the feather responds to high lift-loading with an increasing nose-droop and profile-camber. Wind-tunnel tests conducted with the foremost primary feather of a White Stork (Ciconia ciconia) at Re = 1.8E4 indicated a surprisingly high maximum lift coefficient of 1.5 and a glide ratio of nearly 10. We present evidence that this is due to morphologic characteristics formed by the cristae dorsales as well as air-permeable arrays along the rhachis. Measurements of lift and drag forces with open and closed pores confirmed the efficiency of this mechanism. Porous structures facilitate a blow out, comparable to technical blow-hole turbulators for sailplanes and low speed turbine-blades. From our findings, we conclude that the mechanism has evolved in order to affect the boundary layer and to reduce aerodynamic drag of the feather.

  4. Design, development and evaluation of a precision air bearing rotary table with large diameter through-hole

    SciTech Connect

    Accatino, M.R.

    1991-11-01

    A large diameter precision air bearing rotary table with a 16.0 inch diameter through-hole was designed, fabricated and tested in the course of this research. The rotary table will be used in conjunction with a specialized, computer controlled precision inspection machine being designed for the Department of Energy`s (DOE) Nuclear Weapons Complex (NWC). The design process included a complete engineering analysis to predict the final performance of the rotary table, and to ensure that the rotary table meets the required accuracy of 4.0 microinches of total radial (3.5 microinches average radial) and 4.0 microinches total axial (3.5 microinches average axial) errors. The engineering analysis included structural deformation, thermal sensitivity and dynamic analyses using finite element methods in some cases, as well as other analytic solutions. Comparisons are made between predicted and tested values, which are listed in the rotary table error budget. The rotary table performed as predicted with measured axial and radial stiffnesses of 1.1E06 lbf/inch and 2.9E06 lbf/inch, respectively, as well as average radial, axial and tilt errors of 2.5 microinches, 1.5 microinches, and less than 0.05 arcseconds, respectively.

  5. The cylindrical air holes of the negative-refraction photonic crystal double flat lens group for lightwave target detection and imaging

    NASA Astrophysics Data System (ADS)

    Lu, Jian; Shen, Yang; Shen, TingGen; Lian, YingFei; Wang, FeiFei; Xu, Yang

    2013-06-01

    The influence of the cylindrical air holes of the negative-refraction photonic crystal (NR-PC) double flat lens group on the performance of lightwave target detection and imaging is studied in this paper using the finite-difference time-domain (FDTD) method. Numerical simulations indicate that significant enhancement of the scattering signal can be obtained by using a NR-PC flat lens; consequently, great improvement of the refocusing gain as well as the imaging resolution will be provided. We further research the effects of different positions for target detection by using a NR-PC double flat lens group with cylindrical air holes. Then we use defective air holes instead of perfect ones. By using a dynamic scanning scheme, we find that the distance between two flats could be changed flexibly. And it could improve the lateral resolution of target scanning and enlarge the distance between the target and flat greatly. In conclusion, our investigation optimized the performance of the detection and imaging system, and provided the basis for converting an idealized left-handed material lens into a physically realizable NR-PC double flat lens group.

  6. Running Shoes.

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    This guide explains the purpose of running shoes and provides tips for purchasing them. A brief explanation of the difference between training shoes and racing shoes is followed by a list of characteristics of running shoes that should be considered when buying them. These characteristics include heel fit, heel elevation and width, the inner and…

  7. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  8. Film effectiveness over a flat surface with air and CO{sub 2} injection through compound angle holes using a transient liquid crystal image method

    SciTech Connect

    Ekkad, S.V.; Zapata, D.; Han, J.C.

    1997-07-01

    This paper presents detailed film effectiveness distributions over a flat surface with one row of injection holes inclined streamwise at 35 deg for three blowing ratios (M = 0.5, 1.0, 2.0). Three compound angles of 0, 45, and 90 deg with air (D.R. = 0.98) and CO{sub 2} (D.R. = 1.46) as coolants are tested at an elevated free-stream turbulence condition (Tu {approx} 8.5%). A transient liquid crystal technique is used to measure local heat transfer coefficients and film effectiveness. Detailed film effectiveness results are presented near and around film injection holes. Compound angle injection provides higher film effectiveness than simple angle injection for both coolants. Higher density injectant produces higher effectiveness for simple injection. However, lower density coolant produces higher effectiveness obtained using the transient liquid crystal technique, particularly in the near-hole region, provided a better understanding of the film cooling process in gas turbine components.

  9. Thin air-plasma-treated alkali fluoride layers for improved hole extraction in copper phthalocyanine/C70-based solar cells

    SciTech Connect

    Xiao, Teng; Cui, Weipan; Cai, Min; Liu, Rui; Anderegg, James W.; Shinar, Joseph; Shinar, Ruth

    2012-03-12

    Alkali fluorides, mostly LiF and CsF, are well-known to improve electron injection/extraction in organic light-emitting diodes (OLEDs) and organic solar cells (OSCs). They are also utilized, though to a lesser extent, for hole injection in OLEDs. Here we demonstrate a new role for such fluorides in enhancing OSCs’ hole extraction.We show that an ultrathin air-plasmatreated alkali fluoride layer between the indium tin oxide (ITO) anode and the active layer in copper phthalocyanine ðCuPcÞ∕C70-based OSCs increases the short circuit current by up to ∼17% for cells with LiF and ∼7% for cells with NaF or CsF. The effects of the fluoride layer thickness and treatment duration were evaluated, as were OSCs with oxidized and plasma-treated Li and UV-ozone treated LiF. Measurements included current voltage, absorption, external quantum efficiency (EQE), atomic force microscopy, and x-ray photoelectron spectroscopy, which showed the presence of alkali atoms F and O at the treated ITO/fluoride surface. The EQE of optimized devices with LiF increased at wavelengths >560 nm, exceeding the absorption increase. Overall, the results indicate that the improved performance is due largely to enhanced hole extraction, possibly related to improved energy-level alignment at the fluorinated ITO/CuPc interface, reduced OSC series resistance, and in the case of LiF, improved absorption.

  10. Data from stratigraphic test holes drilled at the U.S. Marine Corps Air Station, Cherry Point, North Carolina, 1994-2001, and periodic water levels, 2000-2003

    USGS Publications Warehouse

    Wrege, Beth M.; Jen, Philip S.

    2004-01-01

    Nine stratigraphic test holes, from 158 to 305 feet deep, were drilled at the U.S. Marine Corps Air Station at Cherry Point, North Carolina, between 1994 and 2001 by the U.S. Geological Survey. These test holes and subsequent wells provide information about the lithology, stratigraphy, and geology at the Marine Corps Air Station. In addition, ground-water-level data were collected at the Air Station through 2003. The U.S. Geological Survey also conducted high-resolution marine and land seismic surveys during this investigation. The ground-water-level data and locations of the seismic survey lines are included in this report. The stratigraphic data combined with the seismic data provide a basis for the delineation of paleochannels beneath the Air Station as well as information for the management of water resources at the Air Station.

  11. Summary of air permeability data from single-hole injection tests in unsaturated fractured tuffs at the Apache Leap Research Site: Results of steady-state test interpretation

    SciTech Connect

    Guzman, A.G.; Geddis, A.M.; Henrich, M.J.; Lohrstorfer, C.F.; Neuman, S.P.

    1996-03-01

    This document summarizes air permeability estimates obtained from single hole pneumatic injection tests in unsaturated fractured tuffs at the Covered Borehole Site (CBS) within the larger apache Leap Research Site (ALRS). Only permeability estimates obtained from a steady state interpretation of relatively stable pressure and flow rate data are included. Tests were conducted in five boreholes inclined at 45{degree} to the horizontal, and one vertical borehole. Over 180 borehole segments were tested by setting the packers 1 m apart. Additional tests were conducted in segments of lengths 0.5, 2.0, and 3.0 m in one borehole, and 2.0 m in another borehole, bringing the total number of tests to over 270. Tests were conducted by maintaining a constant injection rate until air pressure became relatively stable and remained so for some time. The injection rate was then incremented by a constant value and the procedure repeated. The air injection rate, pressure, temperature, and relative humidity were recorded. For each relatively stable period of injection rate and pressure, air permeability was estimated by treating the rock around each test interval as a uniform, isotropic porous medium within which air flows as a single phase under steady state, in a pressure field exhibiting prolate spheroidal symmetry. For each permeability estimate the authors list the corresponding injection rate, pressure, temperature and relative humidity. They also present selected graphs which show how the latter quantities vary with time; logarithmic plots of pressure versus time which demonstrate the importance of borehole storage effects during the early transient portion of each incremental test period; and semilogarithmic plots of pressure versus recovery time at the end of each test sequence.

  12. Heat transfer coefficients over a flat surface with air and CO{sub 2} injection through compound angle holes using a transient liquid crystal image method

    SciTech Connect

    Ekkad, S.V.; Zapata, D.; Han, J.C.

    1997-07-01

    This paper presents the detailed heat transfer coefficients over a flat surface with one row of injection holes inclined streamwise at 35 deg for three blowing ratios (M = 0.5--2.0). Three compound angles of 0, 45, and 90 deg with air (D.R. = 0.98) and CO{sub 2} (D.R. = 1.46) as coolants were tested at an elevated free-stream turbulence condition (Tu {approx} 8.5%). The experimental technique involves a liquid crystal coating on the test surface. Two related transient tests obtained detailed heat transfer coefficients and film effectiveness distributions. Heat transfer coefficients increase with increasing blowing ratio for a constant density ratio, but decrease with increasing density ratio for a constant blowing ratio. Heat transfer coefficients increase for both coolants over the test surface as the compound angle increases from 0 to 90 deg. The detailed heat transfer coefficients obtained using the transient liquid crystal technique, particularly in the near-hole region, will provide a better understanding of the film cooling process in gas turbine components.

  13. Compact interrogator for fiber optic Bragg sensors based on an acousto-optic filter formed by photonic crystal rows of air holes.

    PubMed

    Tsarev, Andrei V; De Leonardis, Francesco; Passaro, Vittorio M N

    2011-10-01

    Fiber optic sensors are typically used with expensive tunable lasers or optical spectrum analyzers for wavelength interrogation. We propose to replace the tunable laser by a broadband optical source incorporated with a novel thin linewidth acousto-optic tunable filter. It utilizes optical beam expanders constituted by photonic crystal rows of air holes in LiNbO(3) waveguide. A new design is numerically studied for a short structure (with 32 photonic crystal rows) by a two-dimensional finite-difference time-domain method. Extrapolation of these results to larger structure sizes (about 1 cm) demonstrates the possibility to develop compact interrogators with 0.4 pm wavelength resolution and 40 nm tunable range around 1550 nm.

  14. Black holes

    PubMed Central

    Brügmann, B.; Ghez, A. M.; Greiner, J.

    2001-01-01

    Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries. PMID:11553801

  15. Black holes.

    PubMed

    Brügmann, B; Ghez, A M; Greiner, J

    2001-09-11

    Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.

  16. Influence of in-hole roughness and high freestream turbulence on film cooling from a shaped hole

    NASA Astrophysics Data System (ADS)

    Schroeder, Robert P.

    Gas turbines are heavily used for electricity generation and aircraft propulsion with a strong desire in both uses to maximize thermal efficiency while maintaining reasonable power output. As a consequence, gas turbines run at high turbine inlet temperatures that require sophisticated cooling technologies to ensure survival of turbine components. One such technology is film cooling with shaped holes, where air is withdrawn from latter stages of the compressor, is bypassed around the combustor, and is eventually ejected out holes in turbine component surfaces. Air ejected from these shaped holes helps maintain components at temperatures lower than flow from the combustor. Many studies have investigated different factors that influence shaped hole performance. However, no studies in open literature have investigated how cooling performance is affected by roughness along interior walls of the shaped hole. The effect of in-hole roughness on shaped hole film cooling was the focus of this research. Investigation of in-hole roughness effects first required the determination of behavior for a shaped hole with smooth walls. A public shaped hole, now used by other investigators as well, was designed with a diffused outlet having 7º expansion angles and an area ratio of 2.5. At low freestream turbulence intensity of 0.5%, film cooling adiabatic effectiveness for this smooth hole was found to peak at a blowing ratio of 1.5. Measurements of flowfields and thermal fields revealed causes of this behavior. Blowing ratio increases above 1.5 caused the jet from the smooth hole to penetrate higher into the surrounding mainstream, exhibit a stronger counter-rotating vortex pair, and have narrower contact with the wall than at lower blowing ratios. Experiments performed at high freestream turbulence intensity of 13% revealed dynamics of how freestream turbulence both diluted and laterally spread coolant. At the high blowing ratio of 3 the dilution and spreading were competing effects

  17. Searching for Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, M.

    1998-01-01

    Our UV/VIS work concentrates on black hole X-ray nova. These objects consist of two stars in close orbit, one of which we believe is a black hole - our goal is to SHOW that one is a black hole. In order to reach this goal we carry out observations in the Optical, UV, IR and X-ray bands, and compare the observations to theoretical models. In the past year, our UV/VIS grant has provided partial support (mainly travel funds and page charges) for work we have done on X-ray nova containing black holes and neutron stars. We have been very successful in obtaining telescope time to support our project - we have completed approximately a dozen separate observing runs averaging 3 days each, using the MMT (5M), Lick 3M, KPNO 2.1M, CTIO 4M, CTIO 1.5M, and the SAO/WO 1.2M telescopes. These observations have allowed the identification of one new black hole (Nova Oph 1977), and allowed the mass of another to be measured (GS2000+25). Perhaps our most exciting new result is the evidence we have gathered for the existence of 'event horizons' in black hole X-ray nova.

  18. Measuring Small Leak Holes

    NASA Technical Reports Server (NTRS)

    Koch, D. E.; Stephenson, J. G.

    1983-01-01

    Hole sizes deduced from pressure measurements. Measuring apparatus consists of pitot tube attached to water-filled manometer. Compartment tested is pressurized with air. Pitot probe placed at known distance from leak. Dynamic pressure of jet measured at that point and static pressure measured in compartment. Useful in situations in which small leaks are tolerable but large leaks are not.

  19. The Antarctic Ozone Hole.

    ERIC Educational Resources Information Center

    Stolarski, Richard S.

    1988-01-01

    Discusses the Airborne Antarctic Ozone Experiment (1987) and the findings of the British Antarctic Survey (1985). Proposes two theories for the appearance of the hole in the ozone layer over Antarctica which appears each spring; air pollution and natural atmospheric shifts. Illustrates the mechanics of both. Supports worldwide chlorofluorocarbon…

  20. How to modify your car to run on alcohol fuel: guidelines for converting gasoline engines with specific instructions for air-cooled volkswagens

    SciTech Connect

    Lippman, R.

    1982-04-01

    It is simple to run an engine on alcohol, but doing it right is more complex. In converting an engine, it is important to obtain good fuel economy and driveability while minimizing exhaust emissions and engine wear. This manual describes significant properties of alcohol and explains the engine changes which must consequently be made, as well as providing step-by-step instructions. Engine modification procedures are presented for the amateur and professional mechanic. Conversion involves modifying the carburetor, intake manifold, and ignition system; installing a cold starting system; and raising the compression ratio. If one can tune up an engine, overhaul a carburetor, replace a cylinder head, and follow directions carefully, he is well qualified to convert his car to run on alcohol. The process will take three or four days, and the cost to the do-it-yourselfer will be $250 to $300.

  1. Obtaining Patterns Of Holes In Directional Couplers

    NASA Technical Reports Server (NTRS)

    Perez, Raul M.

    1992-01-01

    Technique enables reproduction of pattern of holes in hidden common wall of microwave directional coupler. Talcum-dusting procedure yields pattern of powder on adhesive tape showing sizes of distances between holes. Later, coupler cleaned with water or compressed air. Applicable to other equipment containing inaccessible holes in common wall between adjacent tubes.

  2. Ultra-large number of transmission channels in space division multiplexing using few-mode multi-core fiber with optimized air-hole-assisted double-cladding structure.

    PubMed

    Watanabe, Tatsuhiko; Kokubun, Yasuo

    2014-04-07

    The ultimate number of transmission channels in a fiber for the space division multiplexing (SDM) is shown by designing an air-hole-assisted double-cladding few-mode multi-core fiber. The propagation characteristics such as the dispersion and the mode field diameter are almost equalized for all cores owing to the double cladding structure, and the crosstalk between adjacent cores is extremely suppressed by the heterogeneous arrangement of cores and the air holes surrounding the cores. Optimizing the structure of the air-hole-assisted double-cladding, ultra dense core arrangements, e.g. 129 cores in a core accommodated area with 200 μm diameter, can be realized with low crosstalk of less than -34.3 dB at 100km transmission. In this design, each core supports 3 modes i.e. LP(01), LP(11a), and LP(11b) as the transmission channels, so that the number of transmission channels can be 3-hold greater than the number of cores. Therefore, 387 transmission channels can be realized.

  3. Combined target and post-run target strategy for a comprehensive analysis of pesticides in ambient air using liquid chromatography-Orbitrap high resolution mass spectrometry.

    PubMed

    Coscollà, Clara; León, Nuria; Pastor, Agustín; Yusà, Vicent

    2014-11-14

    A comprehensive strategy for the analysis of current airborne pesticides has been developed using liquid chromatography coupled to high resolution mass spectrometry. The methodology includes both quantitative target analysis and post-run target screening analysis. The quantitative method was validated after a previous statistical optimisation of the main factors governing the ion source ionization and a study of the single-stage Orbitrap fragmentation through the HCD cell. The quantitative method presented recoveries ranging from 73 to 116%, with precision (RSD) lower than 20%, for the 35 substances in the scope of the target method. The full-scan accurate mass data were acquired with a resolving power of 50000 FWHM (scan speed, 2 Hz), and alternating two acquisition events, ESI+ without fragmentation and ESI+ with fragmentation. The method-LOQ was 6.5 pg m(-3) for most of the target pesticides. For post-target screening a customized theoretical database, that included pesticides, metabolites and other substances such as emerging flame retardants was built up. For identification, accurate exact mass with less than 5 ppm, and some diagnostic ions including isotopes and/or fragments were used. The strategy was applied to ten samples collected in a rural area of Valencia (Spain). Four pesticides, namely carbendazim, metalaxyl, myclobutanil and terbuthylazine, were detected in concentrations from 16 pg m(-3) to 174 pg m(-3). Some pesticides and metabolites (endothal, fenfuram, terbuthylazine-2-OH), in addition to two flame retardants were tentatively identified in the post-run target screening analysis.

  4. Detailed heat transfer distributions in two-pass smooth and turbulated square channels with bleed holes

    SciTech Connect

    Ekkad, S.V.; Huang, Y.; Han, J.C.

    1996-12-31

    Modern gas turbine blades have internal serpentine passage for providing effective cooling. Rib turbulators are added periodically on the cooling passage surface to enhance heat transfer. Some of the cooling air is ejected out through bleed (or film) holes for external blade film cooling. The presence of periodic rib turbulators and bleed holes creates strong axial and spanwise variations in the heat transfer distributions on the passage surface. Detailed heat transfer coefficient distributions are presented in this study for a two-pass square channel with a 180{degree} turn. One wall of the channel has periodically placed bleed holes. Four different configurations of 90{degree} parallel, 60{degree} parallel, 60{degree} V ribs, and 60{degree} inverted V ribs are studied in conjunction with the effect of bleed holes on the same wall. The surface is coated with a thin layer of thermochromic liquid crystals and a transient test is run to obtain the detailed heat transfer distributions. The 60{degree} parallel, 60{degree} V, and 60{degree} inverted ribbed channels produce similar levels of heat transfer enhancement in the first pass. However, the 60{degree} inverted V ribbed channel produces higher enhancement in the second pass. Regional averaged heat transfer results indicate that a test surface with bleed holes provides similar heat transfer enhancement as that for a test surface without bleed holes although 20--25% of the inlet mass flow exits through the bleed holes.

  5. The calculation of take-off run

    NASA Technical Reports Server (NTRS)

    Diehl, Walter S

    1934-01-01

    A comparatively simple method of calculating length of take-off run is developed from the assumption of a linear variation in net accelerating force with air speed and it is shown that the error involved is negligible.

  6. Gravitational Waves From Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    di Girolamo, Tristano

    2016-10-01

    In this talk, I will present the first direct detections of gravitational waves from binary stellar-mass black hole mergers during the first observing run of the two detectors of the Advanced Laser Interferometer Gravitational-wave Observatory, which opened the field of gravitational-wave astronomy, and then discuss prospects for observing gravitational waves from supermassive black holes with future detectors.

  7. Dr. Sheehan on Running.

    ERIC Educational Resources Information Center

    Sheehan, George A.

    This book is both a personal and technical account of the experience of running by a heart specialist who began a running program at the age of 45. In its seventeen chapters, there is information presented on the spiritual, psychological, and physiological results of running; treatment of athletic injuries resulting from running; effects of diet…

  8. Brane holes

    SciTech Connect

    Frolov, Valeri P.; Mukohyama, Shinji

    2011-02-15

    The aim of this paper is to demonstrate that in models with large extra dimensions under special conditions one can extract information from the interior of 4D black holes. For this purpose we study an induced geometry on a test brane in the background of a higher-dimensional static black string or a black brane. We show that, at the intersection surface of the test brane and the bulk black string or brane, the induced metric has an event horizon, so that the test brane contains a black hole. We call it a brane hole. When the test brane moves with a constant velocity V with respect to the bulk black object, it also has a brane hole, but its gravitational radius r{sub e} is greater than the size of the bulk black string or brane r{sub 0} by the factor (1-V{sup 2}){sup -1}. We show that bulk ''photon'' emitted in the region between r{sub 0} and r{sub e} can meet the test brane again at a point outside r{sub e}. From the point of view of observers on the test brane, the events of emission and capture of the bulk photon are connected by a spacelike curve in the induced geometry. This shows an example in which extra dimensions can be used to extract information from the interior of a lower-dimensional black object. Instead of the bulk black string or brane, one can also consider a bulk geometry without a horizon. We show that nevertheless the induced geometry on the moving test brane can include a brane hole. In such a case the extra dimensions can be used to extract information from the complete region of the brane-hole interior. We discuss thermodynamic properties of brane holes and interesting questions which arise when such an extra-dimensional channel for the information mining exists.

  9. On Running and Psychotherapy.

    ERIC Educational Resources Information Center

    Dukes, Denzel; And Others

    1980-01-01

    Frederic Leer's article "Running as an Adjunct to Psychotherapy" (January 1980 issue of this journal) is criticized by three authors. They focus on the psychological and social effects of running and its usefulness as a treatment for depressed adults. (LAB)

  10. Biomechanics of Distance Running.

    ERIC Educational Resources Information Center

    Cavanagh, Peter R., Ed.

    Contributions from researchers in the field of running mechanics are included in the 13 chapters of this book. The following topics are covered: (1) "The Mechanics of Distance Running: A Historical Perspective" (Peter Cavanagh); (2) "Stride Length in Distance Running: Velocity, Body Dimensions, and Added Mass Effects" (Peter Cavanagh, Rodger…

  11. 40 CFR 89.407 - Engine dynamometer test run.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine dynamometer test run. 89.407... Test Procedures § 89.407 Engine dynamometer test run. (a) Measure and record the temperature of the air... repeated, as long as the engine is preconditioned by running the previous mode. In the case of the...

  12. 40 CFR 86.884-12 - Test run.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Test run. 86.884-12 Section 86.884-12... Heavy-Duty Engines; Smoke Exhaust Test Procedure § 86.884-12 Test run. (a) The temperature of the air... stream if the engine is left running; (7) Precondition the engine by operating it for 10 minutes...

  13. 40 CFR 86.884-12 - Test run.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Test run. 86.884-12 Section 86.884-12... Heavy-Duty Engines; Smoke Exhaust Test Procedure § 86.884-12 Test run. (a) The temperature of the air... stream if the engine is left running; (7) Precondition the engine by operating it for 10 minutes...

  14. 40 CFR 1066.960 - Running loss test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Running loss test. 1066.960 Section 1066.960 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... Procedures for Motor Vehicles § 1066.960 Running loss test. Test vehicles for running loss emissions...

  15. Coronal Holes.

    PubMed

    Cranmer, Steven R

    Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations), and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are established in the extended corona. For example, the importance of kinetic plasma physics and turbulence in coronal holes has been affirmed by surprising measurements from the UVCS instrument on SOHO that heavy ions are heated to hundreds of times the temperatures of protons and electrons. These observations point to specific kinds of collisionless Alfvén wave damping (i.e., ion cyclotron resonance), but complete theoretical models do not yet exist. Despite our incomplete knowledge of the complex multi-scale plasma physics, however, much progress has been made toward the goal of understanding the mechanisms ultimately responsible for producing the observed properties of coronal holes.

  16. The 2002 Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, P. A.; Nash, E. R.; Douglass, A. R.; Kawa, S. R.

    2003-01-01

    Since 1979, the ozone hole has grown from near zero size to over 24 Million km2. This area is most strongly controlled by levels of inorganic chlorine and bromine oncentrations. In addition, dynamical variations modulate the size of the ozone hole by either cooling or warming the polar vortex collar region. We will review the size observations, the size trends, and the interannual variability of the size. Using a simple trajectory model, we will demonstrate the sensitivity of the ozone hole to dynamical forcing, and we will use these observations to discuss the size of the ozone hole during the 2002 Austral spring. We will further show how the Cly decreases in the stratosphere will cause the ozone hole to decrease by 1-1.5% per year. We will also show results from a 3-D chemical transport model (CTM) that has been continuously run since 1999. These CTM results directly show how strong dynamics acts to reduce the size of the ozone hole.

  17. Should the Air Force Teach Running Technique

    DTIC Science & Technology

    2012-02-15

    2004): 345-352. Bruggemann, Gert -Peter, Wolfgang Potthast, Bjorn Braunstein, and Anja Niehoff. “Effect of Increased Mechanical Stimuli on Foot...Daoud, Adam I., Gary J. Geissler, Frank Wang, Jason Saretsky, Yahya A. Daoud, and Daniel E. Lieberman. “Foot Strike and Injury Rates in Endurance...the author. E-mail, 17 October 2011. Edwards, W., David Taylor, Thomas Rudolphi, Jason Gillette, and Timothy Derrick. “Effects of Stride Length and

  18. Can Unshod Running Reduce Running Injuries?

    DTIC Science & Technology

    2012-06-08

    protein? Lieberman considered how humans could take down a boar or antelope while other predators like lions and hyenas were on the prowl. He...referenced research that reported African hunters chasing antelopes and Tarahumara Indians running down deer till their hooves fell off.35 Lieberman...

  19. Well liner running shoe

    SciTech Connect

    Bell, J.F.

    1994-01-11

    Wellbore liners are set with a running shoe comprising a cylindrical body, end cap, check valve and receiver member in assembly. The receiver member includes threads for receiving the coupling sleeve of a running tool, and retaining wickers for engagement with a cement plug or dart to retain the same permanently engaged with and blocking the flow of fluid through the running shoe. A running tool for use with the shoe includes a coupling sleeve which is retained on a support mandrel by a collar which is secured to the mandrel with a shear pin so that pressuring up the workstring, in the event of a stuck coupling sleeve, will permit retrieval of the main part of the running tool and the workstring. The interior parts of the running shoe are made of aluminum or plastic for easy drill-out to extend the wellbore beyond the end of the liner. 3 figs.

  20. Triathlon: running injuries.

    PubMed

    Spiker, Andrea M; Dixit, Sameer; Cosgarea, Andrew J

    2012-12-01

    The running portion of the triathlon represents the final leg of the competition and, by some reports, the most important part in determining a triathlete's overall success. Although most triathletes spend most of their training time on cycling, running injuries are the most common injuries encountered. Common causes of running injuries include overuse, lack of rest, and activities that aggravate biomechanical predisposers of specific injuries. We discuss the running-associated injuries in the hip, knee, lower leg, ankle, and foot of the triathlete, and the causes, presentation, evaluation, and treatment of each.

  1. Overcoming the "Run" Response

    ERIC Educational Resources Information Center

    Swanson, Patricia E.

    2013-01-01

    Recent research suggests that it is not simply experiencing anxiety that affects mathematics performance but also how one responds to and regulates that anxiety (Lyons and Beilock 2011). Most people have faced mathematics problems that have triggered their "run response." The issue is not whether one wants to run, but rather…

  2. Dumb holes: analogues for black holes.

    PubMed

    Unruh, W G

    2008-08-28

    The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.

  3. GASIFICATION TEST RUN TC06

    SciTech Connect

    Southern Company Services, Inc.

    2003-08-01

    This report discusses test campaign TC06 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC06. Test run TC06 was started on July 4, 2001, and completed on September 24, 2001, with an interruption in service between July 25, 2001, and August 19, 2001, due to a filter element failure in the PCD caused by abnormal operating conditions while tuning the main air compressor. The reactor temperature was varied between 1,725 and 1,825 F at pressures from 190 to 230 psig. In TC06, 1,214 hours of solid circulation and 1,025 hours of coal feed were attained with 797 hours of coal feed after the filter element failure. Both reactor and PCD operations were stable during the test run with a stable baseline pressure drop. Due to its length and stability, the TC06 test run provided valuable data necessary to analyze long-term reactor operations and to identify necessary modifications to improve equipment and process performance as well as progressing the goal of many thousands of hours of filter element exposure.

  4. Early black hole signals at the LHC

    SciTech Connect

    Koch, Ben; Bleicher, Marcus; Stoecker, Horst

    2007-10-26

    The production of mini black holes due to large extra dimensions is a speculative but possible scenario. We survey estimates for di-jet suppression, and multi-mono-jet emission due to black hole production. We further look for a possible sub-scenario which is the formation of a stable or meta-stable black hole remnant (BHR). We show that the beauty of such objects is, that they are relatively easy to observe, even in the early phase of LHC running.

  5. Early black hole signals at the LHC

    NASA Astrophysics Data System (ADS)

    Koch, Ben; Bleicher, Marcus; Stöcker, Horst

    2007-10-01

    The production of mini black holes due to large extra dimensions is a speculative but possible scenario. We survey estimates for di-jet suppression, and multi-mono-jet emission due to black hole production. We further look for a possible sub-scenario which is the formation of a stable or meta-stable black hole remnant (BHR). We show that the beauty of such objects is, that they are relatively easy to observe, even in the early phase of LHC running.

  6. Run Anyone?... Everyone!

    PubMed Central

    McInnis, W. P.

    1974-01-01

    Fitness and health have become bywords in the past decade, signifying increased emphasis on these factors as necessary for good psychological and physical health. Reasons are given why we should run and how to do it. There is a discussion of the technique of running, and equipment. Brief mention is made of complications. An attempt is made to interest the individual in the benefits of running as a sport as well as the best method for the average person to achieve fitness and health. PMID:20469054

  7. Thermodynamic phase transition in the rainbow Schwarzschild black hole

    SciTech Connect

    Gim, Yongwan; Kim, Wontae E-mail: wtkim@sogang.ac.kr

    2014-10-01

    We study the thermodynamic phase transition in the rainbow Schwarzschild black hole where the metric depends on the energy of the test particle. Identifying the black hole temperature with the energy from the modified dispersion relation, we obtain the modified entropy and thermodynamic energy along with the modified local temperature in the cavity to provide well defined black hole states. It is found that apart from the conventional critical temperature related to Hawking-Page phase transition there appears an additional critical temperature which is of relevance to the existence of a locally stable tiny black hole; however, the off-shell free energy tells us that this black hole should eventually tunnel into the stable large black hole. Finally, we discuss the reason why the temperature near the horizon is finite in the rainbow black hole by employing the running gravitational coupling constant, whereas it is divergent near the horizon in the ordinary Schwarzschild black hole.

  8. Effect of Flow Misalignment and Multi-Hole Interaction on Boundary-Layer Bleed Hole Flow Coefficient Behavior

    NASA Technical Reports Server (NTRS)

    Davis, David O.; Grimes, Marcus; Schoenenberger, Mark

    1997-01-01

    The effect of flow misalignment on the flow coefficient behavior of a 20 deg. boundary-layer bleed hole and the effect of the interaction between two 90 deg. bleed holes separated by two hole diameters on flow coefficient behavior has been studied experimentally. Both tests were run at freestream Mach numbers of 0.61, 1.62 and 2.49. The flow misalignment study was conducted over a range of 0 to 30 deg. The results show that neither flow misalignment nor hole interaction has much effect on the flow coefficient for the subsonic case. For the supersonic cases, flow misalignment causes significant degradation in the performance of the slant hole. For the supersonic normal hole interaction cases, depending on the hole orientation, either an increase or decrease in overall flow coefficient was observed. The largest change in flow coefficient, 6% increase at near choke conditions, occurred when the holes were oriented in line with the flow direction.

  9. Prevention of running injuries.

    PubMed

    Fields, Karl B; Sykes, Jeannie C; Walker, Katherine M; Jackson, Jonathan C

    2010-01-01

    Evidence for preventive strategies to lessen running injuries is needed as these occur in 40%-50% of runners on an annual basis. Many factors influence running injuries, but strong evidence for prevention only exists for training modification primarily by reducing weekly mileage. Two anatomical factors - cavus feet and leg length inequality - demonstrate a link to injury. Weak evidence suggests that orthotics may lessen risk of stress fracture, but no clear evidence proves they will reduce the risk of those athletes with leg length inequality or cavus feet. This article reviews other potential injury variables, including strength, biomechanics, stretching, warm-up, nutrition, psychological factors, and shoes. Additional research is needed to determine whether interventions to address any of these will help prevent running injury.

  10. Binary Black Hole Mergers and Recoil Kicks

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Baker, J.; Choi, D.; Koppitz, M.; vanMeter, J.; Miller, C.

    2006-01-01

    Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black holes merge. The magnitude of this kick has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters. Here we report the first accurate numerical calculation of this kick, for two nonspinning black holes in a 1.5:1 mass ratio, which is expected based on analytic considerations to give a significant fraction of the maximum possible recoil. We have performed multiple runs with different initial separations, orbital angular momenta, resolutions, extraction radii, and gauges. The full range of our kick speeds is 86-116 kilometers per second, and the most reliable runs give kicks between 86 and 97 kilometers per second. This is intermediate between the estimates from two recent post-Newtonian analyses and suggests that at redshifts z greater than 10, halos with masses less than 10(exp 9) M(sub SUN) will have difficulty retaining coalesced black holes after major mergers.

  11. Who Runs Our Universities?

    ERIC Educational Resources Information Center

    Watson, David

    2012-01-01

    Inside the academy there is a cultural perspective that it should run itself, in the sense that "business as usual" should be done with no one's hands obviously on the levers. This theory reaches its high point in the "self-government" of Oxford and Cambridge colleges. In this article, the author explores the question,…

  12. Running Wheel for Earthworms

    PubMed Central

    Wilson, W. Jeffrey; Johnson, Brandon A.

    2016-01-01

    We describe the construction and use of a running wheel responsive to the movement of the earthworm. The wheel employs readily available, inexpensive components and is easily constructed. Movement of the wheel can be monitored visually or via standard behavioral laboratory computer interfaces. Examples of data are presented, and possibilities for use in the teaching classroom are discussed. PMID:27385934

  13. The Art of Running

    ERIC Educational Resources Information Center

    Brown, Jill Harris

    2007-01-01

    Every year, the Parent-Teacher Association of Ferndale Elementary School in Atlanta, Georgia sponsors a fun road race for the students, teachers, families, and community. This annual event has inspired the author to develop the Running and Art project to show off her students' art and squeeze in a little art history, too. In this article, the…

  14. Nonisolated dynamic black holes and white holes

    SciTech Connect

    McClure, M. L.; Anderson, Kaem; Bardahl, Kirk

    2008-05-15

    Modifying the Kerr-Schild transformation used to generate black and white hole spacetimes, new dynamic black and white holes are obtained using a time-dependent Kerr-Schild scalar field. Physical solutions are found for black holes that shrink with time and for white holes that expand with time. The black hole spacetimes are physical only in the vicinity of the black hole, with the physical region increasing in radius with time. The white hole spacetimes are physical throughout. Unlike the standard Schwarzschild solution the singularities are nonisolated, since the time dependence introduces a mass-energy distribution. The surfaces in the metrics where g{sub tt}=g{sup rr}=0 are dynamic, moving inward with time for the black holes and outward for the white holes, which leads to a question of whether these spacetimes truly have event horizons--a problem shared with Vaidya's cosmological black hole spacetimes. By finding a surface that shrinks or expands at the same rate as the null geodesics move, and within which null geodesics move inward or outward faster than the surfaces shrink or expand, respectively, it is verified that these do in fact behave like black and white holes.

  15. 40 CFR 86.1237-96 - Dynamometer runs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Dynamometer runs. 86.1237-96 Section 86.1237-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Methanol-Fueled Heavy-Duty Vehicles § 86.1237-96 Dynamometer runs. Section 86.1237-96 includes text...

  16. 40 CFR 86.1237-96 - Dynamometer runs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Dynamometer runs. 86.1237-96 Section 86.1237-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Methanol-Fueled Heavy-Duty Vehicles § 86.1237-96 Dynamometer runs. Section 86.1237-96 includes text...

  17. 40 CFR 86.884-12 - Test run.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Test run. 86.884-12 Section 86.884-12... Heavy-Duty Engines; Smoke Exhaust Test Procedure § 86.884-12 Test run. (a) The temperature of the air... steps shall be taken for each test: (1) Start cooling system; (2) Warm up the engine by the...

  18. 40 CFR 86.884-12 - Test run.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Test run. 86.884-12 Section 86.884-12... Engines; Smoke Exhaust Test Procedure § 86.884-12 Test run. (a) The temperature of the air supplied to the... taken for each test: (1) Start cooling system; (2) Warm up the engine by the procedure described in...

  19. 40 CFR 86.884-12 - Test run.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Test run. 86.884-12 Section 86.884-12... Heavy-Duty Engines; Smoke Exhaust Test Procedure § 86.884-12 Test run. (a) The temperature of the air... steps shall be taken for each test: (1) Start cooling system; (2) Warm up the engine by the...

  20. 40 CFR 86.1438 - Test run-EPA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Test run-EPA. 86.1438 Section 86.1438 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF... Short Test Procedures § 86.1438 Test run—EPA. (a) This section describes the test run performed by...

  1. 40 CFR 86.1438 - Test run-EPA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Test run-EPA. 86.1438 Section 86.1438 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF... Short Test Procedures § 86.1438 Test run—EPA. (a) This section describes the test run performed by...

  2. 40 CFR 86.1438 - Test run-EPA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Test run-EPA. 86.1438 Section 86.1438 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF... Short Test Procedures § 86.1438 Test run—EPA. (a) This section describes the test run performed by...

  3. Deburring small intersecting holes

    SciTech Connect

    Gillespie, L.K.

    1980-08-01

    Deburring intersecting holes is one of the most difficult deburring tasks faced by many industries. Only 14 of the 37 major deburring processes are applicable to most intersecting hole applications. Only five of these are normally applicable to small or miniature holes. Basic process capabilities and techniques used as a function of hole sizes and intersection depths are summarized.

  4. Does Addiction Run in Families?

    MedlinePlus

    ... Addiction Run in Families? Does Addiction Run in Families? Listen PDF: EasyToRead_WhatIsAddiction_Final_012017.pdf Addiction ... Español English Español "Heart disease runs in some families. Addiction runs in ours." ©istock.com/ Antonio_Diaz ...

  5. Large hole rotary drill performance

    SciTech Connect

    Workman, J.L.; Calder, P.N.

    1996-12-31

    Large hole rotary drilling is one of the most common methods of producing blastholes in open pit mining. Large hole drilling generally refers to diameters from 9 to 17 inch (229 to 432 mm), however a considerable amount of rotary drilling is done in diameters from 6{1/2} to 9 inch (165 to 229 mm). These smaller diameters are especially prevalent in gold mining and quarrying. Rotary drills are major mining machines having substantial capital cost. Drill bit costs can also be high, depending on the bit type and formation being drilled. To keep unit costs low the drills must perform at a high productivity level. The most important factor in rotary drilling is the penetration rate. This paper discusses the factors affecting penetration rate. An empirical factor in rotary drilling is the penetration rate. This paper discusses the factors affecting penetration rate. An empirical factor is given for calculating the penetration rate based on rock strength, pulldown weight and the RPM. The importance of using modern drill performance monitoring systems to calibrate the penetration equation for specific rock formations is discussed. Adequate air delivered to the bottom of the hole is very important to achieving maximum penetration rates. If there is insufficient bailing velocity cuttings will not be transported from the bottom of the hole rapidly enough and the penetration rate is very likely to decrease. An expression for the balancing air velocity is given. The amount by which the air velocity must exceed the balancing velocity for effective operation is discussed. The effect of altitude on compressor size is also provided.

  6. WRF nature run

    NASA Astrophysics Data System (ADS)

    Michalakes, J.; Hacker, J.; Loft, R.; McCracken, M. O.; Snavely, A.; Wright, N. J.; Spelce, T.; Gorda, B.; Walkup, R.

    2008-07-01

    The Weather Research and Forecast (WRF) model is a model of the atmosphere for mesoscale research and operational numerical weather prediction (NWP). A petascale problem for WRF is a nature run that provides very high-resolution 'truth' against which more coarse simulations or perturbation runs may be com-pared for purposes of studying predictability, stochastic parameterization, and fundamental dynamics. We carried out a nature run involving an idealized high resolution rotating fluid on the hemisphere, at a size and resolution never before attempted, and used it to investigate scales that span the k-3 to k-5/3 kinetic energy spectral transition, via simulations. We used up to 15,360 processors of the New York Blue IBM BG/L machine at Stony Brook Uni-versity and Brookhaven National Laboratory. The grid we employed has 4486 by 4486 horizontal grid points and 101 vertical levels (2 billion cells) at 5km resolution; this is 32 times larger than the previously largest 63 million cell 2.5km resolution WRF CONUS benchmark [10]). To solve a problem of this size, we worked through issues of parallel I/O and scalability and employed more processors than have ever been used in a WRF run. We achieved a sustained 3.4 Tflop/s on the New York Blue sys-tem, inputting and then generating an enormous amount of data to produce a scientifically meaningful result. More than 200 GB of data was input to initialize the run, which then generated output datasets of 40 GB each simulated hour. The cost of output was considered a key component of our investigation. Then we ran the same problem on more than 12K processors of the XT4 system at NERSC and achieved 8.8 Tflop/s. Our primary result however is not just scalability and a high Tflop/s number, but capture of atmosphere features never before represented by simulation, and taking an important step towards understanding weather predict-ability at high resolution.

  7. When will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2006-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the .TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to, both the size and depth of the hole. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. The ozone hole will begin to show first signs of recovery in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. This 2070 recovery is 20 years later than recent projections.

  8. When Will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2005-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. We will show estimates of both when the ozone hole will begin to show first signs of recovery, and when the hole will fully recover to pre-1980 levels.

  9. A Dancing Black Hole

    NASA Astrophysics Data System (ADS)

    Shoemaker, Deirdre; Smith, Kenneth; Schnetter, Erik; Fiske, David; Laguna, Pablo; Pullin, Jorge

    2002-04-01

    Recently, stationary black holes have been successfully simulated for up to times of approximately 600-1000M, where M is the mass of the black hole. Considering that the expected burst of gravitational radiation from a binary black hole merger would last approximately 200-500M, black hole codes are approaching the point where simulations of mergers may be feasible. We will present two types of simulations of single black holes obtained with a code based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of the Einstein evolution equations. One type of simulations addresses the stability properties of stationary black hole evolutions. The second type of simulations demonstrates the ability of our code to move a black hole through the computational domain. This is accomplished by shifting the stationary black hole solution to a coordinate system in which the location of the black hole is time dependent.

  10. Fluid-bed air-supply system

    DOEpatents

    Atabay, Keramettin

    1979-01-01

    The air-supply system for a fluidized-bed furnace includes two air conduits for the same combustion zone. The conduits feed separate sets of holes in a distributor plate through which fluidizing air flows to reach the bed. During normal operation, only one conduit and set of holes is used, but the second conduit and set of holes is employed during start-up.

  11. Running, walking, and hyperventilation causing asthma in children.

    PubMed Central

    Kilham, H; Tooley, M; Silverman, M

    1979-01-01

    To examine further the relation between type of exercise, workload, ventilation, and exercise-induced asthma, we compared treadmill walking with treadmill running and treadmill running with isocapnic hyperventilation in separate studies in children and adolescents. Inspired air conditions were identical during each pair of tests. Walking and running with similar minute ventilation and oxygen consumption were followed by similar falls in peak expiratory flow rate as were running and hyperventilation with similar minute ventilation and end-tidal carbon dioxide tension. This study supports the concept that hyperventilation is a central mechanism in exercise-induced asthma. PMID:515978

  12. 19. TRAVELING CRANE ATOP SUPERSTRUCTURE, FROM RUN LINE DECK. Looking ...

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

    19. TRAVELING CRANE ATOP SUPERSTRUCTURE, FROM RUN LINE DECK. Looking up to north northeast. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  13. Run II luminosity progress

    SciTech Connect

    Gollwitzer, K.; /Fermilab

    2007-06-01

    The Fermilab Tevatron Collider Run II program continues at the energy and luminosity frontier of high energy particle physics. To the collider experiments CDF and D0, over 3 fb{sup -1} of integrated luminosity has been delivered to each. Upgrades and improvements in the Antiproton Source of the production and collection of antiprotons have led to increased number of particles stored in the Recycler. Electron cooling and associated improvements have help make a brighter antiproton beam at collisions. Tevatron improvements to handle the increased number of particles and the beam lifetimes have resulted in an increase in luminosity.

  14. PDU Run 10

    SciTech Connect

    Not Available

    1981-09-01

    PDU Run 10, a 46-day H-Coal syncrude mode operation using Wyodak coal, successfully met all targeted objectives, and was the longest PDU operation to date in this program. Targeted coal conversion of 90 W % was exceeded with a C/sub 4/-975/sup 0/F distillate yield of 43 to 48 W %. Amocat 1A catalyst was qualified for Pilot Plant operation based on improved operation and superior performance. PDU 10 achieved improved yields and lower hydrogen consumption compared to PDU 6, a similar operation. High hydroclone efficiency and high solids content in the vacuum still were maintained throughout the run. Steady operations at lower oil/solids ratios were demonstrated. Microautoclave testing was introduced as an operational aid. Four additional studies were successfully completed during PDU 10. These included a catalyst tracer study in conjunction with Sandia Laboratories; tests on letdown valve trims for Battelle; a fluid dynamics study with Amoco; and special high-pressure liquid sampling.

  15. NASA Now: Black Holes

    NASA Video Gallery

    In this NASA Now episode, Dr. Daniel Patnaude talks about how his team discovered a baby black hole, why this is important and how black holes create tidal forces. Throughout his discussion, Patnau...

  16. Black hole hair removal

    NASA Astrophysics Data System (ADS)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  17. Muscular strategy shift in human running: dependence of running speed on hip and ankle muscle performance.

    PubMed

    Dorn, Tim W; Schache, Anthony G; Pandy, Marcus G

    2012-06-01

    Humans run faster by increasing a combination of stride length and stride frequency. In slow and medium-paced running, stride length is increased by exerting larger support forces during ground contact, whereas in fast running and sprinting, stride frequency is increased by swinging the legs more rapidly through the air. Many studies have investigated the mechanics of human running, yet little is known about how the individual leg muscles accelerate the joints and centre of mass during this task. The aim of this study was to describe and explain the synergistic actions of the individual leg muscles over a wide range of running speeds, from slow running to maximal sprinting. Experimental gait data from nine subjects were combined with a detailed computer model of the musculoskeletal system to determine the forces developed by the leg muscles at different running speeds. For speeds up to 7 m s(-1), the ankle plantarflexors, soleus and gastrocnemius, contributed most significantly to vertical support forces and hence increases in stride length. At speeds greater than 7 m s(-1), these muscles shortened at relatively high velocities and had less time to generate the forces needed for support. Thus, above 7 m s(-1), the strategy used to increase running speed shifted to the goal of increasing stride frequency. The hip muscles, primarily the iliopsoas, gluteus maximus and hamstrings, achieved this goal by accelerating the hip and knee joints more vigorously during swing. These findings provide insight into the strategies used by the leg muscles to maximise running performance and have implications for the design of athletic training programs.

  18. Black Hole Thermodynamics

    NASA Astrophysics Data System (ADS)

    Israel, Werner

    This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.

  19. SAVAGE RUN WILDERNESS, WYOMING.

    USGS Publications Warehouse

    McCallum, M.E.; Kluender, Steven E.

    1984-01-01

    Mineral evaluation and related surveys were conducted in the Savage Run Wilderness in Wyoming and results of these studies indicate probable mineral-resource potential in four areas. Gold and (or) silver mineralization in veins associated with faults was found in two areas; all known occurrences inside the wilderness are very small in size. Slightly anomalous values of platinum, palladium, and nickel were recorded from rock-chip and stream- sediment samples from the southeast portion of the wilderness where layered mafic rocks predominate, and a probable resource potential exists for platinum, palladium, and nickel. An area of sheared rocks in the northeastern corner of the wilderness has a probable resource potential for copper. The nature of the geologic terrane precludes the occurrence of organic fuels.

  20. Running WASP at Argonne

    SciTech Connect

    Huber, C.C.

    1981-01-01

    The WASP model was initially implemented at Argonne for the International Training course on Electric System Planning being conducted at Argonne. This implementation was done with special consideration to course participants who are unfamiliar with WASP and with the computer system they use during the course. Cataloged Procedures were developed for this purpose. The procedures simplify using WASP and enable participants to quickly start using WASP with a minimum of training. Within the procedures, features were added that enhance WASP. These features include a formatted printout of WASP input data and a historical log of all runs and inut data used. For the RENAME step, an alternate method is presented, with special comment concerning the WASP3 release.

  1. The Running Athlete

    PubMed Central

    Henning, P. Troy

    2014-01-01

    Context: Pelvic stress fractures, osteitis pubis, and snapping hip syndrome account for a portion of the overuse injuries that can occur in the running athlete. Evidence Acquisition: PubMed searches were performed for each entity using the following keywords: snapping hip syndrome, coxa sultans, pelvic stress fracture, and osteitis pubis from 2008 to 2013. Topic reviews, case reports, case series, and randomized trials were included for review. Study Design: Clinical review. Level of Evidence: Level 4. Results: Collectively, 188 articles were identified. Of these, 58 were included in this review. Conclusion: Based on the available evidence, the majority of these overuse injuries can be managed non-operatively. Primary treatment should include removal from offending activity, normalizing regional muscle strength/length imbalances and nutritional deficiencies, and mitigating training errors through proper education of the athlete and training staff. Strength of Recommendation Taxonomy: C PMID:24587861

  2. Barefoot running: biomechanics and implications for running injuries.

    PubMed

    Altman, Allison R; Davis, Irene S

    2012-01-01

    Despite the technological developments in modern running footwear, up to 79% of runners today get injured in a given year. As we evolved barefoot, examining this mode of running is insightful. Barefoot running encourages a forefoot strike pattern that is associated with a reduction in impact loading and stride length. Studies have shown a reduction in injuries to shod forefoot strikers as compared with rearfoot strikers. In addition to a forefoot strike pattern, barefoot running also affords the runner increased sensory feedback from the foot-ground contact, as well as increased energy storage in the arch. Minimal footwear is being used to mimic barefoot running, but it is not clear whether it truly does. The purpose of this article is to review current and past research on shod and barefoot/minimal footwear running and their implications for running injuries. Clearly more research is needed, and areas for future study are suggested.

  3. Recovery of the Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve; Schauffler, Sue; Stolarski, Richard S.; Douglass, Anne R.; Pawson, Steven; Nielsen, J. Eric

    2006-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS and OMI instruments. The severity of the hole has been assessed using the minimum total ozone value from the October monthly mean (depth of the hole), the average size during the September-October period, and the ozone mass deficit. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. We use two methods to estimate ozone hole recovery. First, we use projections of halogen levels combined with age-of-air estimates in a parametric model. Second, we use a coupled chemistry climate model to assess recovery. We find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. Furthermore, full recovery to 1980 levels will not occur until approximately 2068. We will also show some error estimates of these dates and the impact of climate change on the recovery.

  4. Black Hole Battery

    NASA Astrophysics Data System (ADS)

    Levin, Janna; D'Orazio, Daniel

    2016-03-01

    Black holes are dark dead stars. Neutron stars are giant magnets. As the neutron star orbits the black hole, an electronic circuit forms that generates a blast of power just before the black hole absorbs the neutron star whole. The black hole battery conceivably would be observable at cosmological distances. Possible channels for luminosity include synchro-curvature radiation, a blazing fireball, or even an unstable, short-lived black hole pulsar. As suggested by Mingarelli, Levin, and Lazio, some fraction of the battery power could also be reprocessed into coherent radio emission to populate a subclass of fast radio bursts.

  5. Black Holes in a Violent Universe

    NASA Astrophysics Data System (ADS)

    Britzen, S.

    2012-02-01

    "Black Holes in a Violent Universe" is a COST Action (MP0905) connecting scientists from different disciplines - astronomers from all wavelength regimes (i.e. radio to TeV), physicists and particle physicists, theoreticians and observers - from currently 25 countries. The aim is to collaborate in a cross-disciplinary and multi-dimensional approach towards a better understanding of the general Black Hole phenomenon. COST (European Cooperation in Science and Technology) is one of the longest-running European instruments supporting cooperation among scientists and researchers across Europe. The goal of MP0905 is to decipher further the way the Universe and the stars and galaxies evolved and - in particular - the role Black Holes play in this. This Action is an open and flexible program of communication and interchange.

  6. Air-cooled, hydrogen-air fuel cell

    NASA Technical Reports Server (NTRS)

    Shelekhin, Alexander B. (Inventor); Bushnell, Calvin L. (Inventor); Pien, Michael S. (Inventor)

    1999-01-01

    An air-cooled, hydrogen-air solid polymer electrolyte (SPE) fuel cell with a membrane electrode assembly operatively associated with a fluid flow plate having at least one plate cooling channel extending through the plate and at least one air distribution hole extending from a surface of the cathode flow field into the plate cooling channel.

  7. Small Break Air Ingress Experiment

    SciTech Connect

    Chang Oh; Eung Soo Kim

    2011-09-01

    The small break air-ingress experiment, described in this report, is designed to investigate air-ingress phenomena postulated to occur in pipes in a very high temperature gas-cooled reactor (VHTRs). During this experiment, air-ingress rates were measured for various flow and break conditions through small holes drilled into a pipe of the experimental apparatus. The holes were drilled at right angles to the pipe wall such that a direction vector drawn from the pipe centerline to the center of each hole was at right angles with respect to the pipe centerline. Thus the orientation of each hole was obtained by measuring the included angle between the direction vector of each hole with respect to a reference line anchored on the pipe centerline and pointing in the direction of the gravitational force. Using this reference system, the influence of several important parameters on the air ingress flow rate were measured including break orientation, break size, and flow velocity . The approach used to study the influence of these parameters on air ingress is based on measuring the changes in oxygen concentrations at various locations in the helium flow circulation system as a function of time using oxygen sensors (or detectors) to estimate the air-ingress rates through the holes. The test-section is constructed of a stainless steel pipe which had small holes drilled at the desired locations.

  8. Black Holes (With 16 figures)

    NASA Astrophysics Data System (ADS)

    Novikov, Igor

    Astrophysics of Black Holes Introduction The Origin of Stellar Black Holes A Nonrotating Black Hole Introduction Schwarzschild Gravitational Field Motion of Photons Along the Radial Direction Radial Motion of Nonrelativistic Particles The Puzzle of the Gravitational Radius R and T Regions Two Types of T-Regions Gravitational Collapse and White Holes Eternal Black Hole? Black Hole Celestial Mechanics Circular Motion Around a Black Hole Gravitational Capture of Particles by a Black Hole Corrections for Gravitational Radiation A Rotating Black Hole Introduction Gravitational Field of a Rotating Black Hole Specific Reference Frames General Properties of the Spacetime of a Rotating Black Hole; - Spacetime Inside the Horizon Celestial Mechanics of a Rotating Black Hole Motion of Particle in the Equatorial Plane Motion of Particles off the Equatorial Plane Peculiarities of the Gravitational Capture of Bodies by a Rotating - Black Hole Electromagnetic Fields Near a Black Hole Introduction Maxwell's Equations in the Neighborhood of a Rotating Black Hole Stationary Electrodynamics Boundary Conditions at the Event Horizon Electromagnetic Fields in Vacuum Magnetosphere of a Black Hole Some Aspects of Physics of Black Holes, Wormholes, and Time Machines Observational Appearence of the Black Holes in the Universe Black Holes in the Interstellar Medium Disk Accretion Black Holes in Stellar Binary Systems Black Holes in Galactic Centers Dynamical Evidence for Black Holes in Galaxy Nuclei Primordial Black Holes Acknowledgements References

  9. Hole qualities in laser trepanning of polymeric materials

    NASA Astrophysics Data System (ADS)

    Choudhury, I. A.; Chong, W. C.; Vahid, G.

    2012-09-01

    The present study focuses the effect of four input controllable laser cutting variables on the hole taper and hole circularity in laser trepan drilling of polymeric materials. Experiments have been conducted on acrylonitrile butadiene styrene (ABS) and polymethyl methacrylate (PMMA) polymer sheets. Laser power, assist gas pressure, cutting speed and stand-off distance were selected as independent process variables. Three different holes of diameters 2 mm, 4 mm and 6 mm were drilled in these work materials of 5 mm thickness. A Taguchi L9 orthogonal array with four factors and three levels of each factor was used to plan and conduct the experiments in order to obtain required information with reduced number of experiments. The process performance was ascertained in terms of hole taper and hole circularity. Initial analysis involved in determining the effect of the four process variables on hole taper and circularity for these two polymers at three different hole diameters. From ANOVA analysis, the optimum levels of the four process variables with respect to materials and hole diameters were evaluated. As it was found that the optimum levels of four process variables were different for different hole size and materials, additional analysis was conducted to incorporate the effect of material and hole diameter on the hole taper. From the analysis, the optimum combinations were obtained at compressed air pressure of 2.0 bar, laser power of 500 W, cutting speed of 0.6 m/min, stand-off distance of 5.0 mm, hole diameter of 2.0 mm and material of PMMA. These combinations produced the minimum taper in the hole. The circularity of the hole was more at the entrance than the exit when ABS polymer was laser drilled while in PMMA, the hole was more circular at the exit than the entrance.

  10. Backward running or absence of running from Creutz ratios

    SciTech Connect

    Giedt, Joel; Weinberg, Evan

    2011-10-01

    We extract the running coupling based on Creutz ratios in SU(2) lattice gauge theory with two Dirac fermions in the adjoint representation. Depending on how the extrapolation to zero fermion mass is performed, either backward running or an absence of running is observed at strong bare coupling. This behavior is consistent with other findings which indicate that this theory has an infrared fixed point.

  11. The QCD running coupling

    DOE PAGES

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-05-09

    Here, we review present knowledge onmore » $$\\alpha_{s}$$, the Quantum Chromodynamics (QCD) running coupling. The dependence of $$\\alpha_s(Q^2)$$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics --from color confinement in the infrared domain to asymptotic freedom at short distances. We will survey our present theoretical and empirical knowledge of $$\\alpha_s(Q^2)$$, including constraints at high $Q^2$ predicted by perturbative QCD, and constraints at small $Q^2$ based on models of nonperturbative dynamics. In the first, introductory, part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss $$\\alpha_s(Q^2)$$ in the high momentum transfer domain of QCD. We review how $$\\alpha_s$$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as `` Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization scale ambiguity. We also report recent important experimental measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the ``Principle of Maximum Conformality" which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of the gauge and renormalization scheme. In last part of the review, we discuss $$\\alpha_s(Q^2)$$ in the low momentum transfer domain, where there has been no consensus on how to define $$\\alpha_s(Q^2)$$ or its analytic behavior. We will discuss the various approaches used for low energy calculations. Among them, we will discuss the light-front holographic approach to QCD in the strongly coupled

  12. The QCD running coupling

    SciTech Connect

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-05-09

    Here, we review present knowledge on $\\alpha_{s}$, the Quantum Chromodynamics (QCD) running coupling. The dependence of $\\alpha_s(Q^2)$ on momentum transfer $Q$ encodes the underlying dynamics of hadron physics --from color confinement in the infrared domain to asymptotic freedom at short distances. We will survey our present theoretical and empirical knowledge of $\\alpha_s(Q^2)$, including constraints at high $Q^2$ predicted by perturbative QCD, and constraints at small $Q^2$ based on models of nonperturbative dynamics. In the first, introductory, part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss $\\alpha_s(Q^2)$ in the high momentum transfer domain of QCD. We review how $\\alpha_s$ is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as `` Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization scale ambiguity. We also report recent important experimental measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the ``Principle of Maximum Conformality" which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of the gauge and renormalization scheme. In last part of the review, we discuss $\\alpha_s(Q^2)$ in the low momentum transfer domain, where there has been no consensus on how to define $\\alpha_s(Q^2)$ or its analytic behavior. We will discuss the various approaches used for low energy calculations. Among them, we will discuss the light-front holographic approach to QCD in the strongly coupled regime and its prediction

  13. Voluntary Wheel Running in Mice

    PubMed Central

    Goh, Jorming; Ladiges, Warren

    2015-01-01

    Voluntary wheel running in the mouse is used to assess physical performance and endurance and to model exercise training as a way to enhance health. Wheel running is a voluntary activity in contrast to other experimental exercise models in mice, which rely on aversive stimuli to force active movement. The basic protocol consists of allowing mice to run freely on the open surface of a slanted plastic saucer-shaped wheel placed inside a standard mouse cage. Rotations are electronically transmitted to a USB hub so that frequency and rate of running can be captured to a software program for data storage and analysis for variable time periods. Mice are individually housed so that accurate recordings can be made for each animal. Factors such as mouse strain, gender, age, and individual motivation, which affect running activity, must be considered in the design of experiments using voluntary wheel running. PMID:26629772

  14. Uniformly accelerated black holes

    NASA Astrophysics Data System (ADS)

    Letelier, Patricio S.; Oliveira, Samuel R.

    2001-09-01

    The static and stationary C metric are examined in a generic framework and their interpretations studied in some detail, especially those with two event horizons, one for the black hole and another for the acceleration. We find that (i) the spacetime of an accelerated static black hole is plagued by either conical singularities or a lack of smoothness and compactness of the black hole horizon, (ii) by using standard black hole thermodynamics we show that accelerated black holes have a higher Hawking temperature than Unruh temperature of the accelerated frame, and (iii) the usual upper bound on the product of the mass and acceleration parameters (<1/27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.

  15. CPT-hole closure

    USGS Publications Warehouse

    Noce, T.E.; Holzer, T.L.

    2003-01-01

    The long-term stability of deep holes 1.75 inches. (4.4 cm) in diameter by 98.4 feet (30 m) created by cone penetration testing (CPT) was monitored at a site in California underlain by Holocene and Pleistocene age alluvial fan deposits. Portions of the holes remained open both below and above the 28.6-foot (8.7 m)-deep water table for approximately three years, when the experiment was terminated. Hole closure appears to be a very slow process that may take decades in the stiff soils studied here. Other experience suggests holes in softer soils may also remain open. Thus, despite their small diameter, CPT holes may remain open for years and provide paths for rapid migration of contaminants. The observations confirm the need to grout holes created by CPT soundings as well as other direct-push techniques in areas where protection of shallow ground water is important.

  16. Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Loeb, Abraham

    2007-04-01

    Recent data indicates that almost all galaxies possess a supermassive black hole at their center. When gas accretes onto the black hole it heats-up and shines, resulting in the appearance of a bright quasar. The earliest quasars are found to exist only a billion years after the big-bang. I will describe recent observations of both the nearest and the most distant supermassive black holes in the universe. The formation and evolution of the black hole population can be described in the context of popular models for galaxy formation. I will describe the key questions that drive current research on supermassive black holes and present theoretical work on the radiative and hydrodynamic effects that quasars have on their cosmic habitat. Within the coming decade it would be possible to test general relativity by monitoring over time, and possibly even imaging, the polarized emission from hot spots around the black hole in the center of our Galaxy (SgrA*).

  17. Biodiversity conservation in running waters

    SciTech Connect

    Allan, J.D. ); Flecker, A.S. )

    1993-01-01

    In the concerns about biodiversity conservation, fresh waters have received less attention than tropical forests and oceans. However, running waters harbor a diverse panoply of species, habitats, and ecosystems, including some of the most threatened and many having great value to human society. An overview of the biological diversity of running waters and the state of imperilment is presented. Six major factors that threaten destruction of running water species and ecosystems are discussed: habitat loss and degradation; species invasions; overharvesting; secondary extinctions; chemical and organic pollution; global climate change. General measures for recovery and restoration of running waters conclude the article.

  18. A Running Start: Resource Guide for Youth Running Programs

    ERIC Educational Resources Information Center

    Jenny, Seth; Becker, Andrew; Armstrong, Tess

    2016-01-01

    The lack of physical activity is an epidemic problem among American youth today. In order to combat this, many schools are incorporating youth running programs as a part of their comprehensive school physical activity programs. These youth running programs are being implemented before or after school, at school during recess at the elementary…

  19. The QCD running coupling

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre; Brodsky, Stanley J.; de Téramond, Guy F.

    2016-09-01

    We review the present theoretical and empirical knowledge for αs, the fundamental coupling underlying the interactions of quarks and gluons in Quantum Chromodynamics (QCD). The dependence of αs(Q2) on momentum transfer Q encodes the underlying dynamics of hadron physics-from color confinement in the infrared domain to asymptotic freedom at short distances. We review constraints on αs(Q2) at high Q2, as predicted by perturbative QCD, and its analytic behavior at small Q2, based on models of nonperturbative dynamics. In the introductory part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain. In the second, more technical, part of the review, we discuss the behavior of αs(Q2) in the high momentum transfer domain of QCD. We review how αs is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as "Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization-scale ambiguity. We also report recent significant measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the "Principle of Maximum Conformality", which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of theoretical conventions such as the renormalization scheme. In the last part of the review, we discuss the challenge of understanding the analytic behavior αs(Q2) in the low momentum transfer domain. We survey various theoretical models for the nonperturbative strongly coupled regime, such as the light-front holographic approach to QCD. This new framework predicts the form of the quark-confinement potential underlying hadron spectroscopy and

  20. The Nearest Black Holes

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); Garcia, M.

    2003-01-01

    The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies. This program facilitates this study by funding related travel, computer equipment, and partial salary for a post-doc.

  1. The Nearest Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, M.; Oliversen, Ronald J. (Technical Monitor)

    2004-01-01

    The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies. This program facilitate this study by funding related travel, computer equipment, and partial salary for a post-doc.

  2. The Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Molina, Mario J.

    Observations of Antarctic ozone levels and the discovery of a hole in the Antarctic region are examined. The effects of chlorofluorocarbons (CFCs) on the level of stratospheric ozone are analyzed. Three cycles explaining the cause of ozone depletion in the poles are proposed. A comparison of field data and proposed depletion cycles reveals that the chemical origin of the ozone hole is due to CFCs. The potential global effects of the Antarctic ozone hole are discussed.

  3. Film cooling effectiveness and heat transfer with injection through holes

    NASA Technical Reports Server (NTRS)

    Eriksen, V. L.

    1971-01-01

    An experimental investigation of the local film cooling effectiveness and heat transfer downstream of injection of air through discrete holes into a turbulent boundary layer of air on a flat plate is reported. Secondary air is injected through a single hole normal to the main flow and through both a single hole and a row of holes spaced at three diameter intervals with an injection angle of 35 deg to the main flow. Two values of the mainstream Reynolds number are used; the blowing rate is varied from 0.1 to 2.0. Photographs of a carbon dioxide-water fog injected into the main flow at an angle of 90 deg are also presented to show interaction between the jet and mainstream.

  4. f(R) Black Holes as Heat Engines

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Liu, Wen-Biao

    2016-12-01

    With the cosmological constant considered as a thermodynamic variable in the extended phase space, it is natural to study the thermodynamic cycles of the black hole, which is conjectured to be performed using renormalization group flow. We first investigate the thermodynamic cycles of a 4-dimensional asymptotically AdS f( R) black hole. Then we study the thermodynamic cycles of higher dimensional asymptotically AdS f( R) black holes. It is found that when Δ V ≪ Δ P, the efficiency of isobar-isochore cycles running between high temperature T H and low temperature T C will increase to its maximum value, which is exactly the Carnot cycles' efficiency both in 4-dimensional and in higher dimensional cases. We speculate that this property is universal for AdS black holes, if there is no phase transition in the thermodynamic cycle. This result may deepen our understanding of the thermodynamics of the AdS black holes.

  5. Learning about Black-Hole Formation from Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Kesden, Michael H.

    2017-01-01

    The first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) discovered gravitational waves from two binary black-hole mergers. Although astrophysical black holes are simple objects fully characterized by their masses and spins, key features of binary black-hole formation such as mass transfer, natal kicks, and common-envelope evolution can misalign black-hole spins with the orbital angular momentum of the binary. These misaligned spins will precess as gravitational-wave emission causes the black holes to inspiral to separations at which the waves are detectable by observatories like LIGO. Spin precession modulates the amplitude and frequency of the gravitational waves observed by LIGO, allowing it to not only test general relativity but also reveal the secrets of black-hole formation. This talk will briefly describe those elements of binary black-hole formation responsible for initial spin misalignments, how spin precession and radiation reaction in general relativity determine how spins evolve from formation until the black holes enter LIGO’s sensitivity band, and how spin-induced gravitational-wave modulation in band can be used as a diagnostic of black-hole formation.

  6. Asymptotic black holes

    NASA Astrophysics Data System (ADS)

    Ho, Pei-Ming

    2017-04-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  7. Evidence for black holes.

    PubMed

    Begelman, Mitchell C

    2003-06-20

    Black holes are common objects in the universe. Each galaxy contains large numbers-perhaps millions-of stellar-mass black holes, each the remnant of a massive star. In addition, nearly every galaxy contains a supermassive black hole at its center, with a mass ranging from millions to billions of solar masses. This review discusses the demographics of black holes, the ways in which they interact with their environment, factors that may regulate their formation and growth, and progress toward determining whether these objects really warp spacetime as predicted by the general theory of relativity.

  8. Power Systems Development Facility Gasification Test Run TC11

    SciTech Connect

    Southern Company Services

    2003-04-30

    This report discusses Test Campaign TC11 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). Test run TC11 began on April 7, 2003, with startup of the main air compressor and the lighting of the gasifier start-up burner. The Transport Gasifier operated until April 18, 2003, when a gasifier upset forced the termination of the test run. Over the course of the entire test run, gasifier temperatures varied between 1,650 and 1,800 F at pressures from 160 to 200 psig during air-blown operations and around 135 psig during enriched-air operations. Due to a restriction in the oxygen-fed lower mixing zone (LMZ), the majority of the test run featured air-blown operations.

  9. Coordinating the 2009 RHIC Run

    ScienceCinema

    Brookhaven Lab - Mei Bai

    2016-07-12

    Physicists working at the Brookhaven National Lab's Relativistic Heavy Ion Collider (RHIC) are exploring the puzzle of proton spin as they begin taking data during the 2009 RHIC run. For the first time, RHIC is running at a record energy of 500 giga-elect

  10. Coordinating the 2009 RHIC Run

    SciTech Connect

    Brookhaven Lab - Mei Bai

    2009-04-13

    Physicists working at the Brookhaven National Lab's Relativistic Heavy Ion Collider (RHIC) are exploring the puzzle of proton spin as they begin taking data during the 2009 RHIC run. For the first time, RHIC is running at a record energy of 500 giga-elect

  11. Oxygen cost of running barefoot vs. running shod.

    PubMed

    Hanson, N J; Berg, K; Deka, P; Meendering, J R; Ryan, C

    2011-06-01

    The purpose of this study was to investigate the oxygen cost of running barefoot vs. running shod on the treadmill as well as overground. 10 healthy recreational runners, 5 male and 5 female, whose mean age was 23.8±3.39 volunteered to participate in the study. Subjects participated in 4 experimental conditions: 1) barefoot on treadmill, 2) shod on treadmill, 3) barefoot overground, and 4) shod overground. For each condition, subjects ran for 6 min at 70% vVO (2)max pace while VO (2), heart rate (HR), and rating of perceived exertion (RPE) were assessed. A 2 × 2 (shoe condition x surface) repeated measures ANOVA revealed that running with shoes showed significantly higher VO (2) values on both the treadmill and the overground track (p<0.05). HR and RPE were significantly higher in the shod condition as well (p<0.02 and p<0.01, respectively). For the overground and treadmill conditions, recorded VO (2) while running shod was 5.7% and 2.0% higher than running barefoot. It was concluded that at 70% of vVO (2)max pace, barefoot running is more economical than running shod, both overground and on a treadmill.

  12. Newborn Black Holes

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  13. Black Hole Simulation

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This graphic shows the computer simulation of a black hole from start to finish. Plasma is falling slowly toward the black hole in a (at the upper left). The plasma has a magnetic field, shown by the white lines. It picks up speed as it falls toward the hole in b (at the upper right), c (lower left) and d (lower right). However, the rotating black hole twists up space itself (and the magnetic field lines) and ejects electromagnetic power along the north and south poles above the black hole. The red and white color shows the immense electromagnetic power output, which eventually will pick up particles and form squirting jets. This simulation was conducted using supercomputers at Japan's National Institute for Fusion Science.

  14. Observing Black Hole Spin

    NASA Astrophysics Data System (ADS)

    Reynolds, Christopher S.

    2015-08-01

    Black hole spin is important in both the fundamental physics and astrophysics realms. In fundamental terms, many extensions and alternatives to General Relativity (GR) reveal themselves through effects related to (or at least of the same order as) spin. Astrophysically, spin is a fossil record of how black holes have grown and may, in addition, be an important source of energy (e.g., powering relativistic jets from black hole systems). I shall review recent progress on observational studies of black hole spin, especially those made in the X-ray waveband. We now have multiple techniques that can be applied in our search for black hole spin; I shall discuss the concordance (or, sometimes, lack thereof) between these techniques. Finally, I shall discuss what we can expect in the next few years with the launch of new X-ray instrumentation as well as the deployment of the Event Horizon Telescope.

  15. 25. PRIMARY POWER TRANSMISSION BELT HOLES IN 1st FLOOR MILL ...

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

    25. PRIMARY POWER TRANSMISSION BELT HOLES IN 1st FLOOR MILL NO. 1 CEILING. WATER-POWERED MACHINERY LOCATED IN BASEMENT RAN LEATHER BELTS THROUGH THESE HOLES. POWER WAS THEN TRANSMITTED TO SHAFTS AND PULLEYS TO RUN MACHINERY ON MILL FLOORS. - Prattville Manufacturing Company, Number One, 242 South Court Street, Prattville, Autauga County, AL

  16. Wheel running in the wild.

    PubMed

    Meijer, Johanna H; Robbers, Yuri

    2014-07-07

    The importance of exercise for health and neurogenesis is becoming increasingly clear. Wheel running is often used in the laboratory for triggering enhanced activity levels, despite the common objection that this behaviour is an artefact of captivity and merely signifies neurosis or stereotypy. If wheel running is indeed caused by captive housing, wild mice are not expected to use a running wheel in nature. This however, to our knowledge, has never been tested. Here, we show that when running wheels are placed in nature, they are frequently used by wild mice, also when no extrinsic reward is provided. Bout lengths of running wheel behaviour in the wild match those for captive mice. This finding falsifies one criterion for stereotypic behaviour, and suggests that running wheel activity is an elective behaviour. In a time when lifestyle in general and lack of exercise in particular are a major cause of disease in the modern world, research into physical activity is of utmost importance. Our findings may help alleviate the main concern regarding the use of running wheels in research on exercise.

  17. Run-to-Run Control Strategy for Diabetes Management

    DTIC Science & Technology

    2007-11-02

    quite serious ( diabetic coma), and the long- term implications of varying glucose levels ( nephropathy , retinopathy, and other tissue damage ) have...Trial Re- search Group, \\The e ect of intensive treatment of diabetes on the development and progression of long{term complications in insulin{dependent...1 RUN-TO-RUN CONTROL STRATEGY FOR DIABETES MANAGEMENT F.J. Doyle III1, B. Srinivasan2, and D. Bonvin2 1Department of Chemical Engineering, University

  18. Why Does My Nose Run?

    MedlinePlus

    ... cold day, your nose tries its best to warm up the cold air you breathe before sending it ... inside your nostrils open wider (dilate), helping to warm up that air. But that extra blood flow leads ...

  19. p-i-n/n-i-p type planar hybrid structure of highly efficient perovskite solar cells towards improved air stability: synthetic strategies and the role of p-type hole transport layer (HTL) and n-type electron transport layer (ETL) metal oxides.

    PubMed

    Mali, Sawanta S; Hong, Chang Kook

    2016-05-19

    There has been fast recent progress in perovskite solar cells (PSCs) towards low cost photovoltaic technology. Organometal mixed halide (MAPbX or FAPbX) perovskites are the most promising light absorbing material sandwiched between the electron transport layer (ETL) and hole transport layer (HTL). These two layers play a critical role in boosting the power conversion efficiency (PCE) and maintaining air stability. However, the device stability is a serious issue in regular as well as p-i-n inverted type perovskite solar cells. This mini-review briefly outlines the state-of-art of p-i-n/n-i-p type planar hybrid perovskite solar cells using MAPbX/FAPbX perovskite absorbing layers. Later, we will focus on recent trends, progress and further opportunities in exploring the air stable hybrid planar structure PSCs.

  20. p-i-n/n-i-p type planar hybrid structure of highly efficient perovskite solar cells towards improved air stability: synthetic strategies and the role of p-type hole transport layer (HTL) and n-type electron transport layer (ETL) metal oxides

    NASA Astrophysics Data System (ADS)

    Mali, Sawanta S.; Hong, Chang Kook

    2016-05-01

    There has been fast recent progress in perovskite solar cells (PSCs) towards low cost photovoltaic technology. Organometal mixed halide (MAPbX or FAPbX) perovskites are the most promising light absorbing material sandwiched between the electron transport layer (ETL) and hole transport layer (HTL). These two layers play a critical role in boosting the power conversion efficiency (PCE) and maintaining air stability. However, the device stability is a serious issue in regular as well as p-i-n inverted type perovskite solar cells. This mini-review briefly outlines the state-of-art of p-i-n/n-i-p type planar hybrid perovskite solar cells using MAPbX/FAPbX perovskite absorbing layers. Later, we will focus on recent trends, progress and further opportunities in exploring the air stable hybrid planar structure PSCs.

  1. 40 CFR 86.1234-96 - Running loss test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  2. 40 CFR 86.1234-96 - Running loss test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  3. 40 CFR 86.134-96 - Running loss test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  4. 40 CFR 86.1234-96 - Running loss test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  5. 40 CFR 86.134-96 - Running loss test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  6. 40 CFR 86.134-96 - Running loss test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  7. 40 CFR 86.134-96 - Running loss test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 95±5 °F (95±2 °F on average) during the running loss test, measured at the inlet to the cooling fan... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  8. 40 CFR 86.134-96 - Running loss test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  9. 40 CFR 86.1234-96 - Running loss test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... °F on average) during the running loss test, measured at the inlet to the cooling fan in front of the... flow through the impingers should be minimized to prevent any losses. (C) Turn off all the fans... of air intake equipment, if applicable, shall be minimized to avoid loss of heat from the...

  10. ULTRAMASSIVE BLACK HOLE COALESCENCE

    SciTech Connect

    Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter E-mail: k.holley@vanderbilt.edu

    2015-01-10

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production.

  11. Entropy of quasiblack holes

    SciTech Connect

    Lemos, Jose P. S.; Zaslavskii, Oleg B.

    2010-03-15

    We trace the origin of the black hole entropy S, replacing a black hole by a quasiblack hole. Let the boundary of a static body approach its own gravitational radius, in such a way that a quasihorizon forms. We show that if the body is thermal with the temperature taking the Hawking value at the quasihorizon limit, it follows, in the nonextremal case, from the first law of thermodynamics that the entropy approaches the Bekenstein-Hawking value S=A/4. In this setup, the key role is played by the surface stresses on the quasihorizon and one finds that the entropy comes from the quasihorizon surface. Any distribution of matter inside the surface leads to the same universal value for the entropy in the quasihorizon limit. This can be of some help in the understanding of black hole entropy. Other similarities between black holes and quasiblack holes such as the mass formulas for both objects had been found previously. We also discuss the entropy for extremal quasiblack holes, a more subtle issue.

  12. Antarctic Ozone Hole, 2000

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Each spring the ozone layer over Antarctica nearly disappears, forming a 'hole' over the entire continent. The hole is created by the interaction of some man-made chemicals-freon, for example-with Antarctica's unique weather patterns and extremely cold temperatures. Ozone in the stratosphere absorbs ultraviolet radiation from the sun, thereby protecting living things. Since the ozone hole was discovered many of the chemicals that destroy ozone have been banned, but they will remain in the atmosphere for decades. In 2000, the ozone hole grew quicker than usual and exceptionally large. By the first week in September the hole was the largest ever-11.4 million square miles. The top image shows the average total column ozone values over Antarctica for September 2000. (Total column ozone is the amount of ozone from the ground to the top of the atmosphere. A relatively typical measurement of 300 Dobson Units is equivalent to a layer of ozone 0.12 inches thick on the Earth's surface. Levels below 220 Dobson Units are considered to be significant ozone depletion.) The record-breaking hole is likely the result of lower than average ozone levels during the Antarctic fall and winter, and exceptionally cold temperatures. In October, however (bottom image), the hole shrank dramatically, much more quickly than usual. By the end of October, the hole was only one-third of it's previous size. In a typical year, the ozone hole does not collapse until the end of November. NASA scientists were surprised by this early shrinking and speculate it is related to the region's weather. Global ozone levels are measured by the Total Ozone Mapping Spectrometer (TOMS). For more information about ozone, read the Earth Observatory's ozone fact sheet, view global ozone data and see these ozone images. Images by Greg Shirah, NASA GSFC Scientific Visualization Studio.

  13. Observations of running penumbral waves.

    NASA Technical Reports Server (NTRS)

    Zirin, H.; Stein, A.

    1972-01-01

    Quiet sunspots with well-developed penumbrae show running intensity waves with period running around 300 sec. The waves appear connected with umbral flashes of exactly half the period. Waves are concentric, regular, with velocity constant around 10 km/sec. They are probably sound waves and show intensity fluctuation in H alpha centerline or wing of 10 to 20%. The energy is tiny compared to the heat deficit of the umbra.

  14. Measuring Black Hole Spin

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    1999-09-01

    WE PROPOSE TO CARRY OUT A SYSTEMATIC STUDY OF EMISSION AND ABSORPTION SPECTRAL FEATURES THAT ARE OFTEN SEEN IN X-RAY SPECTRA OF BLACK HOLE BINARIES. THE EXCELLENT SENSITIVITY AND ENERGY RESOLUTION OF THE ACIS/HETG COMBINATION WILL NOT ONLY HELP RESOLVE AMBIGUITIES IN INTERPRETING THESE FEATURES, BUT MAY ALLOW MODELLING OF THE EMISSION LINE PROFILES IN DETAIL. THE PROFILES MAY CONTAIN INFORMATION ON SUCH FUNDAMENTAL PROPERTIES AS THE SPIN OF BLACK HOLES. THEREFORE, THIS STUDY COULD LEAD TO A MEASUREMENT OF BLACK HOLE SPIN FOR SELECTED SOURCES. THE RESULT CAN THEN BE DIRECTLY COMPARED WITH THOSE FROM PREVIOUS STUDIES BASED ON INDEPENDENT METHODS.

  15. Control drilling solves surface hole problems

    SciTech Connect

    Jean, T.W.

    1986-08-01

    Drilling surface hole offshore is one aspect of drilling practice that should command greater planning and design. Surface hole could be crucial if the well is in an area with a chance of shallow gas, or if it is required to run a 30-in. pin corrector and a long string of riser back to surface. The problem grows more critical with deeper water and a longer riser which in turn gives a longer column of drilling fluid. Consequently, the hydrostatic pressure is much higher at the 30-in. casing shoe. Higher pressure increases the chance of exceeding the fracture gradient and may result in the loss of returns around the 30-in. shoe. This article describes a simple practice which can eliminate some surface hole problems. A control-drilling equation sets the maximum drilling rate (MDR) based on maximum permitted pressures at the casing shoe. Eliminating lost circulation will ultimately save rig downtime due to retrieving the conductor pipe and base plate, relocating the rig, and respudding the hole after suffering losses. This technique also has been successful while drilling out below drive pipe on jack ups and platform wells. Control drilling is most effectively used on these types of wells because only a friction seal (instead of cement coverage) exists around the bottom of the drive pipe.

  16. Analysis of Fuel Vaporization, Fuel-Air Mixing, and Combustion in Integrated Mixer-Flame Holders

    NASA Technical Reports Server (NTRS)

    Deur, J. M.; Cline, M. C.

    2004-01-01

    Requirements to limit pollutant emissions from the gas turbine engines for the future High-Speed Civil Transport (HSCT) have led to consideration of various low-emission combustor concepts. One such concept is the Integrated Mixer-Flame Holder (IMFH). This report describes a series of IMFH analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. To meet the needs of this study, KIVA-II's boundary condition and chemistry treatments are modified. The study itself examines the relationships between fuel vaporization, fuel-air mixing, and combustion. Parameters being considered include: mixer tube diameter, mixer tube length, mixer tube geometry (converging-diverging versus straight walls), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases are run with and without combustion to examine the variations in fuel-air mixing and potential for flashback due to the above parameters. The degree of fuel-air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state. Results indicate that fuel-air mixing can be enhanced by a variety of means, the best being a combination of air inlet swirl and a converging-diverging mixer tube geometry. With the IMFH configuration utilized in the present study, flashback becomes more common as the mixer tube diameter is increased and is instigated by disturbances associated with the dilution hole flow.

  17. Woodwind Tone Hole Acoustics and the Spectrum Transformation Function.

    NASA Astrophysics Data System (ADS)

    Keefe, Douglas Howard

    This report describes an investigation of woodwind musical instrument tone holes and their effect on the radiated spectrum, the total dissipation, the stability of oscillation, the psychoacoustical cues important in perception, and the tuning and response of the instrument. Varying tone hole proportions significantly affect the radiative and frictional damping near a single hole, the mutual interactions between holes, the onset of streaming and turbulence near the holes, and the perceived woodwind timbre. The interconnections between related fields are explored through a brief review of sound production in woodwinds plus more extensive reviews of room and psychological acoustics. A theoretical and experimental discussion of the spectrum transformation function from the mouthpiece into the room relates all these fields. Also, considered are differences between cylindrical and conical bore woodwinds, the systematic shifts in saxophone spectra produced by the beating of the reed, the coupling of many closely spaced tone holes to the room excitation, the role of the player, and the results pertaining to computer music synthesis. The complicated acoustical flow inside the main air column near a single tone hole has been examined using a Green function, integral equation approach. A variational formulation allows explicit calculation of the open and closed hole impedance parameters needed in the transmission line description of a woodwind, and experiments have verified the theory in detail. Major acoustical topics considered are listed below. The effective length t(,e) of an open hole, relevant for instrument design and modification, is calculated and measured in terms of the main bore diameter 2a, hole diameter 2b, and the height t of the hole chimney; the effect of a hanging pad is a semi-empirical correction on t(,e). When the fundamental plane-wave mode of the main air column oscillation is at a pressure node, both the open and closed hole series impedances are

  18. Effects of running velocity on running kinetics and kinematics.

    PubMed

    Brughelli, Matt; Cronin, John; Chaouachi, Anis

    2011-04-01

    Sixteen semiprofessional Australian football players performed running bouts at incremental velocities of 40, 60, 80, and 100% of their maximum velocity on a Woodway nonmotorized force treadmill. As running velocity increased from 40 to 60%, peak vertical and peak horizontal forces increased by 14.3% (effect size [ES] = 1.0) and 34.4% (ES = 4.2), respectively. The changes in peak vertical and peak horizontal forces from 60 to 80% were 1.0% (ES = 0.05) and 21.0% (ES = 2.9), respectively. Finally, the changes in peak vertical and peak horizontal forces from 80% to maximum were 2.0% (ES = 0.1) and 24.3% (ES = 3.4). In addition, both stride frequency and stride length significantly increased with each incremental velocity (p < 0.05). Conversely, contact times and the vertical displacement of the center of mass significantly decreased with increased running velocity (p < 0.05). A significant positive correlation was found between horizontal force and maximum running velocity (r = 0.47). For the kinematic variables, only stride length was found to have a significant positive correlation with maximum running velocity (r = 0.66). It would seem that increasing maximal sprint velocity may be more dependent on horizontal force production as opposed to vertical force production.

  19. Running of the running and entropy perturbations during inflation

    NASA Astrophysics Data System (ADS)

    van de Bruck, Carsten; Longden, Chris

    2016-07-01

    In single field slow-roll inflation, one expects that the spectral index ns-1 is first order in slow-roll parameters. Similarly, its running αs=d ns/d log k and the running of the running βs=d αs/d log k are second and third order and therefore expected to be progressively smaller, and usually negative. Hence, such models of inflation are in considerable tension with a recent analysis hinting that βs may actually be positive, and larger than αs. Motivated by this, in this work we ask the question of what kinds of inflationary models may be useful in achieving such a hierarchy of runnings, particularly focusing on two-field models of inflation in which the late-time transfer of power from isocurvature to curvature modes allows for a much more diverse range of phenomenology. We calculate the runnings due to this effect and briefly apply our results to assess the feasibility of finding |βs|≳|αs| in some specific models.

  20. Introducing the Black Hole

    ERIC Educational Resources Information Center

    Ruffini, Remo; Wheeler, John A.

    1971-01-01

    discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)

  1. Straight hole driller

    SciTech Connect

    Samford, T.L.

    1981-08-25

    For use in a drilling string, the preferred and illustrated embodiment depicts a drill collar to be placed in the lower parts of the drill string for straightening the hole. The preferred embodiment utilizes a generally square drill collar with a thick or heavy wall. It is square in cross section along the greater portion of its length, the four corners being slightly rounded to a specified diameter on rotation, and the four lengthwise corners of the regular cross section are all reinforced with hardfacing material to a specified depth, typically tungsten carbide. The four edges abrade the bore hole as the drill string penetrates the earth. In addition, the lower end of the tubular body includes lengthwise flutes in the form known on a stabilizer to guide the hole straightening device into the hole to be reamed by operation of the device.

  2. Illuminating black holes

    NASA Astrophysics Data System (ADS)

    Barr, Ian A.; Bull, Anne; O'Brien, Eileen; Drillsma-Milgrom, Katy A.; Milgrom, Lionel R.

    2016-07-01

    Two-dimensional shadows formed by illuminating vortices are shown to be visually analogous to the gravitational action of black holes on light and surrounding matter. They could be useful teaching aids demonstrating some of the consequences of general relativity.

  3. Micro-hole drilling and cutting using femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

    Huang, Huan; Yang, Lih-Mei; Liu, Jian

    2014-05-01

    Micro-hole drilling and cutting in ambient air are presented by using a femtosecond fiber laser. At first, the micro-hole drilling was investigated in both transparent (glasses) and nontransparent (metals and tissues) materials. The shape and morphology of the holes were characterized and evaluated with optical and scanning electron microscopy. Debris-free micro-holes with good roundness and no thermal damage were demonstrated with the aspect ratio of 8∶1. Micro-hole drilling in hard and soft tissues with no crack or collateral thermal damage is also demonstrated. Then, trench micromachining and cutting were studied for different materials and the effect of the laser parameters on the trench properties was investigated. Straight and clean trench edges were obtained with no thermal damage.

  4. Water Tank with Capillary Air/Liquid Separation

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Smith, Frederick; Edeen, Gregg; Almlie, Jay C.

    2010-01-01

    A bladderless water tank (see figure) has been developed that contains capillary devices that allow it to be filled and emptied, as needed, in microgravity. When filled with water, the tank shields human occupants of a spacecraft against cosmic radiation. A membrane that is permeable by air but is hydrophobic (neither wettable nor permeable by liquid water) covers one inside surface of the tank. Grooves between the surface and the membrane allow air to flow through vent holes in the surface as the tank is filled or drained. A margin of wettable surface surrounds the edges of the membrane, and all the other inside tank surfaces are also wettable. A fill/drain port is located in one corner of the tank and is covered with a hydrophilic membrane. As filling begins, water runs from the hydrophilic membrane into the corner fillets of the tank walls. Continued filling in the absence of gravity will result in a single contiguous air bubble that will be vented through the hydrophobic membrane. The bubble will be reduced in size until it becomes spherical and smaller than the tank thickness. Draining the tank reverses the process. Air is introduced through the hydrophobic membrane, and liquid continuity is maintained with the fill/drain port through the corner fillets. Even after the tank is emptied, as long as the suction pressure on the hydrophilic membrane does not exceed its bubble point, no air will be drawn into the liquid line.

  5. Black holes and beyond

    SciTech Connect

    Mathur, Samir D.

    2012-11-15

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole. - Highlights: Black-Right-Pointing-Pointer The information paradox is a serious problem. Black-Right-Pointing-Pointer To solve it we need to find 'hair' on black holes. Black-Right-Pointing-Pointer In string theory we find 'hair' by the fuzzball construction. Black-Right-Pointing-Pointer Fuzzballs help to resolve many other issues in gravity.

  6. Life Inside Black Holes

    NASA Astrophysics Data System (ADS)

    Dokuchaev, Vyacheslav

    2013-11-01

    It is considered the test planet and photon orbits of the third kind inside the black hole (BH), which are stable, periodic and neither come out the BH nor terminate at the central singularity. Interiors of the supermassive BHs may be inhabited by advanced civilizations living on the planets with the third kind orbits. In principle, one can get information from the interiors of BHs by observing their white hole counterparts.

  7. Holes in Heisenberg antiferromagnets

    NASA Astrophysics Data System (ADS)

    Chen, Yang

    1990-05-01

    In this Brief Report we show that a recent model proposed by Shankar [Phys. Rev. Lett. 63, 203 (1989)], describing the motion of holes in quantum antiferromagnets is equivalent to the Schwinger model [Phys. Rev. 128, 2425 (1962)] in 1+1 dimensions. Some exact results are deduced. In addition to the superconducting long-range order found by Shankar, it is shown that there is a 2pF hole density wave existing with the superconducting pairing instability.

  8. RHIC Au beam in Run 2014

    SciTech Connect

    Zhang, S. Y.

    2014-09-15

    Au beam at the RHIC ramp in run 2014 is reviewed together with the run 2011 and run 2012. Observed bunch length and longitudinal emittance are compared with the IBS simulations. The IBS growth rate of the longitudinal emittance in run 2014 is similar to run 2011, and both are larger than run 2012. This is explained by the large transverse emittance at high intensity observed in run 2012, but not in run 2014. The big improvement of the AGS ramping in run 2014 might be related to this change. The importance of the injector intensity improvement in run 2014 is emphasized, which gives rise to the initial luminosity improvement of 50% in run 2014, compared with the previous Au-Au run 2011. In addition, a modified IBS model, which is calibrated using the RHIC Au runs from 9.8 GeV/n to 100 GeV/n, is presented and used in the study.

  9. Charged Galileon black holes

    SciTech Connect

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar E-mail: christos.charmousis@th.u-psud.fr

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  10. CDF Run 2 muon system

    SciTech Connect

    C. M. Ginsburg

    2004-02-05

    The CDF muon detection system for Run 2 of the Fermilab Tevatron is described. Muon stubs are detected for |{eta}| < 1.5, and are matched to tracks in the central drift chamber at trigger level 1 for |{eta}| < 1.25. Detectors in the |{eta}| < 1 central region, built for previous runs, have been enhanced to survive the higher rate environment and closer bunch spacing (3.5 {micro}sec to 396 nsec) of Run 2. Azimuthal gaps in the central region have been filled in. New detectors have been added to extend the coverage from |{eta}| < 1 to |{eta}| < 1.5, consisting of four layers of drift chambers covered with matching scintillators for triggering. The Level 1 Extremely Fast Tracker supplies matching tracks with measured p{sub T} for the muon trigger. The system has been in operation for over 18 months. Operating experience and reconstructed data are presented.

  11. Can cycle power predict sprint running performance?

    PubMed

    van Ingen Schenau, G J; Jacobs, R; de Koning, J J

    1991-01-01

    A major criticism of present models of the energetics and mechanics of sprint running concerns the application of estimates of parameters which seem to be adapted from measurements of running during actual competitions. This study presents a model which does not perpetuate this solecism. Using data obtained during supra-maximal cycle ergometer tests of highly trained athletes, the kinetics of the anaerobic and aerobic pathways were modelled. Internal power wasted in the acceleration and deceleration of body limbs and the power necessary to overcome air friction was calculated from data in the literature. Assuming a mechanical efficiency as found during submaximal cycling, a power equation was constructed which also included the power necessary to accelerate the body at the start of movement. The differential equation thus obtained was solved through simulation. The model appeared to predict realistic times at 100 m (10.47 s), 200 m (19.63 s) and 400 m (42.99 s) distances. By comparison with other methods it is argued that power equations of locomotion should include the concept of mechanical efficiency.

  12. Draft air deflecting device

    SciTech Connect

    Riley, J.E.

    1982-05-18

    A draft air deflecting device is mountable proximate to a window contained in a firebox and serves as a conduit which directs draft air across the inner surface of the window prior to its supporting combustion of the fuel in the firebox. In this respect , the draft air deflecting device is formed as a box which communicates with draft air holes located in the firebox and which includes a forwardly extending lip serving to define a nozzle for both increasing the velocity and directing the incoming draft air across the firebox window. The incoming draft air is thus utilized to cool and to prevent soot, creosote and other particulates from accumulating on the window.

  13. [Stress fracture after changing to barefoot running].

    PubMed

    Christensen, Mikkel

    2014-12-15

    Barefoot running is increasing in popularity but little is known about the implications in respect to injuries. It has been proposed that barefoot running is associated with a decrease in running injuries as it represents a more natural way of running. A 50-year-old runner with a weekly running distance of 50 km presented suffering from a stress fracture of the second metatarsal after six weeks of intensive barefoot running.

  14. Estimating when the Antarctic Ozone Hole will Recover

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Douglass, Anne R.; Nielsen, J. Eric; Pawson, Steven; Stolarski, Richard S.

    2007-01-01

    The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). The severity of the hole has been assessed from satellites using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average area coverage during this September-October period. Profile information shows that ozone is completely destroyed in the 14-2 1 km layer by early October. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations. Because atmospheric halogen levels are responding to international a'greements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. We estimate that the ozone hole will begin to show first signs of size decrease in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. Estimates of the ozone hole's recovery from models reveal important differences that will be discussed.

  15. Detecting the Recovery of the Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Kawa, S. Randolph; Montzka, Steve

    2004-01-01

    The Antarctic ozone hole develops each year and culminates by early Spring. Antarctic ozone values have been monitored since 1979 using satellite observations from the TOMS instrument. The severity of the hole has been assessed from TOMS using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average size during the September-October period. Ozone is mainly destroyed by halogen catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this presentation, we show the relationships of halogens and temperature to both the size and depth of the hole. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. We will show estimates of both when the ozone hole will begin to show first signs of recovery, and when the hole will fully recover to pre-1980 levels.

  16. Estimating When the Antarctic Ozone Hole Will Recover

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Douglass, Anne R.; Nielsen, J. Eric; Pawson, Steven; Stolarski, Richard S.

    2007-01-01

    The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). The severity of the hole has been assessed from satellites using the minimum total ozone value from the October monthly mean (depth of the hole) and by calculating the average area coverage during this September-October period. Profile information shows that ozone is completely destroyed in the 14-21 km layer by early October. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations. Because atmospheric halogen levels are responding to international agreements that limit or phase out production, the amount of halogens in the stratosphere should decrease over the next few decades. Using projections of halogen levels combined with age-of-air estimates, we find that the ozone hole is recovering at an extremely slow rate and that large ozone holes will regularly recur over the next 2 decades. We estimate that the ozone hole will begin to show first signs of size decrease in about 2023, and the hole will fully recover to pre-1980 levels in approximately 2070. Estimates of the ozone hole's recovery from models reveal important differences that will be discussed.

  17. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, John

    2009-01-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  18. Merging Black Holes

    NASA Astrophysics Data System (ADS)

    Centrella, Joan

    2009-05-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  19. Teaching Bank Runs through Films

    ERIC Educational Resources Information Center

    Flynn, David T.

    2009-01-01

    The author advocates the use of films to supplement textbook treatments of bank runs and panics in money and banking or general banking classes. Modern students, particularly those in developed countries, tend to be unfamiliar with potential fragilities of financial systems such as a lack of deposit insurance or other safety net mechanisms. Films…

  20. Running and Breathing in Mammals

    NASA Astrophysics Data System (ADS)

    Bramble, Dennis M.; Carrier, David R.

    1983-01-01

    Mechanical constraints appear to require that locomotion and breathing be synchronized in running mammals. Phase locking of limb and respiratory frequency has now been recorded during treadmill running in jackrabbits and during locomotion on solid ground in dogs, horses, and humans. Quadrupedal species normally synchronize the locomotor and respiratory cycles at a constant ratio of 1:1 (strides per breath) in both the trot and gallop. Human runners differ from quadrupeds in that while running they employ several phase-locked patterns (4:1, 3:1, 2:1, 1:1, 5:2, and 3:2), although a 2:1 coupling ratio appears to be favored. Even though the evolution of bipedal gait has reduced the mechanical constraints on respiration in man, thereby permitting greater flexibility in breathing pattern, it has seemingly not eliminated the need for the synchronization of respiration and body motion during sustained running. Flying birds have independently achieved phase-locked locomotor and respiratory cycles. This hints that strict locomotor-respiratory coupling may be a vital factor in the sustained aerobic exercise of endothermic vertebrates, especially those in which the stresses of locomotion tend to deform the thoracic complex.

  1. Analysis of fuel vaporization, fuel/air mixing, and combustion in lean premixed/prevaporized combustors

    SciTech Connect

    Deur, J.M.; Penko, P.F.; Cline, M.C.

    1995-07-01

    Requirements to reduce pollutant emissions from gas turbines used in aircraft propulsion and ground-based power generation have led to consideration of lean premixed/prevaporized (LPP) combustion concepts. This paper describes a series of the LPP combustor analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. Modifications to KIVA-II`s boundary condition and chemistry treatments have been made to meet the needs of the present study. The study examines the relationships between fuel vaporization, fuel/air mixing, and combustion in a generic LPP combustor. Parameters considered include: mixer tube diameter, mixer tube length, mixer tube configuration (straight versus converging/diverging tubes), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases have been run with and without combustion to examine the variations in fuel/air mixing and potential for flashback due to the above parameters. The degree of fuel/air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state.

  2. 40 CFR 86.341-79 - Diesel engine dynamometer test run.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Diesel engine dynamometer test run. 86.341-79 Section 86.341-79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR....341-79 Diesel engine dynamometer test run. (a) This section applies to Diesel engines only....

  3. 40 CFR 1039.501 - How do I run a valid emission test?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false How do I run a valid emission test? 1039.501 Section 1039.501 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Procedures § 1039.501 How do I run a valid emission test? (a) Use the equipment and procedures...

  4. 40 CFR 86.341-79 - Diesel engine dynamometer test run.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Diesel engine dynamometer test run. 86.341-79 Section 86.341-79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR....341-79 Diesel engine dynamometer test run. (a) This section applies to Diesel engines only....

  5. 40 CFR 1039.501 - How do I run a valid emission test?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I run a valid emission test? 1039.501 Section 1039.501 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Procedures § 1039.501 How do I run a valid emission test? (a) Use the equipment and procedures...

  6. 40 CFR 1042.501 - How do I run a valid emission test?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I run a valid emission test? 1042.501 Section 1042.501 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Test Procedures § 1042.501 How do I run a valid emission test? (a) Use the equipment and procedures...

  7. 40 CFR 1042.501 - How do I run a valid emission test?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false How do I run a valid emission test? 1042.501 Section 1042.501 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Test Procedures § 1042.501 How do I run a valid emission test? (a) Use the equipment and procedures...

  8. 40 CFR 1036.501 - How do I run a valid emission test?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false How do I run a valid emission test? 1036.501 Section 1036.501 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... § 1036.501 How do I run a valid emission test? (a) Use the equipment and procedures specified in 40...

  9. 40 CFR 1036.501 - How do I run a valid emission test?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false How do I run a valid emission test? 1036.501 Section 1036.501 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... § 1036.501 How do I run a valid emission test? (a) Use the equipment and procedures specified in 40...

  10. 40 CFR 1036.501 - How do I run a valid emission test?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false How do I run a valid emission test? 1036.501 Section 1036.501 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... § 1036.501 How do I run a valid emission test? (a) Use the equipment and procedures specified in 40...

  11. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  12. Noncommutative black hole thermodynamics

    SciTech Connect

    Banerjee, Rabin; Majhi, Bibhas Ranjan; Samanta, Saurav

    2008-06-15

    We give a general derivation, for any static spherically symmetric metric, of the relation T{sub h}=(K/2{pi}) connecting the black hole temperature (T{sub h}) with the surface gravity (K), following the tunneling interpretation of Hawking radiation. This derivation is valid even beyond the semi-classical regime, i.e. when quantum effects are not negligible. The formalism is then applied to a spherically symmetric, stationary noncommutative Schwarzschild space-time. The effects of backreaction are also included. For such a black hole the Hawking temperature is computed in a closed form. A graphical analysis reveals interesting features regarding the variation of the Hawking temperature (including corrections due to noncommutativity and backreaction) with the small radius of the black hole. The entropy and tunneling rate valid for the leading order in the noncommutative parameter are calculated. We also show that the noncommutative Bekenstein-Hawking area law has the same functional form as the usual one.

  13. Turbulent black holes.

    PubMed

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  14. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2010-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wove detection, testing general relativity, and astrophysics.

  15. Janus black holes

    NASA Astrophysics Data System (ADS)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  16. Ozone Hole Over Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

  17. Bringing Black Holes Home

    NASA Astrophysics Data System (ADS)

    Furmann, John M.

    2003-03-01

    Black holes are difficult to study because they emit no light. To overcome this obstacle, scientists are trying to recreate a black hole in the laboratory. The article gives an overview of the theories of Einstein and Hawking as they pertain to the construction of the Large Hadron Collider (LHC) near Geneva, Switzerland, scheduled for completion in 2006. The LHC will create two beams of protons traveling in opposing directions that will collide and create a plethora of scattered elementary particles. Protons traveling in opposite directions at very high velocities may create particles that come close enough to each other to feel their compacted higher dimensions and create a mega force of gravity that can create tiny laboratory-sized black holes for fractions of a second. The experiments carried out with LHC will be used to test modern string theory and relativity.

  18. Black-hole astrophysics

    SciTech Connect

    Bender, P.; Bloom, E.; Cominsky, L.

    1995-07-01

    Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

  19. Black Hole Paradoxes

    NASA Astrophysics Data System (ADS)

    Joshi, Pankaj S.; Narayan, Ramesh

    2016-10-01

    We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals.

  20. Slowly balding black holes

    SciTech Connect

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-15

    The 'no-hair' theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively ''frozen in'' the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N{sub B}=e{Phi}{sub {infinity}}/({pi}c({h_bar}/2{pi})), where {Phi}{sub {infinity}}{approx_equal}2{pi}{sup 2}B{sub NS}R{sub NS}{sup 3}/(P{sub NS}c) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole's magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  1. Superfluid Black Holes

    NASA Astrophysics Data System (ADS)

    Hennigar, Robie A.; Mann, Robert B.; Tjoa, Erickson

    2017-01-01

    We present what we believe is the first example of a "λ -line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid 4He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  2. Magnonic Black Holes.

    PubMed

    Roldán-Molina, A; Nunez, Alvaro S; Duine, R A

    2017-02-10

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  3. Superfluid Black Holes.

    PubMed

    Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson

    2017-01-13

    We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  4. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.

    2010-01-01

    Black-hole mergers take place in regions of very strong and dynamical gravitational fields, and are among the strongest sources of gravitational radiation. Probing these mergers requires solving the full set of Einstein's equations of general relativity numerically. For more than 40 years, progress towards this goal has been very slow, as numerical relativists encountered a host of difficult problems. Recently, several breakthroughs have led to dramatic progress, enabling stable and accurate calculations of black-hole mergers. This article presents an overview of this field, including impacts on astrophysics and applications in gravitational wave data analysis.

  5. Characterizing Black Hole Mergers

    NASA Technical Reports Server (NTRS)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  6. Euclidean black hole vortices

    NASA Technical Reports Server (NTRS)

    Dowker, Fay; Gregory, Ruth; Traschen, Jennie

    1991-01-01

    We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviors, at the horizon and at infinity, of vortex solutions for the gauge and scalar fields in an abelian Higgs model on a Euclidean Schwarzschild background and interpolate between them by integrating the equations numerically. Calculating the backreaction shows that the effect of the vortex is to cut a slice out of the Schwarzschild geometry. Consequences of these solutions for black hole thermodynamics are discussed.

  7. Magnonic Black Holes

    NASA Astrophysics Data System (ADS)

    Roldán-Molina, A.; Nunez, Alvaro S.; Duine, R. A.

    2017-02-01

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons—the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  8. Electron hole tracking PIC simulation

    NASA Astrophysics Data System (ADS)

    Zhou, Chuteng; Hutchinson, Ian

    2016-10-01

    An electron hole is a coherent BGK mode solitary wave. Electron holes are observed to travel at high velocities relative to bulk plasmas. The kinematics of a 1-D electron hole is studied using a novel Particle-In-Cell simulation code with fully kinetic ions. A hole tracking technique enables us to follow the trajectory of a fast-moving solitary hole and study quantitatively hole acceleration and coupling to ions. The electron hole signal is detected and the simulation domain moves by a carefully designed feedback control law to follow its propagation. This approach has the advantage that the length of the simulation domain can be significantly reduced to several times the hole width, which makes high resolution simulations tractable. We observe a transient at the initial stage of hole formation when the hole accelerates to several times the cold-ion sound speed. Artificially imposing slow ion speed changes on a fully formed hole causes its velocity to change even when the ion stream speed in the hole frame greatly exceeds the ion thermal speed, so there are no reflected ions. The behavior that we observe in numerical simulations agrees very well with our analytic theory of hole momentum conservation and energization effects we call ``jetting''. The work was partially supported by the NSF/DOE Basic Plasma Science Partnership under Grant DE-SC0010491. Computer simulations were carried out on the MIT PSFC parallel AMD Opteron/Infiniband cluster Loki.

  9. Preventing Running Injuries through Barefoot Activity

    ERIC Educational Resources Information Center

    Hart, Priscilla M.; Smith, Darla R.

    2008-01-01

    Running has become a very popular lifetime physical activity even though there are numerous reports of running injuries. Although common theories have pointed to impact forces and overpronation as the main contributors to chronic running injuries, the increased use of cushioning and orthotics has done little to decrease running injuries. A new…

  10. Physiologic Responses to Treadmill and Water Running.

    ERIC Educational Resources Information Center

    Bishop, Phillip A.; And Others

    1989-01-01

    Presents results of a study of the physiological responses of uninjured runners to running on a treadmill and in water. Water running may lessen an injured athlete's rate of deconditioning, but indications are that the metabolic cost of water running is not significantly greater than that of treadmill running. (SM)

  11. Selective running tool for wells

    SciTech Connect

    Semar, J.E.

    1988-05-24

    A downhole running tool for positioning and locking tool support mandrels within landing nipples of thin production tubing string of a well is described comprising: (a) housing means adapted for connection to a tool string and forming an internal receptacle; (b) an elongated core member being disposed within the internal receptacle and being telescopically movable to collapsed and extended positions defined by spaced stops formed by the housing means, a portion of the elongated core member extending from the housing for connection with a tool support mandrel; and (c) releasable retainer means normally retaining the elongated core member at a substantially fixed set position within the internal receptacle and being released responsive to engagement with the landing nipple during upward movement of the downhole running tool to thus permit collapsing telescoping movement of the elongated core to a mandrel locating position within the internal receptacle.

  12. Running: Improving Form to Reduce Injuries.

    PubMed

    2015-08-01

    Running is often perceived as a good option for "getting into shape," with little thought given to the form, or mechanics, of running. However, as many as 79% of all runners will sustain a running-related injury during any given year. If you are a runner-casual or serious-you should be aware that poor running mechanics may contribute to these injuries. A study published in the August 2015 issue of JOSPT reviewed the existing research to determine whether running mechanics could be improved, which could be important in treating running-related injuries and helping injured runners return to pain-free running.

  13. Dipole radiation from a cylindrical hole in the earth.

    SciTech Connect

    Warne, Larry Kevin; Johnson, William Arthur; Basilio, Lorena I.

    2005-08-01

    This report examines the problem of an antenna radiating from a cylindrical hole in the earth and the subsequent far-zone field produced in the upper air half space. The approach used for this analysis was to first examine propagation characteristics along the hole for surrounding geologic material properties. Three cases of sand with various levels of moisture content were considered as the surrounding material to the hole. For the hole diameters and sand cases examined, the radiation through the earth medium was found to be the dominant contribution to the radiation transmitted through to the upper half-space. In the analysis presented, the radiation from a vertical and a horizontal dipole source within the hole is used to determine a closed-form expression for the radiation in the earth medium which represents a modified element factor for the source and hole combination. As the final step, the well-known results for a dipole below a half space, in conjunction with the use of Snell's law to transform the modified element factor to the upper half space, determine closed-form expressions for the far-zone radiated fields in the air region above the earth.

  14. Black hole magnetospheres

    SciTech Connect

    Nathanail, Antonios; Contopoulos, Ioannis

    2014-06-20

    We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.

  15. When Black Holes Collide

    NASA Technical Reports Server (NTRS)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  16. Drilling Square Holes.

    ERIC Educational Resources Information Center

    Smith, Scott G.

    1993-01-01

    A Reuleaux triangle is constructed by drawing an arc connecting each pair of vertices of an equilateral triangle with radius equal to the side of the triangle. Investigates the application of drilling a square hole using a drill bit in the shape of a Reuleaux triangle. (MDH)

  17. Rotating black hole hair

    NASA Astrophysics Data System (ADS)

    Gregory, Ruth; Kubizňák, David; Wills, Danielle

    2013-06-01

    A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that such a system displays much richer phenomenology than its static Schwarzschild or Reissner-Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is conical with respect to a local co-rotating frame, not with respect to the static frame at infinity.

  18. Laser bottom hole assembly

    SciTech Connect

    Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

    2014-01-14

    There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

  19. Octonionic black holes

    NASA Astrophysics Data System (ADS)

    Bossard, Guillaume

    2012-05-01

    Using algebraic tools inspired by the study of nilpotent orbits in simple Lie algebras, we obtain a large class of solutions describing interacting non-BPS black holes in {N} = 8 supergravity, which depend on 44 harmonic functions. For this purpose, we consider a truncation {E_{{{6}({6})}}}/S{p_{{c}}}( {8,{R}} ) subset {E_{{{8}({8})}}}/{{Spin}}_{{c}}^{ * }( {16} ) of the non-linear sigma model describing stationary solutions of the theory, which permits a reduction of algebraic computations to the multiplication of 27 by 27 matrices. The lift to {N} = 8 supergravity is then carried out without loss of information by using a pertinent representation of the moduli parametrizing E7(7)/SUc (8) in terms of complex valued Hermitian matrices over the split octonions, which generalise the projective coordinates of exceptional special K¨ahler manifolds. We extract the electromagnetic charges, mass and angular momenta of the solutions, and exhibit the duality invariance of the black holes distance separations. We discuss in particular a new type of interaction which appears when interacting non-BPS black holes are not aligned. Finally we will explain the possible generalisations toward the description of the most general stationary black hole solutions of {N} = 8 supergravity.

  20. Running Jobs in the Vacuum

    NASA Astrophysics Data System (ADS)

    McNab, A.; Stagni, F.; Ubeda Garcia, M.

    2014-06-01

    We present a model for the operation of computing nodes at a site using Virtual Machines (VMs), in which VMs are created and contextualized for experiments by the site itself. For the experiment, these VMs appear to be produced spontaneously "in the vacuum" rather having to ask the site to create each one. This model takes advantage of the existing pilot job frameworks adopted by many experiments. In the Vacuum model, the contextualization process starts a job agent within the VM and real jobs are fetched from the central task queue as normal. An implementation of the Vacuum scheme, Vac, is presented in which a VM factory runs on each physical worker node to create and contextualize its set of VMs. With this system, each node's VM factory can decide which experiments' VMs to run, based on site-wide target shares and on a peer-to-peer protocol in which the site's VM factories query each other to discover which VM types they are running. A property of this system is that there is no gate keeper service, head node, or batch system accepting and then directing jobs to particular worker nodes, avoiding several central points of failure. Finally, we describe tests of the Vac system using jobs from the central LHCb task queue, using the same contextualization procedure for VMs developed by LHCb for Clouds.

  1. Evolution of Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Filloux, Charline; de Freitas Pacheco, J. A.; Durier, Fabrice; Silk, Joseph

    2010-05-01

    Cosmological simulations describing both the evolution of supermassive black holes and their host galaxies were performed by using the tree PM-SPH code GADGET-2 (Springel 2005). Physical mechanisms affecting the dynamics and the physical conditions of the gas (ionization and cooling processes, local heating by stars, injection of mechanical energy by supernovae, chemical enrichment) were introduced in the present version of the code (Filloux 2009). Black holes in a state of accretion (AGNs) also inject mechanical energy in the surrounding medium, contributing for quenching the star formation activity. In all simulations a ΛCDM cosmology was adopted (h = 0.7, ΩΛ=0.7, Ωm=0.3, Ωb=0.046 and σ8=0.9). Simulations were performed in a volume with a side of 50h-1 Mpc, starting at z = 50 and through the present time (z = 0). For low and intermediate resolution runs, the initial gas mass particles are respectively 5.35× 108 M⊙ and 3.09×108 M⊙. Black holes (BHs) are represented by collisionless particles and seeds of 100 M⊙ were introduced in density peaks at z = 15, growing either by accretion or coalescence. The accretion rate from the “disk mode” is based on a turbulent viscous thin disk model whereas in the “spherical mode” the rate is given by the Bondi-Hoyle formula. When accreting matter, jets, modeled by conical regions perpendicular to the disk plane, inject kinetic energy into the surrounding medium. Two models were tested: in the first, the injected energy rate is about 10% of the gravitational energy rate released in the accretion process while in the second, the injected energy rate is based on the Blandford & Znajek (1977) mechanism. All simulations give, at z = 0, similar black hole mass function but they overestimate slightly the BH density for masses above ~ 108 M⊙. The resulting BH density in this mass range is affected by feedback processes since they control the amount of gas available for accretion. The present simulations are not

  2. Aspects of hairy black holes

    SciTech Connect

    Anabalón, Andrés; Astefanesei, Dumitru

    2015-03-26

    We review the existence of exact hairy black holes in asymptotically flat, anti-de Sitter and de Sitter space-times. We briefly discuss the issue of stability and the charging of the black holes with a Maxwell field.

  3. Towards noncommutative quantum black holes

    SciTech Connect

    Lopez-Dominguez, J. C.; Obregon, O.; Sabido, M.; Ramirez, C.

    2006-10-15

    In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole.

  4. Cascade heat transfer tests of the air cooled W501D first stage vane

    NASA Astrophysics Data System (ADS)

    Tobery, E. W.; Bunce, R. H.

    1984-06-01

    A full scale (three-vane, four-passage) first stage stator segment from a W501D engine has been studied in a cascade test facility that operates on air preheated to engine compressor discharge conditions and fired with a standard combustor and nozzle assembly. The vanes are internally cooled by means of impingement inserts over most of the surface, with pin fins being used in the trailing edge region. External film cooling is introduced by discrete jets over most of the suction surface, as well as over the aft portion of the pressure surface. The tests were run over a range of cascade pressures, temperatures and Reynolds numbers, with the vanes instrumented to yield metal temperatures, internal cooling air temperatures and pressures, and gas path static pressure near the film cooling holes.

  5. Ensuring Fully Soldered Through Holes

    NASA Technical Reports Server (NTRS)

    Blow, Raymond K.

    1987-01-01

    Simple differential-pressure soldering method provides visual evidence that hidden joints are fully soldered. Intended for soldering connector pins in plated through holes in circuit boards. Molten solder flows into plated through holes, drawn by vacuum in manifold over circuit board. Differential-pressure process ensures solder wets entire through hole around connector pin.

  6. Air cell

    NASA Astrophysics Data System (ADS)

    Okamura, Okiyoshi; Wakasa, Masayuki; Tamanoi, Yoshihito

    1991-04-01

    The present invention relates to an air cell. This air cell provides a compact light-weight power source for model aircraft permitting them to fly for an extended period so that they may be used for such practical purposes as crop dusting, surveying, and photographing. The cell is comprised of a current collector so disposed between a magnesium, zinc, or aluminum alloy cathode and a petroleum graphite anode that it is in contact with the anode. The anode is formed by adding polytetrafluoroethylene dispersion liquid in a mixture of active carbon and graphite powder, pouring the mixture into a mold and heating it to form the anode. It is fabricated by a plurality of anode sections and is formed with at least one hole so that it can provide a cell which is compact in size and light in weight yet is capable of generating a high output. The anode, the cathode, and a separator are wetted by an electrolytic liquid. The electrolyte is continuously supplied through the life of the cell.

  7. Devils Hole, Nevada: revisited

    NASA Astrophysics Data System (ADS)

    Spötl, C.; Dublyansky, Y.

    2012-04-01

    Among the ever increasing number of caves visited and studied by paleoclimate scientists around the globe one site is special for a number of reasons. First described in the literature in 1988, Devils Hole is a geometrically simple cave developed along an extensional fracture in the Amargosa Desert of SW Nevada. The deeper portion of this cavity is phreatic and part of a regional aquifer whose lowest discharge point is Death Valley. Landmark studies by Ike Winograd's team examined thick calcite crusts present on the walls of this and a neighboring cave (termed Devils Hole #2) and retrieved one of the most remarkable (and thought-provoking) isotope proxy records covering the last half million of years (1992). More recently, Coplen (2007) scrutinized the stable isotope systematics at Devils Hole. His results suggest that this setting represents a rare example of inorganic calcite precipitation essentially at isotopic equilibrium. We obtained permission from the Death Valley National Park Service to study and sample Devils Hole #2. While previous studies were based on samples from the phreatic zone we cored the calcite crust just above the groundwater table in an attempt to extend the original record further back in time and to obtain direct paleowater isotope data. Stable isotope data obtained along one core show a very high degree of similarity with the published DH11 core and a first set of U-series dates confirms the stratigraphy down to 476 ka. Older calcite also shows glacial-interglacial oscillations in both carbon and oxygen isotopes. A tentative correlation with Antarctic and deep-sea isotope records suggests that the lower part of the calcite is ca. 800 ka old (i.e. MIS 20). The cores show petrographic evidence of falling groundwater levels during MIS 9, 7 and 5e, but there are no indications of major hiati. Interestingly, growth at our drill location ended shortly after 20 ka BP, i.e. much later than at the subaqueous site in Devils Hole proper where DH11

  8. NORTHWEST SIDE OF THE HOUSE WHERE A HOLE HAS BEEN ...

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

    NORTHWEST SIDE OF THE HOUSE WHERE A HOLE HAS BEEN CUT INTO THE WALL TO ALLOW FOR THROUGH WALL AIR CONDITIONERS - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Single-Family Type 6, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

  9. Largest-ever Ozone Hole over Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA instrument has detected an Antarctic ozone 'hole' (what scientists call an 'ozone depletion area') that is three times larger than the entire land mass of the United States-the largest such area ever observed. The 'hole' expanded to a record size of approximately 11 million square miles (28.3 million square kilometers) on Sept. 3, 2000. The previous record was approximately 10.5 million square miles (27.2 million square km) on Sept. 19, 1998. The ozone hole's size currently has stabilized, but the low levels in its interior continue to fall. The lowest readings in the ozone hole are typically observed in late September or early October each year. 'These observations reinforce concerns about the frailty of Earth's ozone layer. Although production of ozone-destroying gases has been curtailed under international agreements, concentrations of the gases in the stratosphere are only now reaching their peak. Due to their long persistence in the atmosphere, it will be many decades before the ozone hole is no longer an annual occurrence,' said Dr. Michael J. Kurylo, manager of the Upper Atmosphere Research Program, NASA Headquarters, Washington, DC. Ozone molecules, made up of three atoms of oxygen, comprise a thin layer of the atmosphere that absorbs harmful ultraviolet radiation from the Sun. Most atmospheric ozone is found between approximately six miles (9.5 km) and 18 miles (29 km) above the Earth's surface. Scientists continuing to investigate this enormous hole are somewhat surprised by its size. The reasons behind the dimensions involve both early-spring conditions, and an extremely intense Antarctic vortex. The Antarctic vortex is an upper-altitude stratospheric air current that sweeps around the Antarctic continent, confining the Antarctic ozone hole. 'Variations in the size of the ozone hole and of ozone depletion accompanying it from one year to the next are not unexpected,' said Dr. Jack Kaye, Office of Earth Sciences Research Director, NASA Headquarters

  10. Barefoot running: does it prevent injuries?

    PubMed

    Murphy, Kelly; Curry, Emily J; Matzkin, Elizabeth G

    2013-11-01

    Endurance running has evolved over the course of millions of years and it is now one of the most popular sports today. However, the risk of stress injury in distance runners is high because of the repetitive ground impact forces exerted. These injuries are not only detrimental to the runner, but also place a burden on the medical community. Preventative measures are essential to decrease the risk of injury within the sport. Common running injuries include patellofemoral pain syndrome, tibial stress fractures, plantar fasciitis, and Achilles tendonitis. Barefoot running, as opposed to shod running (with shoes), has recently received significant attention in both the media and the market place for the potential to promote the healing process, increase performance, and decrease injury rates. However, there is controversy over the use of barefoot running to decrease the overall risk of injury secondary to individual differences in lower extremity alignment, gait patterns, and running biomechanics. While barefoot running may benefit certain types of individuals, differences in running stance and individual biomechanics may actually increase injury risk when transitioning to barefoot running. The purpose of this article is to review the currently available clinical evidence on barefoot running and its effectiveness for preventing injury in the runner. Based on a review of current literature, barefoot running is not a substantiated preventative running measure to reduce injury rates in runners. However, barefoot running utility should be assessed on an athlete-specific basis to determine whether barefoot running will be beneficial.

  11. Black Holes in String Theory

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; El-Showk, Sheer; Vercnocke, Bert

    These lectures notes provide a fast-track introduction to modern developments in black hole physics within string theory, including microscopic computations of the black hole entropy as well as construction and quantization of microstates using supergravity. These notes are largely self-contained and should be accessible to students at an early PhD or Masters level. Topics covered include the black holes in supergravity, D-branes, Strominger-Vafa's computation of the black hole entropy via D-branes, AdS-CFT and its applications to black hole phyisics, multicenter solutions, and the geometric quantization of the latter.

  12. Fatigue associated with prolonged graded running.

    PubMed

    Giandolini, Marlene; Vernillo, Gianluca; Samozino, Pierre; Horvais, Nicolas; Edwards, W Brent; Morin, Jean-Benoît; Millet, Guillaume Y

    2016-10-01

    Scientific experiments on running mainly consider level running. However, the magnitude and etiology of fatigue depend on the exercise under consideration, particularly the predominant type of contraction, which differs between level, uphill, and downhill running. The purpose of this review is to comprehensively summarize the neurophysiological and biomechanical changes due to fatigue in graded running. When comparing prolonged hilly running (i.e., a combination of uphill and downhill running) to level running, it is found that (1) the general shape of the neuromuscular fatigue-exercise duration curve as well as the etiology of fatigue in knee extensor and plantar flexor muscles are similar and (2) the biomechanical consequences are also relatively comparable, suggesting that duration rather than elevation changes affects neuromuscular function and running patterns. However, 'pure' uphill or downhill running has several fatigue-related intrinsic features compared with the level running. Downhill running induces severe lower limb tissue damage, indirectly evidenced by massive increases in plasma creatine kinase/myoglobin concentration or inflammatory markers. In addition, low-frequency fatigue (i.e., excitation-contraction coupling failure) is systematically observed after downhill running, although it has also been found in high-intensity uphill running for different reasons. Indeed, low-frequency fatigue in downhill running is attributed to mechanical stress at the interface sarcoplasmic reticulum/T-tubule, while the inorganic phosphate accumulation probably plays a central role in intense uphill running. Other fatigue-related specificities of graded running such as strategies to minimize the deleterious effects of downhill running on muscle function, the difference of energy cost versus heat storage or muscle activity changes in downhill, level, and uphill running are also discussed.

  13. Black Holes and Firewalls

    NASA Astrophysics Data System (ADS)

    Polchinski, Joseph

    2015-04-01

    Our modern understanding of space, time, matter, and even reality itself arose from the three great revolutions of the early twentieth century: special relativity, general relativity, and quantum mechanics. But a century later, this work is unfinished. Many deep connections have been discovered, but the full form of a unified theory incorporating all three principles is not known. Thought experiments and paradoxes have often played a key role in figuring out how to fit theories together. For the unification of general relativity and quantum mechanics, black holes have been an important arena. I will talk about the quantum mechanics of black holes, the information paradox, and the latest version of this paradox, the firewall. The firewall points to a conflict between our current theories of spacetime and of quantum mechanics. It may lead to a new understanding of how these are connected, perhaps based on quantum entanglement.

  14. Prisons of light : black holes

    NASA Astrophysics Data System (ADS)

    Ferguson, Kitty

    What is a black hole? Could we survive a visit to one -- perhaps even venture inside? Have we yet discovered any real black holes? And what do black holes teach us about the mysteries of our Universe? These are just a few of the tantalizing questions examined in this tour-de-force, jargon-free review of one of the most fascinating topics in modern science. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light - Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.

  15. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.

    1988-01-01

    Processes that may be responsible for the thinning in the ozone layer above the South Pole are described. The chlorine catalytic cycle which destroys ozone is described, as are the major types of reactions that are believed to interfere with this cycle by forming chlorine reservoirs. The suspected contributions of polar stratospheric clouds to these processes are examined. Finally, the possibility that the ozone hole may be due more to a shift in atmospheric dynamics than to chemical destruction is addressed.

  16. Effective leg stiffness in running.

    PubMed

    Blum, Yvonne; Lipfert, Susanne W; Seyfarth, Andre

    2009-10-16

    Leg stiffness is a common parameter used to characterize leg function during bouncing gaits, like running and hopping. In the literature, different methods to approximate leg stiffness based on kinetic and kinematic parameters are described. A challenging point in estimating leg stiffness is the definition of leg compression during contact. In this paper four methods (methods A-D) based on ground reaction forces (GRF) and one method (method E) relying on temporal parameters are described. Leg stiffness calculated by these five methods is compared with running patterns, predicted by the spring mass model. The best and simplest approximation of leg stiffness is method E. It requires only easily accessible parameters (contact time, flight time, resting leg length, body mass and the leg's touch down angle). Method D is of similar quality but additionally requires the time-dependent progression of the GRF. The other three methods show clear differences from the model predictions by over- or underestimating leg stiffness, especially at slow speeds. Leg stiffness is derived from a conceptual model of legged locomotion and does not exist without this model. Therefore, it is important to prove which experimental method is suited best for approximating the stiffness in a specific task. This will help to interpret the predictions of the conceptual model in comparison with experimental data.

  17. Perspectives: Black Holes

    NASA Technical Reports Server (NTRS)

    Dolan, Joseph F.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    When asked to discuss Cyg XR-1, E. E. Salpeter once concluded, 'A black hole in Cyg X(R)-1 is the most conservative hypothesis.' Recent observations now make it likely that a black hole in Cyg XR-1 is the only hypothesis tenable. Chandrasekhar first showed that compact stars - those with the inward force of gravity on their outer layers balanced by the pressure generated by the Pauli exclusion principle acting on its electrons (in white dwarfs) or nucleons (in neutron stars) - have a maximum mass. Equilibrium is achieved at a minimum of the total energy of the star, which is the sum of the positive Fermi energy and the negative gravitational energy. The maximum mass attainable in equilibrium is found by setting E = 0: M(max) = 1.5 M(Sun). If the mass of the star is larger than this, then E can be decreased without bound by decreasing the star's radius and increasing its (negative) gravitational energy. No equilibrium value of the radius exist, and general relativity predicts that gravitational collapse to a point occurs. This point singularity is a black hole.

  18. HVM capabilities of CPE run-to-run overlay control

    NASA Astrophysics Data System (ADS)

    Subramany, Lokesh; Chung, Woong Jae; Gutjahr, Karsten; Garcia-Medina, Miguel; Sparka, Christian; Yap, Lipkong; Demirer, Onur; Karur-Shanmugam, Ramkumar; Riggs, Brent; Ramanathan, Vidya; Robinson, John C.; Pierson, Bill

    2015-03-01

    With the introduction of N2x and N1x process nodes, leading-edge factories are facing challenging demands of shrinking design margins. Previously un-corrected high-order signatures, and un-compensated temporal changes of high-order signatures, carry an important potential for improvement of on-product overlay (OPO). Until recently, static corrections per exposure (CPE), applied separately from the main APC correction, have been the industry's standard for critical layers [1], [2]. This static correction is setup once per device and layer and then updated periodically or when a machine change point generates a new overlay signature. This is a non-ideal setup for two reasons. First, any drift or sudden shift in tool signature between two CPE update periods can cause worse OPO and a higher rework rate, or, even worse, lead to yield loss at end of line. Second, these corrections are made from full map measurements that can be in excess of 1,000 measurements per wafer [3]. Advanced overlay control algorithms utilizing Run-to-Run (R2R) CPE can be used to reduce the overlay signatures on product in High Volume Manufacturing (HVM) environments. In this paper, we demonstrate the results of a R2R CPE control scheme in HVM. The authors show an improvement up to 20% OPO Mean+3Sigma values on several critical immersion layers at the 28nm and 14 nm technology nodes, and a reduction of out-of-spec residual points per wafer (validated on full map). These results are attained by closely tracking process tool signature changes by means of APC, and with an affordable metrology load which is significantly smaller than full wafer measurements.

  19. The variation of heat transfer coefficient, adiabatic effectiveness and aerodynamic loss with film cooling hole shape.

    PubMed

    Sargison, J E; Guo, S M; Oldfield, M L; Rawlinson, A J

    2001-05-01

    The heat transfer coefficient and adiabatic effectiveness of cylindrical, fan shaped holes and a slot are presented for the region zero to 50 diameters downstream of the holes. Narrow-band liquid crystals were used on a heated flat plate with heated air coolant. These parameters have been measured in a steady state, low speed facility at engine representative Reynolds number based on hole diameter and pressure difference ratio (ideal momentum flux ratio). The aerodynamic loss due to each of the film cooling geometries has been measured using a traverse of the boundary layer far downstream of the film cooling holes. Compared to the cylindrical holes, the fan shaped hole case showed an improvement in the uniformity of cooling downstream of the holes and in the level of laterally averaged film cooling effectiveness. The fan effectiveness approached the slot level and both the fan and cylindrical hole cases show lower heat transfer coefficients than the slot and non film cooled cases based on the laterally averaged results. The drawback to the fan shaped hole was that the aerodynamic loss was significantly higher than both the slot and cylindrical hole values due to inefficient diffusion in the hole exit expansion.

  20. Ventilatory Threshold, Running Economy and Distance Running Performance of Trained Athletes.

    ERIC Educational Resources Information Center

    Powers, Scott K.; And Others

    1983-01-01

    In an attempt to identify physiological factors that account for success in distance running, researchers evaluated relationships among ventilatory threshold, running economy, and distance running performance. Subjects were trained male runners with similar maximal aerobic power. (Authors/PP)

  1. Numerical analysis of a side-hole birefringent photonic crystal fiber with high-pressure sensitivity

    NASA Astrophysics Data System (ADS)

    Li, Duanming; Zhang, Wei; Zhou, Guiyao

    2016-09-01

    A birefringent structured side-holes photonic crystal fiber (PCF) with high sensitivity is designed for pressure sensing. Simulation results show that the birefringence and relevant sensitivity are strongly influenced by the air-holes' sizes and the distance between the fiber core and side-hole. The modal birefringence and the polarimetric pressure sensitivity can be up to 3.943×10-3 and -3.67×10-5 MPa-1 at 1.55 μm, respectively. The proposed side-holes PCF possesses promising applications for pressure sensing.

  2. Notch Sensitivity of Fatigue Behavior of a Hi-Nicalon™/SiC-B4C Composite at 1,200 °C in Air and in Steam

    NASA Astrophysics Data System (ADS)

    Ruggles-Wrenn, M. B.; Kurtz, G.

    2013-10-01

    The effect of holes on the fatigue life of a non-oxide ceramic composite processed via chemical vapor infiltration (CVI) was examined at 1,200 °C in laboratory air and in steam. The effect of holes on tensile strength at 1,200 °C was also evaluated. The composite comprised laminated woven Hi-Nicalon™ fibers in an oxidation inhibited matrix, which consisted of alternating layers of silicon carbide and boron carbide. Fiber preforms had pyrolytic carbon fiber coating with boron carbon overlay applied. Unnotched specimens and specimens with a center hole having a radius to width ratio of 0.24 were tested in tension-tension fatigue at 0.1 Hz and at 1.0 Hz. The fatigue stresses ranged from 100 to 140 MPa in air and in steam. Fatigue run-out was defined as 105 cycles at 0.1 Hz and as 2 × 105 cycles at 1.0 Hz. The net-section strength was less than the unnotched ultimate tensile strength. Comparison of notched and unnotched data also revealed that the fatigue performance was notch insensitive in both air and steam environments. Composite microstructure, as well as damage and failure mechanisms were investigated.

  3. Is Running Bad for Your Knees?

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_162903.html Is Running Bad for Your Knees? Study suggests it may ... THURSDAY, Jan. 5, 2017 (HealthDay News) -- Everybody believes running can leave you sore and swollen, right? Well, ...

  4. Running Parallel Discrete Event Simulators on Sierra

    SciTech Connect

    Barnes, P. D.; Jefferson, D. R.

    2015-12-03

    In this proposal we consider porting the ROSS/Charm++ simulator and the discrete event models that run under its control so that they run on the Sierra architecture and make efficient use of the Volta GPUs.

  5. Running as an Adjunct to Psychotherapy.

    ERIC Educational Resources Information Center

    Leer, Frederic

    1980-01-01

    Physical benefits of running have been highly publicized. Explores the equally valuable psychological benefits to be derived from running and examines how mastering a physical skill can be generalized to mastery in other areas of life. (Author)

  6. Adding run history to CLIPS

    NASA Technical Reports Server (NTRS)

    Tuttle, Sharon M.; Eick, Christoph F.

    1991-01-01

    To debug a C Language Integrated Production System (CLIPS) program, certain 'historical' information about a run is needed. It would be convenient for system builders to have the capability to request such information. We will discuss how historical Rete networks can be used for answering questions that help a system builder detect the cause of an error in a CLIPS program. Moreover, the cost of maintaining a historical Rete network is compared with that for a classical Rete network. We will demonstrate that the cost for assertions is only slightly higher for a historical Rete network. The cost for handling retraction could be significantly higher; however, we will show that by using special data structures that rely on hashing, it is also possible to implement retractions efficiently.

  7. Air transparent soundproof window

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Hoon; Lee, Seong-Hyun

    2014-11-01

    A soundproof window or wall which is transparent to airflow is presented. The design is based on two wave theories: the theory of diffraction and the theory of acoustic metamaterials. It consists of a three-dimensional array of strong diffraction-type resonators with many holes centered on each individual resonator. The negative effective bulk modulus of the resonators produces evanescent wave, and at the same time the air holes with subwavelength diameter existed on the surfaces of the window for macroscopic air ventilation. The acoustic performance levels of two soundproof windows with air holes of 20mm and 50mm diameters were measured. The sound level was reduced by about 30 - 35dB in the frequency range of 400 - 5,000Hz with the 20mm window, and by about 20 - 35dB in the frequency range of 700 - 2,200Hz with the 50mm window. Multi stop-band was created by the multi-layers of the window. The attenuation length or the thickness of the window was limited by background noise. The effectiveness of the soundproof window with airflow was demonstrated by a real installation.

  8. Air transparent soundproof window

    SciTech Connect

    Kim, Sang-Hoon; Lee, Seong-Hyun

    2014-11-15

    A soundproof window or wall which is transparent to airflow is presented. The design is based on two wave theories: the theory of diffraction and the theory of acoustic metamaterials. It consists of a three-dimensional array of strong diffraction-type resonators with many holes centered on each individual resonator. The negative effective bulk modulus of the resonators produces evanescent wave, and at the same time the air holes with subwavelength diameter existed on the surfaces of the window for macroscopic air ventilation. The acoustic performance levels of two soundproof windows with air holes of 20mm and 50mm diameters were measured. The sound level was reduced by about 30 - 35dB in the frequency range of 400 - 5,000Hz with the 20mm window, and by about 20 - 35dB in the frequency range of 700 - 2,200Hz with the 50mm window. Multi stop-band was created by the multi-layers of the window. The attenuation length or the thickness of the window was limited by background noise. The effectiveness of the soundproof window with airflow was demonstrated by a real installation.

  9. Dynamic gearing in running dogs.

    PubMed

    Carrier, D R; Gregersen, C S; Silverton, N A

    1998-12-01

    Dynamic gearing is a mechanism that has been suggested to enhance the performance of skeletal muscles by maintaining them at the shortening velocities that maximize their power or efficiency. We investigated this hypothesis in three domestic dogs during trotting and galloping. We used ground force recordings and kinematic analysis to calculate the changes in gear ratio that occur during the production of the external work of locomotion. We also monitored length changes of the vastus lateralis muscle, an extensor muscle of the knee, using sonomicrometry in four additional dogs to determine the nature and rate of active shortening of this muscle. During both trotting and galloping, the gear ratios of the extensor muscles of the elbow, wrist and ankle joints were relatively constant early in limb support, but decreased rapidly during the second half of support. The gear ratio at the hip exerted an extensor moment initially, but decreased throughout limb support and became negative midway through support. This pattern of decreasing gear ratio during the second half of support indicates that dynamic gearing does not maximize muscle power or efficiency at the elbow, wrist, hip and ankle joints. In contrast, the extensor muscles of the shoulder and knee joints exhibited an increase in gear ratio during limb support. In two dogs, the vastus lateralis muscle shortened at a relatively constant rate of 3.7-4 lengths s-1 during intermediate-speed galloping. This pattern of increasing gear ratio and constant velocity of muscle shortening at the knee joint is consistent with the hypothesis of dynamic gearing. Given the amount of work done at the knee and shoulder joints of running dogs, dynamic gearing may contribute to the economy of constant-speed running and may be important to integrated limb function.

  10. Running Patterns of Highly Skilled Distance Runners.

    ERIC Educational Resources Information Center

    Dunetts, Michael J.; Dillman, Charles J.

    The biomechanical elements inherent in the running styles of Olympic-level athletes were examined in order to obtain a range of parameter values for specific running velocities. Forty-eight athletes participated in middle and long distance running events that were filmed and later analyzed to determine the relationship between the physical…

  11. Head injury from a bungee run.

    PubMed

    Singh, Pankaj; Convery, Fiona; Watt, Michael; Fulton, Ailsa; McKinstry, Steven; Flannery, Thomas

    2012-04-01

    An adaptation of bungee jumping, 'bungee running', involves participants attempting to run as far as they can whilst connected to an elastic rope which is anchored to a fixed point. Usually considered a safe recreational activity, we report a potentially life-threatening head injury following a bungee running accident.

  12. An Epidemiologic Perspective. Does Running Cause Osteoarthritis?

    ERIC Educational Resources Information Center

    Eichner, Edward R.

    1989-01-01

    A review of literature on exercise and arthritis considers relevant epidemiologic and experimental studies of animals and humans, focusing on the relationship between running and osteoarthritis. No conclusive evidence exists that running causes osteoarthritis; research trends suggest that running may slow the functional aspects of musculoskeletal…

  13. Power Systems Development Facility Gasification Test Run TC08

    SciTech Connect

    Southern Company Services

    2002-06-30

    This report discusses Test Campaign TC08 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier in air- and oxygen-blown modes during TC08. Test Run TC08 was started on June 9, 2002 and completed on June 29. Both gasifier and PCD operations were stable during the test run with a stable baseline pressure drop. The oxygen feed supply system worked well and the transition from air to oxygen blown was smooth. The gasifier temperature was varied between 1,710 and 1,770 F at pressures from 125 to 240 psig. The gasifier operates at lower pressure during oxygen-blown mode due to the supply pressure of the oxygen system. In TC08, 476 hours of solid circulation and 364 hours of coal feed were attained with 153 hours of pure oxygen feed. The gasifier and PCD operations were stable in both enriched air and 100 percent oxygen blown modes. The oxygen concentration was slowly increased during the first transition to full oxygen-blown operations. Subsequent transitions from air to oxygen blown could be completed in less than 15 minutes. Oxygen-blown operations produced the highest synthesis gas heating value to date, with a projected synthesis gas heating value averaging 175 Btu/scf. Carbon conversions averaged 93 percent, slightly lower than carbon conversions achieved during air-blown gasification.

  14. Black Holes, Worm Holes, and Future Space Propulsion

    NASA Technical Reports Server (NTRS)

    Barret, Chris

    2000-01-01

    NASA has begun examining the technologies needed for an Interstellar Mission. In 1998, a NASA Interstellar Mission Workshop was held at the California Institute of Technology to examine the technologies required. Since then, a spectrum of research efforts to support such a mission has been underway, including many advanced and futuristic space propulsion concepts which are being explored. The study of black holes and wormholes may provide some of the breakthrough physics needed to travel to the stars. The first black hole, CYGXI, was discovered in 1972 in the constellation Cygnus X-1. In 1993, a black hole was found in the center of our Milky Way Galaxy. In 1994, the black hole GRO J1655-40 was discovered by the NASA Marshall Space Flight center using the Gamma Ray Observatory. Today, we believe we have found evidence to support the existence of 19 black holes, but our universe may contain several thousands. This paper discusses the dead star states - - both stable and unstable, white dwarfs, neutron stars, pulsars, quasars, the basic features and types of black holes: nonspinning, nonspinning with charge, spinning, and Hawking's mini black holes. The search for black holes, gravitational waves, and Laser Interferometer Gravitational Wave Observatory (LIGO) are reviewed. Finally, concepts of black hole powered space vehicles and wormhole concepts for rapid interstellar travel are discussed in relation to the NASA Interstellar Mission.

  15. Air Research

    EPA Pesticide Factsheets

    EPA's air research provides the critical science to develop and implement outdoor air regulations under the Clean Air Act and puts new tools and information in the hands of air quality managers and regulators to protect the air we breathe.

  16. The First Black Holes

    NASA Astrophysics Data System (ADS)

    Abel, T.

    star. Within this wide range of possible initial masses the death of these star will lead very different remnants (Heger and Woosley 2001). In the case of stars with masses larger than 260 solar mass no metals may be released in black holes are the natural outcome. This may be an interesting possibility to form intermediate mass black holes which are attractive seeds to be nurtured to the super-massive black holes observed in the centers of nearby galaxies. However, no metals would be released and it would prove difficult to understand the transition to the formation of low mass metal enriched population II stars. Stars with masses below 140 solar masses would enrich the intergalactic medium as well as form massive black holes. The coincidence of the Kelvin Helmholtz time with our computed accretion times at about 120 solar masses may argue in favor of such smaller masses. These first black holes may well leave the halos in which they formed for even rather modest kick velocities >~ 10 km/s. Nevertheless, up to about one hundred thousand of these first black holes may remain in the Milky Way. The realization that structure formation began within one hundred million years after big bang makes it difficult to study observationally these first crucial steps. Future observatories have hence to focus on larger collecting areas and wavelengths for which the universe is transparent up to redshifts of 30. XEUS offers the chance to open a new window to these so far dark ages. The limiting masses quoted here rely on stellar models of primordial stars that do not include rotation, magnetic fields or mass loss and hence are somewhat uncertain.

  17. Bore hole navigator

    SciTech Connect

    Hoffman, G.J.

    1987-09-29

    A bore hole navigator is described comprising a two axis platform for lowering down a bore hole on a cable with its longitudinal axis parallel to the local bore hole direction. The two axis platform has an outer gimbal, bearing supported on the outer gimbal axis for rotation about the longitudinal axis of the platform, and an inner gimbal axis orthogonal the the outer gimbal axis. The inner gimbal axis has multiple axis segments spaced along the longitudinal axis of the platform and each bearing supported on the outer gimbal. The inner gimbal axis segment has a two axis gyro mounted thereon with its spin axis orthogonal to the respective inner gimbal axis segment, a first gyro sensitive axis parallel to the respective inner gimbal axis segment and a second gyro sensitive axis orthogonal to the spin axis. The second inner gimbal axis segment has a pitch torquer thereon operative to provide a controllable torque about the respective inner gimbal axis segment. The third inner gimbal axis segment has a pitch resolver thereon operative to measure rotation of the respective inner gimbal axis segment with respect to the outer gimbal. The first, second and third inner gimbal axis segments are coupled to rotate together. The outer gimbal has a yaw torquer thereon to provide a controllable torque about the outer gimbal axis, and a yaw resolver thereon to measure rotation of the outer gimbal about the outer gimbal axis. The outer gimbal also has a single axis accelerometer therein having its sensitive axis orthogonal to the outer gimbal axis and the inner gimbal axis segments.

  18. Deep Hole in 'Clovis'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1

    At a rock called 'Clovis,' the rock abrasion tool on NASA's Mars Exploration Rover Spirit cut a 9-millimeter (0.35-inch) hole during the rover's 216th martian day, or sol (Aug. 11, 2004). The hole is the deepest drilled in a rock on Mars so far. This approximately true-color view was made from images taken by Spirit's panoramic camera on sol 226 (Aug. 21, 2004) at around 12:50 p.m. local true solar time -- early afternoon in Gusev Crater on Mars. To the right is a 'brush flower' of circles produced by scrubbing the surface of the rock with the abrasion tool's wire brush. Scientists used rover's Moessbauer spectrometer and alpha particle X-ray spectrometer to look for iron-bearing minerals and determine the elemental chemical composition of the rock. This composite combines images taken with the camera's 750-, 530-, and 430-nanometer filters. The grayish-blue hue in this image suggests that the interior of the rock contains iron minerals that are less oxidized than minerals on the surface. The diameter of the hole cut into the rock is 4.5 centimeters (1.8 inches).

    Data on the graph (Figure 1) from the alpha particle X-ray spectrometer instrument on the robotic arm of NASA's Mars Exploration Rover Spirit reveal the elemental chemistry of two rocks, 'Ebenezer' and 'Clovis,' (see PIA06914) in the 'Columbia Hills.' Scientists found, through comparison of the rocks' chemistry, that Ebenezer and Clovis have very different compositions from the rocks on the Gusev plains.

  19. Black Holes in Higher Dimensions

    NASA Astrophysics Data System (ADS)

    Horowitz, Gary T.

    2012-04-01

    List of contributors; Preface; Part I. Introduction: 1. Black holes in four dimensions Gary Horowitz; Part II. Five Dimensional Kaluza-Klein Theory: 2. The Gregory-Laflamme instability Ruth Gregory; 3. Final state of Gregory-Laflamme instability Luis Lehner and Frans Pretorius; 4. General black holes in Kaluza-Klein theory Gary Horowitz and Toby Wiseman; Part III. Higher Dimensional Solutions: 5. Myers-Perry black holes Rob Myers; 6. Black rings Roberto Emparan and Harvey Reall; Part IV. General Properties: 7. Constraints on the topology of higher dimensional black holes Greg Galloway; 8. Blackfolds Roberto Emparan; 9. Algebraically special solutions in higher dimensions Harvey Reall; 10. Numerical construction of static and stationary black holes Toby Wiseman; Part V. Advanced Topics: 11. Black holes and branes in supergravity Don Marolf; 12. The gauge/gravity duality Juan Maldacena; 13. The fluid/gravity correspondence Veronika Hubeny, Mukund Rangamani and Shiraz Minwalla; 14. Horizons, holography and condensed matter Sean Hartnoll; Index.

  20. Particle-Hole Ladders

    NASA Astrophysics Data System (ADS)

    Feldman, Joel; Knörrer, Horst; Trubowitz, Eugene

    A self contained analysis demonstrates that the sum of all particle-hole ladder contributions for a two dimensional, weakly coupled fermion gas with a strictly convex Fermi curve at temperature zero is bounded. This is used in our construction of two dimensional Fermi liquids. This article contains the statements of the main results. The proofs are contained in the full, electronic, article. Electronic Supplementary Material: Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00220-004-1038-2.

  1. Surfing a Black Hole

    NASA Astrophysics Data System (ADS)

    2002-10-01

    Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours [1] Summary An international team of astronomers [2], lead by researchers at the Max-Planck Institute for Extraterrestrial Physics (MPE) , has directly observed an otherwise normal star orbiting the supermassive black hole at the center of the Milky Way Galaxy. Ten years of painstaking measurements have been crowned by a series of unique images obtained by the Adaptive Optics (AO) NAOS-CONICA (NACO) instrument [3] on the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. It turns out that earlier this year the star approached the central Black Hole to within 17 light-hours - only three times the distance between the Sun and planet Pluto - while travelling at no less than 5000 km/sec . Previous measurements of the velocities of stars near the center of the Milky Way and variable X-ray emission from this area have provided the strongest evidence so far of the existence of a central Black Hole in our home galaxy and, implicitly, that the dark mass concentrations seen in many nuclei of other galaxies probably are also supermassive black holes. However, it has not yet been possible to exclude several alternative configurations. In a break-through paper appearing in the research journal Nature on October 17th, 2002, the present team reports their exciting results, including high-resolution images that allow tracing two-thirds of the orbit of a star designated "S2" . It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the Milky Way. The orbital period is just over 15 years. The new measurements exclude with high confidence that the central dark mass consists of a cluster of unusual stars or elementary particles, and leave little doubt of the presence of a supermassive black hole at the centre of the galaxy in which we live . PR Photo 23a/02 : NACO image of the central region of the Milky Way

  2. The Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Jones, Anna E.

    2008-07-01

    Since the mid 1970s, the ozone layer over Antarctica has experienced massive destruction during every spring. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are. We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over Antarctica. For the historical perspective, the events leading up to the discovery of the 'hole' are presented, as well as the response from the international community and the measures taken to protect the ozone layer now and into the future.

  3. Biomechanics and analysis of running gait.

    PubMed

    Dugan, Sheila A; Bhat, Krishna P

    2005-08-01

    Physical activity, including running, is important to general health by way of prevention of chronic illnesses and their precursors. To keep runners healthy, it is paramount that one has sound knowledge of the biomechanics of running and assessment of running gait. More so, improving performance in competitive runners is based in sound training and rehabilitation practices that are rooted firmly in biomechanical principles. This article summarized the biomechanics of running and the means with which one can evaluate running gait. The gait assessment techniques for collecting and analyzing kinetic and kinematic data can provide insights into injury prevention and treatment and performance enhancement.

  4. Acoustic black holes: recent developments in the theory and applications.

    PubMed

    Krylov, Victor

    2014-08-01

    Acoustic black holes are relatively new physical objects that have been introduced and investigated mainly during the last decade. They can absorb almost 100% of the incident wave energy, and this makes them very attractive for such traditional engineering applications as vibration damping in different engineering structures and sound absorption in gases and liquids. They also could be useful for some ultrasonic devices using Lamb wave propagation to provide anechoic termination for such waves. So far, acoustic black holes have been investigated mainly for flexural waves in thin plates, for which the required gradual changes in local wave velocity with distance can be easily achieved by changing the plates' local thickness. The present paper provides a brief review of the theory of acoustic black holes, including their comparison with optic black holes introduced about five years ago. Review is also given of the recent experimental work carried out at Loughborough University on damping structural vibrations using the acoustic black hole effect. This is followed by the discussion on potential applications of the acoustic black hole effect for sound absorption in air.

  5. Inverted Internal Limiting Membrane Flap For Large Traumatic Macular Holes

    PubMed Central

    Abou Shousha, Mohsen Ahmed

    2016-01-01

    Abstract The aim of the study was to assess the role of inverted internal limiting membrane flap as a treatment option for large traumatic macular holes. This is a prospective noncomparative study in which 12 eyes with large traumatic macular holes (basal diameter of 1300–2800 μm) since 3 to 6 months were subjected to standard 23-gauge vitrectomy with removal of the posterior hyaloid, brilliant blue G (BBG)-assisted internal limiting membrane peeling in a circular fashion keeping it attached to the edge of the hole to create a flap. At the end of the surgery, air fluid exchange was done with inversion of the internal limiting membrane flap inside the macular hole using the soft tipped cannula and sulfur hexafluoride 20% as tamponade. The main follow-up measures are the best corrected visual acuity and the optical coherence tomography for 6 to 9 months. All the included eyes had a closed hole from the first week postoperative and along the follow-up period (6–9 months). The best corrected visual acuity improved from 20/2000 to 20/200 with a median of 20/400 preoperatively to 20/400 to 20/50 with a median of 20/100 at the end of follow-up period. Inverted internal limiting membrane flap is a good adjuvant to standard vitrectomy in the management of large traumatic macular holes that led to the 100% closure rate and improvement of best corrected visual acuity. PMID:26817894

  6. Direct Numerical Simulation of A Shaped Hole Film Cooling Flow

    NASA Astrophysics Data System (ADS)

    Oliver, Todd; Moser, Robert

    2015-11-01

    The combustor exit temperatures in modern gas turbine engines are generally higher than the melting temperature of the turbine blade material. Film cooling, where cool air is fed through holes in the turbine blades, is one strategy which is used extensively in such engines to reduce heat transfer to the blades and thus reduce their temperature. While these flows have been investigated both numerically and experimentally, many features are not yet well understood. For example, the geometry of the hole is known to have a large impact on downstream cooling performance. However, the details of the flow in the hole, particularly for geometries similar to those used in practice, are generally know well-understood, both because it is difficult to experimentally observe the flow inside the hole and because much of the numerical literature has focused on round hole simulations. In this work, we show preliminary direct numerical simulation results for a film cooling flow passing through a shaped hole into a the boundary layer developing on a flat plate. The case has density ratio 1.6, blowing ratio 2.0, and the Reynolds number (based on momentum thickness) of incoming boundary layer is approximately 600. We compare the new simulations against both previous experiments and LES.

  7. Inverted Internal Limiting Membrane Flap For Large Traumatic Macular Holes.

    PubMed

    Abou Shousha, Mohsen Ahmed

    2016-01-01

    The aim of the study was to assess the role of inverted internal limiting membrane flap as a treatment option for large traumatic macular holes.This is a prospective noncomparative study in which 12 eyes with large traumatic macular holes (basal diameter of 1300-2800 μm) since 3 to 6 months were subjected to standard 23-gauge vitrectomy with removal of the posterior hyaloid, brilliant blue G (BBG)-assisted internal limiting membrane peeling in a circular fashion keeping it attached to the edge of the hole to create a flap. At the end of the surgery, air fluid exchange was done with inversion of the internal limiting membrane flap inside the macular hole using the soft tipped cannula and sulfur hexafluoride 20% as tamponade. The main follow-up measures are the best corrected visual acuity and the optical coherence tomography for 6 to 9 months.All the included eyes had a closed hole from the first week postoperative and along the follow-up period (6-9 months). The best corrected visual acuity improved from 20/2000 to 20/200 with a median of 20/400 preoperatively to 20/400 to 20/50 with a median of 20/100 at the end of follow-up period.Inverted internal limiting membrane flap is a good adjuvant to standard vitrectomy in the management of large traumatic macular holes that led to the 100% closure rate and improvement of best corrected visual acuity.

  8. Searches for all types of binary mergers in the first Advanced LIGO observing run

    NASA Astrophysics Data System (ADS)

    Read, Jocelyn

    2017-01-01

    The first observational run of the Advanced LIGO detectors covered September 12, 2015 to January 19, 2016. In that time, two definitive observations of merging binary black hole systems were made. In particular, the second observation, GW151226, relied on matched-filter searches targeting merging binaries. These searches were also capable of detecting binary mergers from binary neutron stars and from black-hole/neutron-star binaries. In this talk, I will give an overview of LIGO compact binary coalescence searches, in particular focusing on systems that contain neutron stars. I will discuss the sensitive volumes of the first observing run, the astrophysical implications of detections and non-detections, and prospects for future observations

  9. Menus for Feeding Black Holes

    NASA Astrophysics Data System (ADS)

    Kocsis, Bence; Loeb, Abraham

    2014-09-01

    Black holes are the ultimate prisons of the Universe, regions of spacetime where the enormous gravity prohibits matter or even light to escape to infinity. Yet, matter falling toward the black holes may shine spectacularly, generating the strongest source of radiation. These sources provide us with astrophysical laboratories of extreme physical conditions that cannot be realized on Earth. This chapter offers a review of the basic menus for feeding matter onto black holes and discusses their observational implications.

  10. From Cradle To Grave: Chandra Discovers The History Of Black Hole X-Ray Jets

    NASA Astrophysics Data System (ADS)

    2002-10-01

    eastern jet appears to have traveled farther from the black hole than the western one. However, with this alignment, the eastern jet should be brighter than the western one, while the western jet was actually three times brighter. "This poses a puzzle. The simple model for jets doesn't explain what we are seeing," said Philip Kaaret of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author of another upcoming Astrophysical Journal paper on XTE J1550-564. "Either the black hole may somehow be feeding more energy into the western jet, or that jet has run into a dense cloud." XTE J1550-564 Animations Animation of an X-ray Binary System As jets plow through the interstellar gas, the resistance of the gas slows them down like air resistance slows down moving objects on Earth. Although all jets are believed to decelerate in this way, the observations of XTE J1550-564 mark the first time jets have been caught in the act of slowing down. The observed deceleration underscores the value of small, stellar black holes in our galaxy for studying similar processes that occur in distant quasars and active galactic nuclei. XTE J1550-564, which is about 17,000 light years from Earth, was observed with Chandra's Advanced CCD Imaging Spectrometer and the High Energy Transmission Grating instruments. Radio data used in this study were obtained by the Australia Telescope Compact Array. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for the Office of Space Science, Washington, and TRW, Inc., Redondo Beach, Calif., is the prime contractor. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass.

  11. Highly non-linear solid core photonic crystal fiber with one nano hole

    NASA Astrophysics Data System (ADS)

    Gangwar, Rahul Kumar; Bhardwaj, Vanita; Singh, Vinod Kumar

    2015-08-01

    The numerical study of newly designed solid core photonic crystal fiber (SCPCF) having three hexagonal air hole rings in cladding region and one small nano hole at the center are presented. By using full vectorial finite element method (FV-FEM), we analyses the optical properties like effective area, nonlinearity and confinement loss of the proposed PCF. Results show that the change in core diameter controls the effective area, nonlinearity and confinement loss. A low effective area (3.34 µm2), high nonlinearity (36.34 W-1km-1) and low confinement loss (0.00106 dB/km) are achieved at the communication wavelength 1.55 µm for the SCPCF having core air hole diameter 0.10 µm, cladding air holes diameter 1.00 µm and pitch 2.50 µm. This type of PCF is very useful in non-linear applications such as supercontinuum generation, four wave mixing, second harmonic generation etc.

  12. X-1E Engine Ground Test Run

    NASA Technical Reports Server (NTRS)

    1956-01-01

    The Bell Aircraft Corporation X-1E during a ground engine test run on the NACA High-Speed Flight Station ramp near the Rogers Dry Lake. The rocket technician is keeping the concrete cool by hosing it with water during the test. This also helps in washing away any chemicals that might spill. The test crew worked close to the aircraft during ground tests. There were four versions of the Bell X-1 rocket-powered research aircraft that flew at the NACA High-Speed Flight Research Station, Edwards, California. The bullet-shaped X-1 aircraft were built by Bell Aircraft Corporation, Buffalo, N.Y. for the U.S. Army Air Forces (after 1947, U.S. Air Force) and the National Advisory Committee for Aeronautics (NACA). The X-1 Program was originally designated the XS-1 for EXperimental Supersonic. The X-1's mission was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the 'sound barrier.' Three different X-1s were built and designated: X-1-1, X-1-2 (later modified to become the X-1E), and X-1-3. The basic X-1 aircraft were flown by a large number of different pilots from 1946 to 1951. The X-1 Program not only proved that humans could go beyond the speed of sound, it reinforced the understanding that technological barriers could be overcome. The X-1s pioneered many structural and aerodynamic advances including extremely thin, yet extremely strong wing sections; supersonic fuselage configurations; control system requirements; powerplant compatibility; and cockpit environments. The X-1 aircraft were the first transonic-capable aircraft to use an all-moving stabilizer. The flights of the X-1s opened up a new era in aviation. The first X-1 was air-launched unpowered from a Boeing B-29 Superfortress on January 25, 1946. Powered flights began in December 1946. On October 14, 1947, the X-1-1, piloted by Air Force Captain Charles 'Chuck' Yeager, became the first aircraft to exceed the speed of sound, reaching about

  13. Simulating a High-Spin Black Hole-Neutron Star Binary

    NASA Astrophysics Data System (ADS)

    Derby, John; Lovelace, Geoffrey; Duez, Matt; Foucart, Francois; Simulating Extreme Spacetimes (SXS) Collaboration

    2017-01-01

    During their first observing run (fall 2015) Advanced LIGO detected gravitational waves from merging black holes. In its future observations LIGO could detect black hole neutron star binaries (BHNS). It is important to have numerical simulations to predict these waves, to help find as many of these waves as possible and to estimate the sources properties, because at times near merger analytic approximations fail. Also, numerical models of the disk formed when the black hole tears apart the neutron star can help us learn about these systems' potential electromagnetic counterparts. One area of the parameter space for BHNS systems that is particularly challenging is simulations with high black hole spin. I will present results from a new BHNS simulation that has a black hole spin of 90% of the theoretical maximum. We are part of SXS but not all.

  14. A Star on the Run

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-10-01

    Usually stars that are born together tend to move together but sometimes stars can go rogue and run away from their original birthplace. A pair of astronomers have now discovered the first runaway red supergiant (RSG) ever identified in another galaxy. With a radial velocity discrepancy of 300 km/s, its also the fastest runaway massive star known. Discrepant Speeds: When massive stars form in giant molecular clouds, they create what are known as OB associations: groups of hot, massive, short-lived stars that have similar velocities because theyre moving through space together. But sometimes stars that appear to be part of an OB association dont have the same velocity as the rest of the group. These stars are called runaways.What causes an OB star to run away is still debated, but we know that a fairly significant fraction of OB stars are runaways. In spite of this, surprisingly few runaways have been found that are evolved massive stars i.e., the post-main-sequence state of OB stars. This is presumably because these evolved stars have had more time to move away from their birthplace, and its more difficult to identify a runaway without the context of its original group. An Evolved Runaway: Difference between observed velocity and expected velocity, plotted as a function of expected velocity. The black points are foreground stars. The red points are expected RSGs, clustered around a velocity difference of zero. The green pentagon is the runaway RSG J004330.06+405258.4. [Evans Massey 2015]Despite this challenge, a recent survey of RSGs in the galaxy M31 has led to the detection of a massive star on the run! Kate Evans (Lowell Observatory and California Institute of Technology) and Philip Massey (Lowell Observatory and Northern Arizona University) discovered that RSG J004330.06+405258.4 is moving through the Andromeda Galaxy with a radial velocity thats off by about 300 km/s from the radial velocity expected for its location.Evans and Massey discovered this rogue star

  15. Random Test Run Length and Effectiveness

    NASA Technical Reports Server (NTRS)

    Andrews, James H.; Groce, Alex; Weston, Melissa; Xu, Ru-Gang

    2008-01-01

    A poorly understood but important factor in many applications of random testing is the selection of a maximum length for test runs. Given a limited time for testing, it is seldom clear whether executing a small number of long runs or a large number of short runs maximizes utility. It is generally expected that longer runs are more likely to expose failures -- which is certainly true with respect to runs shorter than the shortest failing trace. However, longer runs produce longer failing traces, requiring more effort from humans in debugging or more resources for automated minimization. In testing with feedback, increasing ranges for parameters may also cause the probability of failure to decrease in longer runs. We show that the choice of test length dramatically impacts the effectiveness of random testing, and that the patterns observed in simple models and predicted by analysis are useful in understanding effects observed.

  16. Thermodynamics of Accelerating Black Holes.

    PubMed

    Appels, Michael; Gregory, Ruth; Kubizňák, David

    2016-09-23

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  17. Black holes and the multiverse

    SciTech Connect

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun E-mail: vilenkin@cosmos.phy.tufts.edu

    2016-02-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

  18. Thermodynamics of Accelerating Black Holes

    NASA Astrophysics Data System (ADS)

    Appels, Michael; Gregory, Ruth; KubizÅák, David

    2016-09-01

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon—even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  19. Ring Around the Black Hole

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

    Regardless of size, black holes easily acquire accretion disks. Supermassive black holes can feast on the bountiful interstellar gas in galactic nuclei. Small black holes formed from collapsing stars often belong to binary systems in which a bulging companion star can spill some of its gas into the black hole s reach. In the chaotic mess of the accretion disk, atoms collide with one another. Swirling plasma reaches speeds upward of 10% that of light and glows brightly in many wavebands, particularly in X-rays. Gas gets blown back by a wind of radiation from the inner disk. New material enters the disks from different directions.

  20. How black holes saved relativity

    NASA Astrophysics Data System (ADS)

    Prescod-Weinstein, Chanda

    2016-02-01

    While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.

  1. Streakline flow visualization of discrete hole film cooling with holes inclined 30 deg to surface

    NASA Technical Reports Server (NTRS)

    Colladay, R. S.; Russell, L. M.; Lane, J. M.

    1976-01-01

    Film injection from three rows of discrete holes angled 30 deg to the surface in line with mainstream flow and spaced 5 diameters apart in a staggered array was visualized by using helium bubbles as tracer particles. Both the main stream and the film injectant were ambient air. Detailed streaklines showing the turbulent motion of the film mixing with the main stream were obtained by photographing small, neutrally buoyant helium-filled soap bubbles which followed the flow field. The ratio of boundary layer thickness to hole diameter and the Reynolds number were typical of gas turbine film cooling applications. The results showed the behavior of the film and its interaction with the main stream for a range of blowing rates and two initial boundary layer thicknesses.

  2. Flow visualization of film cooling with spanwise injection from a small array of holes and compound-angle injection from a large array

    NASA Technical Reports Server (NTRS)

    Russell, L. M.

    1978-01-01

    Film injection from discrete holes in a smooth, flat plate was studied for two configurations: (1) spanwise injection through a four hole staggered array; and (2) compound angle injection through a 49 hole staggered array. The ratio of boundary layer thicknesses to hole diameter and the Reynolds number were typical of gas turbine film cooling applications. Streaklines showing the motion of the injected air were obtained by photographing small, neutrally buoyant, helium-filled soap bubbles that followed the flow field.

  3. Arresting and supplying apparatus for increasing pellet impact drilling speed per run

    NASA Astrophysics Data System (ADS)

    Kovalyov, A. V.; Isaev, Ye D.; Veryevkin, A. V.; Gorbenko, V. M.; Ulyanova, O. S.

    2015-11-01

    The paper describes pellet impact drilling which might be used to increase the drilling rate and the penetration rate of hard and tough rock drilling. Pellet impact drilling implies rock destruction by metal pellets having high kinetic energy in the immediate vicinity of the earth formation encountered. The pellets are recirculated in the bottom of the bore hole by a high velocity fluid jet, which is the principle component of the ejector pellet impact drill bit. The arresting and supplying apparatus is supposed to increase speed per run in pellet impact drilling, as it not only replenishes the pellets but also supplies and then picks up the pellets from the bottom hole. The paper presents the design of the pellet-supplying component which ensures a portion of pellets supply to the bottom hole.

  4. What we can learn about running from barefoot running: an evolutionary medical perspective.

    PubMed

    Lieberman, Daniel E

    2012-04-01

    Barefoot running, which was how people ran for millions of years, provides an opportunity to study how natural selection adapted the human body to run. Because humans evolved to run barefoot, a barefoot running style that minimizes impact peaks and provides increased proprioception and foot strength, is hypothesized to help avoid injury, regardless of whether one is wearing shoes.

  5. Take the monkey and run

    PubMed Central

    Phillips, Kimberley A.; Hambright, M. Karen; Hewes, Kelly; Schilder, Brian M.; Ross, Corinna N.; Tardif, Suzette D.

    2015-01-01

    Background The common marmoset (Callithrix jacchus) is a small, New World primate that is used extensively in biomedical and behavioral research. This short-lived primate, with its small body size, ease of handling, and docile temperament, has emerged as a valuable model for aging and neurodegenerative research. A growing body of research has indicated exercise, aerobic exercise especially, imparts beneficial effects to normal aging. Understanding the mechanisms underlying these positive effects of exercise, and the degree to which exercise has neurotherapeutic effects, is an important research focus. Thus, developing techniques to engage marmosets in aerobic exercise would have great advantages. New method Here we describe the marmoset exercise ball (MEB) paradigm: a safe (for both experimenter and subjects), novel and effective means to engage marmosets in aerobic exercise. We trained young adult male marmosets to run on treadmills for 30 min a day, 3 days a week. Results Our training procedures allowed us to engage male marmosets in this aerobic exercise within 4 weeks, and subjects maintained this frequency of exercise for 3 months. Comparison with existing methods To our knowledge, this is the first described method to engage marmosets in aerobic exercise. A major advantage of this exercise paradigm is that while it was technically forced exercise, it did not appear to induce stress in the marmosets. Conclusions These techniques should be useful to researchers wishing to address physiological responses of exercise in a marmoset model. PMID:25835199

  6. High impact running improves learning.

    PubMed

    Winter, Bernward; Breitenstein, Caterina; Mooren, Frank C; Voelker, Klaus; Fobker, Manfred; Lechtermann, Anja; Krueger, Karsten; Fromme, Albert; Korsukewitz, Catharina; Floel, Agnes; Knecht, Stefan

    2007-05-01

    Regular physical exercise improves cognitive functions and lowers the risk for age-related cognitive decline. Since little is known about the nature and the timing of the underlying mechanisms, we probed whether exercise also has immediate beneficial effects on cognition. Learning performance was assessed directly after high impact anaerobic sprints, low impact aerobic running, or a period of rest in 27 healthy subjects in a randomized cross-over design. Dependent variables comprised learning speed as well as immediate (1 week) and long-term (>8 months) overall success in acquiring a novel vocabulary. Peripheral levels of brain-derived neurotrophic factor (BDNF) and catecholamines (dopamine, epinephrine, norepinephrine) were assessed prior to and after the interventions as well as after learning. We found that vocabulary learning was 20 percent faster after intense physical exercise as compared to the other two conditions. This condition also elicited the strongest increases in BDNF and catecholamine levels. More sustained BDNF levels during learning after intense exercise were related to better short-term learning success, whereas absolute dopamine and epinephrine levels were related to better intermediate (dopamine) and long-term (epinephrine) retentions of the novel vocabulary. Thus, BDNF and two of the catecholamines seem to be mediators by which physical exercise improves learning.

  7. The MICE Run Control System

    NASA Astrophysics Data System (ADS)

    Hanlet, Pierrick; Mice Collaboration

    2014-06-01

    The Muon Ionization Cooling Experiment (MICE) is a demonstration experiment to prove the feasibility of cooling a beam of muons for use in a Neutrino Factory and/or Muon Collider. The MICE cooling channel is a section of a modified Study II cooling channel which will provide a 10% reduction in beam emittance. In order to ensure a reliable measurement, MICE will measure the beam emittance before and after the cooling channel at the level of 1%, or a relative measurement of 0.001. This renders MICE a precision experiment which requires strict controls and monitoring of all experimental parameters in order to control systematic errors. The MICE Controls and Monitoring system is based on EPICS and integrates with the DAQ, Data monitoring systems, and a configuration database. The new MICE Run Control has been developed to ensure proper sequencing of equipment and use of system resources to protect data quality. A description of this system, its implementation, and performance during recent muon beam data collection will be discussed.

  8. Power Systems Development Facility Gasification Test Run TC09

    SciTech Connect

    Southern Company Services

    2002-09-30

    This report discusses Test Campaign TC09 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier during TC09 in air- and oxygen-blown modes. Test Run TC09 was started on September 3, 2002, and completed on September 26, 2002. Both gasifier and PCD operations were stable during the test run, with a stable baseline pressure drop. The oxygen feed supply system worked well and the transition from air to oxygen was smooth. The gasifier temperature varied between 1,725 and 1,825 F at pressures from 125 to 270 psig. The gasifier operates at lower pressure during oxygen-blown mode due to the supply pressure of the oxygen system. In TC09, 414 hours of solid circulation and over 300 hours of coal feed were attained with almost 80 hours of pure oxygen feed.

  9. Impact Accelerations of Barefoot and Shod Running.

    PubMed

    Thompson, M; Seegmiller, J; McGowan, C P

    2016-05-01

    During the ground contact phase of running, the body's mass is rapidly decelerated resulting in forces that propagate through the musculoskeletal system. The repetitive attenuation of these impact forces is thought to contribute to overuse injuries. Modern running shoes are designed to reduce impact forces, with the goal to minimize running related overuse injuries. Additionally, the fore/mid foot strike pattern that is adopted by most individuals when running barefoot may reduce impact force transmission. The aim of the present study was to compare the effects of the barefoot running form (fore/mid foot strike & decreased stride length) and running shoes on running kinetics and impact accelerations. 10 healthy, physically active, heel strike runners ran in 3 conditions: shod, barefoot and barefoot while heel striking, during which 3-dimensional motion analysis, ground reaction force and accelerometer data were collected. Shod running was associated with increased ground reaction force and impact peak magnitudes, but decreased impact accelerations, suggesting that the midsole of running shoes helps to attenuate impact forces. Barefoot running exhibited a similar decrease in impact accelerations, as well as decreased impact peak magnitude, which appears to be due to a decrease in stride length and/or a more plantarflexed position at ground contact.

  10. Dancing around the Black Hole

    NASA Astrophysics Data System (ADS)

    2001-08-01

    the centre of NGC 1808 are plotted at different distances from the nucleus (abscissa). The right half shows the corresponding curve after "removal" of the effect from the rotation - the remaining spread is a direct measure of the "velocity dispersion" and the individual stellar motions. As can be clearly seen, the width of the "band" decreases towards the centre, indicating the presence of a "dynamically cool" central stellar system. For more details, see the text. The scientists embarked upon a project with the goal of investigating in detail the motions of stars in the central regions of some active, comparatively "nearby" galaxies. As the innermost regions of such galaxies are usually quite dusty, the observations were carried out in infrared light that penetrates the dust clouds much better than does visible light. Thanks to its high efficiency and excellent imaging quality and spectral resolution, the VLT Infrared Spectrometer And Array Camera (ISAAC) is superbly suited for such work. Several galaxies with active centres were selected for the first observing runs in 1999 and 2000, among these NGC 1097, NGC 1808 and NGC 5728 that are shown in PR Photos 25a-c/01 . Infrared spectra were obtained in the 2.3 µm wavelength region in which a number of molecular spectral bands are seen, cf. PR Photo 25e/01 . They are caused by carbon monoxide ( 12 CO) molecules in the atmospheres of the stars located near the centres of the galaxies. Stellar motions By measuring the exact wavelengths of these molecular bands, it is possible to determine (from the Doppler effect), first, the mean velocity of the stars ( PR Photo 25f/01 ; left) and, secondly, the spread in this velocity (known as the "velocity dispersion" ; right). The first value reflects the general speed with which the stars move around the central black hole. The second indicates the extent to which the individual stellar motions deviate from that mean value. The comparison with the flight of a swarm of bees is useful

  11. Magnetic fields around black holes

    NASA Astrophysics Data System (ADS)

    Garofalo, David A. G.

    Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and possibly greater. Theory and observation are converging on a model for these objects that involves the conversion of gravitational potential energy of accreting gas to radiation as well as Poynting flux produced by the interaction of the rotating spacetime and the electromagnetic fields originating in the ionized accretion flow. The presence of black holes in astrophysics is taking center stage, with the output from AGN in various forms such as winds and jets influencing the formation and evolution of the host galaxy. This dissertation addresses some of the basic unanswered questions that plague our current understanding of how rotating black holes interact with their surrounding magnetized accretion disks to produce the enormous observed energy. Two magnetic configurations are examined. The first involves magnetic fields connecting the black hole with the inner accretion disk and the other involves large scale magnetic fields threading the disk and the hole. We study the effects of the former type by establishing the consequences that magnetic torques between the black hole and the inner accretion disk have on the energy dissipation profile. We attempt a plausible explanation to the observed "Deep Minimum" state in the Seyfert galaxy MCG-6- 30-15. For the latter type of magnetic geometry, we study the effects of the strength of the magnetic field threading the black hole within the context of the cherished Blandford & Znajek mechanism for black hole spin energy extraction. We begin by addressing the problem in the non-relativistic regime where we find that the black hole-threading magnetic field is stronger for greater disk thickness, larger magnetic Prandtl number, and for a larger accretion disk. We then study the problem in full relativity where we show that our

  12. Endurance running and the evolution of Homo.

    PubMed

    Bramble, Dennis M; Lieberman, Daniel E

    2004-11-18

    Striding bipedalism is a key derived behaviour of hominids that possibly originated soon after the divergence of the chimpanzee and human lineages. Although bipedal gaits include walking and running, running is generally considered to have played no major role in human evolution because humans, like apes, are poor sprinters compared to most quadrupeds. Here we assess how well humans perform at sustained long-distance running, and review the physiological and anatomical bases of endurance running capabilities in humans and other mammals. Judged by several criteria, humans perform remarkably well at endurance running, thanks to a diverse array of features, many of which leave traces in the skeleton. The fossil evidence of these features suggests that endurance running is a derived capability of the genus Homo, originating about 2 million years ago, and may have been instrumental in the evolution of the human body form.

  13. Regular phantom black holes.

    PubMed

    Bronnikov, K A; Fabris, J C

    2006-06-30

    We study self-gravitating, static, spherically symmetric phantom scalar fields with arbitrary potentials (favored by cosmological observations) and single out 16 classes of possible regular configurations with flat, de Sitter, and anti-de Sitter asymptotics. Among them are traversable wormholes, bouncing Kantowski-Sachs (KS) cosmologies, and asymptotically flat black holes (BHs). A regular BH has a Schwarzschild-like causal structure, but the singularity is replaced by a de Sitter infinity, giving a hypothetic BH explorer a chance to survive. It also looks possible that our Universe has originated in a phantom-dominated collapse in another universe, with KS expansion and isotropization after crossing the horizon. Explicit examples of regular solutions are built and discussed. Possible generalizations include k-essence type scalar fields (with a potential) and scalar-tensor gravity.

  14. Prisons of Light - Black Holes

    NASA Astrophysics Data System (ADS)

    Ferguson, Kitty

    1998-05-01

    In this jargon-free review of one of the most fascinating topics in modern science, acclaimed science writer Kitty Ferguson examines the discovery of black holes, their nature, and what they can teach us about the mysteries of the universe. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light--Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.

  15. Numerical Simulation of Black Holes

    NASA Astrophysics Data System (ADS)

    Teukolsky, Saul

    2003-04-01

    Einstein's equations of general relativity are prime candidates for numerical solution on supercomputers. There is some urgency in being able to carry out such simulations: Large-scale gravitational wave detectors are now coming on line, and the most important expected signals cannot be predicted except numerically. Problems involving black holes are perhaps the most interesting, yet also particularly challenging computationally. One difficulty is that inside a black hole there is a physical singularity that cannot be part of the computational domain. A second difficulty is the disparity in length scales between the size of the black hole and the wavelength of the gravitational radiation emitted. A third difficulty is that all existing methods of evolving black holes in three spatial dimensions are plagued by instabilities that prohibit long-term evolution. I will describe the ideas that are being introduced in numerical relativity to deal with these problems, and discuss the results of recent calculations of black hole collisions.

  16. String-Corrected Black Holes

    SciTech Connect

    Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund

    2005-02-07

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect -- the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive! The magnitude of this effect is related to the size of the compactification manifold.

  17. When Charged Black Holes Merge

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-08-01

    Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge

  18. Black hole final state conspiracies

    NASA Astrophysics Data System (ADS)

    McInnes, Brett

    2009-01-01

    The principle that unitarity must be preserved in all processes, no matter how exotic, has led to deep insights into boundary conditions in cosmology and black hole theory. In the case of black hole evaporation, Horowitz and Maldacena were led to propose that unitarity preservation can be understood in terms of a restriction imposed on the wave function at the singularity. Gottesman and Preskill showed that this natural idea only works if one postulates the presence of “conspiracies” between systems just inside the event horizon and states at much later times, near the singularity. We argue that some AdS black holes have unusual internal thermodynamics, and that this may permit the required “conspiracies” if real black holes are described by some kind of sum over all AdS black holes having the same entropy.

  19. Black-Hole Feedback in Quasars

    NASA Video Gallery

    This animation illustrates how black-hole feedback works in quasars. Dense gas and dust in the center simultaneously fuels the black hole and shrouds it from view. The black-hole wind propels large...

  20. Formation and spread of aircraft-induced holes in clouds.

    PubMed

    Heymsfield, Andrew J; Thompson, Gregory; Morrison, Hugh; Bansemer, Aaron; Rasmussen, Roy M; Minnis, Patrick; Wang, Zhien; Zhang, Damao

    2011-07-01

    Hole-punch and canal clouds have been observed for more than 50 years, but the mechanisms of formation, development, duration, and thus the extent of their effect have largely been ignored. The holes have been associated with inadvertent seeding of clouds with ice particles generated by aircraft, produced through spontaneous freezing of cloud droplets in air cooled as it flows around aircraft propeller tips or over jet aircraft wings. Model simulations indicate that the growth of the ice particles can induce vertical motions with a duration of 1 hour or more, a process that expands the holes and canals in clouds. Global effects are minimal, but regionally near major airports, additional precipitation can be induced.

  1. Hidden Structures of Black Holes

    NASA Astrophysics Data System (ADS)

    Vercnocke, Bert

    2010-11-01

    This thesis investigates two main topics concerning black holes in extensions of general relativity inspired by string theory. First, the structure of the equations of motion underlying black hole solutions is considered, in theories of D-dimensional gravity coupled to scalars and vectors. For solutions preserving supersymmetry, the equations of motion have a dramatic simplification: they become first-order instead of the second-order equations one would expect. Recently, it was found that this is a feature some non-supersymmetric black hole solutions exhibit as well. We investigate if this holds more generally, by examining what the conditions are to have first-order equations for the scalar fields of non-supersymmetric black holes, that mimic the form of their supersymmetric counterparts. This is illustrated in examples. Second, the structure of black holes themselves is investigated. String theory has been successful in explaining the Bekenstein-Hawking entropy for (mainly supersymmetric) black holes from a microscopic perspective. However, it is not fully established what the interpretation of the corresponding 'microstates' should be in the gravitational description where the black hole picture is valid. There have been recent advances to understand the nature of black hole microstates in the gravity regime, such as the fuzzball proposal. A related idea says that black hole configurations with multiple centers are related to microstates of single-centered black holes. We report on work relating both pictures. As an aside, a relation between violations of causality for certain spacetimes (presence of closed timelike curves in the geometry) and a breakdown of unitarity in the dual conformal field theory is given.

  2. [Facts and fiction about running shoes].

    PubMed

    Schelde, Jacob

    2012-11-26

    Running as a means of exercise is becoming increasingly popular, but the rate of injury is very high among runners. To prevent running-related injuries much attention has been given the running shoe and its construction, particular its shock-absorbing capabilities and motion control features. It is recommended that running shoes should be purchased based on the runner's medial arch height and degree of pronation, and that the shoes should be changed frequently as their shock-absorbing capabilities decrease with usage. Randomized controlled trials and other studies in the scientific literature do not support these recommendations.

  3. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  4. Refinement of Er3+-doped hole-assisted optical fiber amplifier.

    PubMed

    D'Orazio, A; De Sario, M; Mescia, L; Petruzzelli, V; Prudenzano, F

    2005-12-12

    This paper deals with design and refinement criteria of erbium doped hole-assisted optical fiber amplifiers for applications in the third band of fiber optical communication. The amplifier performance is simulated via a model which takes into account the ion population rate equations and the optical power propagation. The electromagnetic field profile of the propagating modes is carried out by a finite element method solver. The effects of the number of cladding air holes on the amplifier performance are investigated. To this aim, four different erbium doped hole-assisted lightguide fiber amplifiers having a different number of cladding air holes are designed and compared. The simulated optimal gain, optimal length, and optimal noise fig. are discussed. The numerical results highlight that, by increasing the number of air holes, the gain can be improved, thus obtaining a shorter amplifier length. For the erbium concentration NEr=1.8x1024 ions/m3, the optimal gain G(Lopt) increases up to ~2dB by increasing the number of the air holes from M=4 to M=10.

  5. Jets and sprays arising from a spark-induced oscillating bubble near a plate with a hole.

    PubMed

    Karri, Badarinath; Ohl, Siew-Wan; Klaseboer, Evert; Ohl, Claus-Dieter; Khoo, Boo Cheong

    2012-09-01

    An experimental study of jets and sprays formed by a spark-induced bubble collapsing near a plate with a hole is presented. A Perspex plate with a hole at its center is placed in a half-filled water tank with its top face near the air-water interface. A bubble is created using a low-voltage electrical spark below the hole in the plate. The bubble expands against the hole, which pushes the liquid present within the hole and leads to an initial primary jet of water that emerges from the other end of the hole into air. The bubble subsequently collapses and leads to a second jet that is characterized by short bursts of liquid spray followed by a thicker continuous liquid column. The impact of the sprays onto the primary jet leads to perturbations in the jet and the breakup of the latter into fine droplets. The entire phenomenon is recorded using a high-speed camera to visualize the mechanism both within and outside the hole. The results give a clearer indication of the mechanism behind a recently reported phenomenon on the formation of impacting jets caused by bubble expansion and collapse at the micrometer length scale. The variation of the jet characteristics with parameters such as the position of the water-air interface with respect to the plate and the hole geometry (i.e., the hole diameter and the plate thickness) is also presented.

  6. Investigation of Spiral and Sweeping Holes

    NASA Technical Reports Server (NTRS)

    Thurman, Douglas; Poinsatte, Philip; Ameri, Ali; Culley, Dennis; Raghu, Surya; Shyam, Vikram

    2015-01-01

    Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing rations of 1.0, 1.5, 2.0, and 2.5 at a density ration of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.

  7. Retrograde binaries of massive black holes in circumbinary accretion discs

    NASA Astrophysics Data System (ADS)

    Amaro-Seoane, Pau; Maureira-Fredes, Cristián; Dotti, Massimo; Colpi, Monica

    2016-06-01

    Context. We explore the hardening of a massive black hole binary embedded in a circumbinary gas disc under a specific circumstance: when the binary and the gas are coplanar and the gas is counter-rotating. The binary has unequal mass and the interaction of the gas with the lighter secondary black hole is the main cause of the braking torque on the binary that shrinks with time. The secondary black hole, revolving in the direction opposite to the gas, experiences a drag from gas-dynamical friction and from direct accretion of part of it. Aims: In this paper, using two-dimensional (2D) hydrodynamical grid simulations we investigate the effect of changing the accretion prescriptions on the dynamics of the secondary black hole, which in turn affect the binary hardening and eccentricity evolution. Methods: We find that realistic accretion prescriptions lead to results that differ from those inferred assuming accretion of all the gas within the Roche Lobe of the secondary black hole. Results: When considering gas accretion within the gravitational influence radius of the secondary black hole (which is smaller than the Roche Lobe radius) to better describe gas inflows, the shrinking of the binary is slower. In addition, in this case, a smaller amount of accreted mass is required to reduce the binary separation by the same amount. Different accretion prescriptions result in different discs' surface densities, which alter the black hole's dynamics back. Full 3D Smoothed-particle hydrodynamics realizations of a number of representative cases, run over a shorter interval of time, validate the general trends observed in the less computationally demanding 2D simulations. Conclusions: Initially circular black hole binaries increase their eccentricity only slightly, which then oscillates around small values (<0.1) while they harden. By contrast, initially eccentric binaries become more and more eccentric. A semi-analytical model describing the black hole's dynamics under

  8. More Hidden Black Hole Dangers

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

    Black holes such as GRO J1655-40 form from collapsed stars. When stars at least eight times more massive than our Sun exhaust their fuel supply, they no longer have the energy to support their tremendous bulk. These stars explode as supernovae, blasting their outer envelopes into space. If the core is more than three times the mass of the Sun, it will collapse into a singularity, a single point of infinite density.Although light cannot escape black holes, astronomers can see black holes by virtue of the hot, glowing gas often stolen from a neighboring star that orbits these objects. From our vantage point, the light seems to flicker. The Rossi Explorer has recorded this flickering (called quasiperiodic oscillations, or QPOs) around many black holes. QPOs are produced by gas very near the innermost stable orbit the closest orbit a blob of gas can maintain before falling pell-mell into the black hole. As gas whips around the black hole at near light speed, gravity pulls the gas in one direction, then another, adding to the flickering. The QPO is related to the speed and size of this orbit and the mass of the black hole.

  9. Black Hole Grabs Starry Snack

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Poster Version

    This artist's concept shows a supermassive black hole at the center of a remote galaxy digesting the remnants of a star. NASA's Galaxy Evolution Explorer had a 'ringside' seat for this feeding frenzy, using its ultraviolet eyes to study the process from beginning to end.

    The artist's concept chronicles the star being ripped apart and swallowed by the cosmic beast over time. First, the intact sun-like star (left) ventures too close to the black hole, and its own self-gravity is overwhelmed by the black hole's gravity. The star then stretches apart (middle yellow blob) and eventually breaks into stellar crumbs, some of which swirl into the black hole (cloudy ring at right). This doomed material heats up and radiates light, including ultraviolet light, before disappearing forever into the black hole. The Galaxy Evolution Explorer was able to watch this process unfold by observing changes in ultraviolet light.

    The area around the black hole appears warped because the gravity of the black hole acts like a lens, twisting and distorting light.

  10. Distinct stages of adult hippocampal neurogenesis are regulated by running and the running environment.

    PubMed

    Bednarczyk, Matthew R; Hacker, Lindsay C; Fortin-Nunez, Stéphanie; Aumont, Anne; Bergeron, Raynald; Fernandes, Karl J L

    2011-12-01

    Hippocampal neurogenesis continues into adulthood in mammalian vertebrates, and in experimental rodent models it is powerfully stimulated by exposure to a voluntary running wheel. In this study, we demonstrate that exposure to a running wheel environment, in the absence of running, is sufficient to regulate specific aspects of hippocampal neurogenesis. Adult mice were provided with standard housing, housing enriched with a running wheel or housing enriched with a locked wheel (i.e., an environment comparable to that of running animals, without the possibility of engaging in running). We found that mice in the running wheel and locked wheel groups exhibited equivalent increases in proliferation within the neurogenic niche of the dentate gyrus; this included comparable increases in the proliferation of radial glia-like stem cells and the number of proliferating neuroblasts. However, only running animals displayed increased numbers of postmitotic neuroblasts and mature neurons. These results demonstrate that the running wheel environment itself is sufficient for promoting proliferation of early lineage hippocampal precursors, while running per se enables newly generated neuroblasts to survive and mature into functional hippocampal neurons. Thus, both running-independent and running-dependent stimuli are integral to running wheel-induced hippocampal neurogenesis.

  11. The Effect of Training in Minimalist Running Shoes on Running Economy.

    PubMed

    Ridge, Sarah T; Standifird, Tyler; Rivera, Jessica; Johnson, A Wayne; Mitchell, Ulrike; Hunter, Iain

    2015-09-01

    The purpose of this study was to examine the effect of minimalist running shoes on oxygen uptake during running before and after a 10-week transition from traditional to minimalist running shoes. Twenty-five recreational runners (no previous experience in minimalist running shoes) participated in submaximal VO2 testing at a self-selected pace while wearing traditional and minimalist running shoes. Ten of the 25 runners gradually transitioned to minimalist running shoes over 10 weeks (experimental group), while the other 15 maintained their typical training regimen (control group). All participants repeated submaximal VO2 testing at the end of 10 weeks. Testing included a 3 minute warm-up, 3 minutes of running in the first pair of shoes, and 3 minutes of running in the second pair of shoes. Shoe order was randomized. Average oxygen uptake was calculated during the last minute of running in each condition. The average change from pre- to post-training for the control group during testing in traditional and minimalist shoes was an improvement of 3.1 ± 15.2% and 2.8 ± 16.2%, respectively. The average change from pre- to post-training for the experimental group during testing in traditional and minimalist shoes was an improvement of 8.4 ± 7.2% and 10.4 ± 6.9%, respectively. Data were analyzed using a 2-way repeated measures ANOVA. There were no significant interaction effects, but the overall improvement in running economy across time (6.15%) was significant (p = 0.015). Running in minimalist running shoes improves running economy in experienced, traditionally shod runners, but not significantly more than when running in traditional running shoes. Improvement in running economy in both groups, regardless of shoe type, may have been due to compliance with training over the 10-week study period and/or familiarity with testing procedures. Key pointsRunning in minimalist footwear did not result in a change in running economy compared to running in traditional footwear

  12. Biomechanics of Distance Running: A Longitudinal Study

    ERIC Educational Resources Information Center

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

    Training for distance running over a long period produces meaningful changes in the running mechanics of experienced runners, as revealed in this longitudinal study of the biomechanical components of stride length, stride rate, stride time, and support and nonsupport time. (MB)

  13. Running biomechanics: shorter heels, better economy.

    PubMed

    Scholz, M N; Bobbert, M F; van Soest, A J; Clark, J R; van Heerden, J

    2008-10-01

    Better running economy (i.e. a lower rate of energy consumption at a given speed) is correlated with superior distance running performance. There is substantial variation in running economy, even among elite runners. This variation might be due to variation in the storage and reutilization of elastic energy in tendons. Using a simple musculoskeletal model, it was predicted that the amount of energy stored in a tendon during a given movement depends more critically on moment arm than on mechanical properties of the tendon, with the amount of stored energy increasing as the moment arm gets smaller. Assuming a link between elastic energy reutilization and overall metabolic cost of running, a smaller moment arm should therefore be associated with superior running economy. This prediction was confirmed experimentally in a group of 15 highly trained runners. The moment arm of the Achilles tendon was determined from standardized photographs of the ankle, using the position of anatomical landmarks. Running economy was measured as the rate of metabolic energy consumption during level treadmill running at a speed of 16 km h(-1). A strong correlation was found between the moment arm of the Achilles tendon and running economy. Smaller muscle moment arms correlated with lower rates of metabolic energy consumption (r(2)=0.75, P<0.001).

  14. Separating Fact from Fiction: Increasing Running Speed

    ERIC Educational Resources Information Center

    Murgia, Carla

    2008-01-01

    From a biomechanical point of view, this article explores the common belief that one must increase stride length and frequency in order to increase running speed. The limb length, explosive power, and anaerobic capacity of the athlete, as well as the type of running (sprinting vs. long distance) must be considered before making such a…

  15. Minimum Wage Effects in the Longer Run

    ERIC Educational Resources Information Center

    Neumark, David; Nizalova, Olena

    2007-01-01

    Exposure to minimum wages at young ages could lead to adverse longer-run effects via decreased labor market experience and tenure, and diminished education and training, while beneficial longer-run effects could arise if minimum wages increase skill acquisition. Evidence suggests that as individuals reach their late 20s, they earn less the longer…

  16. The Meaning of Running Away for Girls

    ERIC Educational Resources Information Center

    Peled, Einat; Cohavi, Ayelet

    2009-01-01

    Objective: The aim of this qualitative research was to understand how runaway girls perceive the processes involved in leaving home and the meaning they attribute to it. Method: Findings are based on in-depth interviews with 10 Israeli girls aged 13-17 with a history of running away from home. Results: The meaning of running away as it emerged…

  17. The Second Student-Run Homeless Shelter

    ERIC Educational Resources Information Center

    Seider, Scott C.

    2012-01-01

    From 1983-2011, the Harvard Square Homeless Shelter (HSHS) in Cambridge, Massachusetts, was the only student-run homeless shelter in the United States. However, college students at Villanova, Temple, Drexel, the University of Pennsylvania, and Swarthmore drew upon the HSHS model to open their own student-run homeless shelter in Philadelphia,…

  18. Teaching Bank Runs with Classroom Experiments

    ERIC Educational Resources Information Center

    Balkenborg, Dieter; Kaplan, Todd; Miller, Timothy

    2011-01-01

    Once relegated to cinema or history lectures, bank runs have become a modern phenomenon that captures the interest of students. In this article, the authors explain a simple classroom experiment based on the Diamond-Dybvig model (1983) to demonstrate how a bank run--a seemingly irrational event--can occur rationally. They then present possible…

  19. Impact of Running Away on Girls' Pregnancy

    ERIC Educational Resources Information Center

    Thrane, Lisa E.; Chen, Xiaojin

    2012-01-01

    This study assessed the impact of running away on pregnancy in the subsequent year among U.S. adolescents. We also investigated interactions between running away and sexual assault, romance, and school disengagement. Pregnancy among females between 11 and 17 years (n = 6100) was examined utilizing the Longitudinal Study of Adolescent Health (Add…

  20. Run II data analysis on the grid

    SciTech Connect

    Igor Mandrichenko, Igor Terekhov and Frank Wurthwein

    2002-12-02

    In this document, we begin the technical design for the distributed RunII computing for CDF and D0. The present paper defines the three components of the data handling area of Run II computing, namely the Data Handling System, the Storage System and the Application. We outline their functionality and interaction between them. We identify necessary and desirable elements of the interfaces.

  1. Black holes and Higgs stability

    SciTech Connect

    Tetradis, Nikolaos

    2016-09-20

    We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.

  2. Orbital resonances around black holes.

    PubMed

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  3. Quantum mechanics of black holes.

    PubMed

    Witten, Edward

    2012-08-03

    The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely.

  4. Gravitational polarizability of black holes

    SciTech Connect

    Damour, Thibault; Lecian, Orchidea Maria

    2009-08-15

    The gravitational polarizability properties of black holes are compared and contrasted with their electromagnetic polarizability properties. The 'shape' or 'height' multipolar Love numbers h{sub l} of a black hole are defined and computed. They are then compared to their electromagnetic analogs h{sub l}{sup EM}. The Love numbers h{sub l} give the height of the lth multipolar 'tidal bulge' raised on the horizon of a black hole by faraway masses. We also discuss the shape of the tidal bulge raised by a test-mass m, in the limit where m gets very close to the horizon.

  5. On regular rotating black holes

    NASA Astrophysics Data System (ADS)

    Torres, R.; Fayos, F.

    2017-01-01

    Different proposals for regular rotating black hole spacetimes have appeared recently in the literature. However, a rigorous analysis and proof of the regularity of this kind of spacetimes is still lacking. In this note we analyze rotating Kerr-like black hole spacetimes and find the necessary and sufficient conditions for the regularity of all their second order scalar invariants polynomial in the Riemann tensor. We also show that the regularity is linked to a violation of the weak energy conditions around the core of the rotating black hole.

  6. Orbital Resonances Around Black Holes

    NASA Astrophysics Data System (ADS)

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-01

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  7. Rotating regular black hole solution

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon

    2016-07-01

    Based on the Newman-Janis algorithm, the Ayón-Beato-García spacetime metric [Phys. Rev. Lett. 80, 5056 (1998)] of the regular spherically symmetric, static, and charged black hole has been converted into rotational form. It is shown that the derived solution for rotating a regular black hole is regular and the critical value of the electric charge for which two horizons merge into one sufficiently decreases in the presence of the nonvanishing rotation parameter a of the black hole.

  8. Orthopaedic Perspective on Barefoot and Minimalist Running.

    PubMed

    Roth, Jonathan; Neumann, Julie; Tao, Matthew

    2016-03-01

    In recent years, there has been a movement toward barefoot and minimalist running. Advocates assert that a lack of cushion and support promotes a forefoot or midfoot strike rather than a rearfoot strike, decreasing the impact transient and stress on the hip and knee. Although the change in gait is theorized to decrease injury risk, this concept has not yet been fully elucidated. However, research has shown diminished symptoms of chronic exertional compartment syndrome and anterior knee pain after a transition to minimalist running. Skeptics are concerned that, because of the effects of the natural environment and the lack of a standardized transition program, barefoot running could lead to additional, unforeseen injuries. Studies have shown that, with the transition to minimalist running, there is increased stress on the foot and ankle and risk of repetitive stress injuries. Nonetheless, despite the large gap of evidence-based knowledge on minimalist running, the potential benefits warrant further research and consideration.

  9. Imaging Black Hole Magnetic Fields with the Event Horizon Telescope

    NASA Astrophysics Data System (ADS)

    Chael, Andrew; Doeleman, Sheperd; Johnson, Michael D.

    2015-08-01

    The Event Horizon Telescope is a global mm-wavelength Very Long Baseline Interferometry array which, when completed, will achieve a nominal resolution of 20 microarcseconds. Initial observations with three stations have detected Schwarzschild-radius-scale structure around the supermassive black holes in SgrA* and M87. Future, fully polarimetric EHT images of the synchrotron emission near supermassive black holes will reveal fine magnetic field structure, potentially illuminating the role of magnetic fields in driving black hole accretion and the connection between magnetic fields, black hole spin, and relativistic jets. I will review techniques for polarimetric VLBI imaging and present new image reconstruction techniques tailored for polarimetric EHT data. Application to synthetic data from simulations shows that the EHT will be able to image changing magnetic field structure on microarcsecond scales. I will also discuss applications to the variable magnetic fields that could power flares in Sgr A*. Finally, I will present initial results from application of these techniques to data from the 2013 EHT observing run.

  10. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... storm; (2) A run-off control system from the active portion of the landfill to collect and control at least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion...

  11. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... storm; (2) A run-off control system from the active portion of the landfill to collect and control at least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion...

  12. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... storm; (2) A run-off control system from the active portion of the landfill to collect and control at least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion...

  13. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... storm; (2) A run-off control system from the active portion of the landfill to collect and control at least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion...

  14. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... storm; (2) A run-off control system from the active portion of the landfill to collect and control at least the water volume resulting from a 24-hour, 25-year storm. (b) Run-off from the active portion...

  15. LIGO Discovers the Merger of Two Black Holes

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-02-01

    Big news: the Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected its first gravitational-wave signal! Not only is the detection of this signal a major technical accomplishment and an exciting confirmation of general relativity, but it also has huge implications for black-hole astrophysics.What did LIGO see?LIGO is designed to detect the ripples in space-time created by two massive objects orbiting each other. These waves can reach observable amplitudes when a binary system consisting of two especially massive objects i.e., black holes or neutron stars reach the end of their inspiral and merge.LIGO has been unsuccessfully searching for gravitational waves since its initial operations in 2002, but a recent upgrade in its design has significantly increased its sensitivity and observational range. The first official observing run of Advanced LIGO began 18 September 2015, but the instruments were up and running in engineering mode several weeks before that. And it was in this time frame before official observing even began! that LIGO spotted its first gravitational wave signal: GW150914.One of LIGOs two detection sites, located near Hanford in eastern Washington. [LIGO]The signal, detected on 14 September, 2015, provides astronomers with a remarkable amount of information about the merger that caused it. From the detection, the LIGO team has extracted the masses of the two black holes that merged, 36+5-4 and 29+4-4 solar masses, as well as the mass of the final black hole formed by the merger, ~62 solar masses. The team also determined that the merger happened roughly a billion light-years away (at a redshift of z~0.1), and the direction of the signal was localized to an area of ~600 square degrees (roughly 1% of the sky).Why is this detection a big deal?This is the firstdirect detection of gravitational waves, providing spectacular further confirmation of Einsteins theory of general relativity. But the implications of GW150914 go far beyond this

  16. Erratic Black Hole Regulates Itself

    NASA Astrophysics Data System (ADS)

    2009-03-01

    New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

  17. The Holely Coronal Graveyard

    NASA Astrophysics Data System (ADS)

    Ayres, T.

    A 100 ks FUSE pointing will probe the O VI and C III emissions of an archetype denizen of the coronal graveyard--Aldebaran (Alpha Tauri; K5 III). HST spectra suggest the possible--surprising--presence of solar-like magnetic activity on the old, spun-down red giant. But, many of the characteristic 1150-1500 A UV emissions apparently are extinguished by a cool absorber overlying the hot (100,000 K) structures. Detection of O VI by FUSE suggests that the cool absorber opacity thins out just above the LyC edge, so O VI 1032 (and C III 977) could be a sensitive probe of the submerged activity through the far-UV opacity hole. The deep pointing will achieve high S/N, to search for discrete absorption structure in the hot lines, impressed on them by the cool absorber; and will allow an assessment of temporal variability due to the heating process, which might be convective-acoustic but probably is magnetic. If the latter, the buried magnetic activity on red giants possibly plays a key role in driving their winds--a long-standing astrophysical mystery, and a crucial component of galactic chemical evolution. The existing FUSE spectrum is too low in S/N to unambiguously measure discrete absorption components, and its singular nature precludes any variability analysis.

  18. Black hole meiosis

    NASA Astrophysics Data System (ADS)

    van Herck, Walter; Wyder, Thomas

    2010-04-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.

  19. Borehole cylindrical noise during hole-surface and hole-hole resistivity measurements

    NASA Astrophysics Data System (ADS)

    Osiensky, James L.; Nimmer, Robin; Binley, Andrew M.

    2004-04-01

    Drilled boreholes generally are the only feasible means to access the subsurface for the emplacement of downhole electrodes for most hole-hole and hole-surface resistivity experiments. However, the very existence of the borehole itself creates the potential for significant noise due to the inevitable conductivity contrast that develops between the borehole walls and the formation. Borehole cylindrical noise develops whenever a current source is placed in a drilled borehole. Borehole geometries may range from nearly perfect cylinders to highly, irregular, rugose holes in consolidated rock, to relatively minor, collapsed, disturbed zones in caving sediments. Boreholes in non-caving formations generally are filled with artificial, conductive materials to afford crucial, electrical continuity between downhole electrodes and the borehole walls. Filled boreholes form cylindrically shaped heterogeneities that create significant noise due to preferential current flow up and down the conductive columns. Selected conditions are simulated with a finite difference model to illustrate the significance of borehole cylindrical noise on hole-hole and hole-surface mise-à-la-masse electrical potentials near a current electrode. Mise-à-la-masse electrical potentials measured during a field tracer experiment also are presented. These measurements are used to illustrate significant errors may develop in the interpretation of apparent resistivity estimates out to a distance of several meters from the current source if borehole cylindrical noise is not recognized and accounted for in the analysis of electrical potential data.

  20. Air drilling for gas sands: Marianne Field, Sweetwater County, Wyoming

    SciTech Connect

    Wellborn, R.

    1983-08-01

    Marianne field is on the northeast flank of the Rock Springs uplift in Sweetwater County, Wyoming, just south of the town of Superior. The field is located where regional east dip averages 300 ft/mi (57 m/km). Numerous east-northeast-trending normal faults are present across the field with displacements ranging from 20 to 400 ft (6 to 120 m). Updip stratigraphic pinch-outs are responsible for gas accumulations in two separate Second Frontier sandstones with entrapment apparently not related to faulting. There are similar traps in various thin sandstone stringers in the Third Frontier and Muddy sandstones. In addition, a combination stratigraphic-fault trap for hydrocarbons appears to have been found in the Dakota and Lakota sandstones in one well; these horizons were abandoned for mechanical reasons before conclusive testing could be completed. All but one of the wells at Marianne field have been drilled either partially or completely with air. Consequently the potential to produce from various pay zones in nearly every well was determined prior to running production casing. This information generally cannot be obtained through drill stem testing in this area due to the formation damage from the drilling mud on the Cretaceous sandstone reservoirs. If an air-drilled gas reservoir was damaged later by drilling mud or cement, the potential was already known and it could be brought back through fracturing. The field consists of 6 gas wells and 5 dry holes.

  1. A Runs-Test Algorithm: Contingent Reinforcement and Response Run Structures

    ERIC Educational Resources Information Center

    Hachiga, Yosuke; Sakagami, Takayuki

    2010-01-01

    Four rats' choices between two levers were differentially reinforced using a runs-test algorithm. On each trial, a runs-test score was calculated based on the last 20 choices. In Experiment 1, the onset of stimulus lights cued when the runs score was smaller than criterion. Following cuing, the correct choice was occasionally reinforced with food,…

  2. 'Black holes': escaping the void.

    PubMed

    Waldron, Sharn

    2013-02-01

    The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche.

  3. Summary of Magnetic Holes Project

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Magnetic Holes in the solar wind are anomalous decreases in the interplanetary magnetic field as measured at a particular spacecraft. Such signatures have been observed in durations of several hours all the way down to the time resolution of the fastest magnetometer instruments, and with magnetic field decreases anywhere from a few percent to nearly full annihilation. It has been an objective of this study to implement a general strategy for detecting magnetic holes on all scales at which they can be found. Investigations into the properties of magnetic holes began with collections of events appearing distinct to the naked eye, perhaps biased by morphological characteristics or suggestive density and temperature fluctuations. More recent studies have taken the simple approach of cataloging any time period wherein the magnetic field is reduced by more than half. This investigation takes a statistical approach to the problem of identifying real magnetic hole events at all available scales.

  4. The Black Hole Universe Model

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  5. Sputtering Holes with Ion Beamlets

    NASA Technical Reports Server (NTRS)

    Byers, D. C.; Banks, B. A.

    1974-01-01

    Ion beamlets of predetermined configurations are formed by shaped apertures in the screen grid of an ion thruster having a double grid accelerator system. A plate is placed downstream from the screen grid holes and attached to the accelerator grid. When the ion thruster is operated holes having the configuration of the beamlets formed by the screen grid are sputtered through the plate at the accelerator grid.

  6. Analytical Relativity of Black Holes

    NASA Astrophysics Data System (ADS)

    Damour, Thibault

    The successful detection and analysis of gravitational wave (GW) signals from coalescing binary black holes necessitates the accurate prior knowledge of the form of the GW signals. This knowledge can be acquired through a synergy between Analytical Relativity (AR) methods and Numerical Relativity (NR) ones. We describe here the most promising AR formalism for describing the motion and radiation of coalescing binary black holes, the Effective One Body (EOB) method, and discuss its comparison with NR simulations.

  7. The Black Hole Experiment Gallery

    NASA Astrophysics Data System (ADS)

    Gould, R.; Dussault, M.; Griswold, A.; Reinfeld, E.; Steel, S.

    2008-06-01

    We report preliminary findings from the development and prototyping of the Black Hole Experiment Gallery, a NASA and NSF-funded national traveling exhibition and related educational materials on black holes. Among the innovations described are partnerships with community-based programs that enable culturally diverse youth to collaborate in exhibit development; and computer-networked technology that helps personalize visitors' exhibit experiences through the creation of a ``digital diary,'' that extends learning beyond the gallery, and that collects embedded evaluation data.

  8. Radio Studies of Coronal Holes.

    DTIC Science & Technology

    1981-03-01

    Maps Solar Wind Streams Radio Spectra Interplanetary Scintillation 20. A9 RACY (Continue an reveree side If necesary end Identify by block number...summarizes our efforts to identify individual high latitudecoronal holes with high speed solar wind streams far above or below the ecliptic,/The coronal...holes were identified from the Kitt Peak 10830 1 synoptic maps, while the high speed solar wind streams were identified from the interplanetary

  9. Airfoil cooling hole plugging by combustion gas impurities of the type found in coal derived fuels

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.; Lowell, C. E.

    1979-01-01

    The plugging of airfoil cooling holes by typical coal-derived fuel impurities was evaluated using doped combustion gases in an atmospheric pressure burner rig. Very high specific cooling air mass flow rates reduced or eliminated plugging. The amount of flow needed was a function of the composition of the deposit. It appears that plugging of film-cooled holes may be a problem for gas turbines burning coal-derived fuels.

  10. Stripe Correlations of Spins and Holes in Cuprate Superconductors

    NASA Astrophysics Data System (ADS)

    Tranquada, John M.

    1996-03-01

    Several different theoretical approaches have suggested that holes doped into a CuO2 plane might segregate. In particular, a stripe phase has been proposed in which hole-rich stripes alternate periodically with antiferromagnetic domains. Such a phase was first properly identified in the insulating model compounds La_2NiO_4+δ and La_2-xSr_xNiO4 by neutron diffraction studies.(J. M. Tranquada, D. J. Buttrey, V. Sachan, and J. E. Lorenzo, Phys. Rev. Lett. 73), 1003 (1994); V. Sachan, D. J. Buttrey, J. M. Tranquada, J. E. Lorenzo, and G. Shirane, Phys. Rev. B 51, 12742 (1995). That work led to an experiment(J. M. Tranquada, B. J. Sternlieb, J. D. Axe, Y. Nakamura, and S. Uchida, Nature 375), 561 (1995). which revealed evidence for static spin and charge stripes in La_1.6-xNd_0.4Sr_xCuO4 with x=0.12, a cuprate in which superconductivity is anomalously suppressed.(J. D. Axe and M. K. Crawford, J. Low Temp. Phys. 95), 271 (1994); Y. Nakamura and S. Uchida, Phys. Rev. B 46, 5841 (1992). In contrast to the nickelates, where the stripes run diagonally within a plane with one hole per site along a domain wall, the stripes in the cuprate run horizontally (or vertically) with a charge density of half a hole per site. In both cases the order appears to be driven by the charge rather than the magnetism. The magnetic scattering observed in the cuprate is closely related to the purely inelastic magnetic signal found in superconducting La_1.85Sr_0.15CuO_4, thus justifying the inference that dynamical stripe correlations occur in the superconductors. The static order found in the x=0.12 sample can be explained by pinning of the charge modulation by a well known lattice distortion, and is correlated with the suppression of superconductivity.

  11. 30 CFR 57.9360 - Shelter holes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Shelter holes. 57.9360 Section 57.9360 Mineral....9360 Shelter holes. (a) Shelter holes shall be— (1) Provided at intervals adequate to assure the safety... farthest projection of moving equipment. (b) Shelter holes shall not be used for storage unless a...

  12. 30 CFR 57.9360 - Shelter holes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Shelter holes. 57.9360 Section 57.9360 Mineral....9360 Shelter holes. (a) Shelter holes shall be— (1) Provided at intervals adequate to assure the safety... farthest projection of moving equipment. (b) Shelter holes shall not be used for storage unless a...

  13. 30 CFR 57.9360 - Shelter holes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Shelter holes. 57.9360 Section 57.9360 Mineral....9360 Shelter holes. (a) Shelter holes shall be— (1) Provided at intervals adequate to assure the safety... farthest projection of moving equipment. (b) Shelter holes shall not be used for storage unless a...

  14. 30 CFR 57.9360 - Shelter holes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Shelter holes. 57.9360 Section 57.9360 Mineral....9360 Shelter holes. (a) Shelter holes shall be— (1) Provided at intervals adequate to assure the safety... farthest projection of moving equipment. (b) Shelter holes shall not be used for storage unless a...

  15. 30 CFR 57.9360 - Shelter holes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shelter holes. 57.9360 Section 57.9360 Mineral....9360 Shelter holes. (a) Shelter holes shall be— (1) Provided at intervals adequate to assure the safety... farthest projection of moving equipment. (b) Shelter holes shall not be used for storage unless a...

  16. Characterization of the liquid sodium spray generated by a pipework hole

    SciTech Connect

    Torsello, G.; Parozzi, F.; Nericcio, L.; Araneo, L.; Cozzi, F.; Carcassi, M.; Mattei, N.

    2012-07-01

    Due to its advantageous thermodynamic characteristics at high temperature (550 deg. C), liquid sodium is the main candidate to be the cooling fluid for Generation TV nuclear reactors SFR (Sodium-cooled Fast Reactors). Now, sodium reacts very violently, both with the water and the oxygen of the air. Only few data were known about the liquid sodium behaviour when spread in the environment through micro defects. These are often present in a cooling circuit in welded or sealed joints and more rarely in the pipes. Micro defects, on the other hand, can be also generated in a cooling circuit because of the vibrations always present in a circuit into which a fluid runs. A new set-up, named LISOF, was built for testing high temperature liquid sodium when passing through micro defects and generating sprays or jets. Sprays and jets were generated by means of nozzles embedding sub milli-metric holes the diameter of which was: 0.2 mm, 0.4 mm, 0.5 mm. Tests were performed by pressurizing liquid sodium (550 deg. C) at: 3, 6 and 9 barg. Normal and high speed cinematography were used for the direct observation of the liquid sodium sprays while Phase Doppler Interferometry was used for the measurement of the droplets characteristics and velocity. Tests concerning the behaviour of the high temperature liquid sodium firing in air or in contact with the cement cover applied to a scaled down core catcher simulacrum were also performed. The paper presents the built set-up and the collected results. (authors)

  17. Results of Test-Hole Drilling in Well-Field Areas North of Tampa, Florida

    USGS Publications Warehouse

    Hutchinson, C.B.

    2003-01-01

    A total of 32 test holes were drilled in well-field areas of Hillsborough, Pasco, and Pinellas Counties in the early 1970's to collect information on the hydraulic and geologic properties of shallow formations overlying the Upper Floridan aquifer. Lithologic profiles were compiled and geohydrologic units identified for each test hole. At most test holes, natural-gamma logs were run to identify the confining unit that separates the surficial aquifer system from the Upper Floridan aquifer. Selected core samples were analyzed in the laboratory for vertical hydraulic conductivity, grain size, sorting, specific gravity, effective porosity, cation-exchange capacity, and mineralogy. Following drilling, casing was installed in each test hole and water levels were monitored. The data were used in the preparation of regional water-level maps and in the construction of a numerical model of ground-water flow in the well-field areas.

  18. Analysis Of Rearfoot Motion In Running Shoes

    NASA Astrophysics Data System (ADS)

    Cooper, Les

    1986-12-01

    In order to produce better shoes that cushion athletes from the high impact forces of running and still provide stability to the foot it is essential to have a method of quickly and reliably evaluating the performance of prototype shoes. The analysis of rear-foot motion requires the use of film or video recordings of test subjects running on a treadmill. Specific points on the subject are tracked to give a measure of inversion or eversion of the heel. This paper describes the testing procedure and its application to running shoe design. A comparison of film and video systems is also discussed.

  19. Acoustically tunable optical transmission through a subwavelength hole with a bubble

    NASA Astrophysics Data System (ADS)

    Maksymov, Ivan S.; Greentree, Andrew D.

    2017-03-01

    Efficient manipulation of light with sound in subwavelength-sized volumes is important for applications in photonics, phononics, and biophysics, but remains elusive. We theoretically demonstrate the control of light with MHz-range ultrasound in a subwavelength, 300-nm-wide water-filled hole with a 100-nm-radius air bubble. Ultrasound-driven pulsations of the bubble modulate the effective refractive index of the hole aperture, which gives rise to spectral tuning of light transmission through the hole. This control mechanism opens up novel opportunities for tunable acousto-optic and optomechanical metamaterials, and all-optical ultrasound transduction.

  20. Design and Use of a Novel Apparatus for Measuring Capsule Fill Hole Conductance

    SciTech Connect

    Seugling, R M; Nederbragt, W W; Klingmann, J L; Edson, S; Reynolds, J; Cook, R

    2006-11-27

    Description and results of a novel apparatus for determining the flow conductance through a laser drilled hole in a spherical shell for inertial confinement fusion experiments are described. The instrument monitors the pressure of an enclosed volume containing the laser pressure drilled capsule as air bleeds through the hole into the shell. From these measurements one obtains the conductance of the fill hole. This system has proven to be a valuable tool for verifying the conduct conductance into the capsule in a timely and nondestructive manner.

  1. Streakline flow visualization of discrete-hole film cooling with normal, slanted, and compound angle injection

    NASA Technical Reports Server (NTRS)

    Colladay, R. S.; Russell, L. M.

    1976-01-01

    Film injection from discrete holes in a three-row, staggered array with five-diameter spacing was studied for three hole angles: (1) normal, (2) slanted 30 deg to the surface in the direction of the main stream, and (3) slanted 30 deg to the surface and 45 deg laterally to the main stream. The ratio of the boundary layer thickness-to-hole diameter and Reynolds number were typical of gas-turbine film-cooling applications. Detailed streaklines showing the turbulent motion of the injected air were obtained by photographing very small neutrally buoyant, helium-filled soap bubbles which follow the flow field.

  2. Upper limits on the rates of BNS and NSBH mergers from Advanced LIGO's first observing run

    NASA Astrophysics Data System (ADS)

    Lackey, Benjamin; LIGO Collaboration

    2017-01-01

    Last year the Advanced LIGO detectors finished their first observing run and detected two binary black hole mergers with high significance but no binary neutron star (BNS) or neutron-star-black-hole (NSBH) mergers. We present upper limits on the rates of BNS and NSBH mergers in the universe based on their non-detection with two modeled searches. With zero detections, the upper limits depend on the choice of prior, but we find 90% upper limits using a conservative prior of 12 , 000 / Gpc3 / yr for BNS mergers and 1 , 000 - 3 , 000 / Gpc3 / yr for NSBH mergers depending on the black hole mass. Comparing these upper limits to several rates predictions in the literature, we find our upper limits are close to the more optimistic rates estimates. Further non-detections in the second and third observing runs should be able to rule out several rates predictions. Using the observed rate of short gamma ray bursts (GRBs), we can also place lower limits on the average beaming angle of short GRBs. Assuming all short GRBs come from BNS mergers, we find a 90% lower limit of 1-4 degrees on the GRB beaming angle, with the range coming from the uncertainty in short GRB rates.

  3. Rethinking Black Hole Accretion Discs

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg

    Accretion discs are staples of astrophysics. Tapping into the gravitational potential energy of the accreting material, these discs are highly efficient machines that produce copious radiation and extreme outflows. While interesting in their own right, accretion discs also act as tools to study black holes and directly influence the properties of the Universe. Black hole X-ray binaries are fantastic natural laboratories for studying accretion disc physics and black hole phenomena. Among many of the curious behaviors exhibited by these systems are black hole state transitions -- complicated cycles of dramatic brightening and dimming. Using X-ray observations with high temporal cadence, we show that the evolution of the accretion disc spectrum during black hole state transitions can be described by a variable disc atmospheric structure without invoking a radially truncated disc geometry. The accretion disc spectrum can be a powerful diagnostic for measuring black hole spin if the effects of the disc atmosphere on the emergent spectrum are well-understood; however, properties of the disc atmosphere are largely unconstrained. Using statistical methods, we decompose this black hole spin measurement technique and show that modest uncertainties regarding the disc atmosphere can lead to erroneous spin measurements. The vertical structure of the disc is difficult to constrain due to our ignorance of the contribution to hydrostatic balance by magnetic fields, which are fundamental to the accretion process. Observations of black hole X-ray binaries and the accretion environments near supermassive black holes provide mounting evidence for strong magnetization. Performing numerical simulations of accretion discs in the shearing box approximation, we impose a net vertical magnetic flux that allows us to effectively control the level of disc magnetization. We study how dynamo activity and the properties of turbulence driven by the magnetorotational instability depend on the

  4. 1. "X15 RUN UP AREA 230." A somewhat blurred, very ...

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

    1. "X-15 RUN UP AREA 230." A somewhat blurred, very low altitude low oblique view to the northwest. This view predates construction of observation bunkers. Photo no. "14,696 58 A-AFFTC 17 NOV 58." - Edwards Air Force Base, X-15 Engine Test Complex, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

  5. 2. X15 RUN UP AREA (Jan 59). A sharp, higher ...

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

    2. X-15 RUN UP AREA (Jan 59). A sharp, higher altitide low oblique aerial view to the north, showing runway, at far left; X-15 Engine Test Complex in the center. This view predates construction of observation bunkers. - Edwards Air Force Base, X-15 Engine Test Complex, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

  6. Run 16, eIPM Summary

    SciTech Connect

    Connolly, R.; Dawson, C.; Jao, S.; Schoefer, V.; Tepikian, S.

    2016-08-05

    Three problems with the eIPMs were corrected during the 2015 summer shutdown. These involved ac coupling and 'negative profiles', detector 'dead zone' created by biasing, and gain control on ramp. With respect to Run 16, problems dealt with included gain depletion on horizontal MCP and rf pickup on profile signals; it was found that the MCP was severely damaged over part of the aperture. Various corrective measures were applied. Some results of these measured obtained during Run 16 are shown. At the end of Run 16 there was a three-­day beam run to study polarized proton beams in the AGS. Attempts to minimize beam injection errors which increase emittance by using the eIPMs to measure the contribution of injection mismatch to the AGS output beam emittance are recounted. .

  7. Social network structures and bank runs

    NASA Astrophysics Data System (ADS)

    Li, Shouwei; Li, Jiaheng

    2016-05-01

    This paper investigates the impact of social network structures of depositors on bank runs. The analyzed network structures include random networks, small-world networks and scale-free networks. Simulation results show that the probability of bank run occurrence in random networks is larger than that in small-world networks, but the probability of bank run occurrence in scale-free networks drops from the highest to the lowest among the three types of network structures with the increase of the proportion of impatient depositors. The average degree of depositor networks has a significant impact on bank runs, but this impact is related to the proportion of impatient depositors and the confidence levels of depositors in banks.

  8. CDF forward shielding for Run II

    SciTech Connect

    Krivosheev, O.E.; Mokhov, N.V.

    1998-03-16

    Detailed calculations of the accelerator related background in the CDF forward muon spectrometer have been performed with the MARS13 code and a newly developed C++ code for particle tracking in accelerator lattices. Calculated space distributions of background hits are in a good agreement with data taken in Run I. Several shielding configurations in the CDF hall and Tevatron tunnel have been studied. The optimal one provides a 30-fold shielding efficiency compatible with CDF Run II requirements.

  9. Minimum-time running: a numerical approach.

    PubMed

    Maroński, Ryszard; Rogowski, Krzysztof

    2011-01-01

    The article deals with the minimum-time running problem. The time of covering a given distance is minimized. The Hill-Keller model of running employed is based on Newton's second law and the equation of power balance. The problem is formulated in optimal control. The unknown function is the runner's velocity that varies with the distance. The problem is solved applying the direct Chebyshev's pseudospectral method.

  10. RHIC Polarized proton performance in run-8

    SciTech Connect

    Montag,C.; Bai, M.; MacKay, W.W.; Roser, T.; Abreu, N.; Ahrens, L.; Barton, D.; Beebe-Wang, J.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Bunce, G.; Calaga, R.; Cameron, P.; Connolly, R.; D'Ottavio, T.; Drees, A.; Fedotov, A.V.; Fischer, W.; Ganetis, G.; Gardner, C.; Glenn, J.; Hayes, T.; Huang, H.; Ingrassia, P.; Kayran, D.A.; Kewisch, J.; Lee, R.C.; Lin, F.; Litvinenko, V.N.; Luccio, A.U.; Luo, Y.; Makdisi, Y.; Malitsky, N.; Marr, G.; Marusic, A.; Michnoff, R.; Morris, J.; Oerter, B.; Pilat, F.; Pile, P.; Robert-Demolaize, G.; Russo, T.; Satogata, T.; Schultheiss, C.; Sivertz, M.; Smith, K.; Tepikian, S.; D. Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2008-10-06

    During Run-8, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Physics data were taken with vertical orientation of the beam polarization, which in the 'Yellow' RHIC ring was significantly lower than in previous years. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-8, and we discuss possible causes of the not as high as previously achieved polarization performance of the 'Yellow' ring.

  11. RHIC polarized proton performance in run-8.

    SciTech Connect

    Montag,C.; Abreu, N.; Ahrens, L.; Bai, M.; Barton, D.; et al.

    2008-06-23

    During Run-8, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Helical spin rotators at these two interaction regions were used to control the spin orientation of both beams at the collision points. Physics data were taken with different orientations of the beam polarization. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-8.

  12. The Ssart of Run II at CDF

    SciTech Connect

    Marco Rescigno

    2002-10-29

    After a hiatus of almost 6 years and an extensive upgrade, Tevatron, the world largest proton-antiproton collider, has resumed the operation for the so called RUN II. In this paper we give a brief overview of the many new features of the Tevatron complex and of the upgraded CDF experiment, and show the presently achieved detector performances as well as highlights of the RUN II physics program in the beauty and electroweak sector.

  13. Constructing Time-Dependent Coronal Hole Maps Using Synchronized Multi-Instrument EUV Data

    NASA Astrophysics Data System (ADS)

    Caplan, R. M.; Downs, C.; Linker, J.

    2014-12-01

    Coronal holes are manifested as relatively low intensity regions of the corona seen in EUV and X-Ray images. They are usually associated with open magnetic field regions, and their evolution can help us understand how the Sun's magnetic field evolves in time and how these changes propagate out into the heliosphere. Here we discuss our method for detecting coronal holes in EUV imaging data. Our particular focus is on building instantaneous snapshots of hole boundaries by stitching together images from multiple vantage points (provided by STEREO-A, STEREO-B, and SDO), which allows us to study the evolution of large portions of the corona at high cadences for long periods of complete visibility.A key step in our methodology is the proper scaling and preprocessing of the data. Intensity histogram averaging of quiet sun regions over extended series of images is used to scale the instrument's data to each other, and along with a running average of coronal hole intensity, is utilized to fashion limb brightening correction curves, which when applied, remove natural disk-to-limb intensity variations. An image deconvolution using the instrument's known point-spread-functions is also used to reduce scattered light which can artificially brighten coronal holes. Our coronal hole detection method is discussed, which relies on an iterative double-threshold "flood-fill" algorithm. Time-dependent coronal hole maps produced by our method will be presented, and challenges of data flow, processing, and storage will be discussed.

  14. The Ozone Hole -- a Mystery Reborn?

    NASA Astrophysics Data System (ADS)

    von Hobe, M.; Grooß, J.; Müller, R.; Stroh, F.

    2007-12-01

    In 1985, Farman et al. discovered the near complete disappearance of the stratospheric ozone layer over Antarctica in spring. This 'Ozone Hole' took the atmospheric research community by surprise as it could not be explained by the known catalytic cycles removing ozone in the stratosphere. McElroy et al. (1986) and Molina and Molina (1987) seemed to have solved the enigma by proposing two new catalytic cycles -- the ClO-BrO-cycle and the ClO dimer cycle -- that could rapidly destroy ozone at cold temperatures and high zenith angles. Subsequent work describing the kinetics of these cycles as well as stratospheric observations of chlorine and bromine compounds supported their theory and led to atmospheric chemistry models reproducing observed ozone loss reasonably well. Today, more than 20 years after the discovery of the ozone hole and the ratification of the Montreal Protocol, a new laboratory study (Pope et al., 2007) -- suggesting much smaller absorption cross sections and hence photolysis rates of the ClO dimer -- seriously calls into question our understanding of how ozone is destroyed in the spring polar stratosphere. With the new cross sections, both the dimer cycle and the ClO-BrO-cycle run much slower, and observations of neither chlorine compounds nor ozone loss are reproduced by model simulations (von Hobe et al., 2007): the known catalytic cycles cannot cause an ozone hole. Obviously, this also calls into question our ability to predict future polar ozone depletion. In search for an explanation, we discuss possible shortcomings of the Pope et al. experiment that could lead to an underestimation of the dimer absorption and examine various new chemical processes for their likelihood to influence chlorine partitioning and cause significant ozone loss in the atmosphere and at the same time go undetected in laboratory based kinetic studies. A strategy is presented for designing the tests needed to unambiguously confirm or rule out proposed solutions to the

  15. Calcaneal loading during walking and running

    NASA Technical Reports Server (NTRS)

    Giddings, V. L.; Beaupre, G. S.; Whalen, R. T.; Carter, D. R.

    2000-01-01

    PURPOSE: This study of the foot uses experimentally measured kinematic and kinetic data with a numerical model to evaluate in vivo calcaneal stresses during walking and running. METHODS: External ground reaction forces (GRF) and kinematic data were measured during walking and running using cineradiography and force plate measurements. A contact-coupled finite element model of the foot was developed to assess the forces acting on the calcaneus during gait. RESULTS: We found that the calculated force-time profiles of the joint contact, ligament, and Achilles tendon forces varied with the time-history curve of the moment about the ankle joint. The model predicted peak talocalcaneal and calcaneocuboid joint loads of 5.4 and 4.2 body weights (BW) during walking and 11.1 and 7.9 BW during running. The maximum predicted Achilles tendon forces were 3.9 and 7.7 BW for walking and running. CONCLUSIONS: Large magnitude forces and calcaneal stresses are generated late in the stance phase, with maximum loads occurring at approximately 70% of the stance phase during walking and at approximately 60% of the stance phase during running, for the gait velocities analyzed. The trajectories of the principal stresses, during both walking and running, corresponded to each other and qualitatively to the calcaneal trabecular architecture.

  16. Running With an Elastic Lower Limb Exoskeleton.

    PubMed

    Cherry, Michael S; Kota, Sridhar; Young, Aaron; Ferris, Daniel P

    2016-06-01

    Although there have been many lower limb robotic exoskeletons that have been tested for human walking, few devices have been tested for assisting running. It is possible that a pseudo-passive elastic exoskeleton could benefit human running without the addition of electrical motors due to the spring-like behavior of the human leg. We developed an elastic lower limb exoskeleton that added stiffness in parallel with the entire lower limb. Six healthy, young subjects ran on a treadmill at 2.3 m/s with and without the exoskeleton. Although the exoskeleton was designed to provide ~50% of normal leg stiffness during running, it only provided 24% of leg stiffness during testing. The difference in added leg stiffness was primarily due to soft tissue compression and harness compliance decreasing exoskeleton displacement during stance. As a result, the exoskeleton only supported about 7% of the peak vertical ground reaction force. There was a significant increase in metabolic cost when running with the exoskeleton compared with running without the exoskeleton (ANOVA, P < .01). We conclude that 2 major roadblocks to designing successful lower limb robotic exoskeletons for human running are human-machine interface compliance and the extra lower limb inertia from the exoskeleton.

  17. Metadata aided run selection at ATLAS

    NASA Astrophysics Data System (ADS)

    Buckingham, R. M.; Gallas, E. J.; C-L Tseng, J.; Viegas, F.; Vinek, E.; ATLAS Collaboration

    2011-12-01

    Management of the large volume of data collected by any large scale scientific experiment requires the collection of coherent metadata quantities, which can be used by reconstruction or analysis programs and/or user interfaces, to pinpoint collections of data needed for specific purposes. In the ATLAS experiment at the LHC, we have collected metadata from systems storing non-event-wise data (Conditions) into a relational database. The Conditions metadata (COMA) database tables not only contain conditions known at the time of event recording, but also allow for the addition of conditions data collected as a result of later analysis of the data (such as improved measurements of beam conditions or assessments of data quality). A new web based interface called "runBrowser" makes these Conditions Metadata available as a Run based selection service. runBrowser, based on PHP and JavaScript, uses jQuery to present selection criteria and report results. It not only facilitates data selection by conditions attributes, but also gives the user information at each stage about the relationship between the conditions chosen and the remaining conditions criteria available. When a set of COMA selections are complete, runBrowser produces a human readable report as well as an XML file in a standardized ATLAS format. This XML can be saved for later use or refinement in a future runBrowser session, shared with physics/detector groups, or used as input to ELSSI (event level Metadata browser) or other ATLAS run or event processing services.

  18. Negative running can prevent eternal inflation

    SciTech Connect

    Kinney, William H.; Freese, Katherine E-mail: ktfreese@umich.edu

    2015-01-01

    Current data from the Planck satellite and the BICEP2 telescope favor, at around the 2 σ level, negative running of the spectral index of curvature perturbations from inflation. We show that for negative running α < 0, the curvature perturbation amplitude has a maximum on scales larger than our current horizon size. A condition for the absence of eternal inflation is that the curvature perturbation amplitude always remain below unity on superhorizon scales. For current bounds on n{sub S} from Planck, this corresponds to an upper bound of the running α < −9 × 10{sup −5}, so that even tiny running of the scalar spectral index is sufficient to prevent eternal inflation from occurring, as long as the running remains negative on scales outside the horizon. In single-field inflation models, negative running is associated with a finite duration of inflation: we show that eternal inflation may not occur even in cases where inflation lasts as long as 10{sup 4} e-folds.

  19. Fireman's Air Tanks

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Together with NASA's Johnson Space Center, A-T-O Inc.'s Scott Aviation has developed light-weight firefighter's air tanks. New backpack system weighs only 20 pounds for 30 minute air supply, 13 pounds less than conventional firefighting tanks. They are pressurized at 4,500 psi, (twice current tanks). Made of aluminum liner wrapped by resin-impregnated glass fibers, eliminating corrosion as well as lightening the load. Redesigned face mask permits better vision. Warning device to tell fireman he is running out of air is personalized so it can't be heard by others reducing confusion in an already hectic environment. Structural Composites Inc., The Boeing Co., and Martin- Marietta Corp. have developed uses for this technology.

  20. Air bearing provides friction-free support for shaker system slip table

    NASA Technical Reports Server (NTRS)

    Skoff, R. W.

    1966-01-01

    Air bearing system supports a shaker system slip table with minimum friction. At each corner of a square of grooves made on the table, a hole is drilled through the table and fitted with air connections. Air pressure is simultaneously fed to the four fittings forming an air bearing.

  1. Liverpool Telescope follow-up of candidate electromagnetic counterparts during the first run of Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Copperwheat, C. M.; Steele, I. A.; Piascik, A. S.; Bersier, D.; Bode, M. F.; Collins, C. A.; Darnley, M. J.; Galloway, D. K.; Gomboc, A.; Kobayashi, S.; Lamb, G. P.; Levan, A. J.; Mazzali, P. A.; Mundell, C. G.; Pian, E.; Pollacco, D.; Steeghs, D.; Tanvir, N. R.; Ulaczyk, K.; Wiersema, K.

    2016-11-01

    The first direct detection of gravitational waves was made in 2015 September with the Advanced LIGO detectors. By prior arrangement, a worldwide collaboration of electromagnetic follow-up observers were notified of candidate gravitational wave events during the first science run, and many facilities were engaged in the search for counterparts. Three alerts were issued to the electromagnetic collaboration over the course of the first science run, which lasted from 2015 September to 2016 January. Two of these alerts were associated with the gravitational wave events since named GW150914 and GW151226. In this paper we provide an overview of the Liverpool Telescope contribution to the follow-up campaign over this period. Given the hundreds of square degree uncertainty in the sky position of any gravitational wave event, efficient searching for candidate counterparts required survey telescopes with large (˜degrees) fields of view. The role of the Liverpool Telescope was to provide follow-up classification spectroscopy of any candidates. We followed candidates associated with all three alerts, observing 1, 9 and 17 candidates respectively. We classify the majority of the transients we observed as supernovae. No counterparts were identified, which is in line with expectations given that the events were classified as black hole-black hole mergers. However these searches laid the foundation for similar follow-up campaigns in future gravitational wave detector science runs, in which the detection of neutron star merger events with observable electromagnetic counterparts is much more likely.

  2. AEROMETRIC INFORMATION RETRIEVAL SYSTEM (AIRS) - GRAPHICS

    EPA Science Inventory

    Aerometric Information Retrieval System (AIRS) is a computer-based repository of information about airborne pollution in the United States and various World Health Organization (WHO) member countries. AIRS is administered by the U.S. Environmental Protection Agency, and runs on t...

  3. Full-coverage film cooling heat transfer study: Summary of data for normal-hole injection and 30 deg slant-hole injection

    NASA Technical Reports Server (NTRS)

    Crawford, M. E.; Choe, H.; Kays, W. M.; Moffat, R. J.

    1976-01-01

    Heat transfer to a full coverage film cooled turbulent boundary layer over a flat surface was studied. The surface consisted of a discrete hole test section containing 11 rows of holes spaced 5 diameters apart in a staggered array and an instrumented recovery region. Ten diameter spacing was also studied by plugging appropriate holes. Two test sections were used, one having holes normal to the surface and the other having holes angled 30 deg to the surface in the downstream direction. Stanton number data were obtained both in the full coverage region and in the downstream recovery region for a range of blowing ratios, or mass flux ratios, from 0 to 1.3. Initial conditions at the upstream edge of the blowing region were varied from 500 to 5000 for momentum thickness Reynolds number and from 100 to 1800 for enthalpy thickness Reynolds number. The range of Reynolds numbers based on hole diameter and mainstream velocity was 6000 to 22000. Initial boundary layer thicknesses range from 0.5 to 2.0 hole diameters. Air was used as the working fluid. The data were taken for the secondary injection temperature equal to the wall temperature and also equal to the mainstream temperature. Superposition was then used to obtain Stanton number as a continuous function of the injectant temperature. The heat transfer coefficient was defined on the basis of a mainstream-to-wall temperature difference. This definition permits direct comparison of performance between film cooling and transpiration cooling.

  4. Violent flickering in Black Holes

    NASA Astrophysics Data System (ADS)

    2008-10-01

    Unique observations of the flickering light from the surroundings of two black holes provide new insights into the colossal energy that flows at their hearts. By mapping out how well the variations in visible light match those in X-rays on very short timescales, astronomers have shown that magnetic fields must play a crucial role in the way black holes swallow matter. Flickering black hole ESO PR Photo 36/08 Flickering black hole Like the flame from a candle, light coming from the surroundings of a black hole is not constant -- it flares, sputters and sparkles. "The rapid flickering of light from a black hole is most commonly observed at X-ray wavelengths," says Poshak Gandhi, who led the international team that reports these results. "This new study is one of only a handful to date that also explore the fast variations in visible light, and, most importantly how these fluctuations relate to those in X-rays." The observations tracked the shimmering of the black holes simultaneously using two different instruments, one on the ground and one in space. The X-ray data were taken using NASA's Rossi X-ray Timing Explorer satellite. The visible light was collected with the high speed camera ULTRACAM, a visiting instrument at ESO's Very Large Telescope (VLT), recording up to 20 images a second. ULTRACAM was developed by team members Vik Dhillon and Tom Marsh. "These are among the fastest observations of a black hole ever obtained with a large optical telescope," says Dhillon. To their surprise, astronomers discovered that the brightness fluctuations in the visible light were even more rapid than those seen in X-rays. In addition, the visible-light and X-ray variations were found not to be simultaneous, but to follow a repeated and remarkable pattern: just before an X-ray flare the visible light dims, and then surges to a bright flash for a tiny fraction of a second before rapidly decreasing again. None of this radiation emerges directly from the black hole, but from the

  5. Running kinematics and shock absorption do not change after brief exhaustive running.

    PubMed

    Abt, John P; Sell, Timothy C; Chu, Yungchien; Lovalekar, Mita; Burdett, Ray G; Lephart, Scott M

    2011-06-01

    Because of the nature of running, the forces encountered require a proper coordination of joint action of the lower extremity to dissipate the ground reaction forces and accelerations through the kinetic chain. Running-related muscle fatigue may reduce the shock absorbing capacity of the lower extremity and alter running kinematics. The purpose of this study was to determine if a bout of exhaustive running at a physiologically determined high intensity, changes running kinematics, impact accelerations, and alters shock attenuating capabilities. It was hypothesized that as a result of fatigue induced by an exhaustive run, running kinematics, impact accelerations at the head and shank, acceleration reduction, and shock attenuation would change. A within-subject, repeated-measures design was used for this study. Twelve healthy, competitive male and female distance runners participated. Subjects performed 2 testing sessions consisting of a VO2max treadmill protocol to determine the heart rate at ventilatory threshold and a fatigue-inducing running bout at the identified ventilatory threshold heart rate. Kinematic data included knee flexion, pronation, time to maximum knee flexion, and time to maximum pronation. Acceleration data included shank acceleration, head acceleration, and shock attenuation. No significant differences resulted for the kinematic or acceleration variables. Although the results of this study do not support the original hypotheses, the influence of running fatigue on kinematics and accelerations remains inconclusive. Future research is necessary to examine fatigue-induced changes in running kinematics and accelerations and to determine the threshold at which point the changes may occur.

  6. Sex differences in running mechanics and patellofemoral joint kinetics following an exhaustive run.

    PubMed

    Willson, John D; Loss, Justin R; Willy, Richard W; Meardon, Stacey A

    2015-11-26

    Patellofemoral joint pain (PFP) is a common running-related injury that is more prevalent in females and thought to be associated with altered running mechanics. Changes in running mechanics have been observed following an exhaustive run but have not been analyzed relative to the sex bias for PFP. The purpose of this study was to test if females demonstrate unique changes in running mechanics associated with PFP following an exhaustive run. For this study, 18 females and 17 males ran to volitional exhaustion. Peak PFJ contact force and stress, PFJ contact force and stress loading rates, hip adduction excursion, and hip and knee joint frontal plane angular impulse were analyzed between females and males using separate 2 factor ANOVAs (2 (male/female)×2 (before/after exhaustion)). We observed similar changes in running mechanics among males and females over the course of the exhaustive run. Specifically, greater peak PFJ contact force loading rate (5%, P=.01), PFJ stress loading rate (5%, P<.01), hip adduction excursion (1.3°, P<.01), hip abduction angular impulse (4%, P<.01), knee abduction angular impulse (5%, P=.03), average vertical ground reaction force loading rate (10%, P<.01) and step length (2.1cm, P=.001) were observed during exhausted running. These small changes in suspected PFP pathomechanical factors may increase a runner׳s propensity for PFP. However, unique changes in female running mechanics due to exhaustion do not appear to contribute to the sex bias for PFP.

  7. FORCE-FEEDING BLACK HOLES

    SciTech Connect

    Begelman, Mitchell C.

    2012-04-10

    We propose that the growth of supermassive black holes is associated mainly with brief episodes of highly super-Eddington infall of gas ({sup h}yperaccretion{sup )}. This gas is not swallowed in real time, but forms an envelope of matter around the black hole that can be swallowed gradually, over a much longer timescale. However, only a small fraction of the black hole mass can be stored in the envelope at any one time. We argue that any infalling matter above a few percent of the hole's mass is ejected as a result of the plunge in opacity at temperatures below a few thousand degrees kelvin, corresponding to the Hayashi track. The speed of ejection of this matter, compared to the velocity dispersion {sigma} of the host galaxy's core, determines whether the ejected matter is lost forever or returns eventually to rejoin the envelope, from which it can be ultimately accreted. The threshold between matter recycling and permanent loss defines a relationship between the maximum black hole mass and {sigma} that resembles the empirical M{sub BH}-{sigma} relation.

  8. Devils Hole, Nevada--A Primer

    USGS Publications Warehouse

    Landwehr, Jurate M.; Winograd, Isaac J.

    2012-01-01

    This fact sheet summarizes the multifaceted research of the U.S. Geological Survey—published in diverse outlets—that focuses on the subaqueous cavern Devils Hole in Nevada. Questions addressed in the fact sheet are: What is Devils Hole? Why is Devils Hole of interest to paleoclimatologists? How was the isotopic record from the Devils Hole vein calcite dated? What paleoclimate phenomena are recorded by the Devils Hole stable isotopic time series? Where can one find the isotopic records? What contributions has Devils Hole research made to the field of paleoclimatology, paleohydrology, and geochemistry? What does Devils Hole reveal about how long we can expect the present interglaciation to last? What are some practical applications of the Devils Hole findings? Why is Devils Hole of interest to zoologists?

  9. Whole beetroot consumption acutely improves running performance.

    PubMed

    Murphy, Margaret; Eliot, Katie; Heuertz, Rita M; Weiss, Edward

    2012-04-01

    Nitrate ingestion improves exercise performance; however, it has also been linked to adverse health effects, except when consumed in the form of vegetables. The purpose of this study was to determine, in a double-blind crossover study, whether whole beetroot consumption, as a means for increasing nitrate intake, improves endurance exercise performance. Eleven recreationally fit men and women were studied in a double-blind placebo controlled crossover trial performed in 2010. Participants underwent two 5-km treadmill time trials in random sequence, once 75 minutes after consuming baked beetroot (200 g with ≥500 mg nitrate) and once 75 minutes after consuming cranberry relish as a eucaloric placebo. Based on paired t tests, mean running velocity during the 5-km run tended to be faster after beetroot consumption (12.3±2.7 vs 11.9±2.6 km/hour; P=0.06). During the last 1.1 miles (1.8 km) of the 5-km run, running velocity was 5% faster (12.7±3.0 vs 12.1±2.8 km/hour; P=0.02) in the beetroot trial, with no differences in velocity (P≥0.25) in the earlier portions of the 5-km run. No differences in exercise heart rate were observed between trials; however, at 1.8 km into the 5-km run, rating of perceived exertion was lower with beetroot (13.0±2.1 vs 13.7±1.9; P=0.04). Consumption of nitrate-rich, whole beetroot improves running performance in healthy adults. Because whole vegetables have been shown to have health benefits, whereas nitrates from other sources may have detrimental health effects, it would be prudent for individuals seeking performance benefits to obtain nitrates from whole vegetables, such as beetroot.

  10. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  11. What Is the Best Launch Angle To Hit a Home Run?

    NASA Astrophysics Data System (ADS)

    Kagan, David

    2010-04-01

    Your students will proudly raise their hands and answer, "45 degrees!" They are, however, answering a different question. It is true that in the absence of air resistance, for a given initial speed, the launch angle that maximizes the range is 45°. For a real homer, there are many complicating factors that make the question far more challenging to answer. Here is a partial list: 1. The initial speed off the bat is not fixed. Garvey's law, "The harder you hit it, the further it goes" is definitely at play; 2. Air resistance is a substantial influence on the flight of the ball. ; 3. The backspin on a well-hit ball creates lift due to the Magnus effect.2; 4. Atmospheric conditions such as humidity, temperature, air density, and the wind affect the motion as well.3; 5. Baseball parks are unique in size and shape. So, a home run in one park may not be a home run in another.

  12. Evaporation of Primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Hawking, S. W.

    The usual explanation of the isotropy of the universe is that inflation would have smoothed out any inhomogeneities. However, if the universe was initially fractal or in a foam like state, an overall inflation would have l it in the same state. I suggest that the universe did indeed begin with a tangled web of wormholes connecting pairs of black holes but that the inflationary expansion was unstable: wormholes that are slightly smaller correspond to black holes that are hotter than the cosmological background and evaporate away. This picture is supported by calculations with Raphael Bousso of the evaporation of primordial black holes in the s-wave and large N approximations.

  13. Scrambling with matrix black holes

    NASA Astrophysics Data System (ADS)

    Brady, Lucas; Sahakian, Vatche

    2013-08-01

    If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.

  14. Volume inside old black holes

    NASA Astrophysics Data System (ADS)

    Christodoulou, Marios; De Lorenzo, Tommaso

    2016-11-01

    Black holes that have nearly evaporated are often thought of as small objects, due to their tiny exterior area. However, the horizon bounds large spacelike hypersurfaces. A compelling geometric perspective on the evolution of the interior geometry was recently shown to be provided by a generally covariant definition of the volume inside a black hole using maximal surfaces. In this article, we expand on previous results and show that finding the maximal surfaces in an arbitrary spherically symmetric spacetime is equivalent to a 1 +1 geodesic problem. We then study the effect of Hawking radiation on the volume by computing the volume of maximal surfaces inside the apparent horizon of an evaporating black hole as a function of time at infinity: while the area is shrinking, the volume of these surfaces grows monotonically with advanced time, up to when the horizon has reached Planckian dimensions. The physical relevance of these results for the information paradox and the remnant scenarios are discussed.

  15. Quantum Criticality and Black Holes

    SciTech Connect

    Sachdev, Subir

    2007-08-22

    I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.

  16. Quantum Criticality and Black Holes

    ScienceCinema

    Sachdev, Subir [Harvard University, Cambridge, Massachusetts, United States

    2016-07-12

    I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.

  17. Lee-Wick black holes

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Modesto, Leonardo; Wang, Yixu

    2017-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source M exceeds a critical value Mcrit. For M >Mcrit the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for M =Mcrit we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  18. 'Hole' Lotta Grindin' Going On

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The red marks in this image, taken by the Mars Exploration Rover Opportunity's panoramic camera, indicate holes made by the rover's rock abrasion tool, located on its instrument deployment device, or 'arm.' The lower hole, located on a target called 'McKittrick,' was made on the 30th martian day, or sol, of Opportunity's journey. The upper hole, located on a target called 'Guadalupe' was made on sol 34 of the rover's mission. The mosaic image was taken using a blue filter at the 'El Capitan' region of the Meridiani Planum, Mars, rock outcrop. The image, shown in a vertical-perspective map projection, consists of images acquired on sols 27, 29 and 30 of the rover's mission.

  19. The Black Hole Information Problem

    NASA Astrophysics Data System (ADS)

    Polchinski, Joseph

    The black hole information problem has been a challenge since Hawking's original 1975 paper. It led to the discovery of AdS/CFT, which gave a partial resolution of the paradox. However, recent developments, in particular the firewall puzzle, show that there is much that we do not understand. I review the black hole, Hawking radiation, and the Page curve, and the classic form of the paradox. I discuss AdS/CFT as a partial resolution. I then discuss black hole complementarity and its limitations, leading to many proposals for different kinds of `drama.' I conclude with some recent ideas. Presented at the 2014-15 Jerusalem Winter School and the 2015 TASI.

  20. Black holes with vector hair

    NASA Astrophysics Data System (ADS)

    Fan, Zhong-Ying

    2016-09-01

    In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.

  1. Running Speed Can Be Predicted from Foot Contact Time during Outdoor over Ground Running

    PubMed Central

    van Oeveren, Ben; Francke, Agnieta; Zijlstra, Patrick

    2016-01-01

    The number of validation studies of commercially available foot pods that provide estimates of running speed is limited and these studies have been conducted under laboratory conditions. Moreover, internal data handling and algorithms used to derive speed from these pods are proprietary and thereby unclear. The present study investigates the use of foot contact time (CT) for running speed estimations, which potentially can be used in addition to the global positioning system (GPS) in situations where GPS performance is limited. CT was measured with tri axial inertial sensors attached to the feet of 14 runners, during natural over ground outdoor running, under optimized conditions for GPS. The individual relationships between running speed and CT were established during short runs at different speeds on two days. These relations were subsequently used to predict instantaneous speed during a straight line 4 km run with a single turning point halfway. Stopwatch derived speed, measured for each of 32 consecutive 125m intervals during the 4 km runs, was used as reference. Individual speed-CT relations were strong (r2 >0.96 for all trials) and consistent between days. During the 4km runs, median error (ranges) in predicted speed from CT 2.5% (5.2) was higher (P<0.05) than for GPS 1.6% (0.8). However, around the turning point and during the first and last 125m interval, error for GPS-speed increased to 5.0% (4.5) and became greater (P<0.05) than the error predicted from CT: 2.7% (4.4). Small speed fluctuations during 4km runs were adequately monitored with both methods: CT and GPS respectively explained 85% and 73% of the total speed variance during 4km runs. In conclusion, running speed estimates bases on speed-CT relations, have acceptable accuracy and could serve to backup or substitute for GPS during tarmac running on flat terrain whenever GPS performance is limited. PMID:27648946

  2. Compare 100 GeV/n Au Run 2010 with Run 2007

    SciTech Connect

    Zhang, S.Y.

    2011-01-01

    With the very successful commissioning of the vertical stochastic cooling in 100 GeV/n Au Run 2010, the IBS (intra-beam scattering) is no longer the dominant factor in terms of the integrated luminosity. A new luminosity model is needed, where the beam intensity lifetime is more important and the burn-off needs to be accounted for. Toward this goal, a brief review of the Run 2010, compared with Run 2007, is presented.

  3. Big-hole drilling - the state of the art

    SciTech Connect

    Lackey, M.D.

    1983-01-01

    The art of big-hole drilling has been in a continual state of evolution at the Nevada Test Site since the start of underground testing in 1961. Emplacement holes for nuclear devices are still being drilled by the rotary-drilling process, but almost all the hardware and systems have undergone many changes during the intervening years. The current design of bits, cutters, and other big-hole-drilling hardware results from contributions of manufacturers and Test Site personnel. The dual-string, air-lift, reverse-circulation system was developed at the Test Site. Necessity was really the Mother of this invention, but this circulation system is worthy of consideration under almost any condition. Drill rigs for big-hole drilling are usually adaptations of large oil-well drill rigs with minor modifications required to handle the big bits and drilling assemblies. Steel remains the favorite shaft lining material, but a lot of thought is being given to concrete linings, especially precast concrete.

  4. Causes and effects of a hole. [in Antarctic ozone layer

    NASA Technical Reports Server (NTRS)

    Margitan, J. J.

    1987-01-01

    Preliminary results from the U.S. National Ozone Expedition (NOZE) to Antarctica are reviewed. The NOZE ozonesonde measurements showed significant vertical structure in the hole, with 80 percent depletion in some of the 1 km layers but only 20 percent in adjacent layers. The depletion was confined to the 12-20 km region, beginning first at higher altitude and progressing downward. This is strong evidence against the theory that the ozone hole is due to solar activity producing odd nitrogen at high altitudes which is transported downwards, leading to enhanced odd-nitrogen catalytic cycles that destroy ozone. Nitrous oxide data show unusually low concentrations within the polar vortex, which is evidence against the theory that the hole is caused by a purely dynamical mechanism in which rising air motions within the polar vortex lead to reduced column densities of ozone. It is tentatively concluded that a chemical mechanism involving man-made chlorofluorocarbons is the likely cause of ozone depletion in the hole.

  5. Impact of AIRS Thermodynamic Profile on Regional Weather Forecast

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Brad; Jedlovee, Gary

    2010-01-01

    Prudent assimilation of AIRS thermodynamic profiles and quality indicators can improve initial conditions for regional weather models. AIRS-enhanced analysis has warmer and moister PBL. Forecasts with AIRS profiles are generally closer to NAM analyses than CNTL. Assimilation of AIRS leads to an overall QPF improvement in 6-h accumulated precipitation forecasts. Including AIRS profiles in assimilation process enhances the moist instability and produces stronger updrafts and a better precipitation forecast than the CNTL run.

  6. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  7. Tibiocalcaneal kinematics of barefoot versus shod running.

    PubMed

    Stacoff, A; Nigg, B M; Reinschmidt, C; van den Bogert, A J; Lundberg, A

    2000-11-01

    Barefoot running kinematics has been described to vary considerably from shod running. However, previous investigations were typically based on externally mounted shoe and/or skin markers, which have been shown to overestimate skeletal movements. Thus, the purpose of this study was to compare calcaneal and tibial movements of barefoot versus shod running using skeletal markers. Intracortical bone pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The subjects ran barefoot, with a normal shoe, with three shoe soles and two orthotic modifications. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Test variables were defined for eversion and tibial rotation. The results showed that the differences in bone movements between barefoot and shod running were small and unsystematic (mean effects being less than 2 degrees ) compared with the differences between the subjects (up to 10 degrees ). However, differences may occur during midstance when extreme shoe modifications (i.e. posterior orthosis) are used. It is concluded that calcaneal and tibial movement patterns do not differ substantially between barefoot and shod running, and that the effects of these interventions are subject specific. The result of this in vivo study contrasts with previous investigations using skin and shoe mounted markers and suggests that these discrepancies may be the result of the overestimation with externally mounted markers.

  8. Exercise economy in skiing and running.

    PubMed

    Losnegard, Thomas; Schäfer, Daniela; Hallén, Jostein

    2014-01-01

    Substantial inter-individual variations in exercise economy exist even in highly trained endurance athletes. The variation is believed to be determined partly by intrinsic factors. Therefore, in the present study, we compared exercise economy in V2-skating, double poling, and uphill running. Ten highly trained male cross-country skiers (23 ± 3 years, 180 ± 6 cm, 75 ± 8 kg, VO2peak running: 76.3 ± 5.6 mL·kg(-1)·min(-1)) participated in the study. Exercise economy and VO2peak during treadmill running, ski skating (V2 technique) and double poling were compared based on correlation analysis. There was a very large correlation in exercise economy between V2-skating and double poling (r = 0.81) and large correlations between V2-skating and running (r = 0.53) and double poling and running (r = 0.58). There were trivial to moderate correlations between exercise economy and the intrinsic factors VO2peak (r = 0.00-0.23), cycle rate (r = 0.03-0.46), body mass (r = -0.09-0.46) and body height (r = 0.11-0.36). In conclusion, the inter-individual variation in exercise economy could be explained only moderately by differences in VO2peak, body mass and body height. Apparently other intrinsic factors contribute to the variation in exercise economy between highly trained subjects.

  9. Modeling Kicks from the Merger of Generic Black-hole Binaries

    NASA Technical Reports Server (NTRS)

    Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; Miller, M. Coleman; vanMeter, James R.

    2008-01-01

    Recent numerical relativistic results demonstrate that the merger of comparable-mass spinning black holes has a maximum "recoil kick" of up to approx. 4000 km/s. However the scaling of these recoil velocities with mass ratio is poorly understood. We present new runs showing that the maximum possible kick parallel to the orbital axis does not scale as approx. eta(sup 2) (where eta is the symmetric mass ratio), as previously proposed, but is more consistent with approx. eta(sup 3). We discuss the effect of this dependence on galactic ejection scenarios and retention of intermediate-mass black holes in globular clusters. S

  10. Enhancing our Search for Missing Intermediate Mass Black Holes Using Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Jani, Karan; LIGO Scientific Collaboration; Virgo Collaboration Collaboration

    2017-01-01

    The current generation of ground-based gravitational-wave detectors are most sensitive to mergers of intermediate-mass black holes (IMBH), with search volume of cosmological distances of redshift 1 and detectable total-mass up to 1000M⊙ . Two independent searches for binary black holes, matched-filtering and transient burst, are specifically configured to look for IMBH binaries in Advanced LIGO. I summarize the results from both these searches during the first observing run of Advanced LIGO and narrate our plans to enhance detection volume and detectable total-mass.

  11. Strategy Guideline. Compact Air Distribution Systems

    SciTech Connect

    Burdick, Arlan

    2013-06-01

    This guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

  12. Enhanced optical transmission through sub-wavelength centered-polygonal hole arrays in silver thin film on silica substrate.

    PubMed

    Arabi, Hesam Edin; Park, Minkyu; Pournoury, Marzieh; Oh, Kyunghwan

    2011-04-25

    We numerically investigated the enhanced optical transmission through sub-wavelength centered-polygonal hole arrays (CPHA) in a thin Ag film deposited on the silica substrate. In octagonal and decagonal-CPHAs, we observed new hybrid transmission characteristics that were inherited from both crystalline and quasi-crystalline hole arrays. This peculiar nature was attributed to the unique arrangement of CPHAs which can be covered with copies of a single unit cell as in crystalline arrays, and their rotational symmetry as observed in quasi-crystalline arrays. Hybrid natures in CPHAs were further investigated in the transmission spectra and Fourier space representations of the arrays. Contributions from the nearest neighbor hole-to-hole distance to enhanced transmission were analyzed in order to quantify the plasmonic contributions from the Air/Ag interface and Silica/Ag interface. We also investigated the impact of layer structure, Air/Ag/Air versus Air/Ag/Silica in the transmissions and found that in CPHAs in Air/Ag/Silica structures, contributions from the Air/Ag interface became dominant in contrast to crystalline hole arrays with lower fold symmetry.

  13. Strategy Guideline: Compact Air Distribution Systems

    SciTech Connect

    Burdick, A.

    2013-06-01

    This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

  14. Predicting application run times using historical information.

    SciTech Connect

    Foster, I.; Smith, W.; Taylor, V.

    1999-06-25

    The authors present a technique for deriving predictions for the run times of parallel applications from the run times of similar applications that have executed in the past. The novel aspect of the work is the use of search techniques to determine those application characteristics that yield the best definition of similarity for the purpose of making predictions. They use four workloads recorded from parallel computers at Argonne National Laboratory, the Cornell Theory Center, and the San Diego Supercomputer Center to evaluate the effectiveness of the approach.They show that on these workloads the techniques achieve predictions that are between 14 and 60% better than those achieved by other researchers; the approach achieves mean prediction errors that are between 41 and 65% of mean application run times.

  15. Predicting running speed from a simple questionnaire.

    PubMed Central

    Campbell, M J

    1985-01-01

    Of 221 competitors in a University half marathon in 1983, 98 replied to a questionnaire before the race which asked for details of training, age, height, weight and resting pulse rate. Finishing times of all competitors were recorded. In a multiple regression analysis significant predictors of running speed were: amount of training, expressed as distance run per week and number of weeks training for the event, the Body Mass Index (weight/height) and resting pulse rate. We conclude that for assessing running speed amongst competitors with similar amounts of training, the Body Mass Index and the resting pulse rate are useful substitutes for more elaborate and expensive measures. Images p142-a PMID:4075062

  16. Jefferson Lab Data Acquisition Run Control System

    SciTech Connect

    Vardan Gyurjyan; Carl Timmer; David Abbott; William Heyes; Edward Jastrzembski; David Lawrence; Elliott Wolin

    2004-10-01

    A general overview of the Jefferson Lab data acquisition run control system is presented. This run control system is designed to operate the configuration, control, and monitoring of all Jefferson Lab experiments. It controls data-taking activities by coordinating the operation of DAQ sub-systems, online software components and third-party software such as external slow control systems. The main, unique feature which sets this system apart from conventional systems is its incorporation of intelligent agent concepts. Intelligent agents are autonomous programs which interact with each other through certain protocols on a peer-to-peer level. In this case, the protocols and standards used come from the domain-independent Foundation for Intelligent Physical Agents (FIPA), and the implementation used is the Java Agent Development Framework (JADE). A lightweight, XML/RDF-based language was developed to standardize the description of the run control system for configuration purposes.

  17. Is running associated with degenerative joint disease

    SciTech Connect

    Panush, R.S.; Schmidt, C.; Caldwell, J.R.; Edwards, N.L.; Longley, S.; Yonker, R.; Webster, E.; Nauman, J.; Stork, J.; Pettersson, H.

    1986-03-07

    Little information is available regarding the long-term effects, if any, of running on the musculoskeletal system. The authors compared the prevalence of degenerative joint disease among 17 male runners with 18 male nonrunners. Running subjects (53% marathoners) ran a mean of 44.8 km (28 miles)/wk for 12 years. Pain and swelling of hips, knees, ankles and feet and other musculoskeletal complaints among runners were comparable with those among nonrunners. Radiologic examinations (for osteophytes, cartilage thickness, and grade of degeneration) also were without notable differences among groups. They did not find an increased prevalence of osteoarthritis among the runners. Our observations suggest that long-duration, high-mileage running need to be associated with premature degenerative joint disease in the lower extremities.

  18. Improved black hole fireworks: Asymmetric black-hole-to-white-hole tunneling scenario

    NASA Astrophysics Data System (ADS)

    De Lorenzo, Tommaso; Perez, Alejandro

    2016-06-01

    A new scenario for gravitational collapse has been recently proposed by Haggard and Rovelli. Presenting the model under the name of black hole fireworks, they claim that the accumulation of quantum gravitational effects outside the horizon can cause the tunneling of geometry from a black hole to a white hole, allowing a bounce of the collapsing star which can eventually go back to infinity. In this paper, we discuss the instabilities of this model and propose a simple minimal modification which eliminates them, as well as other related instabilities discussed in the literature. The new scenario is a time-asymmetric version of the original model with a time scale for the final explosion that is shorter than m log m in Planck units. Our analysis highlights the importance of irreversibility in gravitational collapse which, in turn, uncovers important issues that cannot be addressed in detail without a full quantum gravity treatment.

  19. Footwear Decreases Gait Asymmetry during Running

    PubMed Central

    Hoerzer, Stefan; Federolf, Peter A.; Maurer, Christian; Baltich, Jennifer; Nigg, Benno M.

    2015-01-01

    Previous research on elderly people has suggested that footwear may improve neuromuscular control of motion. If footwear does in fact improve neuromuscular control, then such an influence might already be present in young, healthy adults. A feature that is often used to assess neuromuscular control of motion is the level of gait asymmetry. The objectives of the study were (a) to develop a comprehensive asymmetry index (CAI) that is capable of detecting gait asymmetry changes caused by external boundary conditions such as footwear, and (b) to use the CAI to investigate whether footwear influences gait asymmetry during running in a healthy, young cohort. Kinematic and kinetic data were collected for both legs of 15 subjects performing five barefoot and five shod over-ground running trials. Thirty continuous gait variables including ground reaction forces and variables of the hip, knee, and ankle joints were computed for each leg. For each individual, the differences between the variables for the right and left leg were calculated. Using this data, a principal component analysis was conducted to obtain the CAI. This study had two main outcomes. First, a sensitivity analysis suggested that the CAI had an improved sensitivity for detecting changes in gait asymmetry caused by external boundary conditions. The CAI may, therefore, have important clinical applications such as monitoring the progress of neuromuscular diseases (e.g. stroke or cerebral palsy). Second, the mean CAI for shod running (131.2 ± 48.5; mean ± standard deviation) was significantly lower (p = 0.041) than the CAI for barefoot running (155.7 ± 39.5). This finding suggests that in healthy, young adults gait asymmetry is reduced when running in shoes compared to running barefoot, which may be a result of improved neuromuscular control caused by changes in the afferent sensory feedback. PMID:26488484

  20. Footwear Decreases Gait Asymmetry during Running.

    PubMed

    Hoerzer, Stefan; Federolf, Peter A; Maurer, Christian; Baltich, Jennifer; Nigg, Benno M

    2015-01-01

    Previous research on elderly people has suggested that footwear may improve neuromuscular control of motion. If footwear does in fact improve neuromuscular control, then such an influence might already be present in young, healthy adults. A feature that is often used to assess neuromuscular control of motion is the level of gait asymmetry. The objectives of the study were (a) to develop a comprehensive asymmetry index (CAI) that is capable of detecting gait asymmetry changes caused by external boundary conditions such as footwear, and (b) to use the CAI to investigate whether footwear influences gait asymmetry during running in a healthy, young cohort. Kinematic and kinetic data were collected for both legs of 15 subjects performing five barefoot and five shod over-ground running trials. Thirty continuous gait variables including ground reaction forces and variables of the hip, knee, and ankle joints were computed for each leg. For each individual, the differences between the variables for the right and left leg were calculated. Using this data, a principal component analysis was conducted to obtain the CAI. This study had two main outcomes. First, a sensitivity analysis suggested that the CAI had an improved sensitivity for detecting changes in gait asymmetry caused by external boundary conditions. The CAI may, therefore, have important clinical applications such as monitoring the progress of neuromuscular diseases (e.g. stroke or cerebral palsy). Second, the mean CAI for shod running (131.2 ± 48.5; mean ± standard deviation) was significantly lower (p = 0.041) than the CAI for barefoot running (155.7 ± 39.5). This finding suggests that in healthy, young adults gait asymmetry is reduced when running in shoes compared to running barefoot, which may be a result of improved neuromuscular control caused by changes in the afferent sensory feedback.

  1. Abort Gap Cleaning for LHC Run 2

    SciTech Connect

    Uythoven, Jan; Boccardi, Andrea; Bravin, Enrico; Goddard, Brennan; Hemelsoet, Georges-Henry; Höfle, Wolfgang; Jacquet, Delphine; Kain, Verena; Mazzoni, Stefano; Meddahi, Malika; Valuch, Daniel; Gianfelice-Wendt, Eliana

    2014-07-01

    To minimize the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.

  2. CDF - Run II Status and Prospects

    SciTech Connect

    Manfred Paulini

    2003-03-17

    After a five year upgrade period, the CDF detector located at the Fermilab Tevatron Collider is back in operation taking high quality data with all subsystems functional. We report on the status of the CDF experiment in Run II and discuss the start-up of the Tevatron accelerator. First physics results from CDF are presented. We also discuss the prospects for B physics in RunII, in particular the measurements of B{sub S}{sup 0} flavour oscillations and CP violation in B decays.

  3. CANOZE measurements of the Arctic ozone hole

    NASA Technical Reports Server (NTRS)

    Evans, W. F. J.; Kerr, J. B.; Fast, H.

    1988-01-01

    In CANOZE 1 (Canadian Ozone Experiment), a series of 20 ozone profile measurements were made in April, 1986 from Alert at 82.5 N. CANOZE is the Canadian program for study of the Arctic winter ozone layer. In CANOZE 2, ozone profile measurements were made at Saskatoon, Edmonton, Churchill and Resolute during February and March, 1987 with ECC ozonesondes. Ground based measurements of column ozone, nitrogen dioxide and hydrochloric acid were conducted at Saskatoon. Two STRATOPROBE balloon flights were conducted on February 26 and March 19, 1987. Two aerosol flights were conducted by the University of Wyoming. The overall results of this study will be reported and compared with the NOZE findings. The results from CANOZE 3 in 1988, are also discussed. In 1988, as part of CANOZE 3, STRATOPROBE balloon flights were conducted from Saskatchewan on January 27 and February 13. A new lightweight infrared instrument was developed and test flown. A science flight was successfully conducted from Alert (82.5 N) on March 9, 1988 when the vortex was close to Alert; a good measurement of the profile of nitric acid was obtained. Overall, the Arctic spring ozone layer exhibits many of the features of the Antarctic ozone phenomenon, although there is obviously not a hole present every year. The Arctic ozone field in March, 1986 demonstrated many similarities to the Antarctic ozone hole. The TOMS imagery showed a crater structure in the ozone field similar to the Antarctic crater in October. Depleted layers of ozone were found in the profiles around 15 km, very similar to those reported from McMurdo. Enhanced levels of nitric acid were measured in air which had earlier been in the vortex. The TOMS imagery for March 1987 did not show an ozone crater, but will be examined for an ozone crater in February and March, 1988, the target date for the CANOZE 3 project.

  4. 2. DETAIL OF STRUCTURAL SYSTEM FOR CANTILEVERED HOG RUN; BUILDING ...

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

    2. DETAIL OF STRUCTURAL SYSTEM FOR CANTILEVERED HOG RUN; BUILDING 168 (1960 HOG KILL) IS BENEATH HOG RUN - Rath Packing Company, Cantilevered Hog Run, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  5. Black Holes: A Selected Bibliography.

    ERIC Educational Resources Information Center

    Fraknoi, Andrew

    1991-01-01

    Offers a selected bibliography pertaining to black holes with the following categories: introductory books; introductory articles; somewhat more advanced articles; readings about Einstein's general theory of relativity; books on the death of stars; articles on the death of stars; specific articles about Supernova 1987A; relevant science fiction…

  6. From Pinholes to Black Holes

    SciTech Connect

    Fenimore, Edward E.

    2014-10-06

    Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.

  7. Gravitational Collapse and Black Holes

    ERIC Educational Resources Information Center

    Ryder, Lewis

    1973-01-01

    The newest and most exotic manner in which stars die is investigated. A brief outline is presented, along with a discussion of the role supernova play, followed by a description of how the black holes originate, exist, and how they might be detected. (DF)

  8. Atmospheric holes and small comets

    NASA Technical Reports Server (NTRS)

    Frank, L. A.; Sigwarth, J. B.

    1993-01-01

    Global images of Earth's UV dayglow as gained with an imaging photometer on board Dynamics Explorer 1 exhibit transient decreases, or atmospheric holes, in the dayglow intensities over areas with diameters about 50 km. Features of these atmospheric holes include (1) preferential motion in the east-to-west direction across the sunlit face of Earth, (2) similar diurnal variations in occurrence rates as those for radar meteors, (3) correlation of the occurrence rates with the nonshower rates as determined with forward scatter radar, and (4) larger angular diameters for these atmospheric holes when the spacecraft approaches Earth during its perigee passes. These atmospheric holes are interpreted in terms of obscuration of the dayglow by water clouds from the disruption and subsequent vaporization of small comets at low altitudes above the atmosphere. Supporting evidence for the existence of these small comets is given by their telescopic sighting at greater altitudes before disruption and the detection of water bursts in Earth's upper atmosphere. The small-comet hypothesis and its relationship to geophysical, lunar, and interplanetary phenomena are discussed.

  9. Side hole drilling in boreholes

    NASA Technical Reports Server (NTRS)

    Collins, Jr., Earl R. (Inventor)

    1980-01-01

    Apparatus for use in a borehole or other restricted space to bore a side hole into the strata surrounding the borehole, including a flexible shaft with a drill at its end, and two trains of sheathing members that can be progressively locked together into a rigid structure around the flexible shaft as it is directed sidewardly into the strata.

  10. Prisons of Light - Black Holes

    NASA Astrophysics Data System (ADS)

    Ferguson, Kitty

    1998-02-01

    Prologue; 1. A cosmic case of burnout; 2. Matters of gravity: Newton and Einstein; 3. The capture of light; 4. Tripping the theoretical fantastic; 5. Crossing the bar; 6. Contemplating an enormous nothing; 7. Evidence in the case; 8. Hearts of darkness; 9. The search goes on; 10. Passages into the labyrinth; 11. Black hole legends and far out ideas; Epilogue.

  11. Dynamics of Coronal Hole Boundaries

    NASA Astrophysics Data System (ADS)

    Higginson, A. K.; Antiochos, S. K.; DeVore, C. R.; Wyper, P. F.; Zurbuchen, T. H.

    2017-03-01

    Remote and in situ observations strongly imply that the slow solar wind consists of plasma from the hot, closed-field corona that is released onto open magnetic field lines. The Separatrix Web theory for the slow wind proposes that photospheric motions at the scale of supergranules are responsible for generating dynamics at coronal-hole boundaries, which result in the closed plasma release. We use three-dimensional magnetohydrodynamic simulations to determine the effect of photospheric flows on the open and closed magnetic flux of a model corona with a dipole magnetic field and an isothermal solar wind. A rotational surface motion is used to approximate photospheric supergranular driving and is applied at the boundary between the coronal hole and helmet streamer. The resulting dynamics consist primarily of prolific and efficient interchange reconnection between open and closed flux. The magnetic flux near the coronal-hole boundary experiences multiple interchange events, with some flux interchanging over 50 times in one day. Additionally, we find that the interchange reconnection occurs all along the coronal-hole boundary and even produces a lasting change in magnetic-field connectivity in regions that were not driven by the applied motions. Our results show that these dynamics should be ubiquitous in the Sun and heliosphere. We discuss the implications of our simulations for understanding the observed properties of the slow solar wind, with particular focus on the global-scale consequences of interchange reconnection.

  12. The PyCBC search for compact binary mergers in the second run of Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Dal Canton, Tito; PyCBC Team

    2017-01-01

    The PyCBC software implements a matched-filter search for gravitational-wave signals associated with mergers of compact binaries. During the first observing run of Advanced LIGO, it played a fundamental role in the discovery of the binary-black-hole merger signals GW150914, GW151226 and LVT151012. In preparation for Advanced LIGO's second run, PyCBC has been modified with the goal of increasing the sensitivity of the search, reducing its computational cost and expanding the explored parameter space. The ability to report signals with a latency of tens of seconds and to perform inference on the parameters of the detected signals has also been introduced. I will give an overview of PyCBC and present the new features and their impact.

  13. Two Monster Black Holes at Work

    NASA Video Gallery

    Zoom into Markarian 739, a nearby galaxy hosting two monster black holes. Using NASA's Swift and Chandra, astronomers have shown that both black holes are producing energy as gas falls into them. T...

  14. A Hole in the Sun's Corona

    NASA Video Gallery

    This timelapse video shows a coronal hole, as captured in ultraviolet light by NASA's Solar Dynamics Observatory on Jan. 10, 2011. Coronal holes are areas of the sun's surface that are the source o...

  15. Astronomy: Intermediate-mass black hole found

    NASA Astrophysics Data System (ADS)

    Gültekin, Kayhan

    2017-02-01

    The existence of medium-sized black holes has long been debated. Such an object has now been discovered in the centre of a dense cluster of stars, potentially enhancing our understanding of all black holes. See Letter p.203

  16. Noise generated by cavitating single-hole and multi-hole orifices in a water pipe

    NASA Astrophysics Data System (ADS)

    Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.

    2007-02-01

    This paper presents an experimental study of the acoustical effects of cavitation caused by a water flow through an orifice. A circular-centered single-hole orifice and a multi-hole orifice are tested. Experiments are performed under industrial conditions: the pressure drop across the orifice varies from 3 to 30 bar, corresponding to cavitation numbers from 0.74 to 0.03. Two regimes of cavitation are discerned. In each regime, the broadband noise spectra obtained far downstream of the orifice are presented. A nondimensional representation is proposed: in the intermediate ‘developed cavitation’ regime, spectra collapse reasonably well; in the more intense ‘super cavitation’ regime, spectra depend strongly on the quantity of air remaining in the water downstream of the orifice, which is revealed by the measure of the speed of sound at the downstream transducers. In the ‘developed cavitation’ regime, whistling associated with periodic vortex shedding is observed. The corresponding Strouhal number agrees reasonably well with literature for single-phase flows. In the 'super cavitation’ regime, the whistling disappears.

  17. Change in running kinematics after cycling are related to alterations in running economy in triathletes.

    PubMed

    Bonacci, Jason; Green, Daniel; Saunders, Philo U; Blanch, Peter; Franettovich, Melinda; Chapman, Andrew R; Vicenzino, Bill

    2010-07-01

    Emerging evidence suggests that cycling may influence neuromuscular control during subsequent running but the relationship between altered neuromuscular control and run performance in triathletes is not well understood. The aim of this study was to determine if a 45 min high-intensity cycle influences lower limb movement and muscle recruitment during running and whether changes in limb movement or muscle recruitment are associated with changes in running economy (RE) after cycling. RE, muscle activity (surface electromyography) and limb movement (sagittal plane kinematics) were compared between a control run (no preceding cycle) and a run performed after a 45 min high-intensity cycle in 15 moderately trained triathletes. Muscle recruitment and kinematics during running after cycling were altered in 7 of 15 (46%) triathletes. Changes in kinematics at the knee and ankle were significantly associated with the change in VO(2) after cycling (p<0.05). The change in ankle angle at foot contact alone explained 67.1% of the variance in VO(2). These findings suggest that cycling does influence limb movement and muscle recruitment in some triathletes and that changes in kinematics, especially at the ankle, are closely related to alterations in running economy after cycling.

  18. Effects of a minimalist shoe on running economy and 5-km running performance.

    PubMed

    Fuller, Joel T; Thewlis, Dominic; Tsiros, Margarita D; Brown, Nicholas A T; Buckley, Jonathan D

    2016-09-01

    The purpose of this study was to determine if minimalist shoes improve time trial performance of trained distance runners and if changes in running economy, shoe mass, stride length, stride rate and footfall pattern were related to any difference in performance. Twenty-six trained runners performed three 6-min sub-maximal treadmill runs at 11, 13 and 15 km·h(-1) in minimalist and conventional shoes while running economy, stride length, stride rate and footfall pattern were assessed. They then performed a 5-km time trial. In the minimalist shoe, runners completed the trial in less time (effect size 0.20 ± 0.12), were more economical during sub-maximal running (effect size 0.33 ± 0.14) and decreased stride length (effect size 0.22 ± 0.10) and increased stride rate (effect size 0.22 ± 0.11). All but one runner ran with a rearfoot footfall in the minimalist shoe. Improvements in time trial performance were associated with improvements in running economy at 15 km·h(-1) (r = 0.58), with 79% of the improved economy accounted for by reduced shoe mass (P < 0.05). The results suggest that running in minimalist shoes improves running economy and 5-km running performance.

  19. A running controller for a powered transfemoral prosthesis.

    PubMed

    Huff, Amanda M; Lawson, Brian E; Goldfarb, Michael

    2012-01-01

    This paper describes a running controller for a powered knee and ankle prosthesis. The running controller was implemented on a powered prosthesis prototype and evaluated by a transfemoral amputee subject running on a treadmill at a speed of 2.25 m/s (5.0 mph). The ability of the prosthesis and controller to provide the salient features of a running gait was assessed by comparing the kinematics of running provided by the powered prosthesis to the averaged kinematics of five healthy subjects running at the same speed. This comparison indicates that the powered prosthesis and running controller are able to provide essential features of a healthy running gait.

  20. Comparison of Running Economy Values While Wearing No Shoes, Minimal Shoes, and Normal Running Shoes.

    PubMed

    Cochrum, Robbie G; Connors, Ryan T; Coons, John M; Fuller, Dana K; Morgan, Don W; Caputo, Jennifer L

    2017-03-01

    Cochrum, RG, Connors, RT, Coons, JM, Fuller, DK, Morgan, DW, and Caputo, JL. Comparison of running economy values while wearing no shoes, minimal shoes, and normal running shoes. J Strength Cond Res 31(3): 595-601, 2017-The purpose of this study was to quantify differences in running economy (RE) at 50 and 70% of each subject's velocity at V[Combining Dot Above]O2max (vV[Combining Dot Above]O2max) across barefoot and 2 mass, stack height, and heel-to-toe-drop controlled footwear conditions (minimal shoes and normal running shoes) in 9 recreational distance runners (mean age 26.8 ± 6.8 years). Over 3 days, subjects ran in one of the footwear conditions while RE (oxygen consumption) and step frequency were measured at each speed with a 5-minute rest between each trial. A 2-way repeated-measures multivariate analysis of variance (p ≤ 0.05) and Bonferroni-adjusted follow-up analyses revealed that RE was not significantly different across footwear conditions at either speed. However, those running barefoot exhibited a higher step frequency than when running in minimal (50%, p = 0.007; and 70%, p < 0.001) and standard footwear conditions (70% only, p < 0.001). Higher step frequencies were also exhibited by those running in minimal versus standard footwear (70% only, p = 0.007). Thus, RE is not affected by footwear or running barefoot in those with experience running in minimal-type footwear. Significant adjustments in step frequency when alternative footwear was introduced may help explain why RE was statistically maintained during each footwear and speed condition across but not between subjects. Therefore, determination of footwear for the enhancement of RE should be based on individual physical characteristics and preferences rather than a global recommendation of an economical running shoe.

  1. The D0 run II trigger system

    SciTech Connect

    Schwienhorst, Reinhard; /Michigan State U.

    2004-11-01

    The D0 detector at the Fermilab Tevatron was upgraded for Run II. This upgrade included improvements to the trigger system in order to be able to handle the increased Tevatron luminosity and higher bunch crossing rates compared to Run I. The D0 Run II trigger is a highly exible system to select events to be written to tape from an initial interaction rate of about 2.5 MHz. This is done in a three-tier pipelined, buffered system. The first tier (level 1) processes fast detector pick-off signals in a hardware/firmware based system to reduce the event rate to about 1. 5kHz. The second tier (level 2) uses information from level 1 and forms simple Physics objects to reduce the rate to about 850 Hz. The third tier (level 3) uses full detector readout and event reconstruction on a filter farm to reduce the rate to 20-30 Hz. The D0 trigger menu contains a wide variety of triggers. While the emphasis is on triggering on generic lepton and jet final states, there are also trigger terms for specific final state signatures. In this document we describe the D0 trigger system as it was implemented and is currently operating in Run II.

  2. Validity of Self-Reported Running Distance.

    PubMed

    Dideriksen, Mette; Soegaard, Cristina; Nielsen, Rasmus O

    2016-06-01

    It is unclear whether there is a difference between subjective evaluation and objective global positioning systems (GPS) measurement of running distance. The purpose of this study was to investigate if such difference exists. A total of 100 participants (51% men; median age, 41.5; body mass, 78.1 kg ±13.8 SD) completed a run of free choice, then subjectively reported the distance in kilometer (km). This information was subsequently compared with the distance derived from a nondifferential GPS watch using paired t-tests and Bland-Altman's 95% limits of agreement. No significant difference was found between the mean paired differences between subjective evaluations and GPS measurements (1.86%, 95% confidence interval = -1.53%; 5.25%, p = 0.96). The Bland-Altman 95% limits of agreement revealed considerable variation (lower limit = -28% and upper limit = 40%). Such variation exceeds the clinical error range of 10%. In conclusion, the mean running distance (km) is similar between self-reporting and GPS measurements. However, researchers should consider using GPS measurements in favor of subjective reporting of running distance because of considerable variation on an individual level.

  3. Healthy Living Initiative: Running/Walking Club

    ERIC Educational Resources Information Center

    Stylianou, Michalis; Kulinna, Pamela Hodges; Kloeppel, Tiffany

    2014-01-01

    This study was grounded in the public health literature and the call for schools to serve as physical activity intervention sites. Its purpose was twofold: (a) to examine the daily distance covered by students in a before-school running/walking club throughout 1 school year and (b) to gain insights on the teachers perspectives of the club.…

  4. The running athlete: Roentgenograms and remedies

    SciTech Connect

    Pavlov, H.; Torg, J.S.

    1986-01-01

    The authors have put together an atlas of radiographs of almost every conceivable running injury to the foot, ankle, leg, knee, femur, groin, and spine. Text material is limited to legends which describe the figures, and the remedies listed are brief. The text indicates conservative versus surgical treatment and, in some instances, recommends a surgical procedure.

  5. An Orthopedic Perspective. Does Running Cause Osteoarthritis?

    ERIC Educational Resources Information Center

    Pascale, Mark; Grana, William A.

    1989-01-01

    Discusses the development of osteoarthritis and whether running and other impact loading sports promote it. Although these sports do not cause arthritis in normal weight bearing limbs, they can accelerate it in damaged joints. It is important to identify people with preeexisting joint disease so they can choose nonimpact-loading aerobic exercise.…

  6. Brook Trout Back in Aaron Run

    EPA Pesticide Factsheets

    Following a series of acid mine drainage (AMD) projects funded largely by EPA’s Clean Water Act Section 319 non-point source program, the pH level in Aaron Run is meeting Maryland’s water quality standard – and the brook trout are back.

  7. South Africa/Time Running Out.

    ERIC Educational Resources Information Center

    Clark, Todd, Ed.

    1984-01-01

    Based on the book, "South Africa: Time Running Out," a report of the Study Commission on U.S. Policy Toward Southern Africa, this 10-20 day unit of study is designed to help high school students learn about the history, geography, and present situation in South Africa and its relationship to the United States. The first of four sections…

  8. Utah CTE: Running in New Circles

    ERIC Educational Resources Information Center

    Dobson, Kristine; Fischio, Shannon; Thomas, Susan

    2011-01-01

    Although the authors admit that they do not have any fool-proof formulas to offer for using Web site, blog, Facebook, Twitter, or YouTube in order to more successfully share one's career and technical education (CTE) story, they share a story of their own journey and hope that it may help people to run faster and more effectively in these new…

  9. Jet physics at CDF Run II

    SciTech Connect

    Safonov, A.; /UC, Davis

    2004-12-01

    The latest results on jet physics at CDF are presented and discussed. Particular attention is paid to studies of the inclusive jet cross section using 177 pb{sup -1} of Run II data. Also discussed is a study of gluon and quark jet fragmentation.

  10. Individualism, innovation, and long-run growth

    PubMed Central

    Gorodnichenko, Yuriy; Roland, Gerard

    2011-01-01

    Countries having a more individualist culture have enjoyed higher long-run growth than countries with a more collectivist culture. Individualist culture attaches social status rewards to personal achievements and thus, provides not only monetary incentives for innovation but also social status rewards, leading to higher rates of innovation and economic growth. PMID:22198759

  11. Resource Letter BH-1: Black Holes.

    ERIC Educational Resources Information Center

    Detweiler, Steven

    1981-01-01

    Lists resources on black holes, including: (1) articles of historical interest; (2) books and journal articles on elementary expositions; (3) elementary and advanced textbooks; and (4) research articles on analytic structure of black holes, black hole dynamics, and astrophysical processes. (SK)

  12. Compensating Scientism through "The Black Hole."

    ERIC Educational Resources Information Center

    Roth, Lane

    The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for…

  13. Electroformed screens with uniform hole size

    NASA Technical Reports Server (NTRS)

    Schaer, G. R.

    1968-01-01

    Efficient method electroforms fine-mesh nickel screens, or plagues, with uniform hole size and accurate spacing between holes. An electroformed nickel mandrel has nonconducting silicone rubber projections that duplicate the desired hole size and shape in the finished nickel screen.

  14. High precision, rapid laser hole drilling

    DOEpatents

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2007-03-20

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  15. High precision, rapid laser hole drilling

    DOEpatents

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2005-03-08

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  16. High precision, rapid laser hole drilling

    DOEpatents

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2013-04-02

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  17. Gravitational Lensing of STU Black Holes

    NASA Astrophysics Data System (ADS)

    Saadat, H.

    2013-12-01

    In this paper we study gravitational lensing by STU black holes. We considered extremal limit of two special cases of zero-charged and one-charged black holes, and obtain the deflection angle. We find that the black hole charge increases the deflection angle.

  18. Horndeski scalar-tensor black hole geodesics

    NASA Astrophysics Data System (ADS)

    Tretyakova, Darya; Melkoserov, Dmitry; Adyev, Timur

    2016-10-01

    We examine massive particles and null geodesics for the scalar-tensor black hole in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits, corresponding to circular and elliptic orbits, are absent for the black hole solution with the static scalar field. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations.

  19. Signatures of black holes at the LHC

    NASA Astrophysics Data System (ADS)

    Cavaglià, Marco; Godang, Romulus; Cremaldi, Lucien M.; Summers, Donald J.

    2007-06-01

    Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

  20. Lubricating Holes for Corroded Nuts and Bolts

    NASA Technical Reports Server (NTRS)

    Penn, B. G.; Clemons, J. M.; Ledbetter, Frank E., III

    1986-01-01

    Corroded fasteners taken apart more easily. Lubricating holes bored to thread from three of flats. Holes facilitate application of penetrating oil to help loosen nut when rusted onto bolt. Holes make it possible to apply lubricants and rust removers directly to more of thread than otherwise reachable.

  1. Ballistic-hole spectroscopy of interfaces

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.; Bell, L. D.; Kaiser, W. J.; Davis, L. C.

    1990-01-01

    A new technique allows direct control and measurement of ballistic-hole transport through interfaces. This spectroscopy has been applied to determine the detailed properties of hole transmission through metal-semiconductor interfaces and probe the valence-band structure of subsurface semiconductor heterostructures. The ballistic-hole probe is created by electron-tunneling-microscopy methods and provides high-spatial-resolution capabilities.

  2. Straight hole drilling machines for coal mines

    NASA Astrophysics Data System (ADS)

    Timonin, VV; Kokoulin, DI; Alekseev, SE; Kubanychbek, B.

    2017-02-01

    The authors prove the demand for drilling machines capable of making long straight holes in rocks with the strength up to 120 MPa. The paper describes the designed, manufactured and tested down-the-hole hammers for rotary–percussion drilling of long straight directional holes. The hammers have been delivered to Berezovskaya Mine for further trial and commercial operation.

  3. The characteristic black hole mass resulting from direct collapse in the early Universe

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Schleicher, D. R. G.; Schmidt, W.; Niemeyer, J. C.

    2013-12-01

    Black holes of a billion solar masses are observed in the infant Universe a few hundred million years after the big bang. The direct collapse of protogalactic gas clouds in primordial haloes with Tvir ≥ 104 K provides the most promising way to assemble massive black holes. In this study, we aim to determine the characteristic mass scale of seed black holes and the time evolution of the accretion rates resulting from the direct collapse model. We explore the formation of supermassive black holes via cosmological large eddy simulations (LES) by employing sink particles and following their evolution for 20 000 yr after the formation of the first sink. As the resulting protostars were shown to have cool atmospheres in the presence of strong accretion, we assume here that UV feedback is negligible during this calculation. We confirm this result in a comparison run without sinks. Our findings show that black hole seeds with characteristic mass of 105 M⊙ are formed in the presence of strong Lyman-Werner flux which leads to an isothermal collapse. The characteristic mass is about two times higher in LES compared to the implicit large eddy simulations. The accretion rates increase with time and reach a maximum value of 10 M⊙ yr-1 after 104 yr. Our results show that the direct collapse model is clearly feasible as it provides the expected mass of the seed black holes.

  4. Impingement of a drop train enhance the liquid infiltration into a closed end hole

    NASA Astrophysics Data System (ADS)

    Sanada, Toshiyuki; Yamaguchi, Eri; Muraki, Shunsuke

    2016-11-01

    Liquid infiltration is an important process for cleaning inside fine holes. However, it is difficult to infiltrate liquid into closed end holes having small diameter. Because the surface tension prevents the deformation of gas-liquid interface for entering them. In this study we observed the liquid infiltration process into a closed end hole by applying external pressure under two ways, i.e. gradual pressurization with a hand pump and impingement of a droplet train. As a result, it is found that the amount of dissolved air into liquid by applying pressure is small, and it has small effect for the liquid infiltration. In addition, it is also found that the high liquid infiltration rate can be achieved by applying a droplet train impact. It is observed that the trapped bubbles inside the holes were ejected by repetition of droplet impingement.

  5. Marathon run: cardiovascular adaptation and cardiovascular risk.

    PubMed

    Predel, Hans-Georg

    2014-11-21

    The first marathon run as an athletic event took place in the context of the Olympic Games in 1896 in Athens, Greece. Today, participation in a 'marathon run' has become a global phenomenon attracting young professional athletes as well as millions of mainly middle-aged amateur athletes worldwide each year. One of the main motives for these amateur marathon runners is the expectation that endurance exercise (EE) delivers profound beneficial health effects. However, with respect to the cardiovascular system, a controversial debate has emerged whether the marathon run itself is healthy or potentially harmful to the cardiovascular system, especially in middle-aged non-elite male amateur runners. In this cohort, exercise-induced increases in cardiac biomarkers-troponin and brain natriuretic peptide-and acute functional cardiac alterations have been observed and interpreted as potential cardiac damage. Furthermore, in the cohort of 40- to 65-year-old males engaged in intensive EE, a significant risk for the development of atrial fibrillation has been identified. Fortunately, recent studies demonstrated a normalization of the cardiac biomarkers and the functional alterations within a short time frame. Therefore, these alterations may be perceived as physiological myocardial reactions to the strenuous exercise and the term 'cardiac fatigue' has been coined. This interpretation is supported by a recent analysis of 10.9 million marathon runners demonstrating that there was no significantly increased overall risk of cardiac arrest during long-distance running races. In conclusion, intensive and long-lasting EE, e.g. running a full-distance Marathon, results in high cardiovascular strain whose clinical relevance especially for middle-aged and older athletes is unclear and remains a matter of controversy. Furthermore, there is a need for evidence-based recommendations with respect to medical screening and training strategies especially in male amateur runners over the age of

  6. Core hole drilling and the ''rain current'' phenomenon at Newberry Volcano, Oregon

    SciTech Connect

    Swanberg, C.A.; Walkey, W.C.; Combs, J.

    1988-09-10

    Two core holes have been completed on the flanks of Newberry Volcano, Oregon. Core hole Geo N-1 has a heat flow of 180 mW m/sup -2/, reflecting subsurface temperatures, sufficient for commerical exploitation of geothermally generated electricity. GEO N-3, which has a heat flow of 86 mW m/sup -2/, is less encouraging. We emphasize the ''rain curtain'' effect with the hope that a detailed discussion of this phenomenon at two distinct localities will lead to a better understanding of the physical processes in operation. Cole hole GEO N-1 was cored to a depth of 1387 m at a site located 9.3 km south of the center of the volcano. Core hole GEO N-3 was cored to a depth of 1220 m at a site located 12.6 km north of the center of the volcano. Both core holes penetrated interbedded pyroclastic lava flows and lithic tuffs ranging in composition from basalt to rhyolite, basaltic andesite being the most common rock type. Potassium-argon age dates range up to 2 Ma. Caving and sloughing were encountered in both core holes at depths near the regional water table. Both core holes penetrate three distinct thermal regimes. The uppermost regime is isothemal at mean air temperature down to about 900-1000 m (the rain curtain).

  7. SSME seal test program: Test results for smooth, hole-pattern and helically-grooved stators

    NASA Technical Reports Server (NTRS)

    Childs, Dara W.

    1987-01-01

    All of the listed seals were tested in a liquid Halon test facility at high Reynolds numbers. In addition, a helically-grooved-stator seal was tested in an air seal facility. An analysis of the test results with comparisons to theoretical predictions supports the following conclusions: (1) For small seals, the Hirs' friction-factor model is more restricted than had been thought; (2) For smooth seals, predictions of stiffness and damping improve markedly as the radical clearance is reduced; (3) Friction-factor data for hole-pattern-seal stators frequently deviates from the Hirs model; (4) Predictions of stiffness and damping coefficients for hole-pattern-stator seals is generally reasonable; (5) Tests for the hole-pattern stators at reduced clearances show no clear optimum for hole-pattern seals with respect to either hole-area ratio or hole depth to minimum clearance ratios; (6) Tests of these hole-pattern stators show no significant advantage in net damping over smooth seals; (7) Tests of helically-grooved seal stators in Halon show reasonable agreement between theory and prediction for leakage and direct stiffness but poor agreement for the net damping coefficient.

  8. Power Systems Development Facility Gasification Test Run TC10

    SciTech Connect

    Southern Company Services

    2002-12-30

    This report discusses Test Campaign TC10 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier during TC10 in air- (mainly for transitions and problematic operations) and oxygen-blown mode. Test Run TC10 was started on November 16, 2002, and completed on December 18, 2002. During oxygen-blown operations, gasifier temperatures varied between 1,675 and 1,825 F at pressures from 150 to 180 psig. After initial adjustments were made to reduce the feed rate, operations with the new fluidized coal feeder were stable with about half of the total coalfeed rate through the new feeder. However, the new fluidized-bed coal feeder proved to be difficult to control at low feed rates. Later the coal mills and original coal feeder experienced difficulties due to a high moisture content in the coal from heavy rains. Additional operational difficulties were experienced when several of the pressure sensing taps in the gasifier plugged. As the run progressed, modifications to the mills (to address processing the wet coal) resulted in a much larger feed size. This eventually resulted in the accumulation of large particles in the circulating solids causing operational instabilities in the standpipe and loop seal. Despite problems with the coal mills, coal feeder, pressure tap nozzles and the standpipe, the gasifier did experience short periods of stability during oxygenblown operations. During these periods, the syngas quality was high. During TC10, the gasifier gasified over 609 tons of Powder River Basin subbituminous coal and

  9. Chandra Catches "Piranha" Black Holes

    NASA Astrophysics Data System (ADS)

    2007-07-01

    Supermassive black holes have been discovered to grow more rapidly in young galaxy clusters, according to new results from NASA's Chandra X-ray Observatory. These "fast-track" supermassive black holes can have a big influence on the galaxies and clusters that they live in. Using Chandra, scientists surveyed a sample of clusters and counted the fraction of galaxies with rapidly growing supermassive black holes, known as active galactic nuclei (or AGN). The data show, for the first time, that younger, more distant galaxy clusters contained far more AGN than older, nearby ones. Galaxy clusters are some of the largest structures in the Universe, consisting of many individual galaxies, a few of which contain AGN. Earlier in the history of the universe, these galaxies contained a lot more gas for star formation and black hole growth than galaxies in clusters do today. This fuel allows the young cluster black holes to grow much more rapidly than their counterparts in nearby clusters. Illustration of Active Galactic Nucleus Illustration of Active Galactic Nucleus "The black holes in these early clusters are like piranha in a very well-fed aquarium," said Jason Eastman of Ohio State University (OSU) and first author of this study. "It's not that they beat out each other for food, rather there was so much that all of the piranha were able to really thrive and grow quickly." The team used Chandra to determine the fraction of AGN in four different galaxy clusters at large distances, when the Universe was about 58% of its current age. Then they compared this value to the fraction found in more nearby clusters, those about 82% of the Universe's current age. The result was the more distant clusters contained about 20 times more AGN than the less distant sample. AGN outside clusters are also more common when the Universe is younger, but only by factors of two or three over the same age span. "It's been predicted that there would be fast-track black holes in clusters, but we never

  10. Calculated in situ rock density from gravity observations, UA-1 (Cannikin) emplacement hole, Amchitka Island, Alaska

    USGS Publications Warehouse

    Healey, D.L.

    1971-01-01

    Gravity observations were made on the ground surface and at a depth of 5,854 feet in drill hole UA-1. Two attempts to measure the free-air gradient utilizing the headframe over the drill hole were unsuccessful owing to mechanical vibrations in the structure. Because of the uncertainty in the measured free-air gradients these values were discarded and the average value (0.09406 mgal/ft) was used in the calculations. The calculated in situ bulk density is 2.36 g/cc. The weighted average bulk density determined from 47 core samples taken in the adjacent UAE-1 drill hole is also 2.36 g/cc. An analysis of selected portions of density logs provides an in situ bulk density of 2.37 g/cc.

  11. The influence of a new sole geometry while running

    PubMed Central

    Knoepfli-Lenzin, Claudia; Waech, Jennifer Carole; Gülay, Turgut; Schellenberg, Florian; Lorenzetti, Silvio

    2014-01-01

    Abstract Running shoe construction influences the forces experienced by the human body while running. The aim of this study was to ascertain whether the new sole architecture of the On running shoe reduces ground reaction forces compared with running barefoot or with a conventional running shoe and whether it changes the physiological parameters of running in shoes. Thirty-seven trained male participants were studied while running at submaximal speeds wearing their conventional running shoe, wearing the On running shoe and while barefoot. Additional biomechanical and physiological values were investigated to determine whether the On running shoe induced any changes in these parameters compared with conventional running shoes. The On exhibited similar ground reaction forces as conventional shoes, and these were different from the forces experienced while running barefoot, showing that the On was more similar to typical shoed running. No difference was observed in running economy between the On and a conventional shoe model. However, a slightly lower heart rate (HR) (≈1.3%) and blood lactate concentration (≈5.5%) were observed during submaximal running with the On running shoe compared with a conventional running shoe, as well as a greater lateral deviation of the centre of pressure mid-stance. The ramifications of the reduced HR and blood lactate concentration for competitive performance are unknown. PMID:24977468

  12. The influence of a new sole geometry while running.

    PubMed

    Knoepfli-Lenzin, Claudia; Waech, Jennifer Carole; Gülay, Turgut; Schellenberg, Florian; Lorenzetti, Silvio

    2014-01-01

    Running shoe construction influences the forces experienced by the human body while running. The aim of this study was to ascertain whether the new sole architecture of the On running shoe reduces ground reaction forces compared with running barefoot or with a conventional running shoe and whether it changes the physiological parameters of running in shoes. Thirty-seven trained male participants were studied while running at submaximal speeds wearing their conventional running shoe, wearing the On running shoe and while barefoot. Additional biomechanical and physiological values were investigated to determine whether the On running shoe induced any changes in these parameters compared with conventional running shoes. The On exhibited similar ground reaction forces as conventional shoes, and these were different from the forces experienced while running barefoot, showing that the On was more similar to typical shoed running. No difference was observed in running economy between the On and a conventional shoe model. However, a slightly lower heart rate (HR) (≈1.3%) and blood lactate concentration (≈5.5%) were observed during submaximal running with the On running shoe compared with a conventional running shoe, as well as a greater lateral deviation of the centre of pressure mid-stance. The ramifications of the reduced HR and blood lactate concentration for competitive performance are unknown.

  13. Physiological assessment of isolated running does not directly replicate running capacity after triathlon-specific cycling.

    PubMed

    Etxebarria, Naroa; Hunt, Julie; Ingham, Steve; Ferguson, Richard

    2014-01-01

    Triathlon running is affected by prior cycling and power output during triathlon cycling is variable in nature. We compared constant and triathlon-specific variable power cycling and their effect on subsequent submaximal running physiology. Nine well-trained male triathletes (age 24.6 ± 4.6 years, [Formula: see text] 4.5 ± 0.4 L · min(-1); mean ± SD) performed a submaximal incremental run test, under three conditions: no prior exercise and after a 1 h cycling trial at 65% of maximal aerobic power with either a constant or a variable power profile. The variable power protocol involved multiple 10-90 s intermittent efforts at 40-140% maximal aerobic power. During cycling, pulmonary ventilation (22%, ± 14%; mean; ± 90% confidence limits), blood lactate (179%, ± 48%) and rating of perceived exertion (7.3%, ± 10.2%) were all substantially higher during variable than during constant power cycling. At the start of the run, blood lactate was 64%, ± 61% higher after variable compared to constant power cycling, which decreased running velocity at 4 mM lactate threshold by 0.6, ± 0.9 km · h(-1). Physiological responses to incremental running are negatively affected by prior cycling and, to a greater extent, by variable compared to even-paced cycling. Testing and training of triathletes should account foe higher physiological cost of triathlon-specific cycling and its effect on subsequent running.

  14. Kinematic and kinetic analyses of novice running in dress shoes and running shoes.

    PubMed

    Lee, Yongku; Kim, Young-Kwan; Kim, Yoon Hyuk; Kong, Sejin; Lee, Ki-Kwang

    2011-01-01

    The purpose of the study was to investigate how novice runners adjust their lower extremities in heel-toe running while they wear dress shoes and running shoes. Ten novice male runners repeatedly ran across a force plate at 4 m/s in each type of shoes. Joint kinematics and kinetics, vertical ground reaction force, and utilized coefficient of friction during the stance phase were quantified. The results obtained showed no differences in impact peaks, stance time, stride length and joint kinematics. However, dorsiflexion moment was significantly greater with dress shoes (407 Nm) compared to that with running shoes (304 Nm; p<0.05). Compared to the runners in running shoes (0.23), the runners in dress shoes (0.20) achieved a significantly lower utilized coefficient of friction ( p<0.05). When running in dress shoes, novice runners tended to use better a dorsiflexion moment than when running in running shoes. This adaptation appears to minimize the chances of slipping at the moment of heel strike.

  15. Effects of treadmill running and fatigue on impact acceleration in distance running.

    PubMed

    García-Pérez, José Antonio; Pérez-Soriano, Pedro; Llana Belloch, Salvador; Lucas-Cuevas, Angel Gabriel; Sánchez-Zuriaga, Daniel

    2014-09-01

    The effects of treadmill running on impact acceleration were examined together with the interaction between running surface and runner's fatigue state. Twenty recreational runners (11 men and 9 women) ran overground and on a treadmill (at 4.0 m/s) before and after a fatigue protocol consisting of a 30-minute run at 85% of individual maximal aerobic speed. Impact accelerations were analysed using two lightweight capacitive uniaxial accelerometers. A two-way repeated-measure analysis of variance showed that, in the pre-fatigue condition, the treadmill running decreased head and tibial peak impact accelerations and impact rates (the rate of change of acceleration), but no significant difference was observed between the two surfaces in shock attenuation. There was no significant difference in acceleration parameters between the two surfaces in the post-fatigue condition. There was a significant interaction between surface (treadmill and overground) and fatigue state (pre-fatigue and post-fatigue). In particular, fatigue when running overground decreased impact acceleration severity, but it had no such effect when running on the treadmill. The effects of treadmill running and the interaction need to be taken into account when interpreting the results of studies that use a treadmill in their experimental protocols, and when prescribing physical exercise.

  16. A novel running mechanic's class changes kinematics but not running economy.

    PubMed

    Craighead, Daniel H; Lehecka, Nick; King, Deborah L

    2014-11-01

    A novel method of running technique instruction, Midstance to Midstance Running (MMR), was studied to determine how MMR affected kinematics and running economy (RE) of recreational runners. An experimental pre-post randomized groups design was used. Participants (n = 18) were recreational runners who ran at least 3 days a week and 5 km per run. All testing was performed on a treadmill at 2.8 m·s. The intervention group (n = 9) completed 8 weeks of instruction in MMR; the control group (n = 9) continued running without instruction. The MMR group showed significant decreases in stride length (SL) (p = 0.02) and maximum knee flexion velocity in stance (p = 0.01), and a significant increase in stride rate (SR) (p = 0.02) after 8 weeks. No significant changes were found in heart rate, rating of perceived exertion, or RE. Midstance to Midstance Running was effective in changing SR and SL, but was not effective in changing other kinematic variables such as foot contact position and maximum knee flexion during swing. Midstance to Midstance Running did not affect RE. Evidence suggests that MMR may be an appropriate instructional method for recreational runners trying to decrease SL and increase SR.

  17. Black Holes, Thermodynamics, and Quantum Theory

    NASA Astrophysics Data System (ADS)

    Wald, Robert

    2017-01-01

    A black hole is a region of ``no escape'' that remains behind after a body has undergone complete gravitational collapse. It is truly remarkable that (i) black holes obey the ordinary laws of thermodynamics, (ii) the entropy of a black hole is given by a simple formula involving geometrical properties of its event horizon, and (iii) quantum theory plays an essential role in the thermodynamic properties of black holes. In this talk, I will review some of the key developments related to these properties of black holes, which fascinated me as a graduate student and continue to fascinate me now.

  18. Noncritical superstring-black hole transition

    SciTech Connect

    Parnachev, Andrei; Sahakyan, David A.

    2006-04-15

    An interesting case of string/black hole transition occurs in two-dimensional noncritical string theory dressed with a compact CFT. In these models the high energy densities of states of perturbative strings and black holes have the same leading behavior when the Hawking temperature of the black hole is equal to the Hagedorn temperature of perturbative strings. We compare the first subleading terms in the black hole and closed string entropies in this setting and argue that the entropy interpolates between these expressions as the energy is varied. We compute the subleading correction to the black hole entropy for a specific simple model.

  19. Spectral Hole Burning via Kerr Nonlinearity

    NASA Astrophysics Data System (ADS)

    Khan, Anwar Ali; Abdul Jabar, M. S.; Jalaluddin, M.; Bacha, Bakht Amin; Iftikhar, Ahmad

    2015-10-01

    Spectral hole burning is investigated in an optical medium in the presence of Doppler broadening and Kerr nonlinearity. The Kerr nonlinearity generates coherent hole burning in the absorption spectrum. The higher order Kerr nonlinearity enhances the typical lamb dip of the hole. Normal dispersion in the hole burning region while Steep anomalous dispersion between the two hole burning regions also enhances with higher order Kerr effect. A large phase shift creates large delay or advancement in the pulse propagation while no distortion is observed in the pulse. These results provide significant steps to improve optical memory, telecom devices, preservation of information and image quality. Supported by Higher Education Commission (HEC) of Pakistan

  20. Muscle injury after low-intensity downhill running reduces running economy.

    PubMed

    Baumann, Cory W; Green, Michael S; Doyle, J Andrew; Rupp, Jeffrey C; Ingalls, Christopher P; Corona, Benjamin T

    2014-05-01

    Contraction-induced muscle injury may reduce running economy (RE) by altering motor unit recruitment, lowering contraction economy, and disturbing running mechanics, any of which may have a deleterious effect on endurance performance. The purpose of this study was to determine if RE is reduced 2 days after performing injurious, low-intensity exercise in 11 healthy active men (27.5 ± 5.7 years; 50.05 ± 1.67 VO2peak). Running economy was determined at treadmill speeds eliciting 65 and 75% of the individual's peak rate of oxygen uptake (VO2peak) 1 day before and 2 days after injury induction. Lower extremity muscle injury was induced with a 30-minute downhill treadmill run (6 × 5 minutes runs, 2 minutes rest, -12% grade, and 12.9 km·h(-1)) that elicited 55% VO2peak. Maximal quadriceps isometric torque was reduced immediately and 2 days after the downhill run by 18 and 10%, and a moderate degree of muscle soreness was present. Two days after the injury, steady-state VO2 and metabolic work (VO2 L·km(-1)) were significantly greater (4-6%) during the 65% VO2peak run. Additionally, postinjury VCO2, VE and rating of perceived exertion were greater at 65% but not at 75% VO2peak, whereas whole blood-lactate concentrations did not change pre-injury to postinjury at either intensity. In conclusion, low-intensity downhill running reduces RE at 65% but not 75% VO2peak. The results of this study and other studies indicate the magnitude to which RE is altered after downhill running is dependent on the severity of the injury and intensity of the RE test.