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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. Investigation of air stream from combustor-liner air entry holes, 3

    NASA Technical Reports Server (NTRS)

    Aiba, T.; Nakano, T.

    1979-01-01

    Jets flowing from air entry holes of the combustor liner of a gas turbine were investigated. Cold air was supplied through the air entry holes into the primary hot gas flows. The mass flow of the primary hot gas and issuing jets was measured, and the behavior of the air jets was studied by the measurement of the temperature distribution of the gas mixture. The air jets flowing from three circular air entry holes, single streamwise long holes, and two opposing circular holes, parallel to the primary flow were studied along with the effects of jet and gas stream velocities, and of gas temperature. The discharge coefficient, the maximum penetration of the jets, the jet flow path, the mixing of the jets, and temperature distribution across the jets were investigated. Empirical expressions which describe the characteristics of the jets under the conditions of the experiments were formulated.

  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. Multi-hole pressure probes to air data system for subsonic small-scale air vehicles

    NASA Astrophysics Data System (ADS)

    Shevchenko, A. M.; Berezin, D. R.; Puzirev, L. N.; Tarasov, A. Z.; Kharitonov, A. M.; Shmakov, A. S.

    2016-10-01

    A brief review of research performed to develop multi-hole probes to measure of aerodynamic angles, dynamic head, and static pressure of a flying vehicle. The basis of these works is the application a well-known classical multi-hole pressure probe technique of measuring of a 3D flow to use in the air data system. Two multi-hole pressure probes with spherical and hemispherical head to air-data system for subsonic small-scale vehicles have been developed. A simple analytical probe model with separation of variables is proposed. The probes were calibrated in the wind tunnel, one of them is in-flight tested.

  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. Oxygen intake in track and treadmill running with observations on the effect of air resistance

    PubMed Central

    Pugh, L. G. C. E.

    1970-01-01

    1. The relation of V̇O2 and speed was measured on seven athletes running on a cinder track and an all-weather track. The results were compared with similar observations on four athletes running on a treadmill. 2. In treadmill running the relation was linear and the zero intercept coincided with resting V̇O2. 3. In track running the relation was curvilinear, but was adequately represented by a linear regression over a range of speeds extending from 8·0 km/hr (2·2 m/sec) to 21·5 km/hr (6·0 m/sec). The slope of this line was substantially steeper than the regression line slope for treadmill running. 4. The influence of air resistance in running was estimated from measurements of V̇O2 on a subject running on a treadmill at constant speed against wind of varying velocity. 5. The extra O2 intake (ΔV̇O2) associated with wind increased as the square of wind velocity. If wind velocity and running velocity are equal, as in running on a track in calm air, ΔV̇O2 will increase as the cube of velocity. 6. It was estimated that the energy cost of overcoming air resistance in track running is about 8% of total energy cost at 21·5 km/hr (5000 m races) and 16% for sprinting 100 m in 10·0 sec. ImagesFig. 4 PMID:5532903

  7. Oxygen intake in track and treadmill running with observations on the effect of air resistance.

    PubMed

    Pugh, L G

    1970-05-01

    1. The relation of V(O2) and speed was measured on seven athletes running on a cinder track and an all-weather track. The results were compared with similar observations on four athletes running on a treadmill.2. In treadmill running the relation was linear and the zero intercept coincided with resting V(O2).3. In track running the relation was curvilinear, but was adequately represented by a linear regression over a range of speeds extending from 8.0 km/hr (2.2 m/sec) to 21.5 km/hr (6.0 m/sec). The slope of this line was substantially steeper than the regression line slope for treadmill running.4. The influence of air resistance in running was estimated from measurements of V(O2) on a subject running on a treadmill at constant speed against wind of varying velocity.5. The extra O(2) intake (DeltaV(O2)) associated with wind increased as the square of wind velocity. If wind velocity and running velocity are equal, as in running on a track in calm air, DeltaV(O2) will increase as the cube of velocity.6. It was estimated that the energy cost of overcoming air resistance in track running is about 8% of total energy cost at 21.5 km/hr (5000 m races) and 16% for sprinting 100 m in 10.0 sec.

  8. Searching for mini black holes signatures in cosmic rays air shower

    SciTech Connect

    Lamri, S.; Kalli, S.; Mimouni, J.

    2012-06-27

    Theories with extra dimensions at low Planck scale, offer the exciting possibility of mini black holes production in ultra high-energy particles interactions. In particular, cosmic neutrinos interaction can produce black holes deep in the Earth's atmosphere. These mini black holes then decay and produce 'characteristic' air showers. In this paper, we examine the properties of the mini black holes (mBH) air showers and compare them to the standard model (mSM) ones. We point out to some possible criteria that help distinguishing mBH air showers.

  9. New methodology to determine air quality in urban areas based on runs rules for functional data

    NASA Astrophysics Data System (ADS)

    Sancho, J.; Martínez, J.; Pastor, J. J.; Taboada, J.; Piñeiro, J. I.; García-Nieto, P. J.

    2014-02-01

    Functional data appear in a multitude of industrial applications and processes. However, in many cases at present, such data continue to be studied from the conventional standpoint based on Statistical Process Control (SPC), losing the capacity of analysing different aspects over the time. In this study, the well-known runs rules for Shewhart Type Control Charts are adapted to the case of functional data. Also, in the application of this functional approach, a number of advantages over the classical one are described. Furthermore, the results of applying this new methodology are analysed to determine the air quality of urban areas from the gas emissions at different weather stations.

  10. Interaction between bubble and air-backed plate with circular hole

    NASA Astrophysics Data System (ADS)

    Liu, Y. L.; Wang, S. P.; Zhang, A. M.

    2016-06-01

    This paper investigates the nonlinear interaction between a violent bubble and an air-backed plate with a circular hole. A numerical model is established using the incompressible potential theory coupled with the boundary integral method. A double-node technique is used to solve the overdetermined problem caused by the intersection between the solid wall and the free surface. A spark-generated bubble near the air-backed plate with a circular hole is observed experimentally using a high-speed camera. Our numerical results agree well with the experimental results. Both experimental and numerical results show that a multilevel spike emerges during the bubble's expansion and contraction. Careful numerical simulation reveals that this special type of spike is caused by the discontinuity in the boundary condition. The influences of the hole size and depth on the bubble and spike dynamics are also analyzed.

  11. 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.

  12. Burner rig study of variables involved in hole plugging of air cooled turbine engine vanes

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    The effects of combustion gas composition, flame temperatures, and cooling air mass flow on the plugging of film cooling holes by a Ca-Fe-P-containing deposit were investigated. The testing was performed on film-cooled vanes exposed to the combustion gases of an atmospheric Mach 0.3 burner rig. The extent of plugging was determined by measurement of the open hole area at the conclusion of the tests as well as continuous monitoring of some of the tests using stop-action photography. In general, as the P content increased, plugging rates also increased. The plugging was reduced by increasing flame temperature and cooling air mass flow rates. At times up to approximately 2 hours little plugging was observed. This apparent incubation period was followed by rapid plugging, reaching in several hours a maximum closure whose value depended on the conditions of the test.

  13. Design of a polarized filtering photonic-crystal fiber with gold-coated air holes.

    PubMed

    Wang, Guangyao; Li, Shuguang; An, Guowen; Wang, Xinyu; Zhao, Yunyan; Zhang, Wan

    2015-10-20

    A novel design of a gold-coated photonic-crystal fiber (PCF) is studied by using the finite element method. The cross-section structure of the PCF is composed of a square lattice of air holes in which two air holes are gold coated, and the air-hole layout is modified. The resonance strength and the impact of structural parameters of the PCF on the polarization filter characteristics are studied. Numerical results show that the resonance strength and wavelengths are different in two polarized directions. The resonance strengths that we obtain can reach a value of 720 dB/cm at the wavelength of 1.31 μm. When the fiber length is 400 μm, the crosstalk can reach a value of 247.2 dB at the wavelength of 1.31 μm, which can be applied in many polarization filter devices. And when the length of fiber is longer than 200 μm, the crosstalk is better than 20 dB with wavelength ranges from 1.2 to 2 μm. Meanwhile, we can realize the filtering effect with a very short fiber.

  14. 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.

  15. 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.

  16. 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.

  17. A Basic Study on Countermeasure Against Aerodynamic Force Acting on Train Running Inside Tunnel Using Air Blowing

    NASA Astrophysics Data System (ADS)

    Suzuki, Masahiro; Nakade, Koji

    A basic study of flow controls using air blowing was conducted to reduce unsteady aerodynamic force acting on trains running in tunnels. An air blowing device is installed around a model car in a wind tunnel. Steady and periodic blowings are examined utilizing electromagnetic valves. Pressure fluctuations are measured and the aerodynamic force acting on the car is estimated. The results are as follows: a) The air blowing allows reducing the unsteady aerodynamic force. b) It is effective to blow air horizontally at the lower side of the car facing the tunnel wall. c) The reduction rate of the unsteady aerodynamic force relates to the rate of momentum of the blowing to that of the uniform flow. d) The periodic blowing with the same frequency as the unsteady aerodynamic force reduces the aerodynamic force in a manner similar to the steady blowing.

  18. 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.

    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%.

  19. Tunable complete photonic band gap in anisotropic photonic crystal slabs with non-circular air holes using liquid crystals

    NASA Astrophysics Data System (ADS)

    Fathollahi Khalkhali, T.; Bananej, A.

    2016-06-01

    In this study, we analyze the tunability of complete photonic band gap of square and triangular photonic crystal slabs composed of square and hexagonal air holes in anisotropic tellurium background with SiO2 as cladding material. The non-circular holes are infiltrated with liquid crystal. Using the supercell method based on plane wave expansion, we study the variation of complete band gap by changing the optical axis orientation of liquid crystal. Our numerical results show that noticeable tunability of complete photonic band gap can be obtained in both square and triangular structures with non-circular holes.

  20. Effect of marathon run and air travel on pre- and post-run soluble d-dimer, microparticle procoagulant activity, and p-selectin levels.

    PubMed

    Parker, Beth A; Augeri, Amanda L; Capizzi, Jeffrey A; Ballard, Kevin D; Kupchak, Brian R; Volek, Jeffrey S; Troyanos, Christopher; Kriz, Peter; D'Hemecourt, Pierre; Thompson, Paul D

    2012-05-15

    D-dimer, microparticles, and p-selectin are venous thrombotic risk markers. Elevated p-selectin is associated with increased cardiovascular events. We examined the effects of exercise and air travel on the markers of vascular risk in marathon runners. Forty-one persons participating in the 114th Boston Marathon (April 19, 2010) were divided into travel (n = 23) and nontravel "control" (n = 18) groups according to whether they lived more than a 4-hour plane flight or less than a 2-hour car trip from Boston. The subjects provided venous blood samples the day before, immediately after, and after returning home the day after the marathon. The blood was analyzed for soluble d-dimer, microparticle procoagulant activity, and p-selectin. D-dimer levels increased more before to immediately after (142 ± 83 to 387 ± 196 ng/mL) in the travel group than in the controls (85 ± 26 to 233 ± 95 ng/mL; p = 0.02). Moreover, 6 travel subjects versus 0 controls had d-dimer values >500 ng/mL after returning home the day after the marathon, the clinical threshold for excluding venous thrombosis (p = 0.03). P-selectin increased with exercise (p <0.01) regardless of travel (p = 0.09) but age was related to p-selectin (p = 0.01) such that older subjects exhibited greater p-selectin values before (r(2) = 0.14; p = 0.02) and after returning home the day after the marathon (r(2) = 0.16, p = 0.01). In conclusion, the combination of exercise and travel increases venous and arterial thrombotic risk. Moreover, the p-selectin levels at rest and after exercise were greater with age. These results might explain the reports of venous thrombosis with air travel after athletic events and the reports of cardiac events in older participants running marathons.

  1. Coupled-wave analysis for photonic-crystal surface-emitting lasers on air holes with arbitrary sidewalls.

    PubMed

    Peng, Chao; Liang, Yong; Sakai, Kyosuke; Iwahashi, Seita; Noda, Susumu

    2011-11-21

    The coupled-wave theory (CWT) is extended to a photonic crystal structure with arbitrary sidewalls, and a simple, fast, and effective model for the quantitatively analysis of the radiative characteristics of two-dimensional (2D) photonic-crystal surface-emitting lasers (PC-SELs) has been developed. For illustrating complicated coupling effects accurately, sufficient numbers of waves are included in the formulation, by considering their vertical field profiles. The radiation of band-edge modes is analyzed for two in-plane air-hole geometries, in the case of two types of sidewalls: i.e. "tapered case" and "tilted case." The results of CWT analysis agree well with the results of finite-difference time-domain (FDTD) numerical simulation. From the analytical solutions of the CWT, the symmetry properties of the band-edge modes are investigated. In-plane asymmetry of the air holes is crucial for achieving high output power because it causes partial constructive interference. Asymmetric air holes and tilted sidewalls help in inducing in-plane asymmetries. By breaking the symmetries with respect to the two orthogonal symmetric axes of the band-edge modes, the two factors can be tuned independently, so that the radiation power is enhanced while preserving the mode selectivity performance. Finally, top-down reactive ion etching (RIE) approach is suggested for the fabrication of such a structure. PMID:22109495

  2. 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.

  3. Promising low-damage fabrication method for the photonic crystals with hexagonal or triangular air holes: selective area metal organic vapor phase epitaxy.

    PubMed

    Yang, Lin; Motohisa, Junichi; Takeda, Junichiro; Fukui, Takashi

    2005-12-26

    The photonic band diagrams of the photonic crystal slabs (PCSs) with various structural air holes were calculated by plane wave expansion method with super cell method. The calculated results indicate that the PCSs with hexagonal or triangular air holes have enough large photonic band gaps in the guided mode spectrum, hence they are good candidates to be used for the PC devices. The PCs with hexagonal or triangular air holes were fabricated successfully on n-type GaAs (111)B substrate by selective-area metal organic vapor phase epitaxy (SA-MOVPE). Vertical and smooth facets are formed and the uniformities are very good. The same process was also used to fabricate hexagonal air hole arrays with the width of 100 nm successfully. A procedure was proposed and utilized to fabricate the air-bridge PCS with normal hexagonal air holes. The fabricated hexagonal air holes are very uniform and the sidewalls are smooth and vertical. Our experimental results indicate that SA-MOVPE growth is a promising low-damage fabrication method for PC devices and photonic nano-strucutres.

  4. 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.

  5. Simulation of Q-factor, bandgap frequency and defect band structure dependence upon hole radius of air formed in InxGa1-xAs waveguides

    NASA Astrophysics Data System (ADS)

    Ali, Latef M.

    2016-06-01

    In this study, the structure being investigated consists of periodic layers of In0.2Ga0.8As that have a defect region in air holes and GaAs. Using the finite-difference time-domain method (FDTD), we show that the influences of hole radius on the Q-factor, frequency of defect region and the defect band structure. Also, we investigate property of the defect region on the bandgap structures.

  6. 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.

  7. Running Away

    MedlinePlus

    ... Got Homework? Here's Help White House Lunch Recipes Running Away KidsHealth > For Kids > Running Away Print A ... life on the streets. continue The Reality of Running Away When you think about running away, you ...

  8. 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.

  9. UV/ozone treated Au for air-stable, low hole injection barrier electrodes in organic electronics

    SciTech Connect

    Rentenberger, S.; Vollmer, A.; Zojer, E.; Schennach, R.; Koch, N.

    2006-09-01

    Ultraviolet and x-ray photoelectron spectroscopies were used to study electronic properties of interfaces between Au substrates and a number of organic semiconductors (small molecules and polymers). Au surface work function ({phi}) values before organic deposition were {approx}4.7 eV (exposed to air), {approx}5.2 eV (atomically clean), and {approx}5.5 eV (UV/ozone treated). The high {phi} obtained for UV/O{sub 3} treated Au was due to Au oxide formation and surface-adsorbed carbon and oxygen species. Au surface morphology remained essentially unchanged by UV/ozone exposure, as observed by atomic force microscopy. Hole injection barriers (HIBs) at interfaces between UV/ozone treated Au and the organic semiconductors were systematically lower than those for untreated Au (both atomically clean and air exposed). Reductions in HIB of up to 1.4 eV (for p-sexiphenyl) were achieved. In addition, good long-term stability of reduced HIBs of such interfaces was observed for air storage of up to several days.

  10. 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.

  11. 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. PMID:27340730

  12. Experimental demonstration of ultracompact air hole photonic crystal ring resonator fabricated on silicon-on-insulator wafer.

    PubMed

    Ren, Xiaoyuan; Feng, Lishuang; Lin, Zhili; Feng, Junbo

    2013-05-01

    A photonic crystal ring resonator (PCRR) of air hole arrays is fabricated on a silicon-on-insulator wafer by using electron-beam lithography and inductively coupled plasma etching. The designed PCRR is modeled and its performance is simulated by the two-dimensional finite difference time domain method. The simulation results show that the PCRR has two resonant wavelengths, 1598 and 1606 nm, and their corresponding quality factors are 3994 and 4015, respectively. A sample of the PCRR structure is fabricated and tested by the established experimental setup. Compared with the simulation results, the experimental resonant wavelengths drift to some extent and the quality factors are reduced by about one order of magnitude. The fabrication error and irregularity are the main reasons for the above results, which can be further reduced by improving the process technology. In addition, one more resonant wavelength emerged for the PCRR sample, which can be attributed to the change of the coupling strength. PMID:23632503

  13. 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.

  14. New efficient ligand for sub-mol % copper-catalyzed C-N cross-coupling reactions running under air.

    PubMed

    Larsson, Per-Fredrik; Astvik, Peter; Norrby, Per-Ola

    2012-01-01

    A new efficient ligand, N,N''-dimethyldiethylene triamine (DMDETA), has been synthesized and evaluated for sub-mol % copper-catalyzed C-N cross-coupling reactions. The efficiency of the ligand was determined by kinetic methods. DMDETA proved to display efficiency similar to DMEDA and, in addition, the resulting catalyst was tolerant to air. PMID:23209530

  15. New efficient ligand for sub-mol % copper-catalyzed C–N cross-coupling reactions running under air

    PubMed Central

    Larsson, Per-Fredrik; Astvik, Peter

    2012-01-01

    Summary A new efficient ligand, N,N’’-dimethyldiethylene triamine (DMDETA), has been synthesized and evaluated for sub-mol % copper-catalyzed C–N cross-coupling reactions. The efficiency of the ligand was determined by kinetic methods. DMDETA proved to display efficiency similar to DMEDA and, in addition, the resulting catalyst was tolerant to air. PMID:23209530

  16. 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.

  17. 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.

  18. 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. PMID:20938776

  19. 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.

  20. 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 ...

  1. Air-Stable, Cross-Linkable, Hole-Injecting/Transporting Interlayers for Improved Charge Injection in Organic Light-Emitting Diodes

    SciTech Connect

    Li,J.; Marks, T.

    2008-01-01

    Modification of inorganic electrode surfaces has attracted great attention in the quest to optimize organic optoelectronic devices. An air-stable, cross-linkable trimethoxysilane functionalized hole-transporting triarylamine (4,4'-bis[(p-trimethoxysilylpropylphenyl)phenylamino]biphenyl, TPD-[Si(OMe)3]2) has been synthesized and self-assembled or spin-coated onto tin-doped indium oxide (ITO) anode surfaces to form monolayers or multilayer siloxane films, respectively. The modified ITO surfaces were characterized by advancing aqueous contact angle, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and cyclic voltammetry (CV). Increased surface work function and enhanced ITO-hole transport layer (HTL) contact via robust covalent bonding are expected to facilitate hole injection from the ITO anode, resulting in organic light-emitting diode (OLED) performance enhancement versus that of a device without such interlayers. For a device having the structure ITO/spin-coated-TPD-[Si(OMe)3]2 from aqueous alcohol + acetic acid blend solution (40 nm)/NPB (20 nm)/Alq (60 nm)/LiF (1 nm)/Al (100 nm), a maximum light output of 32800 cd/m2, a 4.25 V turn-on voltage, and a maximum current efficiency of 5.8 cd/A is achieved. This performance is comparable to or superior to that of analogous devices prepared with analogous trichorosilyl precursors. The air-stable interlayer material developed here is also applicable to large-area coating techniques.

  2. 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.

  3. Barefoot Running

    PubMed Central

    Mullen, Scott; Cotton, Jon; Bechtold, Megan; Toby, E. Bruce

    2014-01-01

    Background: It has been proposed that running barefoot can lead to improved strength and proprioception. However, the duration that a runner must train barefoot to observe these changes is unknown. Hypothesis: Runners participating in a barefoot running program will have improved proprioception, increased lower extremity strength, and an increase in the volume or size of the intrinsic musculature of the feet. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: In this 8-week study, 29 runners with a mean age of 36.34 years were randomized into either a control group (n = 10) who completed training in their regular running shoes or to an experimental barefoot group (n = 14). Pretraining tests consisted of a volumetric measurement of the foot followed by a strength and dynamic balance assessment. Five subjects completed the pretests but did not complete the study for reasons not related to study outcomes. Participants then completed 8 weeks of training runs. They repeated the strength and dynamic balance assessment after 8 weeks. Results: Significant changes from baseline to 8 weeks were observed within the barefoot group for single-leg hop (right, P = .0121; left, P = .0430) and reach and balance (right, P = .0029) and within the control group for single–left leg hop (P = .0286) and reach and balance (right, P = .0096; left, P = .0014). However, when comparing the differences in changes from baseline to 8 weeks between the barefoot and control groups, the improvements were not significant at the .05 level for all measures. Conclusion: Although statistically significant changes were not observed between the pre- and posttest evaluations in strength and proprioception with the 8-week low-intensity barefoot running regimen, this does not necessarily mean that these changes do not occur. It is possible that it may take months or years to observe these changes, and a short course such as this trial is insufficient. PMID:26535308

  4. 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.

  5. 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

  6. 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

  7. Scour hole ('wielen') sediments as historical archive of floods, vegetation, and air and water quality in lowlands

    NASA Astrophysics Data System (ADS)

    Cremer, Holger; van Hoof, Thomas; Bunnik, Frans; Donders, Timme

    2010-05-01

    The sediment record from a maximum 18 m deep scour hole lake (Haarsteegse Wiel) near the embanked Meuse River in the Netherlands was studied for past changes in flooding frequency, water quality, and landscape change using a combined geochemical, geobiological and historical approach. The results are highly significant for determining long-term trends of river flood frequency, eutrophication, atmospheric pollution, and vegetation development. Haarsteegse Wiel consists of two basins connected by a shallow sill. The first flooding event is indicated in the sediment at AD 1610 when the 8 m deep southern basin of the lake was created by flood water masses bursting through the embankment. In AD 1740 embankments burst again and resulted in the formation of the northern basin of Haarsteegse Wiel. This part of the lake was originally 21 m deep and was filled up with a 3.50 m thick sediment layer since then. The sediment was dated by combining 137Cs activity measurements, biostratigraphical ages of pollen, microtephra, and historically documented floods indicated by the magnetic susceptibility of the sediment. The resulting chronology is highly accurate and shows that sedimentation rates decrease sharply with the widespread change from cereal cultivation to pasture land from around AD 1875 (agricultural crisis) as a direct result of falling wheat prices and intensified cattle farming. Water quality (total phosphorus concentration) was reconstructed using a diatom-based transfer function. Results show that the currently nutrient enriched lake has mostly been in a mesotrophic state prior to AD 1920, with the exception of several sharp eutrophication events that are generally coeval with river floods. After 1920, eutrophication of Haarsteegse Wiel is clearly documented and generally caused by the increased population, enhanced use of fertilizers and settlement of dairy industry in the region. Industrial development in both the vicinity and the hinterland of Haarsteegse Wiel

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  12. Muscle metabolism, temperature, and function during prolonged, intermittent, high-intensity running in air temperatures of 33 degrees and 17 degrees C.

    PubMed

    Morris, J G; Nevill, M E; Boobis, L H; Macdonald, I A; Williams, C

    2005-12-01

    Nine unacclimatized university sportsmen performed a prolonged, intermittent, high-intensity shuttle running test in hot (HT) (33 degrees C, dry bulb temperature, approximately 28 %, relative humidity) and moderate (MT) (17 degrees C, 63 %) environmental conditions. Subjects performed 60 m of walking, a 15-m sprint, 60 m of cruising ( approximately 85 % V.O (2max)), and 60 m of jogging ( approximately 45 %V.O (2max)) for 14.8 +/- 0.1 min followed by a 3-min rest, repeated until volitional exhaustion. The hot trial was performed first followed, 14 days later, by the moderate trial. During exercise subjects drank water ad libitum. Subjects ran almost twice as far in the moderate as in the hot trial (HT 11216 +/- 1411, MT 21644 +/- 1629, m, p < 0.01), and the decline in average 15-m sprint performance was greater in the heat (HT, 0.17 +/- 0.05, MT, 0.09 +/- 0.03, s, p < 0.05). Average heart rates, blood lactate and glucose, and plasma adrenaline and noradrenaline concentrations were greater in the HT (main effect trial, p < 0.01), as were serum cortisol concentration (main effect trial p < 0.05, n = 5) and muscle temperature (HT exhaustion vs. same time point in MT, 40.2 +/- 0.3 vs. 39.3 +/- 0.2, degrees C, p < 0.01). Peak torque during knee flexion and extension was not different pre-and post-exercise in the HT. Muscle glycogen utilization tended to be greater in the heat (HT 193.2 +/- 19.5, MT 143.8 +/- 23.9, mmol . kg dry wt (-1), p = 0.055, n = 8). In 7 out of the 8 subjects the increase in utilization was between 19 and just over 200 % greater in the HT. Glycogen remaining in the muscle at exhaustion was greater in the hot than moderate trial (HT 207.4 +/- 34.3, MT 126.5 +/- 46.8, mmol . kg dry wt (-1), p < 0.01, n = 8). Rectal temperature (T (rec)) was higher in the HT at exhaustion than at the same point in time in the moderate trial (HT, 39.60 +/- 0.15 vs. MT 38.75 +/- 0.10, degrees C, interaction trial-time, p < 0.01). There was a very strong negative

  13. An examination of the relationship between the Southern Annular Mode and Antarctic surface air temperatures in the CMIP5 historical runs

    NASA Astrophysics Data System (ADS)

    Marshall, Gareth J.; Bracegirdle, Thomas J.

    2015-09-01

    Strong relationships exist between the Southern Annular Mode (SAM) and surface air temperature (SAT) across much of Antarctica. Changes in the SAM will have a profound influence on future Antarctic climate so it is important that the models used to predict climate change can accurately reproduce current SAM-SAT relationships. We analyse data from 50 Climate Model Intercomparison Project (CMIP) 5 models to assess how well they reproduce the observed mean and variability of annual and seasonal SAM-SAT relationships at six Antarctic stations. Overall, the models do better at reproducing these relationships when meridional flow has its largest influence on SAT, doing best (worst) in winter (autumn and summer). They are generally unable to replicate existing seasonal cycles in the strength of the SAM-SAT relationship and show much less spatial and especially temporal variability in the strength of these relationships than is observed. Using an estimate of intrinsic variability to quantify the skill of the CMIP5 models, their average ability to successfully replicate a seasonal SAM-SAT relationship at the six locations studied ranges from 16 % in autumn to 32 % in winter. The mean success rate of a single model across all four seasons is 24 %, ranging from 8 to 38 % (compared to a `perfect model' with 46 %). Analysing the different atmospheric circulation patterns associated with extreme SAM-SAT correlations in the models demonstrates the importance of correctly reproducing both the climatological mean and variability of the planetary longwaves at Southern Hemisphere high-latitudes (particularly wave-number 3), in order to accurately reproduce observed SAM-SAT relationships across Antarctica.

  14. Retinal holes.

    PubMed

    Foos, R Y

    1978-09-01

    Holes of the peripheral retina, defined as full-thickness breaks of trophic origin with no associated flap or free operculum, were found in 136 (2.4%) eyes from 2,800 autopsied subjects. Primary retinal holes (those with no indication of a proximal causative lesion and with no lattice degeneration in either eye) occurred in only eight of the 5,600 eyes studied; all were unilateral, single, less than 0.25 disk diameter in size, within the basal zone, and in eyes from elderly subjects. Secondary holes were found in 128 (2.3%) of eyes and of these, lattice degeneration was the most common cause (103). Other lesions complicated by hole formation included zonular traction tufts (10), chorioretinitis (9), meridional folds (3), and pavingstone degeneration (2). Retinal holes in surgically aphakic eyes did not differ qualitatively or quantitatively from those in age-matched phakic eyes.

  15. 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…

  16. 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)

  17. 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…

  18. Running and osteoarthritis.

    PubMed

    Willick, Stuart E; Hansen, Pamela A

    2010-07-01

    The overall health benefits of cardiovascular exercise, such as running, are well established. However, it is also well established that in certain circumstances running can lead to overload injuries of muscle, tendon, and bone. In contrast, it has not been established that running leads to degeneration of articular cartilage, which is the hallmark of osteoarthritis. This article reviews the available literature on the association between running and osteoarthritis, with a focus on clinical epidemiologic studies. The preponderance of clinical reports refutes an association between running and osteoarthritis.

  19. 40 CFR 89.407 - Engine dynamometer test run.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 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...

  20. 40 CFR 89.407 - Engine dynamometer test run.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 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...

  1. 40 CFR 89.407 - Engine dynamometer test run.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true 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...

  2. 40 CFR 89.407 - Engine dynamometer test run.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 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...

  3. 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...

  4. 1. LOOKING DOWNSTREAM (NORTHEAST) ALONG WINTER'S RUN TOWARD THE MITCHELL'S ...

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

    1. LOOKING DOWNSTREAM (NORTHEAST) ALONG WINTER'S RUN TOWARD THE MITCHELL'S MILL BRIDGE, SHOWING THE SETTING OF THE BRIDGE. CARRS MILL ROAD APPROACHES THE BRIDGE FROM THE SOUTH, ON THE RIGHT. - Mitchell's Mill Bridge, Spanning Winter's Run on Carrs Mill Road, west of Bel Air, Bel Air, Harford County, MD

  5. 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.

  6. 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.

  7. 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, "who runs our…

  8. 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.

  9. 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.

  10. 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

  11. Running for Your Health.

    ERIC Educational Resources Information Center

    Adams, George M.

    1979-01-01

    One way of coping with stress is through regular exercise. The author suggests jogging, or running, and presents some basic rules and suggestions for anyone who is about to take up this method of exercise. (KC)

  12. 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.

  13. The LHCb Run Control

    NASA Astrophysics Data System (ADS)

    Alessio, F.; Barandela, M. C.; Callot, O.; Duval, P.-Y.; Franek, B.; Frank, M.; Galli, D.; Gaspar, C.; Herwijnen, E. v.; Jacobsson, R.; Jost, B.; Neufeld, N.; Sambade, A.; Schwemmer, R.; Somogyi, P.

    2010-04-01

    LHCb has designed and implemented an integrated Experiment Control System. The Control System uses the same concepts and the same tools to control and monitor all parts of the experiment: the Data Acquisition System, the Timing and the Trigger Systems, the High Level Trigger Farm, the Detector Control System, the Experiment's Infrastructure and the interaction with the CERN Technical Services and the Accelerator. LHCb's Run Control, the main interface used by the experiment's operator, provides access in a hierarchical, coherent and homogeneous manner to all areas of the experiment and to all its sub-detectors. It allows for automated (or manual) configuration and control, including error recovery, of the full experiment in its different running modes. Different instances of the same Run Control interface are used by the various sub-detectors for their stand-alone activities: test runs, calibration runs, etc. The architecture and the tools used to build the control system, the guidelines and components provided to the developers, as well as the first experience with the usage of the Run Control will be presented

  14. 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.

  15. From Walking to Running

    NASA Astrophysics Data System (ADS)

    Rummel, Juergen; Blum, Yvonne; Seyfarth, Andre

    The implementation of bipedal gaits in legged robots is still a challenge in state-of-the-art engineering. Human gaits could be realized by imitating human leg dynamics where a spring-like leg behavior is found as represented in the bipedal spring-mass model. In this study we explore the gap between walking and running by investigating periodic gait patterns. We found an almost continuous morphing of gait patterns between walking and running. The technical feasibility of this transition is, however, restricted by the duration of swing phase. In practice, this requires an abrupt gait transition between both gaits, while a change of speed is not necessary.

  16. Fermilab DART run control

    SciTech Connect

    Oleynik, G.; Engelfried, J.; Mengel, L.

    1995-05-01

    DART is the high speed, Unix based data acquisition system being developed by Fermilab in collaboration with seven High Energy Physics Experiments. This paper describes DART run control, which has been developed over the past year and is a flexible, distributed, extensible system for the, control and monitoring of the data acquisition systems. We discuss the unique and interesting concepts of the run control and some of our experiences in developing it. We also give a brief update and status of the whole DART system.

  17. 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…

  18. Running Wheel for Earthworms.

    PubMed

    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.

  19. Running Wheel for Earthworms.

    PubMed

    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

  20. 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

  1. 40 CFR 86.884-12 - Test run.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CFR 1065.530. (3) Determine by experimentation the dynamometer inertia and dynamometer load required... 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...

  2. 40 CFR 86.1237-96 - Dynamometer runs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 20 2013-07-01 2013-07-01 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...

  3. 40 CFR 86.1237-96 - Dynamometer runs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 20 2012-07-01 2012-07-01 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...

  4. 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...

  5. 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...

  6. Strategies for reducing the climate noise in model simulations: ensemble runs versus a long continuous run

    NASA Astrophysics Data System (ADS)

    Decremer, Damien; Chung, Chul E.; Räisänen, Petri

    2015-03-01

    Climate modelers often integrate the model with constant forcing over a long time period, and make an average over the period in order to reduce climate noise. If the time series is persistent, as opposed to rapidly varying, such an average does not reduce noise efficiently. In this case, ensemble runs, which ideally represent independent runs, can reduce noise more efficiently. We quantify the noise reduction gain by using ensemble runs over a long continuous run in constant-forcing simulations. We find that in terms of the amplitude of the noise, a continuous simulation of 30 years may be equivalent to as few as five 3-year long ensemble runs in a slab ocean-atmosphere coupled model and as few as two 3-year long ensemble runs in a fully coupled model. The outperformance of ensemble runs over a continuous run is strictly a function of the persistence of the time series. We find that persistence depends on model, location and variable, and that persistence in surface air temperature has robust spatial structures in coupled models. We demonstrate that lag-1 year autocorrelation represents persistence fairly well, but the use of lag-1 year-lag-5 years autocorrelations represents the persistence far more sufficiently. Furthermore, there is more persistence in coupled model output than in the output of a first-order autoregressive model with the same lag-1 autocorrelation.

  7. Design of a circular photonic crystal fiber with flattened chromatic dispersion using a defected core and selectively reduced air holes: Application to supercontinuum generation at 1.55 μm

    NASA Astrophysics Data System (ADS)

    Medjouri, Abdelkader; Simohamed, Lotfy Mokhtar; Ziane, Omar; Boudrioua, Azzedine; Becer, Zoubir

    2015-08-01

    In this paper, we present and numerically investigate a new and simple design of Circular Lattice Photonic Crystal Fiber (CL-PCF) with near zero ultra-flattened chromatic dispersion. The near zero dispersion is obtained by introducing a defect into the solid core and the dispersion flatness is achieved by appropriately reducing the diameter of the core-neighboring air holes ring. Simulations are performed by using the finite-difference frequency-domain (FDFD) method combined with the perfectly matched layer (PML) boundary condition. Results show that an ultra-flattened chromatic dispersion as small as ±0.66 ps/nm km is obtained over a broad band of 400 nm with high nonlinearity and ultra-low confinement loss. Furthermore, the supercontinuum (SC) generation over a short length of the proposed CL-PCF is numerically investigated. Results indicate that flat SC spectrum with a Full Width at Half Maximum (FWHM) of 600 nm is achieved with 25 cm of fiber length.

  8. 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.

  9. 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.

  10. Hole-Aligning Tool

    NASA Technical Reports Server (NTRS)

    Collins, Frank A.; Saude, Frank; Sep, Martin J.

    1996-01-01

    Tool designed for use in aligning holes in plates or other structural members to be joined by bolt through holes. Holes aligned without exerting forces perpendicular to planes of holes. Tool features screw-driven-wedge design similar to (but simpler than) that of some automotive exhaust-pipe-expanding tools.

  11. Does running strengthen bone?

    PubMed

    Boudenot, Arnaud; Achiou, Zahra; Portier, Hugues

    2015-12-01

    Bone is a living tissue needing mechanical stress to maintain strength. Traditional endurance exercises offer only modest effects on bone. Walking and running produce low impact but lead to bone fatigue. This article is specifically addressed to therapists and explains the mechanisms involved for the effects of exercise on bone. Intermittent exercise limits bone fatigue, and downhill exercises increase ground impact forces and involve eccentric muscle contractions, which are particularly osteogenic. PMID:26562001

  12. Discharge coefficients of cooling holes with radiused and chamfered inlets

    NASA Astrophysics Data System (ADS)

    Hay, N.; Spencer, A.

    1991-06-01

    The flow of cooling air within the internal passages of gas turbines is controlled and metered using holes in disks and casings. The effects of inlet radiusing and chamfering of these holes on the discharge coefficient are discussed. Experimental results for a range of radiusing and chamfering ratios for holes of different length to diameter ratios are presented, covering the range of pressure ratios of practical interest. The results indicate that radiusing and chamfering are both beneficial in increasing the discharge coefficient. Increases of 10-30 percent are possible. Chamfered holes give the more desirable performance characteristics in addition to being easier to produce than radiused holes.

  13. 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.

  14. The aerodynamic signature of running spiders.

    PubMed

    Casas, Jérôme; Steinmann, Thomas; Dangles, Olivier

    2008-05-07

    Many predators display two foraging modes, an ambush strategy and a cruising mode. These foraging strategies have been classically studied in energetic, biomechanical and ecological terms, without considering the role of signals produced by predators and perceived by prey. Wolf spiders are a typical example; they hunt in leaf litter either using an ambush strategy or by moving at high speed, taking over unwary prey. Air flow upstream of running spiders is a source of information for escaping prey, such as crickets and cockroaches. However, air displacement by running arthropods has not been previously examined. Here we show, using digital particle image velocimetry, that running spiders are highly conspicuous aerodynamically, due to substantial air displacement detectable up to several centimetres in front of them. This study explains the bimodal distribution of spider's foraging modes in terms of sensory ecology and is consistent with the escape distances and speeds of cricket prey. These findings may be relevant to the large and diverse array of arthropod prey-predator interactions in leaf litter.

  15. 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.

  16. 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.

  17. When Will the Antarctic Ozone Hole Recover?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.

    2006-01-01

    The Antarctic ozone hole develops each year and culminates by early spring (late September - early October). 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 area coverage during this September-October period. Ozone is mainly destroyed by halogen (chlorine and bromine) catalytic cycles, and these losses are modulated by temperature variations in the collar of the polar lower stratospheric vortex. In this talk, I will 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. I will also discuss current assessments of mid-latitude ozone recovery.

  18. 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.

  19. 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

  20. Biomechanics of sprint running. A review.

    PubMed

    Mero, A; Komi, P V; Gregor, R J

    1992-06-01

    Understanding of biomechanical factors in sprint running is useful because of their critical value to performance. Some variables measured in distance running are also important in sprint running. Significant factors include: reaction time, technique, electromyographic (EMG) activity, force production, neural factors and muscle structure. Although various methodologies have been used, results are clear and conclusions can be made. The reaction time of good athletes is short, but it does not correlate with performance levels. Sprint technique has been well analysed during acceleration, constant velocity and deceleration of the velocity curve. At the beginning of the sprint run, it is important to produce great force/power and generate high velocity in the block and acceleration phases. During the constant-speed phase, the events immediately before and during the braking phase are important in increasing explosive force/power and efficiency of movement in the propulsion phase. There are no research results available regarding force production in the sprint-deceleration phase. The EMG activity pattern of the main sprint muscles is described in the literature, but there is a need for research with highly skilled sprinters to better understand the simultaneous operation of many muscles. Skeletal muscle fibre characteristics are related to the selection of talent and the training-induced effects in sprint running. Efficient sprint running requires an optimal combination between the examined biomechanical variables and external factors such as footwear, ground and air resistance. Further research work is needed especially in the area of nervous system, muscles and force and power production during sprint running. Combining these with the measurements of sprinting economy and efficiency more knowledge can be achieved in the near future.

  1. Nonstationary analogue black holes

    NASA Astrophysics Data System (ADS)

    Eskin, Gregory

    2014-12-01

    We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model see Unruh (1981 Phys. Rev. Lett. 46 1351). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes. We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symmetric nonstationary metrics.

  2. 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.

  3. 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.

  4. Does Addiction Run in Families?

    MedlinePlus

    ... runs in some families. Addiction runs in ours." Matt's family has a history of addiction. He realizes ... may be more likely to become addicted. Read Matt's story About the National Institute on Drug Abuse ( ...

  5. Steerable percussion air drilling system

    SciTech Connect

    Bui, H.D.; Meyers, J.A.; Yost, A.B. II

    1998-12-31

    By increasing penetration rates and bit life, especially in hard formations, the use of down-hole air hammers in the oil field has significantly reduced drilling costs in the Northeast US and West Texas. Unfortunately, drilling by this percussion method has been limited mostly to straight hole applications. This paper presents a new concept of a percussion drilling tool which performs both the function of a down-hole hammer as well as that of a down-hole motor. Such a drilling tool, being introduced here as Steerable Percussion Air Drilling System (SPADS), eliminates the necessity to rotate the drill string and, consequently, enables the use of down-hole air hammers to drill directional wells.

  6. 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.

  7. 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

  8. Why Does My Nose Run?

    MedlinePlus

    ... Homework? Here's Help White House Lunch Recipes Why Does My Nose Run? KidsHealth > For Kids > Why Does My Nose Run? Print A A A Text ... smell, you must be upside down! But why does your nose run? Read on to find out ...

  9. 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...

  10. Black holes without firewalls

    NASA Astrophysics Data System (ADS)

    Larjo, Klaus; Lowe, David A.; Thorlacius, Larus

    2013-05-01

    The postulates of black hole complementarity do not imply a firewall for infalling observers at a black hole horizon. The dynamics of the stretched horizon, that scrambles and reemits information, determines whether infalling observers experience anything out of the ordinary when entering a large black hole. In particular, there is no firewall if the stretched horizon degrees of freedom retain information for a time of the order of the black hole scrambling time.

  11. The Nearest Black Hole

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald (Technical Monitor); Garcia, Michael

    2005-01-01

    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.

  12. 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.

  13. 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.

  14. Searching for Black Holes

    NASA Technical Reports Server (NTRS)

    Garica, M.

    2001-01-01

    In 1995 we proposed to carry out ground-based observations in order to securely identify stellar mass black holes in our galaxy. This type 4 proposal under NASA's UV, Visible, and Gravitational Astrophysics program compliments NASA's space-based research by following up black hole candidates found and studied with space-based observatories, in order to determine if they are indeed black holes. While our primary goal is to securely identify black holes by measuring their masses, a secondary goal is identifying unique visible-range signatures for black holes.

  15. 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.

  16. Black hole accretion.

    PubMed

    Narayan, Ramesh; Quataert, Eliot

    2005-01-01

    Black holes are most often detected by the radiation produced when they gravitationally pull in surrounding gas, in a process called accretion. The efficiency with which the hot gas radiates its thermal energy strongly influences the geometry and dynamics of the accretion flow. Both radiatively efficient thin disks and radiatively inefficient thick disks are observed. When the accreting gas gets close to the central black hole, the radiation it produces becomes sensitive to the spin of the hole and the presence of an event horizon. Analysis of the luminosities and spectra of accreting black holes has yielded tantalizing evidence for both rotating holes and event horizons. Numerical simulations imply that the relativistic jets often seen from accreting black holes may be powered in part by the spin of the hole. PMID:15637269

  17. 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

  18. Voluntary Wheel Running in Mice.

    PubMed

    Goh, Jorming; Ladiges, Warren

    2015-12-02

    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. This 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 via 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.

  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. 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.

  1. 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…

  2. 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.

  3. Quantization of Black Holes

    NASA Astrophysics Data System (ADS)

    He, Xiao-Gang; Ma, Bo-Qiang

    We show that black holes can be quantized in an intuitive and elegant way with results in agreement with conventional knowledge of black holes by using Bohr's idea of quantizing the motion of an electron inside the atom in quantum mechanics. We find that properties of black holes can also be derived from an ansatz of quantized entropy Δ S = 4π k Δ R/{{-{λ }}}, which was suggested in a previous work to unify the black hole entropy formula and Verlinde's conjecture to explain gravity as an entropic force. Such an Ansatz also explains gravity as an entropic force from quantum effect. This suggests a way to unify gravity with quantum theory. Several interesting and surprising results of black holes are given from which we predict the existence of primordial black holes ranging from Planck scale both in size and energy to big ones in size but with low energy behaviors.

  4. 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.

  5. Naked black holes

    SciTech Connect

    Horowitz, G.T.; Ross, S.F.

    1997-08-01

    It is shown that there are large static black holes for which all curvature invariants are small near the event horizon, yet any object which falls in experiences enormous tidal forces {ital outside} the horizon. These black holes are charged and near extremality, and exist in a wide class of theories including string theory. The implications for cosmic censorship and the black hole information puzzle are discussed. {copyright} {ital 1997} {ital The American Physical Society}

  6. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Molina, Mario J.

    1988-01-01

    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.

  7. 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

  8. 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

  9. Slim holes haul in savings

    SciTech Connect

    Floyd, K.

    1987-07-01

    This article reports that during 1986 BP Exploration Company Ltd. successfully drilled six UK land wells with a Microdrill MD-3 ultra-slimhole drilling rig. The objective of the program was to evaluate the slimhole drilling technique, from both a technical and cost-effective viewpoint. Earlier studies indicated up to 30 percent savings in well costs compared to conventionally drilled UK land wells. The technology of drilling slim holes with small rigs is not new. For many years the mineral exploration industry has used small drilling and coring rigs. However, these rigs are not normally equipped with pressure control equipment, oilfield mud and cementing systems or the ability to run complex logs or production test. More recently, the oil industry has made efforts to adapt these rigs to slimhole oil and gas exploration, notably in Australia and Canada. The Microdrill MD-3 rig is a product of this evolution.

  10. 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.

  11. Open-hole fishing

    SciTech Connect

    Pietrobono, J.T.

    1988-01-01

    This paper reports on losing equipment in the hole that is one of the most expensive and potentially dangerous things that can go wrong in drilling a well. Drilling must come to a halt until the equipment is recovered, or the hole must be sidetracked. The well also can become hard to control with essential tools out of reach, increasing the risk of a blowout. Fishing, or recovering lost or stuck equipment in the hole, is therefore a critical procedure at any drilling operation. Fishing can be divided into two broad categories: open hole and cased hole. a major difference between the two is timing: open-hole fishing is done as the well is being drilled, whereas cased-hole fishing is performed during production or well workover. Fishing techniques and types of equipment used also vary between the tow. This lesson describes some of the basic techniques and tools used in open-hole fishing-that is, retrieving fish from a hole that is being drilled but is not yet cased.

  12. 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.

  13. 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.

  14. Wheel running in the wild.

    PubMed

    Meijer, Johanna H; Robbers, Yuri

    2014-07-01

    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.

  15. APS runControl library

    SciTech Connect

    Saunders, C.; Borland, M.

    1995-10-25

    This document serves as a User`s Manual and Reference for the runControl library. This library is designed to be used by closed- loop EPICS control applications which are generally run in the background on the controls workstations. It permits an application to `register` itself with an EPICS record, thereby preventing additional instances of the same application from being run. In addition, the executing application may in turn be suspended or aborted via an MEDM control screen or other standard channel access client.

  16. 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…

  17. Can we track holes?

    PubMed Central

    Horowitz, Todd S.; Kuzmova, Yoana

    2011-01-01

    The evidence is mixed as to whether the visual system treats objects and holes differently. We used a multiple object tracking task to test the hypothesis that figural objects are easier to track than holes. Observers tracked four of eight items (holes or objects). We used an adaptive algorithm to estimate the speed allowing 75% tracking accuracy. In Experiments 1–5, the distinction between holes and figures was accomplished by pictorial cues, while red-cyan anaglyphs were used to provide the illusion of depth in Experiment 6. We variously used Gaussian pixel noise, photographic scenes, or synthetic textures as backgrounds. Tracking was more difficult when a complex background was visible, as opposed to a blank background. Tracking was easier when disks carried fixed, unique markings. When these factors were controlled for, tracking holes was no more difficult than tracking figures, suggesting that they are equivalent stimuli for tracking purposes. PMID:21334361

  18. 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.

  19. Piketty in the long run.

    PubMed

    Cowell, Frank A

    2014-12-01

    I examine the idea of 'the long run' in Piketty (2014) and related works. In contrast to simplistic interpretations of long-run models of income- and wealth-distribution Piketty (2014) draws on a rich economic analysis that models the intra- and inter-generational processes that underly the development of the wealth distribution. These processes inevitably involve both market and non-market mechanisms. To understand this approach, and to isolate the impact of different social and economic factors on inequality in the long run, we use the concept of an equilibrium distribution. However the long-run analysis of policy should not presume that there is an inherent tendency for the wealth distribution to approach equilibrium. PMID:25516348

  20. 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.

  1. Hole-ness of point clouds

    NASA Astrophysics Data System (ADS)

    Gronz, Oliver; Seeger, Manuel; Klaes, Björn; Casper, Markus C.; Ries, Johannes B.

    2015-04-01

    Accurate and dense 3D models of soil surfaces can be used in various ways: They can be used as initial shapes for erosion models. They can be used as benchmark shapes for erosion model outputs. They can be used to derive metrics, such as random roughness... One easy and low-cost method to produce these models is structure from motion (SfM). Using this method, two questions arise: Does the soil moisture, which changes the colour, albedo and reflectivity of the soil, influence the model quality? How can the model quality be evaluated? To answer these questions, a suitable data set has been produced: soil has been placed on a tray and areas with different roughness structures have been formed. For different moisture states - dry, medium, saturated - and two different lighting conditions - direct and indirect - sets of high-resolution images at the same camera positions have been taken. From the six image sets, 3D point clouds have been produced using VisualSfM. The visual inspection of the 3D models showed that all models have different areas, where holes of different sizes occur. But it is obviously a subjective task to determine the model's quality by visual inspection. One typical approach to evaluate model quality objectively is to estimate the point density on a regular, two-dimensional grid: the number of 3D points in each grid cell projected on a plane is calculated. This works well for surfaces that do not show vertical structures. Along vertical structures, many points will be projected on the same grid cell and thus the point density rather depends on the shape of the surface but less on the quality of the model. Another approach has been applied by using the points resulting from Poisson Surface Reconstructions. One of this algorithm's properties is the filling of holes: new points are interpolated inside the holes. Using the original 3D point cloud and the interpolated Poisson point set, two analyses have been performed: For all Poisson points, the

  2. 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.

  3. Black holes and beyond

    NASA Astrophysics Data System (ADS)

    Mathur, Samir D.

    2012-11-01

    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.

  4. 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.

  5. 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.

  6. Walking and running at resonance.

    PubMed

    Ahlborn, Boye K; Blake, Robert W

    2002-01-01

    Humans and other animals can temporarily store mechanical energy in elastic oscillations, f(el), of body parts and in pendulum oscillations, f(p) = const sq.rt (g/L), of legs, length L, or other appendages, and thereby reduce the energy consumption of locomotion. However, energy saving only occurs if these oscillations are tuned to the leg propagation frequency f. It has long been known that f is tuned to the pendulum frequency of the free-swinging leg of walkers. During running the leg frequency increases to some new value f = f(r). We propose that in order to maintain resonance the animal, mass M, actively increases its leg pendulum frequency to the new value f(p,r) =const sq.rt (a(y)/L)=f(r), by giving its hips a vertical acceleration a(y)= F(y)/M. The pendulum frequency is increased if the impact force F(y) of the stance foot is larger than Mg, explaining the observation by Alexander and Bennet-Clark (1976) that F(v) becomes larger than Mg when animals start to run. Our model predictions of the running velocity U(r) as function of L, F(v), are in agreement with measurements of these quantities (Farley et al. 1993). The leg's longitudinal elastic oscillation frequency scales as f(el) = const sq.rt (k/M). Experiments by Ferris et al., (1998) show that runners adjust their leg's stiffness, k, when running on surfaces of different elasticity so that the total stiffness k remains constant. Our analysis of their data suggests that the longitudinal oscillations of the stance leg are indeed kept in tune with the running frequency. Therefore we conclude that humans, and by extension all animals, maintain resonance during running. Our model also predicts the Froude number of walking-running transitions, Fr = U(2)/gL approximately 0.5 in good agreement with measurements.

  7. 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.

  8. 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

  9. 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.

  10. Effect of hole geometry and Electric-Discharge Machining (EDM) on airflow rates through small diameter holes in turbine blade material

    NASA Technical Reports Server (NTRS)

    Hippensteele, S. A.; Cochran, R. P.

    1980-01-01

    The effects of two design parameters, electrode diameter and hole angle, and two machine parameters, electrode current and current-on time, on air flow rates through small-diameter (0.257 to 0.462 mm) electric-discharge-machined holes were measured. The holes were machined individually in rows of 14 each through 1.6 mm thick IN-100 strips. The data showed linear increase in air flow rate with increases in electrode cross sectional area and current-on time and little change with changes in hole angle and electrode current. The average flow-rate deviation (from the mean flow rate for a given row) decreased linearly with electrode diameter and increased with hole angle. Burn time and finished hole diameter were also measured.

  11. 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.

  12. 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)

  13. 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.

  14. Astrophysics: Monster black holes

    NASA Astrophysics Data System (ADS)

    Cappellari, Michele

    2011-12-01

    A combination of ground-based and spacecraft observations has uncovered two black holes of 10 billion solar masses in the nearby Universe. The finding sheds light on how these cosmic monsters co-evolve with galaxies.

  15. Helical superconducting black holes.

    PubMed

    Donos, Aristomenis; Gauntlett, Jerome P

    2012-05-25

    We construct novel static, asymptotically five-dimensional anti-de Sitter black hole solutions with Bianchi type-VII(0) symmetry that are holographically dual to superconducting phases in four spacetime dimensions with a helical p-wave order. We calculate the precise temperature dependence of the pitch of the helical order. At zero temperature the black holes have a vanishing entropy and approach domain wall solutions that reveal homogenous, nonisotropic dual ground states with an emergent scaling symmetry.

  16. Orthotropic hole element

    NASA Technical Reports Server (NTRS)

    Markham, J. W.; Smith, C. V.

    1983-01-01

    A finite element was developed to adequately represent the state of stress in the region around a circular hole in orthotropic material experiencing reasonably general loading. This has been achieved through a complementary virtual work formulation of the stiffness and stress matrices for a square element with a center circular hole. The element has been incorporated into COSMIC/NASTRAN as a dummy element. Sample problems have been solved and these results are presented.

  17. 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.

  18. How Fast Can a Human Run? - Bipedal vs. Quadrupedal Running.

    PubMed

    Kinugasa, Ryuta; Usami, Yoshiyuki

    2016-01-01

    Usain Bolt holds the current world record in the 100-m run, with a running time of 9.58 s, and has been described as the best human sprinter in history. However, this raises questions concerning the maximum human running speed, such as "Can the world's fastest men become faster still?" The correct answer is likely "Yes." We plotted the historical world records for bipedal and quadrupedal 100-m sprint times according to competition year. These historical records were plotted using several curve-fitting procedures. We found that the projected speeds intersected in 2048, when for the first time, the winning quadrupedal 100-m sprint time could be lower, at 9.276 s, than the winning bipedal time of 9.383 s. Video analysis revealed that in quadrupedal running, humans employed a transverse gallop with a small angular excursion. These results suggest that in the future, the fastest human on the planet might be a quadrupedal runner at the 2048 Olympics. This may be achieved by shifting up to the rotary gallop and taking longer strides with wide sagittal trunk motion. PMID:27446911

  19. How Fast Can a Human Run? - Bipedal vs. Quadrupedal Running.

    PubMed

    Kinugasa, Ryuta; Usami, Yoshiyuki

    2016-01-01

    Usain Bolt holds the current world record in the 100-m run, with a running time of 9.58 s, and has been described as the best human sprinter in history. However, this raises questions concerning the maximum human running speed, such as "Can the world's fastest men become faster still?" The correct answer is likely "Yes." We plotted the historical world records for bipedal and quadrupedal 100-m sprint times according to competition year. These historical records were plotted using several curve-fitting procedures. We found that the projected speeds intersected in 2048, when for the first time, the winning quadrupedal 100-m sprint time could be lower, at 9.276 s, than the winning bipedal time of 9.383 s. Video analysis revealed that in quadrupedal running, humans employed a transverse gallop with a small angular excursion. These results suggest that in the future, the fastest human on the planet might be a quadrupedal runner at the 2048 Olympics. This may be achieved by shifting up to the rotary gallop and taking longer strides with wide sagittal trunk motion.

  20. Energetics of bipedal running. II. Limb design and running mechanics.

    PubMed

    Roberts, T J; Chen, M S; Taylor, C R

    1998-10-01

    Compared with quadrupeds, bipedal runners of the same weight have longer legs, take longer steps and can presumably use slower, more economical muscle fibers. One might predict that bipedal running is less expensive, but it is not. We hypothesized that bipeds recruit a larger volume of muscle to support their weight, eliminating the potential economy of longer legs and slower steps. To test our hypothesis, we calculated the relative volume of muscle needed to support body weight over a stride in small dogs (Canis familiaris) and wild turkeys (Meleagris gallopavo) of the same weight. First, we confirmed that turkeys and dogs use approximately the same amount of energy to run at the same speed, and found that turkeys take 1. 8-fold longer steps. Higher muscle forces and/or longer muscle fibers would require a greater volume of active muscle, since muscle volume is proportional to the product of force and fascicle length. We measured both mean fascicle length and mean mechanical advantage for limb extensor muscles. Turkeys generated approximately the same total muscle force to support their weight during running and used muscle fascicles that are on average 2.1 times as long as in dogs, thus requiring a 2.5-fold greater active muscle volume. The greater volume appears to offset the economy of slower rates of force generation, supporting our hypothesis and providing a simple explanation for why it costs the same to run on two and four legs.

  1. 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.

  2. Braneworld Black Holes

    NASA Astrophysics Data System (ADS)

    Whisker, Richard

    2008-10-01

    In this thesis we investigate black holes in the Randall-Sundrum braneworld scenario. We begin with an overview of extra-dimensional physics, from the original proposal of Kaluza and Klein up to the modern braneworld picture of extra dimensions. A detailed description of braneworld gravity is given, with particular emphasis on its compatibility with experimental tests of gravity. We then move on to a discussion of static, spherically symmetric braneworld black hole solutions. Assuming an equation of state for the ``Weyl term'', which encodes the effects of the extra dimension, we are able to classify the general behaviour of these solutions. We then use the strong field limit approach to investigate the gravitational lensing properties of some candidate braneworld black hole solutions. It is found that braneworld black holes could have significantly different observational signatures to the Schwarzschild black hole of standard general relativity. Rotating braneworld black hole solutions are also discussed, and we attempt to generate rotating solutions from known static solutions using the Newman-Janis complexification ``trick''.

  3. Slim-hole casing program adapted to horizontal well

    SciTech Connect

    Foster, L. )

    1993-09-06

    A type of slim-hole well design reduced the cost of drilling a horizontal well in the southern North Sea. The basic slim-hole drilling and casing program was similar to that used in conventional directional wells in the field, but with slight modifications for drilling with logging-while-drilling (LWD) tools and running production liners. Nearly 2,600 ft were successfully drilled at over 80[degree] inclination in ARCO British Ltd.'s Pickerill A6 well, the first time in the southern North Sea that a horizontal well was drilled through the reservoir without first casting off the overlying evaporite sequence. The paper describes the well design, the pilot hole plan, the evaluation program for directional drilling, a horizontal sidetrack plan, its evaluation and drilling, hole conditions, liners, well completion, and results.

  4. High-power slim-hole drilling system

    SciTech Connect

    Cohen, J.H.; Maurer, W.C.; Leitko, C.E.

    1995-12-31

    Economic conditions in the oil and gas industry have encouraged the use of new methods to reduce drilling costs. Slim-hole drilling, abandoned in the past, has found new life because it offers savings by reducing equipment size, tubular products, and environmental impact. A new high-power slim-hole drilling system has been developed that overcomes many of the problems that led to the abandonment of slim holes in the past. This new system is composed of a new high-power positive-displacement motor and new TSP bits developed to run at high horsepowers and produce high drilling rates, The new slim-hole system has the potential for reducing drilling costs by 40 to 60 percent.

  5. Children's Fitness. Managing a Running Program.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott; Tuckman, Bruce W.

    1987-01-01

    A running program to increase the cardiovascular fitness levels of fourth-, fifth-, and sixth-grade children is described. Discussed are the running environment, implementation of a running program, feedback, and reinforcement. (MT)

  6. Apparent horizons in binary black hole spacetimes

    NASA Astrophysics Data System (ADS)

    Shoemaker, Deirdre Marie

    horizon tracker by evolving a binary black hole spacetime in Kerr-Schild coordinates without the horizon tracking; and then using the information from the horizon tracking to run the simulation further. Because of the apparent horizon tracking, the results shown in this dissertation are of the first binary black hole merger in the Grand Challenge Binary Black Hole Coalescence Alliance code. We have taken a significant step forward in the binary black hole merger problem.

  7. 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.

  8. 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.

  9. 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…

  10. 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.

  11. 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.

  12. 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.

  13. Running free: embracing a healthy lifestyle through distance running.

    PubMed

    Shipway, Richard; Holloway, Immy

    2010-11-01

    Sport and leisure activity contribute to both health and quality of life. There is a dearth of qualitative studies on the lived experiences of active people, so the aim of this paper is to develop a deeper understanding of the experiences of one particular group of active leisure participants, distance runners, and to highlight the associated health and well-being benefits that result from participating in this increasingly popular form of active leisure. In doing so, this paper will briefly explore the potential opportunities and implications for sport and leisure policy and provision, and highlight examples of how distance running could positively contribute towards government objectives linked to tackling obesity levels, healthy living and physical well-being. It is suggested that similar benefits also exist across other forms of physical activity, exercise and sport. Qualitative methods of enquiry were adopted to understand the nature of the social world of long distance runners through interviews and observations, which were thematically analyzed. One of the key themes emerging from the data was the desire to embrace a healthy lifestyle, which then led to the emergence of four main sub-themes. The first was linked to the importance of seeking self-esteem and confirmation through running; second, an investigation of a selection of negative aspects associated with exercise addiction; third, the need to exercise among sport and leisure participants; and finally, an understanding of the concept of the 'running body'. Cautionary notes also identified negative aspects associated with exercise and physical activity. The findings highlight the potential role that distance running can play as an easily accessible and enjoyable leisure activity, one that can help facilitate increased participation in exercise and physical activity as an integral part of an active and healthy lifestyle.

  14. 40 CFR 86.341-79 - Diesel engine dynamometer test run.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 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....

  15. 40 CFR 86.341-79 - Diesel engine dynamometer test run.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 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....

  16. 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....

  17. 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....

  18. 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.

  19. Heel-shoe interactions and the durability of EVA foam running-shoe midsoles.

    PubMed

    Verdejo, R; Mills, N J

    2004-09-01

    A finite element analysis (FEA) was made of the stress distribution in the heelpad and a running shoe midsole, using heelpad properties deduced from published force-deflection data, and measured foam properties. The heelpad has a lower initial shear modulus than the foam (100 vs. 1050 kPa), but a higher bulk modulus. The heelpad is more non-linear, with a higher Ogden strain energy function exponent than the foam (30 vs. 4). Measurements of plantar pressure distribution in running shoes confirmed the FEA. The peak plantar pressure increased on average by 100% after 500 km run. Scanning electron microscopy shows that structural damage (wrinkling of faces and some holes) occurred in the foam after 750 km run. Fatigue of the foam reduces heelstrike cushioning, and is a possible cause of running injuries.

  20. Interplanetary magnetic holes: Theory

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Lemaire, J. F.

    1978-01-01

    Magnetic holes in the interplanetary medium are explained as stationary, non-propagating, equilibrium structures in which there are field-aligned enhancements of the plasma density and/or temperature. Magnetic anti-holes are considered to be associated with depressions in the plasma pressure. In this model, the observed changes in the magnetic field intensity and direction are due to diamagnetic currents that are carried by ions which drift in a sheath as the result of gradients in the magnetic field and in the plasma pressure within the sheath. The thickness of the sheaths considered is approximately a few ion Larmor radii. An electric field is normal to the magnetic field in the sheath. Solutions of Vlasov's equation and Maxwell's equations are presented which account for several types of magnetic holes, including null-sheets, that were observed.

  1. 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

  2. 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.

  3. 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.

  4. 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. PMID:25768746

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Growth of Primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Harada, Tomohiro

    Primordial black holes have important observational implications through Hawking evaporation and gravitational radiation as well as being a candidate for cold dark matter. Those black holes are assumed to have formed in the early universe typically with the mass scale contained within the Hubble horizon at the formation epoch and subsequently accreted mass surrounding them. Numerical relativity simulation shows that primordial black holes of different masses do not accrete much, which contrasts with a simplistic Newtonian argument. We see that primordial black holes larger than the 'super-horizon' primordial black holes have decreasing energy and worm-hole like struture, suggesting the formation through quamtum processes.

  11. What Keeps Us on the Run?

    ERIC Educational Resources Information Center

    McCutcheon, Lynn

    Running is a popular form of exercise which people do for different reasons. Competitive runners (N=99) and noncompetitive runners (N=28) responded to a survey of 10 reasons for running by choosing their most important reasons for running. Subjects also indicated their age, sex, how long they had been running, their average weekly mileage, how…

  12. 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)

  13. 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…

  14. 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.

  15. 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.

  16. Infinitely coloured black holes

    NASA Astrophysics Data System (ADS)

    Mavromatos, Nick E.; Winstanley, Elizabeth

    2000-04-01

    We formulate the field equations for SU (icons/Journals/Common/infty" ALT="infty" ALIGN="TOP"/> ) Einstein-Yang-Mills theory, and use an analytic approximation to elucidate the properties of spherically symmetric black hole solutions. This model may be motivated by string theory considerations, given the enormous gauge symmetries which characterize string theory. The solutions simplify considerably in the presence of a negative cosmological constant, particularly for the limiting cases of a very large cosmological constant or very small gauge field. The black holes possess infinite amounts of gauge field hair, and we speculate on possible consequences of this for quantum decoherence, which, however, we do not tackle here.

  17. 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.

  18. 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.

  19. 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.

  20. Black-hole-scalar-field interactions in spherical symmetry

    NASA Astrophysics Data System (ADS)

    Marsa, R. L.; Choptuik, M. W.

    1996-10-01

    We examine the interactions of a black hole with a massless scalar field using a coordinate system which extends ingoing Eddington-Finkelstein coordinates to dynamic spherically-symmetric spacetimes. We avoid problems with the singularity by excising the region of the black-hole interior to the apparent horizon. We use a second-order finite difference scheme to solve the equations. The resulting program is stable and convergent and will run forever without problems. We are able to observe quasinormal ringing and power-law tails as well as an interesting nonlinear feature.

  1. Slim-hole Measurement While Drilling (MWD) system for underbalanced drilling

    SciTech Connect

    Harrison, W.H.; Harrison, J.D.; Rubin, L.A.

    1995-08-01

    The objective of this program is to make commercially available, wireless Measurement-while-drilling tools to reliably operate in air, air-mist, air-foam, and other unbalanced drilling environments during oil and gas directional drilling operations in conjunction with down-hole motors or other assemblies. Progress is described.

  2. Tunnelling from black holes and tunnelling into white holes

    NASA Astrophysics Data System (ADS)

    Chatterjee, Bhramar; Ghosh, A.; Mitra, P.

    2008-03-01

    Hawking radiation is nowadays being understood as tunnelling through black hole horizons. Here, the extension of the Hamilton-Jacobi approach to tunnelling for non-rotating and rotating black holes in different non-singular coordinate systems not only confirms this quantum emission from black holes but also reveals the new phenomenon of absorption into white holes by quantum mechanical tunnelling. The rôle of a boundary condition of total absorption or emission is also clarified.

  3. 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.

  4. 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.

  5. 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.

  6. Hot-hole photodetectors

    NASA Astrophysics Data System (ADS)

    2014-05-01

    By injecting high-energy charge carriers (dubbed 'hot holes') into a semiconductor, scientists have succeeded in realizing photodetectors capable of detecting ultralong wavelengths. Unil Perera from Georgia State University in the USA explains how the devices work and how they can be improved.

  7. 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)

  8. Laser bottom hole assembly

    DOEpatents

    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.

  9. Moulting Black Holes

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; Chowdhury, Borun D.; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2012-03-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no black holes were thought to exist.

  10. 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.

  11. "Holes": Folklore Redux.

    ERIC Educational Resources Information Center

    Mascia, Elizabeth G.

    2001-01-01

    Demonstrates that a careful reading of the book for young adults, "Holes" by Louis Sachar, reveals how this contemporary story is grounded in folklore, and that it is this debt to folk literature that allows readers to accept an improbable plot. Shows how the story weaves together elements from traditional folk literature and stretches them across…

  12. Roof bolt hole groover

    SciTech Connect

    Not Available

    1985-11-05

    A hole groover comprising a pair of grooving bits radially protruding from the surface of a drill rod and connected to swivel upwardly and downwardly near the end of the drill rod where the drill bit is connected. A connecting rod is connected to the inside ends of the groove bits and causes arcuate movement of the grooving bits as it reciprocates. The hole groover further includes a gear box which is connectable to a rotary drilling unit which converts rotational movement of the rotary drill until to reciprocating movement of a lever. The lever is connected to the connecting rod which causes movement of the grooving bits. The device is readily adaptable to be connected to most rotary drill units and the depth and intervals of the grooves can be easily controlled by adjusting the length of the grooving bits and the gear ratios. The device enables grooves to be cut in a wall hole surface, concurrently with the drilling of the hole.

  13. 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.

  14. Run and tumble, run and reverse, or run reverse and flick - who wins the chemotaxis race?

    NASA Astrophysics Data System (ADS)

    Zaburdaev, Vasily; Denisov, Sergey; Weitz, David

    2012-02-01

    Run and tumble of E.coli bacteria is a well understood example of the stochastic cell motion that is alternated in the presence of signaling chemicals. By regulating the tumbling frequency bacteria are able to navigate toward the food sources. Another bacteria that use twitching to move on a surface, M. xanthus, utilize a different strategy - at the end of the run they completely reverse the direction of motion and continue moving in the opposite direction. The frequency of reversals was shown to be connected to the chemotactic response of the cell. Recently yet another pattern was discovered in marine bacteria V. alginolyticus which alternate sharp reversals with flicks -- making a turn to an angle with a broad distribution and centered around 90 degrees. In this work we are presenting a theoretical framework that describes all above motion patterns. As a highlight of the developed approach we find the exact analytical expressions for the mean squared displacement of moving cells for arbitrary distribution of run times. That allows us to quantitatively compare the performance of bacteria exploring the environment with and without signaling chemicals and, therefore, to find the winner of the chemotactic race.

  15. Slowly balding black holes

    NASA Astrophysics Data System (ADS)

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-01

    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 NB=eΦ∞/(πcℏ), where Φ∞≈2π2BNSRNS3/(PNSc) 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.

  16. Global impact of the Antarctic ozone hole - Chemical propagation

    NASA Technical Reports Server (NTRS)

    Prather, Michael; Jaffe, Andrew H.

    1990-01-01

    A model is presented for the chemical mixing of stratospheric air, that combines photochemistry, molecular diffusion, and strain (i.e., the stretching of air parcels due to wind shear). The model is applied to the case in which chemically perturbed air parcels from the Antarctic stratosphere are transported to mid-latidudes and strained into thin ribbon-like filaments until they are diffusively mixed with the ambient stratosphere. Results show that, following the breakup of the polar vortex, Antarctic air with substantially depleted ozone will not contribute any additional ozone loss at mid-latitudes as it is mixed with ambient air, supporting the results of simulations of the Antarctic ozone hole by Prather et al. (1990). Nevertheless, air processed by polar stratospheric clouds but transported to mid-latitudes before substantive ozone depletion, can lead to additional loss after mixing with ambient air.

  17. Variable Joint Elasticities in Running

    NASA Astrophysics Data System (ADS)

    Peter, Stephan; Grimmer, Sten; Lipfert, Susanne W.; Seyfarth, Andre

    In this paper we investigate how spring-like leg behavior in human running is represented at joint level. We assume linear torsion springs in the joints and between the knee and the ankle joint. Using experimental data of the leg dynamics we compute how the spring parameters (stiffness and rest angles) change during gait cycle. We found that during contact the joints reveal elasticity with strongly changing parameters and compare the changes of different parameters for different spring arrangements. The results may help to design and improve biologically inspired spring mechanisms with adjustable parameters.

  18. 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. PMID:27456477

  19. 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

  20. 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

  1. 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

  2. Effect of Minimalist Footwear on Running Efficiency

    PubMed Central

    Gillinov, Stephen M.; Laux, Sara; Kuivila, Thomas; Hass, Daniel; Joy, Susan M.

    2015-01-01

    Background: Although minimalist footwear is increasingly popular among runners, claims that minimalist footwear enhances running biomechanics and efficiency are controversial. Hypothesis: Minimalist and barefoot conditions improve running efficiency when compared with traditional running shoes. Study Design: Randomized crossover trial. Level of Evidence: Level 3. Methods: Fifteen experienced runners each completed three 90-second running trials on a treadmill, each trial performed in a different type of footwear: traditional running shoes with a heavily cushioned heel, minimalist running shoes with minimal heel cushioning, and barefoot (socked). High-speed photography was used to determine foot strike, ground contact time, knee angle, and stride cadence with each footwear type. Results: Runners had more rearfoot strikes in traditional shoes (87%) compared with minimalist shoes (67%) and socked (40%) (P = 0.03). Ground contact time was longest in traditional shoes (265.9 ± 10.9 ms) when compared with minimalist shoes (253.4 ± 11.2 ms) and socked (250.6 ± 16.2 ms) (P = 0.005). There was no difference between groups with respect to knee angle (P = 0.37) or stride cadence (P = 0.20). When comparing running socked to running with minimalist running shoes, there were no differences in measures of running efficiency. Conclusion: When compared with running in traditional, cushioned shoes, both barefoot (socked) running and minimalist running shoes produce greater running efficiency in some experienced runners, with a greater tendency toward a midfoot or forefoot strike and a shorter ground contact time. Minimalist shoes closely approximate socked running in the 4 measurements performed. Clinical Relevance: With regard to running efficiency and biomechanics, in some runners, barefoot (socked) and minimalist footwear are preferable to traditional running shoes. PMID:26131304

  3. Effective-one-body modeling of precessing black hole binaries

    NASA Astrophysics Data System (ADS)

    Taracchini, Andrea; Babak, Stanislav; Buonanno, Alessandra

    2016-03-01

    Merging black hole binaries with generic spins that undergo precessional motion emit complicated gravitational-wave signals. We discuss how such waveforms can be accurately modeled within an effective-one-body approach by (i) exploiting the simplicity of the signals in a frame that corotates with the orbital plane of the binary and (ii) relying on an accurate model of nonprecessing black hole binaries. The model is validated by extensive comparisons to 70 numerical relativity simulations of precessing black hole binaries and can generate inspiral-merger-ringdown waveforms for mass ratios up to 100 and any spin configuration. This work is an essential tool for studying and characterizing candidate gravitational-wave events in science runs of advanced LIGO.

  4. Interplanetary magnetic holes - Theory

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Lemaire, J. F.

    1978-01-01

    Magnetic holes in the interplanetary medium are explained as stationary nonpropagating equilibrium structures in which there are field-aligned enhancements of the plasma density and/or temperature. Magnetic antiholes are considered to be associated with depressions in the plasma pressure. In this model the observed changes in the magnetic field intensity and direction are due to diamagnetic currents that are carried by ions which drift in a sheath as the result of gradients in the magnetic field and in the plasma pressure within the sheath. The thickness of the sheaths that we consider is approximately a few ion Larmor radii. An electric field is normal to the magnetic field in the sheath. Solutions of Vlasov's equation and Maxwell's equations are presented which account for several types of magnetic holes, including 'null sheets,' that have been observed.

  5. 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.

  6. 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.

  7. 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)

  8. 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.

  9. BLACK HOLE AURORA POWERED BY A ROTATING BLACK HOLE

    SciTech Connect

    Takahashi, Masaaki; Takahashi, Rohta

    2010-05-15

    We present a model for high-energy emission sources generated by a standing magnetohydrodynamical (MHD) shock in a black hole magnetosphere. The black hole magnetosphere would be constructed around a black hole with an accretion disk, where a global magnetic field could be originated by currents in the accretion disk and its corona. Such a black hole magnetosphere may be considered as a model for the central engine of active galactic nuclei, some compact X-ray sources, and gamma-ray bursts. The energy sources of the emission from the magnetosphere are the gravitational and electromagnetic energies of magnetized accreting matters and the rotational energy of a rotating black hole. When the MHD shock generates in MHD accretion flows onto the black hole, the plasma's kinetic energy and the black hole's rotational energy can convert to radiative energy. In this Letter, we demonstrate the huge energy output at the shock front by showing negative energy postshock accreting MHD flows for a rapidly rotating black hole. This means that the extracted energy from the black hole can convert to the radiative energy at the MHD shock front. When an axisymmetric shock front is formed, we expect a ring-shaped region with very hot plasma near the black hole; this would look like an 'aurora'. The high-energy radiation generated from there would carry to us the information for the curved spacetime due to the strong gravity.

  10. 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.

  11. Diphoton excess and running couplings

    NASA Astrophysics Data System (ADS)

    Bae, Kyu Jung; Endo, Motoi; Hamaguchi, Koichi; Moroi, Takeo

    2016-06-01

    The recently observed diphoton excess at the LHC may suggest the existence of a singlet (pseudo-)scalar particle with a mass of 750 GeV which couples to gluons and photons. Assuming that the couplings to gluons and photons originate from loops of fermions and/or scalars charged under the Standard Model gauge groups, we show that there is a model-independent upper bound on the cross section σ (pp → S → γγ) as a function of the cutoff scale Λ and masses of the fermions and scalars in the loop. Such a bound comes from the fact that the contribution of each particle to the diphoton event amplitude is proportional to its contribution to the one-loop β functions of the gauge couplings. We also investigate the perturbativity of running Yukawa couplings in models with fermion loops, and show the upper bounds on σ (pp → S → γγ) for explicit models.

  12. Tissue vibration in prolonged running.

    PubMed

    Friesenbichler, Bernd; Stirling, Lisa M; Federolf, Peter; Nigg, Benno M

    2011-01-01

    The impact force in heel-toe running initiates vibrations of soft-tissue compartments of the leg that are heavily dampened by muscle activity. This study investigated if the damping and frequency of these soft-tissue vibrations are affected by fatigue, which was categorized by the time into an exhaustive exercise. The hypotheses were tested that (H1) the vibration intensity of the triceps surae increases with increasing fatigue and (H2) the vibration frequency of the triceps surae decreases with increasing fatigue. Tissue vibrations of the triceps surae were measured with tri-axial accelerometers in 10 subjects during a run towards exhaustion. The frequency content was quantified with power spectra and wavelet analysis. Maxima of local vibration intensities were compared between the non-fatigued and fatigued states of all subjects. In axial (i.e. parallel to the tibia) and medio-lateral direction, most local maxima increased with fatigue (supporting the first hypothesis). In anterior-posterior direction no systematic changes were found. Vibration frequency was minimally affected by fatigue and frequency changes did not occur systematically, which requires the rejection of the second hypothesis. Relative to heel-strike, the maximum vibration intensity occurred significantly later in the fatigued condition in all three directions. With fatigue, the soft tissue of the triceps surae oscillated for an extended duration at increased vibration magnitudes, possibly due to the effects of fatigue on type II muscle fibers. Thus, the protective mechanism of muscle tuning seems to be reduced in a fatigued muscle and the risk of potential harm to the tissue may increase. PMID:20846656

  13. 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…

  14. 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…

  15. 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 ...

  16. 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.

  17. Measurement of the temperature field downstream of simulated leading-edge film-cooling holes

    NASA Astrophysics Data System (ADS)

    Mee, D. J.; Ireland, P. T.; Bather, S.

    Experiments to measure the temperature field downstream of simulated leading-edge-region film-cooling holes were performed in an 11 m/s wind tunnel flow. Heated air was passed to a hollow 140 mm diameter cylinder in which three 10.5 mm diameter, spanwise-inclined, film-cooling holes had been machined. A fine nylon mesh, coated with encapsulated thermochromic liquid crystals, was used to measure temperature contours downstream of the holes by moving the mesh relative to the holes and adjusting the power to the air heater. The measurements indicate the extent of the lateral spreading of the coolant gas and show the influence of hole location and coolant mass flow rate on film trajectory and spreading.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  8. 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. PMID:25073137

  9. 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

  10. f(R) Black Holes as Heat Engines

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Liu, Wen-Biao

    2016-08-01

    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 ΔV ≪ ΔP, 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.

  11. Hole drilling with fiber-optically delivered visible lasers

    SciTech Connect

    Kautz, D.D.; Berzins, L.V.; Dragon, E.P.

    1994-12-31

    The use of lasers for high-speed drilling of holes in materials is well documented. To allow easier use of lasers in manufacturing processes, fiber-optically delivered beams are preferable to the use of conventional optics. Lawrence Livermore National Laboratory (LLNL) has adapted fiber-optic technology to its visible light, copper vapor lasers for use in hole drilling studies. Visible lasers afford better coupling of light to the workpiece and when fiber-optically delivered, allow high quality holes to be drilled in difficult accessibility areas and with easier setup. A fiber-optic delivery system was attached to the presently hard-optic copper vapor laser system. This system consisted of a 0.6 mm (0.024 in.) fiber that was then telescoped and refocused by a hard optics package at the workstation end of the fiber. The optics package produced a 0.2 mm (0.008 in.) focused spot size at the workpiece. This system was then run down to a 3-axis CNC machining table to allow part movement for these studies. The fiber-optically delivered light was found to work extremely well for drilling small diameter holes. In summary, it was found that fiber-optically delivered, visible laser beams have several advantages in drilling over those same beams delivered through conventional hard optics. These include much easier setup, reduced system maintenance, and typically higher hole quality.

  12. 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.

  13. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running.

    PubMed

    Jones, A M; Doust, J H

    1996-08-01

    When running indoors on a treadmill, the lack of air resistance results in a lower energy cost compared with running outdoors at the same velocity. A slight incline of the treadmill gradient can be used to increase the energy cost in compensation. The aim of this study was to determine the treadmill gradient that most accurately reflects the energy cost of outdoor running. Nine trained male runners, thoroughly habituated to treadmill running, ran for 6 min at six different velocities (2.92, 3.33, 3.75, 4.17, 4.58 and 5.0 m s-1) with 6 min recovery between runs. This routine was repeated six times, five times on a treadmill set at different grades (0%, 0%, 1%, 2%, 3%) and once outdoors along a level road. Duplicate collections of expired air were taken during the final 2 min of each run to determine oxygen consumption. The repeatability of the methodology was confirmed by high correlations (r = 0.99) and non-significant differences between the duplicate expired air collections and between the repeated runs at 0% grade. The relationship between oxygen uptake (VO2) and velocity for each grade was highly linear (r > 0.99). At the two lowest velocities, VO2 during road running was not significantly different from treadmill running at 0% or 1% grade, but was significantly less than 2% and 3% grade. For 3.75 m s-1, the VO2 during road running was significantly different from treadmill running at 0%, 2% and 3% grades but not from 1% grade. For 4.17 and 4.58 m s-1, the VO2 during road running was not significantly different from that at 1% or 2% grade but was significantly greater than 0% grade and significantly less than 3% grade. At 5.0 m s-1, the VO2 for road running fell between the VO2 value for 1% and 2% grade treadmill running but was not significantly different from any of the treadmill grade conditions. This study demonstrates equality of the energetic cost of treadmill and outdoor running with the use of a 1% treadmill grade over a duration of approximately 5 min

  14. Ultrarelativistic black hole formation.

    PubMed

    East, William E; Pretorius, Frans

    2013-03-01

    We study the head-on collision of fluid particles well within the kinetic energy dominated regime (γ = 8 to 12) by numerically solving the Einstein-hydrodynamic equations. We find that the threshold for black hole formation is lower (by a factor of a few) than simple hoop conjecture estimates, and, moreover, near this threshold two distinct apparent horizons first form postcollision and then merge. We argue that this can be understood in terms of a gravitational focusing effect. The gravitational radiation reaches luminosities of 0.014 c(5)/G, carrying 16 ± 2% of the total energy.

  15. 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

  16. 40 CFR 258.26 - Run-on/run-off control systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Run-on/run-off control systems. 258.26 Section 258.26 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.26 Run-on/run-off control systems....

  17. Dynamical moving mirrors and black holes

    NASA Astrophysics Data System (ADS)

    Chung, Tze-Dan; Verlinde, Herman

    1994-04-01

    A simple quantum mechanical model of N free scalar fields interacting with a dynamical moving mirror is formulated and shown to be equivalent to two-dimensional dilaton gravity. We derive the semi-classical dynamics of this system, by including the back reaction due to the quantum radiation. We develop a hamiltonian formalism that describes the time evolution as seen by an asymptotic observer, and write a scattering equation that relates the in-falling and out-going modes at low energies. At higher incoming energy flux, however, the semi-classical model appears to become unstable and the mirror seems to accelerate forever along a trajectory that runs off to infinity. This instability provides a useful paradigm for black hole formation and introduces an analogous information paradox. Finally, we indicate a possible mechanism that may restore the stability of the system at the quantum level without destroying quantum coherence.

  18. Dynamical moving mirrors and black holes.

    NASA Astrophysics Data System (ADS)

    Tzedan, Chung; Verlinde, H.

    1994-04-01

    A simple quantum mechanical model of N free scalar fields interacting with a dynamical moving mirror is formulated and shown to be equivalent to two-dimensional dilaton gravity. The authors derive the semi-classical dynamics of this system, by including the back reaction due to the quantum radiation. They develop a hamiltonian formalism that describes the time evolution as seen by an asymptotic observer, and write a scattering equation that relates the in-falling and out-going modes at low energies. At higher incoming energy flux, however, the semi-classical model appears to become unstable and the mirror seems to accelerate forever along a trajectory that runs off to infinity. This instability provides a useful paradigm for black hole formation and introduces an analogous information paradox.

  19. 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.

  20. Acceleration of black hole universe

    NASA Astrophysics Data System (ADS)

    Zhang, T. X.; Frederick, C.

    2014-01-01

    Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

  1. Black holes as antimatter factories

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Dolgov, Alexander D.; Petrov, Alexey A.

    2009-09-01

    We consider accretion of matter onto a low mass black hole surrounded by ionized medium. We show that, because of the higher mobility of protons than electrons, the black hole would acquire positive electric charge. If the black hole's mass is about or below 1020 g, the electric field at the horizon can reach the critical value which leads to vacuum instability and electron-positron pair production by the Schwinger mechanism. Since the positrons are ejected by the emergent electric field, while electrons are back-captured, the black hole operates as an antimatter factory which effectively converts protons into positrons.

  2. Black holes and the multiverse

    NASA Astrophysics Data System (ADS)

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

    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.

  3. 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.

  4. String duality and black holes

    NASA Astrophysics Data System (ADS)

    Kalara, S.; Nanopoulos, D. V.

    1991-09-01

    In the context of (semi) classical general relativity, the physics of black holes poses many unanswered and unsettling questions. Notable among them are the loss of quantum coherence, which casts doubts on the basic foundations of quantum mechanics, and the understanding of the enormous entropy carried by black holes which is at odds with strong ``no hair'' theorems. We point out that in string theory, black-hole type solutions (S-black holes) carry local discrete charges inherited from the duality symmetries of the string, which allow S-black holes to carry ``quantum hair''. It is further noted that the conservation of the discrete charges and the presence of quantum hair precludes the information about a quantum state from being completely lost in the black hole thus rescuing quantum coherence. We also note that a large number of quantum hair carried by S-black holes may explain their enormous entropy, i.e. it is the duality symmetry of the string theory which redeems outstanding problems of black-hole dynamics. We also discuss a possible description of black holes as solitons of string theory. Supported in part by DOE Grant DE-AS05-81 ER40039.

  5. Can Black Hole Relax Unitarily?

    NASA Astrophysics Data System (ADS)

    Solodukhin, S. N.

    2005-03-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  6. 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.

  7. 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.

  8. 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. PMID:26837933

  9. 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.

  10. Rectal temperature after marathon running.

    PubMed Central

    Maughan, R J; Leiper, J B; Thompson, J

    1985-01-01

    Rectal temperature was measured in 62 male runners who competed in the 1983 Dundee marathon race: all measurements were made immediately after the race. Competitors' times were noted at 5, 10, 15 and 20 miles (8.0, 16.1, 24.1, 32.2 km) and at the finish (26.2 miles, 42.2 km). Mean finishing time of the group was 3 hr 33 min +/- 48 min (mean +/- S.D.; range = 2 hr 17 min-5 hr 11 min). Mean running speed of the group decreased progressively as the distance covered increased. Mean post-race rectal temperature was 38.7 +/- 0.9 degrees C (range 35.6-40.3 degrees C). The post-race temperature was correlated (p less than 0.01) with the time taken to cover the last 6.2 miles (10 km) of the race, but not with the overall finishing time (p greater than 0.05). Only the fastest runners were able to maintain an approximately constant pace throughout the race, whereas the slower runners slowed down progressively. The runners with the highest post-race temperature, although not necessarily the fastest runners, also tended to maintain a steady pace throughout. The runners with the lowest post-race temperature slowed down markedly only over the last 6.2 mile section of the race. The results clearly indicate that runners forced by fatigue or injury to slow down in the latter stages of races held at low ambient temperatures may already be hypothermic or at serious risk of hypothermia. Images p192-a p192-b p192-c PMID:4092138

  11. Running characteristics of the magnetically levitated train in a curved track section

    SciTech Connect

    Ohashi, S.; Ohsaki, H.; Masada, E.

    1997-09-01

    A three-dimensional running simulation program of the train motion which includes both electromagnetic and mechanical systems has been developed. For verification of running stability, the motion of the Maglev train with four bogies and three cars running into the curved section was calculated. Because the spring strength of the secondary suspension between bogies and cabins was much smaller than that of the electrodynamic suspension, interaction among bogies was small. The lateral displacement reached 0.045m, which is about 50% of the lateral air gap. Therefore train can run without touching the wall of the guideway. As this lateral air gap caused roll torque, total roll angle of the bogie became 12.5% larger than the cant angle of the curved section.

  12. Running sprint interval training induces fat loss in women.

    PubMed

    Hazell, Tom J; Hamilton, Craig D; Olver, T Dylan; Lemon, Peter W R

    2014-08-01

    Data on whether sprint interval training (SIT) (repeated supermaximal intensity, short-duration exercise) affects body composition are limited, and the data that are available suggest that men respond more favourably than do women. Moreover, most SIT data involve cycling exercise, and running may differ because of the larger muscle mass involved. Further, running is a more universal exercise type. This study assessed whether running SIT can alter body composition (air displacement plethysmography), waist circumference, maximal oxygen consumption, peak running speed, and (or) the blood lipid profile. Fifteen recreationally active women (age, 22.9 ± 3.6 years; height, 163.9 ± 5.1 cm; mass, 60.8 ± 5.2 kg) completed 6 weeks of running SIT (4 to 6, 30-s "all-out" sprints on a self-propelled treadmill separated by 4 min of rest performed 3 times per week). Training decreased body fat mass by 8.0% (15.1 ± 3.6 to 13.9 ± 3.4 kg, P = 0.002) and waist circumference by 3.5% (80.1 ± 4.2 to 77.3 ± 4.4 cm, P = 0.048), whereas it increased fat-free mass by 1.3% (45.7 ± 3.5 to 46.3 ± 2.9 kg, P = 0.05), maximal oxygen consumption by 8.7% (46 ± 5 to 50 ± 6 mL/(kg·min), P = 0.004), and peak running speed by 4.8% (16.6 ± 1.7 to 17.4 ± 1.4 km/h, P = 0.026). There were no differences in food intake assessed by 3-day food records (P > 0.329) or in blood lipids (P > 0.595), except for a slight decrease in high-density lipoprotein concentration (1.34 ± 0.28 to 1.24 ± 0.24 mmol/L, P = 0.034). Running SIT is a time-efficient strategy for decreasing body fat while increasing aerobic capacity, peak running speed, and fat-free mass in healthy young women.

  13. Computing Thermodynamic And Transport Properties Of Air

    NASA Technical Reports Server (NTRS)

    Thompson, Richard A.; Gupta, Roop N.; Lee, Kam-Pui

    1994-01-01

    EQAIRS computer program is set of FORTRAN 77 routines for computing thermodynamic and transport properties of equilibrium air for temperatures from 100 to 30,000 K. Computes properties from 11-species, curve-fit mathematical model. Successfully implemented on DEC VAX-series computer running VMS, Sun4-series computer running SunOS, and IBM PC-compatible computer running MS-DOS.

  14. 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.

  15. 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. PMID:15549097

  16. On the water lapping of felines and the water running of lizards: A unifying physical perspective.

    PubMed

    Aristoff, Jeffrey M; Stocker, Roman; Reis, Pedro M; Jung, Sunghwan

    2011-03-01

    We consider two biological phenomena taking place at the air-water interface: the water lapping of felines and the water running of lizards. Although seemingly disparate motions, we show that they are intimately linked by their underlying hydrodynamics and belong to a broader class of processes called Froude mechanisms. We describe how both felines and lizards exploit inertia to defeat gravity, and discuss water lapping and water running in the broader context of water exit and water entry, respectively.

  17. 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

  18. Running spectral index from inflation with modulations

    SciTech Connect

    Kobayashi, Takeshi; Takahashi, Fuminobu E-mail: fuminobu.takahashi@ipmu.jp

    2011-01-01

    We argue that a large negative running spectral index, if confirmed, might suggest that there are abundant structures in the inflaton potential, which result in a fairly large (both positive and negative) running of the spectral index at all scales. It is shown that the center value of the running spectral index suggested by the recent CMB data can be easily explained by an inflaton potential with superimposed periodic oscillations. In contrast to cases with constant running, the perturbation spectrum is enhanced at small scales, due to the repeated modulations. We mention that such features at small scales may be seen by 21 cm observations in the future.

  19. Physiological correlates to 800 meter running performance.

    PubMed

    Deason, J; Powers, S K; Lawler, J; Ayers, D; Stuart, M K

    1991-12-01

    Much of the previous research efforts aimed at determining those physiological characteristics that contribute to distance running success have centered around distances greater than 1500 meters with little attention to events such as the 800 meter run. Therefore, this investigation examined the relationship between selected physiological and body composition, characteristics and performance in an 800 meter run. Measurements of body composition, VO2max, running economy, and performance times for 100 and 300 meter dashes were obtained on 11 male track athletes. Stepwise multiple regression analysis was performed using 800 meter race time as the dependent variable. Although the combination of 300 and 100 meter run times, percent body fat, running economy and VO2 max as independent variables accounted for the greatest amount of total variance (r2 = .89), the additional variance explained by the model did not increase significantly (p greater than 0.05), when VO2max, percent body fat, and running economy were added to a model which contained 300 and 100 meter run time (r2 = .85) as the explanatory variables. These data offer additional support for the notion that much of the intramuscular ATP produce and utilized during an 800 meter run comes from anaerobic metabolic pathway.

  20. Tool For Making Curved Holes

    NASA Technical Reports Server (NTRS)

    Allard, Robert; Calve, Andrew; Pastreck, Edwin; Padden, Edward

    1992-01-01

    Tool for use in electrical-discharge machining (EDM) guides EDM electrode in making curved holes. Guide rod fits in slot in arm, which moves through arc. Motion drives electrode into workpiece along desired curved path. Electrode burns into workpiece while arm rotates on spindle. Discharge cuts hole of same radius of curvature.

  1. Distorted stationary rotating black holes

    NASA Astrophysics Data System (ADS)

    Shoom, Andrey A.

    2015-03-01

    We study the interior of distorted stationary rotating black holes on the example of a Kerr black hole distorted by external static and axisymmetric mass distribution. We show that there is a duality transformation between the outer and inner horizons of the black hole, which is different from that of an electrically charged static distorted black hole. The duality transformation is directly related to the discrete symmetry of the space-time. The black hole horizon areas, surface gravity, and angular momentum satisfy the Smarr formula constructed for both the horizons. We formulate the zeroth, the first, and the second laws of black hole thermodynamics for both the horizons of the black hole and show the correspondence between the local and the global forms of the first law. The Smarr formula and the laws of thermodynamics formulated for both the horizons are related by the duality transformation. The distortion is illustrated on the example of a quadrupole and octupole fields. The distortion fields noticeably affect the proper time of a free fall from the outer to the inner horizon of the black hole along the symmetry semiaxes. There is some minimal nonzero value of the quadrupole and octupole moments when the time becomes minimal. The minimal proper time indicates the closest approach of the horizons due to the distortion.

  2. Thermodynamic Curvature and Black Holes

    NASA Astrophysics Data System (ADS)

    Ruppeiner, George

    In my talk, I will discuss black hole thermodynamics, particularly what happens when you add thermodynamic curvature to the mix. Although black hole thermodynamics is a little off the main theme of this workshop, I hope nevertheless that my message will be of some interest to researchers in supersymmetry and supergravity.

  3. Air Abrasion

    MedlinePlus

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  4. 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.

  5. 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

  6. 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...

  7. Fear of holes.

    PubMed

    Cole, Geoff G; Wilkins, Arnold J

    2013-10-01

    Phobias are usually described as irrational and persistent fears of certain objects or situations, and causes of such fears are difficult to identify. We describe an unusual but common phobia (trypophobia), hitherto unreported in the scientific literature, in which sufferers are averse to images of holes. We performed a spectral analysis on a variety of images that induce trypophobia and found that the stimuli had a spectral composition typically associated with uncomfortable visual images, namely, high-contrast energy at midrange spatial frequencies. Critically, we found that a range of potentially dangerous animals also possess this spectral characteristic. We argue that although sufferers are not conscious of the association, the phobia arises in part because the inducing stimuli share basic visual characteristics with dangerous organisms, characteristics that are low level and easily computed, and therefore facilitate a rapid nonconscious response.

  8. 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.

  9. Digesting the doughnut hole.

    PubMed

    Joyce, Geoffrey F; Zissimopoulos, Julie; Goldman, Dana P

    2013-12-01

    Despite its success, Medicare Part D has been widely criticized for the gap in coverage, the so-called "doughnut hole". We compare the use of prescription drugs among beneficiaries subject to the coverage gap with usage among beneficiaries who are not exposed to it. We find that the coverage gap does, indeed, disrupt the use of prescription drugs among seniors with diabetes. But the declines in usage are modest and concentrated among higher cost, brand-name medications. Demand for high cost medications such as antipsychotics, antiasthmatics, and drugs of the central nervous system decline by 8-18% in the coverage gap, while use of lower cost medications with high generic penetration such as beta blockers, ACE inhibitors and antidepressants decline by 3-5% after reaching the gap. More importantly, lower adherence to medications is not associated with increases in medical service use. PMID:24308883

  10. 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. PMID:21719676

  11. Formation and Spread of Aircraft-Induced Holes in Clouds

    NASA Astrophysics Data System (ADS)

    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.

  12. 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.

  13. Interagency cooperative scientific program to investigate antarctic ozone hole

    SciTech Connect

    Not Available

    1987-09-01

    NASA, The Department of Commerce National Oceanic and Atmospheric Administration, the National Science Foundation and its National Center for Atmospheric Research, and the Chemical Manufacturer's Association have announced a cooperative investigation of the Antarctic ozone hole. The Airborne Antarctic Ozone Experiment will fly specially instrumented NASA ER-2 and DC-8 aircraft into the Antarctic ozone hole from August 17 through September 29. The experiments have been designed not only to test existing Antarctic ozone hole theories but to provide for a wide base of high quality atmospheric data in the event that none of the current hypotheses proves to be adequate. This experiment is prompted by recent observations that have shown a dramatic and unexpected downward trend in the amount of ozone in a column of air over the Antarctic in the period between late winter and early spring.

  14. 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…

  15. 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.

  16. 40 CFR 92.126 - Test run.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... acquisition is terminated prematurely; or (B) For engine testing, the engine speed or power output exceeds the... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Test run. 92.126 Section 92.126... POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.126 Test run. (a) The following...

  17. 40 CFR 92.126 - Test run.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... acquisition is terminated prematurely; or (B) For engine testing, the engine speed or power output exceeds the... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Test run. 92.126 Section 92.126... POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.126 Test run. (a) The following...

  18. 40 CFR 92.126 - Test run.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... acquisition is terminated prematurely; or (B) For engine testing, the engine speed or power output exceeds the... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Test run. 92.126 Section 92.126... POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.126 Test run. (a) The following...

  19. 40 CFR 92.126 - Test run.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... acquisition is terminated prematurely; or (B) For engine testing, the engine speed or power output exceeds the... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Test run. 92.126 Section 92.126... POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.126 Test run. (a) The following...

  20. 40 CFR 92.126 - Test run.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... acquisition is terminated prematurely; or (B) For engine testing, the engine speed or power output exceeds the... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Test run. 92.126 Section 92.126... POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.126 Test run. (a) The following...

  1. 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)

  2. 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…

  3. 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…

  4. 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…

  5. 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…

  6. 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,…

  7. First Run II results from CDF

    SciTech Connect

    S. Donati

    2002-06-04

    In this paper we report on the first run II results from the CDF experiment. A brief description of the Tevatron collider and CDF detector upgrades and performance achieved in the first part of run II is followed by the CDF expectations in the fields of beauty, top, electroweak and Higgs physics.

  8. EnergyPlus Run Time Analysis

    SciTech Connect

    Hong, Tianzhen; Buhl, Fred; Haves, Philip

    2008-09-20

    EnergyPlus is a new generation building performance simulation program offering many new modeling capabilities and more accurate performance calculations integrating building components in sub-hourly time steps. However, EnergyPlus runs much slower than the current generation simulation programs. This has become a major barrier to its widespread adoption by the industry. This paper analyzed EnergyPlus run time from comprehensive perspectives to identify key issues and challenges of speeding up EnergyPlus: studying the historical trends of EnergyPlus run time based on the advancement of computers and code improvements to EnergyPlus, comparing EnergyPlus with DOE-2 to understand and quantify the run time differences, identifying key simulation settings and model features that have significant impacts on run time, and performing code profiling to identify which EnergyPlus subroutines consume the most amount of run time. This paper provides recommendations to improve EnergyPlus run time from the modeler?s perspective and adequate computing platforms. Suggestions of software code and architecture changes to improve EnergyPlus run time based on the code profiling results are also discussed.

  9. Alternative methods of normalising EMG during running.

    PubMed

    Albertus-Kajee, Yumna; Tucker, Ross; Derman, Wayne; Lamberts, Robert P; Lambert, Michael I

    2011-08-01

    We evaluated possible methods of normalising EMG measured during running. MVC, Sprint and 70% Peak Running Speed methods were evaluated and their repeatability, reliability and sensitivity to incremental running speed were compared. Twelve runners performed the same experimental protocol on three separate occasions. Each day, subjects firstly performed MVCs, followed by a 20 m maximal sprint (with a 20-30 m run-up). Following this, they performed the peak running speed (PRS) test until exhaustion. After which they ran at 70% of PRS for 5 laps. Results indicated that normalising EMG data to MVC and Sprint methods are more repeatable for VM, BF, MG and RF, VL, LG, respectively, with the average ICC>0.80. The 70% PRS demonstrated poor to fair levels of repeatability ranging between ICC 0.27 and 0.70. Whereas the 70% PRS method had the least intra-subject variability and the greatest sensitivity to increasing running speeds. More specifically, demonstrating significant changes in muscle activity in VM with increasing running speed while MVC and Sprint methods were unable to detect these changes. The dynamic methods were the most appropriate for EMG normalisation showing repeatability, better intra-subject reliability and better sensitivity during running over different days and for once-off measurements. PMID:21531148

  10. 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.

  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. 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.

  13. 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

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. Superconducting electron and hole lenses

    NASA Astrophysics Data System (ADS)

    Cheraghchi, H.; Esmailzadeh, H.; Moghaddam, A. G.

    2016-06-01

    We show how a superconducting region (S), sandwiched between two normal leads (N), in the presence of barriers, can act as a lens for propagating electron and hole waves by virtue of the so-called crossed Andreev reflection (CAR). The CAR process, which is equivalent to Cooper pair splitting into two N electrodes, provides a unique possibility of constructing entangled electrons in solid state systems. When electrons are locally injected from an N lead, due to the CAR and normal reflection of quasiparticles by the insulating barriers at the interfaces, sequences of electron and hole focuses are established inside another N electrode. This behavior originates from the change of momentum during electron-hole conversion beside the successive normal reflections of electrons and holes due to the barriers. The focusing phenomena studied here are fundamentally different from the electron focusing in other systems, such as graphene p-n junctions. In particular, due to the electron-hole symmetry of the superconducting state, the focusing of electrons and holes is robust against thermal excitations. Furthermore, the effects of the superconducting layer width, the injection point position, and barrier strength are investigated on the focusing behavior of the junction. Very intriguingly, it is shown that by varying the barrier strength, one can separately control the density of electrons or holes at the focuses.

  20. 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.

  1. Air plasma jet with hollow electrodes at atmospheric pressure

    SciTech Connect

    Hong, Yong Cheol; Uhm, Han Sup

    2007-05-15

    Atmospheric-pressure plasma jet with air is produced through hollow electrodes and dielectric with a hole of 1 mm diam. The plasma jet device is operated by injecting pressurized air into the electrode hole. The air plasma jet device at average powers less than 5 W exhibits a cold plasma jet of about 2 cm in length and near the room temperature, being low enough to treat thermally sensitive materials. Preliminary studies on the discharge characteristics and application tests are also presented by comparing the air plasma jet with the nitrogen and argon plasma jet.

  2. Black Holes and Quasiblack Holes in Einstein-Maxwell Theory

    NASA Astrophysics Data System (ADS)

    Meinel, Reinhard; Breithaupt, Martin; Liu, Yu-Chun

    2015-01-01

    Continuous sequences of asymptotically flat solutions to the Einstein-Maxwell equations describing regular equilibrium configurations of ordinary matter can reach a black hole limit. For a distant observer, the spacetime becomes more and more indistinguishable from the metric of an extreme Kerr-Newman black hole outside the horizon when approaching the limit. From an internal perspective, a still regular but non-asymptotically flat spacetime with the extreme Kerr-Newman near-horizon geometry at spatial infinity forms at the limit. Interesting special cases are sequences of Papapetrou-Majumdar distributions of electrically counterpoised dust leading to extreme Reissner-Nordström black holes and sequences of rotating uncharged fluid bodies leading to extreme Kerr black holes.

  3. Electroweak Prospects for Tevatron RunII

    SciTech Connect

    D. Glenzinski

    2002-10-21

    In RunI each experiment collected about 100 pb{sup -1} of data. During RunIIa, each experiment is expected to collect about 2 fb{sup -1} of data. The center-of-mass energy for RunII, {radical}s = 2.0 TeV, is a bit larger than the 1.8 TeV of RunI and results in an increase of about 10% (35%) in the production cross-sections for W and Z (t{bar t}) events. Additional gains in the event yield are expected due to improvements in the detector acceptance and performance. Taken together, the RunIIa upgrades are expected to yield 2300k (800) W (t{bar t}) events per experiment, including the effects of event selection and triggering, which can be compared to the RunI yields of 77k (20) events. With the RunI data-set, CDF and D0 produced a breadth of electroweak results and obtained the world's only sample of top quarks. While the RunII electroweak physics program is very similar, the RunII upgrade improvements should yield many precision results. The Tevatron began delivering steady data in about June, 2001. The first six months of data taking was ''commissioning dominated'' for CDF and D0. Starting around January, 2002, the experiments were largely commissioned and began taking ''analysis quality'' data. The physics results reported at this conference are based on about 10-20pb{sup -1} (depending on the data-set) per experiment. Thus, the presently available event samples are smaller than those available in RunI. At this early stage of RunII, it is interesting to compare the present detector performance to that assumed when making the RunII physics projections. In the following sections the author discusses some RunII projections for a few electroweak measurements of particular importance, namely the precision determinations of the W-boson mass, M{sub W}, and the top-quark mass, M{sub t}.

  4. Black holes and Higgs stability

    NASA Astrophysics Data System (ADS)

    Tetradis, Nikolaos

    2016-09-01

    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.

  5. Black Holes: A Traveler's Guide

    NASA Astrophysics Data System (ADS)

    Pickover, Clifford A.

    1998-03-01

    BLACK HOLES A TRAVELER'S GUIDE Clifford Pickover's inventive and entertaining excursion beyond the curves of space and time. "I've enjoyed Clifford Pickover's earlier books . . . now he has ventured into the exploration of black holes. All would-be tourists are strongly advised to read his traveler's guide." -Arthur C. Clarke. "Many books have been written about black holes, but none surpass this one in arousing emotions of awe and wonder towards the mysterious structure of the universe." -Martin Gardner. "Bucky Fuller thought big. Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." -Wired. "The book is fun, zany, in-your-face, and refreshingly addictive." -Times Higher Education Supplement.

  6. Quantum mechanics of black holes.

    PubMed

    Witten, Edward

    2012-08-01

    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.

  7. 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.

  8. Thermodynamics of Lifshitz black holes

    NASA Astrophysics Data System (ADS)

    Devecioǧlu, Deniz Olgu; Sarıoǧlu, Özgür

    2011-06-01

    We apply the recently extended conserved Killing charge definition of Abbott-Deser-Tekin formalism to compute, for the first time, the energies of analytic Lifshitz black holes in higher dimensions. We then calculate the temperature and the entropy of this large family of solutions, and study and discuss the first law of black hole thermodynamics. Along the way we also identify the possible critical points of the relevant quadratic curvature gravity theories. Separately, we also apply the generalized Killing charge definition to compute the energy and the angular momentum of the warped AdS3 black hole solution of the three-dimensional new massive gravity theory.

  9. 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. PMID:25768747

  10. 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.

  11. 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 left 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.

  12. Quantum mechanics of black holes.

    PubMed

    Witten, Edward

    2012-08-01

    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. PMID:22859480

  13. 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.

  14. 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,…

  15. Impact of Environmental Parameters on Marathon Running Performance

    PubMed Central

    El Helou, Nour; Tafflet, Muriel; Berthelot, Geoffroy; Tolaini, Julien; Marc, Andy; Guillaume, Marion; Hausswirth, Christophe; Toussaint, Jean-François

    2012-01-01

    Purpose The objectives of this study were to describe the distribution of all runners' performances in the largest marathons worldwide and to determine which environmental parameters have the maximal impact. Methods We analysed the results of six European (Paris, London, Berlin) and American (Boston, Chicago, New York) marathon races from 2001 to 2010 through 1,791,972 participants' performances (all finishers per year and race). Four environmental factors were gathered for each of the 60 races: temperature (°C), humidity (%), dew point (°C), and the atmospheric pressure at sea level (hPA); as well as the concentrations of four atmospheric pollutants: NO2 – SO2 – O3 and PM10 (μg.m−3). Results All performances per year and race are normally distributed with distribution parameters (mean and standard deviation) that differ according to environmental factors. Air temperature and performance are significantly correlated through a quadratic model. The optimal temperatures for maximal mean speed of all runners vary depending on the performance level. When temperature increases above these optima, running speed decreases and withdrawal rates increase. Ozone also impacts performance but its effect might be linked to temperature. The other environmental parameters do not have any significant impact. Conclusions The large amount of data analyzed and the model developed in this study highlight the major influence of air temperature above all other climatic parameter on human running capacity and adaptation to race conditions. PMID:22649525

  16. 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

  17. Characterization of running with compliant curved legs.

    PubMed

    Jun, Jae-Yun; Clark, Jonathan E

    2015-07-07

    Running with compliant curved legs involves the progression of the center of pressure, the changes of both the leg's stiffness and effective rest length, and the shift of the location of the maximum stress point along the leg. These phenomena are product of the geometric and material properties of these legs, and the rolling motion produced during stance. We examine these aspects with several reduced-order dynamical models to relate the leg's design parameters (such as normalized foot radius, leg's effective stiffness, location of the maximum stress point and leg shape) to running performance (such as robustness and efficiency). By using these models, we show that running with compliant curved legs can be more efficient, robust with fast recovery behavior from perturbations than running with compliant straight legs. Moreover, the running performance can be further improved by tuning these design parameters in the context of running with rolling. The results shown in this work may serve as potential guidance for future compliant curved leg designs that may further improve the running performance.

  18. 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...

  19. 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

  20. 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.

  1. 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.

  2. Comment on Dissociation between running economy and running performance in elite Kenyan distance runners.

    PubMed

    Santos-Concejero, Jordan; Tucker, Ross

    2016-01-01

    Mooses and colleagues suggest that running economy alone does not explain superior distance running performance in elite Kenyan runners. Whilst we agree with the multi-factorial hypothesis for Kenyan running success, we do not believe that running economy can be overlooked to the extent that it was based on this particular study. Based on the methods used and the range of athletes tested, in this response letter we question whether this study provides any basis for downplaying the influence of running economy or suggesting that other factors compensate for it to enable superior performance.

  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. '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.

  5. Black hole accretion disc impacts

    NASA Astrophysics Data System (ADS)

    Pihajoki, P.

    2016-04-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength λ = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  6. 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

  7. Two-dimensional photonic crystals from semiconductor material with polymer filled holes

    NASA Astrophysics Data System (ADS)

    van der Heijden, Rob; Kjellander, Charlotte; Carlström, Carl-Fredrik; Snijders, Juri; van der Heijden, Rob W.; Bastiaansen, Kees; Broer, Dick; Karouta, Fouad; Nötzel, Richard; van der Drift, Emile; Salemink, Huub W. M.

    2006-04-01

    Polymer filling of the air holes of indiumphosphide based two-dimensional photonic crystals is reported. The filling is performed by infiltration with a liquid monomer and solidification of the infill in situ by thermal polymerization. Complete hole filling is obtained with infiltration under ambient pressure. This conclusion is based both on cross-sectional scanning electron microscope inspection of the filled samples as well as on optical transmission measurements.

  8. 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.

  9. Black holes: fundamentals and controversies

    NASA Astrophysics Data System (ADS)

    Romero, G. E.

    2016-08-01

    Black holes are fully gravitational collapsed objects. They have been studied from a theoretical point of view during more than 40 years using the theory of General Relativity. Recently they have been also investigated in the context of alternative theories of gravitation. In this paper I review the main properties of black holes and I discuss, in an accesible way, some recent controversies about the nature of these objects.

  10. 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.

  11. Black holes as parts of entangled systems

    NASA Astrophysics Data System (ADS)

    Basini, G.; Capozziello, S.; Longo, G.

    A possible link between EPR-type quantum phenomena and astrophysical objects like black holes, under a new general definition of entanglement, is established. A new approach, involving backward time evolution and topology changes, is presented bringing to a definition of the system black hole-worm hole-white hole as an entangled system.

  12. 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)

  13. Revisiting mask contact hole measurements

    NASA Astrophysics Data System (ADS)

    Higuchi, Masaru; Gallagher, Emily; Ceperley, Daniel; Brunner, Timothy; Bowley, Reg; McGuire, Anne

    2006-10-01

    Contact holes represent one of the biggest critical dimension (CD) mask metrology challenges for 45nm technology mask development. The challenge is a consequence of both wafer and mask sensitivities. Large mask error factors and the small process windows found when contact holes are imaged on wafers impose very tight mask specifications for CD uniformity. The resultant CD error budget leaves little room for mask metrology. Current advanced mask metrology deploys a CD-SEM to characterize the mask contact hole CD uniformity. Measuring a contact hole is complex since it is inherently two-dimensional and is not always well-characterized by one-dimensional x- and y-axis measurements. This paper will investigate contact metrics such as line edge roughness (LER), region of interest (ROI) size, area, and CD sampling methods. The relative merits of each will be explored. Ultimately, an understanding of the connection between what is physically measured on the mask and what impacts wafer imaging must be understood. Simulations will be presented to explore the printability of a contact hole's physical attributes. The results will be summarized into a discussion of optimal contact hole metrology for 45nm technology node masks.

  14. 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.

  15. 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.

  16. Flood-plain delineation for Horsepen Run, Sugarland Run, Nichols Run, Pond Branch, Clarks Branch, and Mine Run Branch basins, Fairfax County, Virginia

    USGS Publications Warehouse

    Soule, Pat LeRoy

    1978-01-01

    Water-surface profiles of the 25-, 50-, and 100-year recurrence interval discharges have been computed for all streams and reaches of channels in Fairfax County, Virginia, having a drainage area greater than 1 square mile except for Dogue Creek, Little Hunting Creek, and that portion of Cameron Run above Lake Barcroft. Maps have a 2-foot contour interval and a horizontal scale of 1 inch equals 100 feet were used for base on which flood boundaries were delineated for 25-, 50-, and 100-year floods to be expected in each basin under ultimate development conditions. This report is one of a series and presents a discussion of techniques employed in computing discharges and profiles as well as the flood profiles and maps on which flood boundaries have been delineated for the Horsepen Run, Sugarland Run, Nichols Run, and Pond Branch basins in Fairfax County. (Woodard-USGS)

  17. 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.

  18. 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.

  19. Close encounters of three black holes

    SciTech Connect

    Campanelli, Manuela; Lousto, Carlos O.; Zlochower, Yosef

    2008-05-15

    We present the first fully relativistic long-term numerical evolutions of three equal-mass black holes in a system consisting of a third black hole in a close orbit about a black-hole binary. These close-three-black-hole systems have very different merger dynamics from black-hole binaries; displaying complex trajectories, a redistribution of energy that can impart substantial kicks to one of the holes, distinctive waveforms, and suppression of the emitted gravitational radiation. In one configuration the binary is quickly disrupted and the individual holes follow complicated trajectories and merge with the third hole in rapid succession, while in another, the binary completes a half-orbit before the initial merger of one of the members with the third black hole, and the resulting two-black-hole system forms a highly elliptical, well separated binary that shows no significant inspiral for (at least) the first t{approx}1000M of evolution.

  20. 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.

  1. 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.

  2. Sprint running: a new energetic approach.

    PubMed

    di Prampero, P E; Fusi, S; Sepulcri, L; Morin, J B; Belli, A; Antonutto, G

    2005-07-01

    The speed of the initial 30 m of an all-out run from a stationary start on a flat track was determined for 12 medium level male sprinters by means of a radar device. The peak speed of 9.46+/-0.19 m s(-1) (mean +/- s.d.) was attained after about 5 s, the highest forward acceleration (a(f)), attained immediately after the start, amounting to 6.42+/-0.61 m s(-2). During acceleration, the runner's body (assumed to coincide with the segment joining the centre of mass and the point of contact foot terrain) must lean forward, as compared to constant speed running, by an angle alpha = arctang/a(f) (g = acceleration of gravity). The complement (90-alpha) is the angle, with respect to the horizontal, by which the terrain should be tilted upwards to bring the runner's body to a position identical to that of constant speed running. Therefore, accelerated running is similar to running at constant speed up an ;equivalent slope' ES = tan(90-alpha). Maximum ES was 0.643+/-0.059. Knowledge of ES allowed us to estimate the energy cost of sprint running (C(sr), J kg(-1) m(-1)) from literature data on the energy cost measured during uphill running at constant speed. Peak Csr was 43.8+/-10.4 J kg(-1) m(-1); its average over the acceleration phase (30 m) was 10.7+/-0.59 J kg(-1) m(-1), as compared with 3.8 for running at constant speed on flat terrain. The corresponding metabolic powers (in W kg(-1)) amounted to 91.9+/-20.5 (peak) and 61.0+/-4.7 (mean). PMID:16000549

  3. 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.

  4. 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.

  5. A new metric for the size and depth of the Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2014-05-01

    The extent of the seasonal ozone loss in the Antarctic ozone hole has traditionally been quantified by the ozone hole area and the ozone mass deficit. The ozone hole area is defined as the area of the region where total ozone is less than 220 DU. The ozone mass deficit is defined as the mass of ozone that has to be added in order to reach a total column of 220 DU in those areas where total ozone is inferior to this value. Under certain circumstances these metrics can give a wrong impression of the degree of ozone loss. During several of the recent ozone hole seasons there has been transport of ozone rich air from middle latitudes at altitudes above 20 km and that has acted as a lid on top of the ozone depleted region below, typically between 14 and 20 km altitude. In several cases ozonesonde profiles show substantial ozone loss typical of an ozone hole situation, yet total ozone is well above the 220 DU threshold due to the dynamically enhanced amounts of ozone at higher altitudes. The present paper presents an alternative metric to quantify the degree of ozone loss in the Antarctic ozone hole that is not affected by in-flux of ozone rich air at altitudes above 20 km. With such a metric one obtains a more correct comparison of the ozone holes of different years.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Engine's Running, But Where's the Fuel?

    NASA Astrophysics Data System (ADS)

    2006-01-01

    Astronomers have found a relatively tiny galaxy whose black-hole-powered "central engine" is pouring out energy at a rate equal to that of much larger galaxies, and they're wondering how it manages to do so. The astronomers used the National Science Foundation's Very Large Array (VLA) radio telescope and optical telescopes at the Apache Point Observatory to study a galaxy dubbed J170902+641728, more than a billion light-years from Earth. The VLA The Very Large Array CREDIT: NRAO/AUI/NSF (Click on image for VLA gallery) "This thing looks like a quasar in VLA images, but quasars come in big galaxies, not little ones like this," said Neal Miller, an astronomer with the National Radio Astronomy Observatory. In visible-light images, the galaxy is lost in the glare from the bright central engine, but those images place strong limits on the galaxy's size, Miller explained. Miller and Kurt Anderson of New Mexico State University presented their findings to the American Astronomical Society's meeting in Washington, DC. Most galaxies have black holes at their centers. The black hole, a concentration of mass whose gravity is so strong that not even light can escape it, can draw material into itself from the surrounding galaxy. If the black hole has gas or stars to "eat," that process generates large amounts of energy as the infalling gas is compressed and heated to high temperatures. This usually is seen in young galaxies,massive galaxies, or in galaxies that have experienced close encounters with companions, stirring up the material and sending it close enough to the black hole to be gobbled up. The black hole in J170902+641728 is about a million times more massive than the Sun, the astronomers say. Their images show that the galaxy can be no larger than about 2,000 light-years across. Our Milky Way Galaxy is about 100,000 light-years across. "There are other galaxies that are likely to be the same size as this one that have black holes of similar mass. However, their black

  16. 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. PMID:26525514

  17. 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.

  18. 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.

  19. 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.

  20. Air resources

    SciTech Connect

    1995-10-01

    This section describes the ambient (surrounding) air quality of the TVA region, discusses TVA emission contributions to ambient air quality, and identifies air quality impacts to human health and welfare. Volume 2 Technical Document 2, Environmental Consequences, describes how changes in TVA emissions could affect regional air quality, human health, environmental resources, and materials. The primary region of the affected environment is broadly defined as the state of Tennessee, as well as southern Kentucky, western Virginia, southern West Virginia, western North Carolina, and northern Georgia, Alabama, and Mississippi. This area represents the watershed of the Tennessee River and the 201 counties of the greater TVA service area. Emissions from outside the Tennessee Valley region contribute to air quality in the Valley. Also, TVA emissions are transported outside the Valley and have some impact on air quality beyond the primary study area. Although the study area experiences a number of air quality problems, overall air quality is good.

  1. Supermassive black hole ancestors

    NASA Astrophysics Data System (ADS)

    Petri, A.; Ferrara, A.; Salvaterra, R.

    2012-05-01

    In the attempt to alleviate the difficulties created by their early formation, we study a model in which supermassive black holes (SMBHs) can grow by the combined action of gas accretion on heavy seeds and mergers of both heavy ? and light ? seeds. The former results from the direct collapse of gas in ? K, H2-free haloes; the latter are the end product of a standard H2-based star formation process. The H2-free condition is attained by exposing haloes to a strong (J21≳ 103) Lyman-Werner ultraviolet (UV) background produced by both accreting BHs and stars, thus establishing a self-regulated growth regime. We find that this condition is met already at z˜ 18 in the highly biased regions in which quasars are born. The key parameter allowing the formation of SMBHs by z= 6-7 is the fraction of haloes that can form heavy seeds: the minimum requirement is that fheavy≳ 0.001; SMBH as large as 2 × 1010 M⊙ can be obtained when fheavy approaches unity. Independently of fheavy, the model produces a high-z stellar bulge-BH mass relation which is steeper than the local one, implying that SMBHs formed before their bulge was in place. The formation of heavy seeds, allowed by the Lyman-Werner radiative feedback in the quasar-forming environment, is crucial to achieve a fast growth of the SMBH by merger events in the early phases of its evolution, i.e. z≳ 7. The UV photon production is largely dominated by stars in galaxies, i.e. BH accretion radiation is subdominant. Interestingly, we find that the final mass of light BHs and of the SMBH in the quasar is roughly equal by z= 6; by the same time, only 19 per cent of the initial baryon content has been converted into stars. The SMBH growth is dominated at all epochs z > 7.2 by mergers (exceeding accretion by a factor of 2-50); at later times, accretion becomes by far the most important growth channel. We finally discuss possible shortcomings of the model.

  2. Measurement-while-drilling (MWD) development for air drilling

    SciTech Connect

    Rubin, L.A.; Harrison, W.H.

    1992-01-01

    The objective of this program is to tool-harden and make commercially available an existing wireless MWD tool to reliably operate in an air, air-mist, or air-foam environment during Appalachian Basin oil and gas directional drilling operations in conjunction with downhole motors and/or (other) bottom-hole assemblies. The application of this technology is required for drilling high angle (holes) and horizontal well drilling in low-pressure, water sensitive, tight gas formations that require air, air-mist, and foam drilling fluids. The basic approach to accomplishing this objective was to modify GEC's existing electromagnetic (e-m) CABLELESS''{trademark} MWD tool to improve its reliability in air drilling by increasing its tolerance to higher vibration and shock levels (hardening). Another important aim of the program is to provide for continuing availability of the resultant tool for use on DOE-sponsored, and other, air-drilling programs.

  3. Measurement-while-drilling (MWD) development for air drilling

    SciTech Connect

    Rubin, L.A.; Harrison, W.H.

    1992-06-01

    The objective of this program is to tool-harden and make commercially available an existing wireless MWD tool to reliably operate in an air, air-mist, or air-foam environment during Appalachian Basin oil and gas directional drilling operations in conjunction with downhole motors and/or (other) bottom-hole assemblies. The application of this technology is required for drilling high angle (holes) and horizontal well drilling in low-pressure, water sensitive, tight gas formations that require air, air-mist, and foam drilling fluids. The basic approach to accomplishing this objective was to modify GEC`s existing electromagnetic (e-m) ``CABLELESS``{trademark} MWD tool to improve its reliability in air drilling by increasing its tolerance to higher vibration and shock levels (hardening). Another important aim of the program is to provide for continuing availability of the resultant tool for use on DOE-sponsored, and other, air-drilling programs.

  4. 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.

  5. Running with a load increases leg stiffness.

    PubMed

    Silder, Amy; Besier, Thor; Delp, Scott L

    2015-04-13

    Spring-mass models have been used to characterize running mechanics and leg stiffness in a variety of conditions, yet it remains unknown how running while carrying a load affects running mechanics and leg stiffness. The purpose of this study was to test the hypothesis that running with a load increases leg stiffness. Twenty-seven subjects ran at a constant speed on a force-measuring treadmill while carrying no load, and while wearing weight vests loaded with 10%, 20%, and 30% of body weight. We measured lower extremity motion and created a scaled musculoskeletal model of each subject, which we used to estimate lower extremity joint angles and leg length. We estimated dimensionless leg stiffness as the ratio of the peak vertical ground reaction force (normalized to body weight) and the change in stance phase leg length (normalized to leg length at initial foot contact). Leg length was calculated as the distance from the center of the pelvis to the center-of-pressure under the foot. We found that dimensionless leg stiffness increased when running with load (p=0.001); this resulted from an increase in the peak vertical ground reaction force (p<0.001) and a smaller change in stance phase leg length (p=0.025). When running with load, subjects had longer ground contact times (p<0.020), greater hip (p<0.001) and knee flexion (p=0.048) at the time of initial foot contact, and greater peak stance phase hip, knee, and ankle flexion (p<0.05). Our results reveal that subjects run in a more crouched posture and with higher leg stiffness to accommodate an added load.

  6. Running with a load increases leg stiffness.

    PubMed

    Silder, Amy; Besier, Thor; Delp, Scott L

    2015-04-13

    Spring-mass models have been used to characterize running mechanics and leg stiffness in a variety of conditions, yet it remains unknown how running while carrying a load affects running mechanics and leg stiffness. The purpose of this study was to test the hypothesis that running with a load increases leg stiffness. Twenty-seven subjects ran at a constant speed on a force-measuring treadmill while carrying no load, and while wearing weight vests loaded with 10%, 20%, and 30% of body weight. We measured lower extremity motion and created a scaled musculoskeletal model of each subject, which we used to estimate lower extremity joint angles and leg length. We estimated dimensionless leg stiffness as the ratio of the peak vertical ground reaction force (normalized to body weight) and the change in stance phase leg length (normalized to leg length at initial foot contact). Leg length was calculated as the distance from the center of the pelvis to the center-of-pressure under the foot. We found that dimensionless leg stiffness increased when running with load (p=0.001); this resulted from an increase in the peak vertical ground reaction force (p<0.001) and a smaller change in stance phase leg length (p=0.025). When running with load, subjects had longer ground contact times (p<0.020), greater hip (p<0.001) and knee flexion (p=0.048) at the time of initial foot contact, and greater peak stance phase hip, knee, and ankle flexion (p<0.05). Our results reveal that subjects run in a more crouched posture and with higher leg stiffness to accommodate an added load. PMID:25728581

  7. Air Pollution.

    ERIC Educational Resources Information Center

    Gilpin, Alan

    A summary of one of our most pressing environmental problems, air pollution, is offered in this book by the Director of Air Pollution Control for the Queensland (Australia) State Government. Discussion of the subject is not restricted to Queensland or Australian problems and policies, however, but includes analysis of air pollution the world over.…

  8. 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.

  9. SEARCH FOR GRAVITATIONAL WAVES ASSOCIATED WITH GAMMA-RAY BURSTS DURING LIGO SCIENCE RUN 6 AND VIRGO SCIENCE RUNS 2 AND 3

    SciTech Connect

    Abadie, J.; Abbott, B. P.; Abbott, R.; Adhikari, R. X.; Ajith, P.; Anderson, S. B.; Arai, K.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Adams, C.; Affeldt, C.; Allen, B.; Agathos, M.; Agatsuma, K.; Ceron, E. Amador; Anderson, W. G.; Amariutei, D.; Arain, M. A.; Collaboration: LIGO Scientific Collaboration; Virgo Collaboration; and others

    2012-11-20

    We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole, and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10{sup -2} M {sub Sun} c {sup 2} at 150 Hz, with a median limit of 17 Mpc. For short-hard GRBs we place exclusion distances on binary neutron star and neutron-star-black-hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc, respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.

  10. Effect of holed reflector on acoustic radiation force in noncontact ultrasonic dispensing of small droplets

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiroki; Wada, Yuji; Mizuno, Yosuke; Nakamura, Kentaro

    2016-06-01

    We investigated the fundamental aspects of droplet dispensing, which is an important procedure in the noncontact ultrasonic manipulation of droplets in air. A holed reflector was used to dispense a droplet from a 27.4 kHz standing-wave acoustic field to a well. First, the relationship between the hole diameter of the reflector and the acoustic radiation force acting on a levitated droplet was clarified by calculating the acoustic impedance of the point just above the hole. When the hole diameter was half of (or equal to) the acoustic wavelength λ, the acoustic radiation force was ∼80% (or 50%) of that without a hole. The maximal diameters of droplets levitated above the holes through flat and half-cylindrical reflectors were then experimentally investigated. For instance, with the half-cylindrical reflector, the maximal diameter was 5.0 mm for a hole diameter of 6.0 mm, and droplets were levitatable up to a hole diameter of 12 mm (∼λ).

  11. The ``Uberbank'': A search for compact binary coalescences in the first Observing run of Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Capano, Collin; LIGO Scientific Collaboration; Virgo Collaboration

    2016-03-01

    Modeled searches for gravitational waves from compact binary coalescence (CBC) use a ``bank'' of template waveforms to search the wide range of parameters that binaries may have. Recent advances in waveform modeling and template placement techniques have opened up the possibility to efficiently search for systems with non-precessing spin, using waveforms that model the inspiral, merger, and ringdown of coalescing binaries. I discuss how these advances were combined to produce the template bank used to search for CBCs in the first observing run of Advanced LIGO. This bank covered the full range of plausible masses and non-precessing spins of binary neutron stars, stellar-mass binary black holes, and binaries consisting of a neutron star and a stellar-mass black hole.

  12. Effects of velocity and weight support on ground reaction forces and metabolic power during running.

    PubMed

    Grabowski, Alena M; Kram, Rodger

    2008-08-01

    The biomechanical and metabolic demands of human running are distinctly affected by velocity and body weight. As runners increase velocity, ground reaction forces (GRF) increase, which may increase the risk of an overuse injury, and more metabolic power is required to produce greater rates of muscular force generation. Running with weight support attenuates GRFs, but demands less metabolic power than normal weight running. We used a recently developed device (G-trainer) that uses positive air pressure around the lower body to support body weight during treadmill running. Our scientific goal was to quantify the separate and combined effects of running velocity and weight support on GRFs and metabolic power. After obtaining this basic data set, we identified velocity and weight support combinations that resulted in different peak GRFs, yet demanded the same metabolic power. Ideal combinations of velocity and weight could potentially reduce biomechanical risks by attenuating peak GRFs while maintaining aerobic and neuromuscular benefits. Indeed, we found many combinations that decreased peak vertical GRFs yet demanded the same metabolic power as running slower at normal weight. This approach of manipulating velocity and weight during running may prove effective as a training and/or rehabilitation strategy.

  13. Wormholes as black hole foils

    NASA Astrophysics Data System (ADS)

    Damour, Thibault; Solodukhin, Sergey N.

    2007-07-01

    We study to what extent wormholes can mimic the observational features of black holes. It is surprisingly found that many features that could be thought of as “characteristic” of a black hole (endowed with an event horizon) can be closely mimicked by a globally static wormhole, having no event horizon. This is the case for the apparently irreversible accretion of matter down a hole, no-hair properties, quasi-normal-mode ringing, and even the dissipative properties of black hole horizons, such as a finite surface resistivity equal to 377 Ohms. The only way to distinguish the two geometries on an observationally reasonable time scale would be through the detection of Hawking’s radiation, which is, however, too weak to be of practical relevance for astrophysical black holes. We point out the existence of an interesting spectrum of quantum microstates trapped in the throat of a wormhole which could be relevant for storing the information lost during a gravitational collapse.

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

    PubMed

    de Ruiter, Cornelis J; van Oeveren, Ben; Francke, Agnieta; Zijlstra, Patrick; van Dieen, Jaap H

    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

  15. 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

  16. 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.

  17. 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.

  18. Chandra Clinches Case for Missing Link Black Hole

    NASA Astrophysics Data System (ADS)

    2000-09-01

    The strongest evidence yet that the universe is home to a new type of black hole was reported by several groups of scientists today Using NASA's Chandra X-ray Observatory, scientists have zeroed in on a mid-mass black hole in the galaxy M82. This black hole - located 600 light years away from the center of a galaxy - may represent the missing link between smaller stellar black holes and the supermassive variety found at the centers of galaxies. "This opens a whole new field of research," said Martin Ward of the University of Leicester, UK, a lead author involved with the observations. "No one was sure that such black holes existed, especially outside the centers of galaxies." The black hole in M82 packs the mass of at least 500 suns into a region about the size of the Moon. Such a black hole would require extreme conditions for its creation, such as the collapse of a "hyperstar" or the merger of scores of black holes. The result comes as Chandra starts its second year of operation and is testimony to how Chandra's power and precision is changing the field of astronomy. "This black hole might eventually sink to the center of the galaxy," said Dr. Hironori Matsumoto of the Massachusetts Institute of Technology, the lead author on one of three Chandra papers scheduled to be published on the mid-mass black hole, "where it could grow to become a supermassive black hole." Although previous X-ray data from the German-U.S. Roentgen Satellite and the Japan-U.S. ASCA Satellite suggested that a mid-mass black hole might exist in M82, the crucial breakthrough came when astronomers compared the new high resolution Chandra data with optical, radio, and infrared maps of the region. They determined that most of the X-rays were coming from a single bright source. Repeated observations of M82 over a period of eight months showed the bright X-ray source gradually peaking in X-ray brightness before dimming. Another critical discovery was that the intensity of the X rays was rising and

  19. 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.

  20. Validity of Self-Reported Running Distance.

    PubMed

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

    2016-06-01

    Dideriksen, M, Soegaard, C, and Nielsen, RO. Validity of self-reported running distance. J Strength Cond Res 30(6): 1592-1596, 2016-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. PMID:26479023

  1. Exercise economy in skiing and running

    PubMed Central

    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. PMID:24478718

  2. 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

  3. Low-mass black holes as the remnants of primordial black hole formation

    NASA Astrophysics Data System (ADS)

    Greene, Jenny E.

    2012-12-01

    Bridging the gap between the approximately ten solar mass `stellar mass' black holes and the `supermassive' black holes of millions to billions of solar masses are the elusive `intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ~104-105Msolar black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

  4. Calabi-Yau black holes

    NASA Astrophysics Data System (ADS)

    Shmakova, Marina

    1997-07-01

    We find the entropy of N=2 extreme black holes associated with general Calabi-Yau moduli space and the prepotential F=dABC(XAXBXC/X0). We show that for arbitrary dABC and black hole charges p and q the entropy-area formula depends on combinations of these charges and parameters dABC. These combinations are the solutions of a simple system of algebraic equations. We give a few examples of particular Calabi-Yau moduli spaces for which this system has an explicit solution. For the special case when one of the black hole charges is equal to zero (p0=0) the solution always exists.

  5. 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.

  6. Liouvillian perturbations of black holes

    NASA Astrophysics Data System (ADS)

    Couch, W. E.; Holder, C. L.

    2007-10-01

    We apply the well-known Kovacic algorithm to find closed form, i.e., Liouvillian solutions, to the differential equations governing perturbations of black holes. Our analysis includes the full gravitational perturbations of Schwarzschild and Kerr, the full gravitational and electromagnetic perturbations of Reissner-Nordstrom, and specialized perturbations of the Kerr-Newman geometry. We also include the extreme geometries. We find all frequencies ω, in terms of black hole parameters and an integer n, which allow Liouvillian perturbations. We display many classes of black hole parameter values and their corresponding Liouvillian perturbations, including new closed-form perturbations of Kerr and Reissner-Nordstrom. We also prove that the only type 1 Liouvillian perturbations of Schwarzschild are the known algebraically special ones and that type 2 Liouvillian solutions do not exist for extreme geometries. In cases where we do not prove the existence or nonexistence of Liouvillian perturbations we obtain sequences of Diophantine equations on which decidability rests.

  7. Tomograms of spinning black holes

    SciTech Connect

    Krishnan, Chethan

    2009-12-15

    The classical internal structure of spinning black holes is vastly different from that of static black holes. We consider spinning Banados-Teitelboim-Zanelli black holes, and probe their interior from the gauge theory. Utilizing the simplicity of the geometry and reverse engineering from the geodesics, we propose a thermal correlator construction which can be interpreted as arising from two entangled conformal field theories. By analytic continuation of these correlators, we can probe the Cauchy horizon. Correlators that capture the Cauchy horizon in our work have a structure closely related to those that capture the singularity in a nonrotating Banados-Teitelboim-Zanelli. As expected, the regions beyond the Cauchy horizon are not probed in this picture, protecting cosmic censorship.

  8. 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.

  9. Nonrotating and slowly rotating holes

    NASA Astrophysics Data System (ADS)

    MacDonald, Douglas A.; Price, Richard H.; Thorne, Kip S.; Suen, Wai-Mo

    The 3+1 formalism is applied to model Schwarzschild spacetime around a black hole. Particular note is taken of the 3+1 split of the laws of electrodynamics, and of the tendency of the approach to freeze motion at the event horizon. The null horizon is replaced with a timelike physical membrane which exhibits mechanical, thermodynamic and electrical properties, and which 'stretches' the horizon. The usefulness of the stretching approach is illustrated by considering a black hole penetrated by vibrating magnetic field lines anchored in a perfectly conducting surrounding sphere. The necessity of modeling the field structure near the actual horizon is avoided by having the field end at the membrane. The surface charge, current, resistivity and ohmic heating of the stretched horizon are also considered, and the Lorentz force imparted to the stretched horizon surface by the field lines is investigated by examining a nearly Schwarzschild hole behaving as the rotor of an electric motor.

  10. Neutron stars and black holes

    NASA Technical Reports Server (NTRS)

    Lamb, F. K.

    1991-01-01

    The radiation of neutron stars is powered by accretion, rotation, or internal heat; accreting black holes are thought to be the central engines of AGNs and of a handful of binary X-ray sources in the Galaxy. The evolution of a neutron star depends on the coupling between the rotating neutron and proton fluids in the interior, and between these fluids and the crust; it also depends on the magnetic and thermal properties of the star. Significant progress has been made in recent years in the understanding of radial and disk accretion by black holes. Radiation from pair plasmas may make an important contribution to the X- and gamma-ray spectra of AGNs and black holes in binary systems.

  11. 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.

  12. 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.

  13. Holographic Ricci dark energy as running vacuum

    NASA Astrophysics Data System (ADS)

    George, Paxy; Mathew, Titus K.

    2016-04-01

    Holographic Ricci dark energy (DE) that has been proposed ago has faced problems of future singularity. In the present work, we consider the Ricci DE with an additive constant in its density as running vacuum energy. We have analytically solved the Friedmann equations and also the role played by the general conservation law followed by the cosmic components together. We have shown that the running vacuum energy status of the Ricci DE helps to remove the possible future singularity in the model. The additive constant in the density of the running vacuum played an important role, such that, without that, the model predicts either eternal deceleration or eternal acceleration. But along with the additive constant, equivalent to a cosmological constant, the model predicts a late time acceleration in the expansion of the universe, and in the far future of the evolution it tends to de Sitter universe.

  14. Flame structure of wall-impinging diesel fuel sprays injected by group-hole nozzles

    SciTech Connect

    Gao, Jian; Moon, Seoksu; Nishida, Keiya; Matsumoto, Yuhei; Zhang, Yuyin

    2009-06-15

    This paper describes an investigation of the flame structure of wall-impinging diesel sprays injected by group-hole nozzles in a constant-volume combustion vessel at experimental conditions typical of a diesel engine. The particular emphasis was on the effect of the included angle between two orifices (0-15 deg. in current study) on the flame structure and combustion characteristics under various simulated engine load conditions. The laser absorption scattering (LAS) technique was applied to analyze the spray and mixture properties. Direct flame imaging and OH chemiluminescence imaging were utilized to quantify the ignition delay, flame geometrical parameters, and OH chemiluminescence intensity. The images show that the asymmetric flame structure emerges in wall-impinging group-hole nozzle sprays as larger included angle and higher engine load conditions are applied, which is consistent with the spray shape observed by LAS. Compared to the base nozzle, group-hole nozzles with large included angles yield higher overall OH chemiluminescence intensity, wider flame area, and greater proportion of high OH intensity, implying the better fuel/air mixing and improved combustion characteristics. The advantages of group-hole nozzle are more pronounced under high load conditions. Based on the results, the feasibility of group-hole nozzle for practical direct injection diesel engines is also discussed. It is concluded that the asymmetric flame structure of a group-hole nozzle spray is favorable to reduce soot formation over wide engine loads. However, the hole configuration of the group-hole nozzle should be carefully considered so as to achieve proper air utilization in the combustion chamber. Stoichiometric diesel combustion is another promising application of group-hole nozzle. (author)

  15. 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.

  16. Flame hole dynamics simulation of Sandia Flame F

    NASA Astrophysics Data System (ADS)

    Knaus, Robert; Hewson, John; Domino, Stefan; Pantano, Carlos

    2014-11-01

    The Sandia Flame ``F'' is a piloted methane/air diffusion flame containing high levels of local extinction. These regions of local extinction reduce the efficiency of combustion and can increase the production of certain pollutants (e.g. carbon monoxide) as well as limit the overall stability of the flame. We present a flame hole dynamics model describing evolution of local extinction zones (flame holes) in a turbulent diffusion flame and apply it to perform a direct numerical simulation of the Sandia Flame F using Sandia's ``SIERRA low Mach Module, Nalu.'' The flame hole dynamics model is a phase-field model that describes the state of the flame (burning or extinguished) through a surface partial differential equation modeling extinction, reignition and advection of the flame state on the moving stoichiometric surface using edge flame properties. The solution of the surface equation is then extended away from the surface and used for state evaluations using a flamelet library with steady flamelets in the burning region and a transient solution in the quenched regions. The flame hole dynamics approach allows tracking extinction and reignition in turbulent diffusion flames without using the computationally costly detailed chemistry explicitly.

  17. 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.

  18. 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.

  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. Astrophysical Black Holes: Evidence of a Horizon?

    NASA Astrophysics Data System (ADS)

    Colpi, Monica

    In this Lecture Note we first follow a short account of the history of the black hole hypothesis. We then review on the current status of the search for astrophysical black holes with particular attention to the black holes of stellar origin. Later, we highlight a series of observations that reveal the albeit indirect presence of supermassive black holes in galactic nuclei, with mention to forthcoming experiments aimed at testing directly the black hole hypothesis. We further focus on evidences of a black hole event horizon in cosmic sources.

  1. Running on age in a 15-km road run: minor influence of age on performance.

    PubMed

    Celie, Floortje; Faes, Miriam; Hopman, Maria; Stalenhoef, Anton F H; Rikkert, Marcel G M Olde

    2010-04-01

    The importance of exercise in the elderly is widely recognized, but data on performances and drop-out in short running contests are lacking. This hinders stimulation and coaching of elderly persons in active aging. The aim of the study was to determine age-related changes in running performance in the most popular Dutch road run, and how this is influenced by gender, training, and increased participation rate over the last decade. This is a retrospective analysis of 194,560 participants of a 15-km run from 1995 to 2007. Multiple regression analysis of running time by age, gender, and training was performed. Trends in participation were examined by chi-square tests and ANOVA. Trends in running time and speed were examined by t tests. With aging, running time increased with 0.20% per year (P < 0.001). Running time was on average 13% (P < 0.001) shorter in men than in women and was 15.7% (P < 0.001) shorter in participants who trained on a regular basis. Decline in performance with age was 5.9% larger for men than women (P < 0.01) and 4.5% larger for trained than untrained participants (P < 0.01). Over the last decade, participation numbers increased most for elderly (≥60 years) and female participants, mean running performance declined with 9.9% (P < 0.001). Drop-out number was low at all ages (0.13-0.29%). It appears that aging has only minor negative influences on running performance, which can even be attenuated by training. Our data suggest that exercise by means of running is a safe and rewarding option for improvement of healthy and active aging. PMID:21124752

  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. 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.

  4. 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

  5. Building Black Holes: Supercomputer Cinema

    NASA Astrophysics Data System (ADS)

    Shapiro, Stuart L.; Teukolsky, Saul A.

    1988-07-01

    A new computer code can solve Einstein's equations of general relativity for the dynamical evolution of a relativistic star cluster. The cluster may contain a large number of stars that move in a strong gravitational field at speeds approaching the speed of light. Unstable star clusters undergo catastrophic collapse to black holes. The collapse of an unstable cluster to a supermassive black hole at the center of a galaxy may explain the origin of quasars and active galactic nuclei. By means of a supercomputer simulation and color graphics, the whole process can be viewed in real time on a movie screen.

  6. 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

  7. 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

  8. 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

  9. Validation of Distance Run Tests for Elementary School Children

    ERIC Educational Resources Information Center

    Jackson, Andrew S.; Coleman, A. Eugene

    1976-01-01

    The author reports that 9- and 12-minute distance runs proved to be significantly correlated with maximum oxygen uptake and that the runs were suitable tests of the distance running ability of elementary school boys and girls. (GW)

  10. Pendulum models of ponytail motion during walking and running

    NASA Astrophysics Data System (ADS)

    Plaut, Raymond H.; Virgin, Lawrence N.

    2013-08-01

    Steady-state motions of a woman's ponytail during level, straight, walking and running are examined. Based on reported data, formulas have been developed for the relationship of the forward speed to the frequencies of vertical and sideways motion of the head, and of the form of that motion. The ponytail is modeled as a compound pendulum or a multi-bar pendulum with 2, 3, or 5 rigid bars. Motions in the vertical plane perpendicular to the direction of progression are analyzed. Rotational springs and dashpots are placed at the joints, and aerodynamic damping (air drag) is included. Attention is focused on the variation of the amplitudes of the bars as the woman's walking speed and then running speed increase. An example of three-dimensional motions of a spherical-pendulum model also is included. Experiments were conducted on a double pendulum with parabolic applied motion at the top. The damping is modeled by rotational friction (i.e., a constant resisting moment at the top and internal joints), and the numerical results agree well with the test data.

  11. Evidence for diabatic cooling and poleward transport within and around the 1987 Antarctic ozone hole

    SciTech Connect

    Proffitt, M.H.; Powell, J.A. Univ. of Colorado, Boulder ); Kelly, K.K. ); Gray, B.L. ); Loewenstein, M.; Podolske, J.R.; Strahan, S.E.; Chan, K.R. )

    1989-11-30

    Combining in situ measurements of nitrous oxide, total water, and NO{sub y} with meteorological data, including potential vorticity, taken during the 1987 Airborne Antarctic Ozone Experiment, a consistent picture emerges of a gradual poleward movement of air extending from about 10{degree} in latitude outside the boundary of the ozone hole to about 5{degree} inside. The data analysis is concentrated in the potential temperature range of 425-450 K, corresponding to geometric altitudes of 17.5-19 km. Evidence of ongoing diabatic cooling throughout this region is presented, and cooling rates of about 1.75 K in potential temperature per day (approximately 0.8 K per day in temperature at constant pressure) are calculated from the data outside the boundary of the ozone hole. An interpretation of the data is presented that describes the movement of air that has come from lower latitudes into the ozone hole, as diabatically descending and spiraling poleward. The result of this spiraling motion is a dominantly advective flow of ozone rich air across the boundary and into the ozone hole. This simple picture precludes requiring extensive isentropic mixing with accompanying vertical descent to maintain the steep poleward isentropic gradients found in nitrous oxide. Data are presented to show that the necessary accompanying outflow of stratospheric air from within the ozone hole occurs at potential temperatures less than 425 K and that, during the mission, there was no significant transport of processed air across the boundary and out of the ozone hole from 425 to 450 K. Arguments involving conservation of angular momentum are also used to support this model.

  12. Lithium-Air Battery: High Performance Cathodes for Lithium-Air Batteries

    SciTech Connect

    2010-08-01

    BEEST Project: Researchers at Missouri S&T are developing an affordable lithium-air (Li-Air) battery that could enable an EV to travel up to 350 miles on a single charge. Today’s EVs run on Li-Ion batteries, which are expensive and suffer from low energy density compared with gasoline. This new Li-Air battery could perform as well as gasoline and store 3 times more energy than current Li-Ion batteries. A Li-Air battery uses an air cathode to breathe oxygen into the battery from the surrounding air, like a human lung. The oxygen and lithium react in the battery to produce electricity. Current Li-Air batteries are limited by the rate at which they can draw oxygen from the air. The team is designing a battery using hierarchical electrode structures to enhance air breathing and effective catalysts to accelerate electricity production.

  13. 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.

  14. High Energy Efficiency Air Conditioning

    SciTech Connect

    Edward McCullough; Patrick Dhooge; Jonathan Nimitz

    2003-12-31

    This project determined the performance of a new high efficiency refrigerant, Ikon B, in a residential air conditioner designed to use R-22. The refrigerant R-22, used in residential and small commercial air conditioners, is being phased out of production in developed countries beginning this year because of concerns regarding its ozone depletion potential. Although a replacement refrigerant, R-410A, is available, it operates at much higher pressure than R-22 and requires new equipment. R-22 air conditioners will continue to be in use for many years to come. Air conditioning is a large part of expensive summer peak power use in many parts of the U.S. Previous testing and computer simulations of Ikon B indicated that it would have 20 - 25% higher coefficient of performance (COP, the amount of cooling obtained per energy used) than R-22 in an air-cooled air conditioner. In this project, a typical new R-22 residential air conditioner was obtained, installed in a large environmental chamber, instrumented, and run both with its original charge of R-22 and then with Ikon B. In the environmental chamber, controlled temperature and humidity could be maintained to obtain repeatable and comparable energy use results. Tests with Ikon B included runs with and without a power controller, and an extended run for several months with subsequent analyses to check compatibility of Ikon B with the air conditioner materials and lubricant. Baseline energy use of the air conditioner with its original R-22 charge was measured at 90 deg F and 100 deg F. After changeover to Ikon B and a larger expansion orifice, energy use was measured at 90 deg F and 100 deg F. Ikon B proved to have about 19% higher COP at 90 deg F and about 26% higher COP at 100 deg F versus R-22. Ikon B had about 20% lower cooling capacity at 90 deg F and about 17% lower cooling capacity at 100 deg F versus R-22 in this system. All results over multiple runs were within 1% relative standard deviation (RSD). All of these

  15. 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.

  16. BEAM SCRUBBING FOR RHIC POLARIZED PROTON RUN.

    SciTech Connect

    ZHANG,S.Y.FISCHER,W.HUANG,H.ROSER,T.

    2004-07-05

    One of the intensity limiting factor of RHIC polarized proton beam is the electron cloud induced pressure rise. A beam scrubbing study shows that with a reasonable period of time of running high intensity 112-bunch proton beam, the pressure rise can be reduced, allowing higher beam intensity.

  17. 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

  18. 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.…

  19. Bull Run Fossil Plant toxicity biomonitoring study

    SciTech Connect

    Hackney, P.A.; Moses, J.

    1986-11-01

    This report presents the results of toxicity testing of the whole waste discharge from the Bull Run Steam-Electric Plant ashpond. Water chemistry tests were conducted for heavy metals content and suspended solids. Both acute and chronic toxicity tests were conducted on Daphnia pulex, Ceriodaphnia spp., Pimephales promelas, Micropterus salmoides, Lepomis macrochirus, and Cyprinus carpio. (ACR)

  20. A luminosity model of RHIC gold runs

    SciTech Connect

    Zhang, S.Y.

    2011-11-01

    In this note, we present a luminosity model for RHIC gold runs. The model is applied to the physics fills in 2007 run without cooling, and with the longitudinal cooling applied to one beam only. Having good comparison, the model is used to project a fill with the longitudinal cooling applied to both beams. Further development and possible applications of the model are discussed. To maximize the integrated luminosity, usually the higher beam intensity, smaller longitudinal and transverse emittance, and smaller {beta} are the directions to work on. In past 10 years, the RHIC gold runs have demonstrated a path toward this goal. Most recently, a successful commissioning of the bunched beam stochastic cooling, both longitudinal and transverse, has offered a chance of further RHIC luminosity improvement. With so many factors involved, a luminosity model would be useful to identify and project gains in the machine development. In this article, a preliminary model is proposed. In Section 2, several secondary factors, which are not yet included in the model, are identified based on the RHIC operation condition and experience in current runs. In Section 3, the RHIC beam store parameters used in the model are listed, and validated. In Section 4, the factors included in the model are discussed, and the luminosity model is presented. In Section 5, typical RHIC gold fills without cooling, and with partial cooling are used for comparison with the model. Then a projection of fills with more coolings is shown. In Section 6, further development of the model is discussed.

  1. DNA fuel for free-running nanomachines.

    PubMed

    Turberfield, A J; Mitchell, J C; Yurke, B; Mills, A P; Blakey, M I; Simmel, F C

    2003-03-21

    We describe kinetic control of DNA hybridization: loop complexes are used to inhibit the hybridization of complementary oligonucleotides; rationally designed DNA catalysts are shown to be effective in promoting their hybridization. This is the basis of a strategy for using DNA as a fuel to drive free-running artificial molecular machines.

  2. 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…

  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. 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 provides…

  5. 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.

  6. 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.

  7. Repairing Holes in Pressure Walls

    NASA Technical Reports Server (NTRS)

    Mori, Paul Bruce Y.; Capriloa, Laurie J.; Corocado, Alexander R.; Gibbins, Martin N.; Horne, Robert B.

    1987-01-01

    Patches and easy-to-use tools yield pressure-tight seal. Repairer lifts patch from repair kit with hook-and-pile-tipped tool and positions it over puncture hole. With tool, even gloved repairer easily manipulates patch without damaging it.

  8. 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…

  9. 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.

  10. 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)

  11. '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. PMID:23351000

  12. 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.

  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. Superradiance from a charged dilation black hole

    SciTech Connect

    Shiraishi, K. )

    1992-12-07

    In this paper, the authors study the behavior of the wave function of charged Klein-Gordon field around a charge dilaton black hole. The rate of spontaneous charge loss is estimated for large black hole case.

  16. Full coverage discrete hole film cooling - Cooling effectiveness

    NASA Astrophysics Data System (ADS)

    Andrews, G. E.; Gupta, M. L.; Mkpadi, M. C.

    1985-09-01

    The development of a test facility for investigating full coverage discrete hole wall cooling for gas turbine combustion chamber wall cooling is described. A low temperature test condition of 750 K mainstream temperature and 300 K coolant temperature was used to investigate the influence of coolant flow rate at a constant cross flow Mach number. Practical combustion conditions of 2100 K combustor temperature and 700 K coolant temperature are investigated to establish the validity of applying the low temperature results to practical conditions. For both situations a heat balance program taking into account the heat transfer within the wall, was used to compute the film heat transfer coefficients. The mixing of the coolant air with the mainstream gases was studied through boundary layer temperature and CO2 profiles. It is shown that entrainment of hot flame gases between the injection holes results in a very low 'adiabatic' film cooling effectiveness.

  17. Cardiac Risks Associated With Marathon Running

    PubMed Central

    Day, Sharlene M.; Thompson, Paul D.

    2010-01-01

    Context: A recent cluster of sudden cardiac deaths in marathon runners has attracted considerable media attention and evoked concern over the safety of long-distance running and competition. This review discusses the acute and potential long-term risks associated with marathon running and puts these into perspective with the many health benefits afforded by habitual vigorous exercise. Evidence Acquisition: Data sources included peer-reviewed publications from 1979 to January 2010 as identified via PubMed and popular media. Results: Marathon running is associated with a transient and low risk of sudden cardiac death. This risk appears to be even lower in women and is independent of marathon experience or the presence of previously reported symptoms. Most deaths are due to underlying coronary artery disease. The value of preparticipation screening is limited by its insensitivity and impracticality of widespread implementation. Appropriate preparation and deployment of trained medical personnel and availability of automatic external defibrillators are expected to have a major impact on survival from cardiac arrests during marathons. Cardiac biochemical and functional abnormalities are commonly observed transiently following completion of a marathon, although their clinical significance is unknown. Conclusions: Sudden cardiac deaths associated with marathon running are exceedingly rare events. Prevention should focus on recognition and investigation of prodromal symptoms, if present, and access to rapid defibrillation and trained medical personnel. The robust association of endurance running with improved quality of life and longevity underscores the importance of putting risks into perspective with other well-established health benefits of regular vigorous exercise. PMID:23015951

  18. 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

  19. Tropospheric ozone in the vicinity of the ozone hole - 1987 Airborne Antarctic Ozone Experiment

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Warren, Linda S.; Hypes, Warren D.; Tuck, Adrian F.; Kelly, Kenneth K.; Krueger, Arlin J.

    1989-01-01

    Results are presented on ozone measurements in the upper troposphere/lower stratosphere over Antarctica, obtained by NASA DC-8 aircraft during the August/September 1987 Airborne Antarctic Ozone Experiment. The ozone mixing ratios as high as several hundred ppbv were measured, but in all cases these ratios were observed in pockets of upper atmospheric air, both in the vicinity of and away from the location of the ozone hole. The background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed in the course of the experiment. During the August 28 - September 2 flights, encounters with ozone-rich air were limited, and the background tropospheric ozone appeared to decrease beneath the hole. For the later flights, and as the ozone hole deepened, the ozone-rich air was frequently observed in the vicinity of the hole, and the average ozone values at the flight altitude were frequently higher than the background values.

  20. The case for artificial black holes.

    PubMed

    Leonhardt, Ulf; Philbin, Thomas G

    2008-08-28

    The event horizon is predicted to generate particles from the quantum vacuum, an effect that bridges three areas of physics--general relativity, quantum mechanics and thermodynamics. The quantum radiation of real black holes is too feeble to be detectable, but black-hole analogues may probe several aspects of quantum black holes. In this paper, we explain in simple terms some of the motivations behind the study of artificial black holes.

  1. Merging galaxies and black hole ejections

    NASA Technical Reports Server (NTRS)

    Valtonen, M. J.

    1990-01-01

    In mergers of galaxies their central black holes are accumulated together. Researchers show that few black hole systems arise which decay through black hole collisions and black hole ejections. The ejection statistics are calculated and compared with two observed systems where ejections have been previously suggested: double radio sources and high redshift quasars near low redshift galaxies. In both cases certain aspects of the associations are explained by the merger hypothesis.

  2. Rotating Black Holes in Higher Dimensions

    NASA Astrophysics Data System (ADS)

    Kleihaus, Burkhard; Kunz, Jutta; Navarro-Lérida, Francisco

    2008-03-01

    The properties of higher-dimensional black holes can differ significantly from those of black holes in four dimensions, since neither the uniqueness theorem, nor the staticity theorem or the topological censorship theorem generalize to higher dimensions. We first discuss black holes of Einstein-Maxwell theory and Einstein-Maxwell-Chern-Simons theory with spherical horizon topology. Here new types of stationary black holes are encountered. We then discuss nonuniform black strings and present evidence for a horizon topology changing transition.

  3. 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

  4. Information retrieval from black holes

    NASA Astrophysics Data System (ADS)

    Lochan, Kinjalk; Chakraborty, Sumanta; Padmanabhan, T.

    2016-08-01

    It is generally believed that, when matter collapses to form a black hole, the complete information about the initial state of the matter cannot be retrieved by future asymptotic observers, through local measurements. This is contrary to the expectation from a unitary evolution in quantum theory and leads to (a version of) the black hole information paradox. Classically, nothing else, apart from mass, charge, and angular momentum is expected to be revealed to such asymptotic observers after the formation of a black hole. Semiclassically, black holes evaporate after their formation through the Hawking radiation. The dominant part of the radiation is expected to be thermal and hence one cannot know anything about the initial data from the resultant radiation. However, there can be sources of distortions which make the radiation nonthermal. Although the distortions are not strong enough to make the evolution unitary, these distortions carry some part of information regarding the in-state. In this work, we show how one can decipher the information about the in-state of the field from these distortions. We show that the distortions of a particular kind—which we call nonvacuum distortions—can be used to fully reconstruct the initial data. The asymptotic observer can do this operationally by measuring certain well-defined observables of the quantum field at late times. We demonstrate that a general class of in-states encode all their information content in the correlation of late time out-going modes. Further, using a 1 +1 dimensional dilatonic black hole model to accommodate backreaction self-consistently, we show that observers can also infer and track the information content about the initial data, during the course of evaporation, unambiguously. Implications of such information extraction are discussed.

  5. Extremal higher spin black holes

    NASA Astrophysics Data System (ADS)

    Bañados, Máximo; Castro, Alejandra; Faraggi, Alberto; Jottar, Juan I.

    2016-04-01

    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3 d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require supersymmetry, we exemplify its consequences in the context of sl(3|2) ⊕ sl(3|2) Chern-Simons theory and show that, as usual, not all extremal solutions preserve supersymmetries. Remarkably, we find in addition that the higher spin setup allows for non-extremal supersymmetric black hole solutions. Furthermore, we discuss our results from the perspective of the holographic duality between sl(3|2) ⊕ sl(3|2) Chern-Simons theory and two-dimensional CFTs with W (3|2) symmetry, the simplest higher spin extension of the N = 2 super-Virasoro algebra. In particular, we compute W (3|2) BPS bounds at the full quantum level, and relate their semiclassical limit to extremal black hole or conical defect solutions in the 3 d bulk. Along the way, we discuss the role of the spectral flow automorphism and provide a conjecture for the form of the semiclassical BPS bounds in general N = 2 two-dimensional CFTs with extended symmetry algebras.

  6. Study on stress distribution around holes in metal plates and transition to fracture

    NASA Astrophysics Data System (ADS)

    Gaffney, John; Hu, Biyu; Yoshida, Sanichiro

    2009-11-01

    With strength analysis of metal connectors used for buildings in mind, stress distribution around holes in tensile-loaded thin metal plates has been investigated. An optical interferometer sensitive to in-plane displacement of the specimen is set up in front of the tensile machine. Interferometric fringe patterns as a whole image of the specimen are formed on a real-time basis at a preset interval in the order of few seconds. A previously observed bright band-like fringe patterns representing stress concentration in similar specimens without holes are observed around the hole at a late stage of deformation. This band-like pattern is found to run at about 45 deg to the tensile axis through the hole. Sometimes two patterns appear simultaneously around the same hole, forming an ``X'' like shape. The appearance of the pattern greatly depends on the thickness of the specimen, the locations of the holes and the type of the metal. To a certain extent, the transition to fracture can be predicted from the shape of the pattern. Comparison with finite element analysis indicates that this pattern appears in the region where the von-Mises yield criterion is satisfied.

  7. 30 CFR 77.1010 - Collaring holes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Collaring holes. 77.1010 Section 77.1010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... Control § 77.1010 Collaring holes. (a) Starter steels shall be used when collaring holes with...

  8. 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)

  9. 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 transcendent…

  10. 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.

  11. 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.

  12. 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.

  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. Scalar field radiation from dilatonic black holes

    NASA Astrophysics Data System (ADS)

    Gohar, H.; Saifullah, K.

    2012-12-01

    We study radiation of scalar particles from charged dilaton black holes. The Hamilton-Jacobi method has been used to work out the tunneling probability of outgoing particles from the event horizon of dilaton black holes. For this purpose we use WKB approximation to solve the charged Klein-Gordon equation. The procedure gives Hawking temperature for these black holes as well.

  15. Development of a machine for automatically measuring static/dynamic running parallelism in linear guideways.

    PubMed

    Hsieh, Tung-Hsien; Huang, Hsueh-Liang; Jywe, Wen-Yuh; Liu, Chien-Hung

    2014-03-01

    This work develops a machine for automatically measuring static/dynamic running parallelism for use in the linear guideway manufacturing industry. The automatic static/dynamic running parallelism measurement machine consists of a running parallelism measurement system, a linear motor, a precision granite air-suspension table, and a PC-based human-machine interface. The machine can be used simultaneously to measure the horizontal and vertical running parallelism of a linear guideway and automatically determine its accuracy. The measured parallelism is digitalized and analyzed to detect turning points in the linear guideway. The results concerning the accuracy of the running parallelism are not affected by the measurement platform. Experimental results showed that the standard deviation of the running parallelism measurement system is 0.4 μm and the measuring time is about 10 s for every 1000 mm of length (equal to a measuring speed of 0.1 m/s); this measurement time is 80% shorter than that of a traditional measurement system (which has a maximum speed of 1 m/s, a maximum sampling frequency of 100 kHz, and a maximum measurement length of 2000 mm). PMID:24689628

  16. Development of a machine for automatically measuring static/dynamic running parallelism in linear guideways.

    PubMed

    Hsieh, Tung-Hsien; Huang, Hsueh-Liang; Jywe, Wen-Yuh; Liu, Chien-Hung

    2014-03-01

    This work develops a machine for automatically measuring static/dynamic running parallelism for use in the linear guideway manufacturing industry. The automatic static/dynamic running parallelism measurement machine consists of a running parallelism measurement system, a linear motor, a precision granite air-suspension table, and a PC-based human-machine interface. The machine can be used simultaneously to measure the horizontal and vertical running parallelism of a linear guideway and automatically determine its accuracy. The measured parallelism is digitalized and analyzed to detect turning points in the linear guideway. The results concerning the accuracy of the running parallelism are not affected by the measurement platform. Experimental results showed that the standard deviation of the running parallelism measurement system is 0.4 μm and the measuring time is about 10 s for every 1000 mm of length (equal to a measuring speed of 0.1 m/s); this measurement time is 80% shorter than that of a traditional measurement system (which has a maximum speed of 1 m/s, a maximum sampling frequency of 100 kHz, and a maximum measurement length of 2000 mm).

  17. 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. PMID:25325770

  18. 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.

  19. 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.

  20. 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.

  1. Determinants of milk flow through nipple units. Role of hole size and nipple thickness.

    PubMed

    Mathew, O P

    1990-02-01

    The aim of the present study was to elucidate the role of hole size and thickness in determining milk flow through nipple units during bottle feeding. Commonly used standard nipple units (SMA single-hole, Enfamil single-hole, and Twist-on) for term and preterm infants, as well as Nuk-type nipple units (SMA Nuk, Enfamil Natural, and Nuk) were tested. The size of the nipple hole and wall thickness were determined for each nipple unit. Airflow was measured by forcing pressurized air through the feed hole. Simulated sucks were used to measure the milk flow. A marked variability in airflow and milk flow was observed within and among the various types of nipple units studied. Within each type of nipple unit, both milk flow and airflow measurements correlated well with hole size. The thickness of the nipple units contributed minimally to the observed variability. We conclude that differences in hole size primarily account for the observed variability in milk flow. This finding may be clinically important in that rapid milk flow can lead to apnea and bradycardia in some preterm infants. The above observations imply that design changes are necessary to reduce the variability of milk flow within each nipple type. Moreover, milk-flow measurements made using a simple mechanical system and airflow measurements used by the industry are equally sensitive to evaluate nipple flow.

  2. 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.

  3. 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).

  4. Black holes die hard: Can one spin up a black hole past extremality?

    SciTech Connect

    Bouhmadi-Lopez, Mariam; Nerozzi, Andrea; Rocha, Jorge V.; Cardoso, Vitor

    2010-04-15

    A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here, we reconsider this gedanken experiment for a variety of black hole geometries, from black holes in higher dimensions to black rings. We show that this particular way of destroying a black hole does not succeed and that cosmic censorship is preserved.

  5. The Relationship between Running Velocity and the Energy Cost of Turning during Running

    PubMed Central

    Hatamoto, Yoichi; Yamada, Yosuke; Sagayama, Hiroyuki; Higaki, Yasuki; Kiyonaga, Akira; Tanaka, Hiroaki

    2014-01-01

    Ball game players frequently perform changes of direction (CODs) while running; however, there has been little research on the physiological impact of CODs. In particular, the effect of running velocity on the physiological and energy demands of CODs while running has not been clearly determined. The purpose of this study was to examine the relationship between running velocity and the energy cost of a 180°COD and to quantify the energy cost of a 180°COD. Nine male university students (aged 18–22 years) participated in the study. Five shuttle trials were performed in which the subjects were required to run at different velocities (3, 4, 5, 6, 7, and 8 km/h). Each trial consisted of four stages with different turn frequencies (13, 18, 24 and 30 per minute), and each stage lasted 3 minutes. Oxygen consumption was measured during the trial. The energy cost of a COD significantly increased with running velocity (except between 7 and 8 km/h, p = 0.110). The relationship between running velocity and the energy cost of a 180°COD is best represented by a quadratic function (y = −0.012+0.066x +0.008x2, [r = 0.994, p = 0.001]), but is also well represented by a linear (y = −0.228+0.152x, [r = 0.991, p<0.001]). These data suggest that even low running velocities have relatively high physiological demands if the COD frequency increases, and that running velocities affect the physiological demands of CODs. These results also showed that the energy expenditure of COD can be evaluated using only two data points. These results may be useful for estimating the energy expenditure of players during a match and designing shuttle exercise training programs. PMID:24497913

  6. An overview of hip injuries in running.

    PubMed

    Paluska, Scott A

    2005-01-01

    Running has steadily gained in worldwide popularity and is the primary exercise modality for many individuals of all ages. Its low cost, versatility, convenience and related health benefits appeal to men and women of broad cultural, ethnic and economic backgrounds. With more children and adults participating in recreational and competitive running, the incidence of injuries has steadily increased. Most running-related injuries affecting the lower extremities are due to preventable training errors, and some may necessitate medical evaluation or a significant reduction in training. Hip injuries in runners are due to interactions of intrinsic and extrinsic factors that adversely affect the complex regional anatomy. Acute or chronic hip pain presents a diagnostic and therapeutic challenge because the vague, nonspecific symptoms and signs may originate from local, regional or distant foci. Muscle strains and tendonitis are the most common aetiologies of hip pain and typically result from sudden acceleration/deceleration manoeuvres, direction changes or eccentric contractions. Apophysitis and avulsion fractures may affect younger runners and produce localised pain at muscle attachment sites. Iliotibial band syndrome is a common cause of lateral hip and knee symptoms characterised by sharp or burning pain that is exacerbated by activity. Bursitis, due to repetitive activity or acute trauma, may affect the trochanteric, ischial or iliopectineal bursae. Hip osteoarthritis may also produce persistent pain that worsens with running. Stress fractures are potentially serious conditions that affect women more frequently than men. Snapping hip syndrome is a benign condition that results from tight connective tissues' passing repeatedly over the greater trochanter, anterior hip capsule, lesser trochanter, femoral head or iliopectineal eminence. Acetabular labral tears, sports hernias and nerve entrapment syndromes are also potential causes of persistent hip pain in runners

  7. Run scenarios for the linear collider

    SciTech Connect

    M. Battaglia et al.

    2002-12-23

    We have examined how a Linear Collider program of 1000 fb{sup -1} could be constructed in the case that a very rich program of new physics is accessible at {radical}s {le} 500 GeV. We have examined possible run plans that would allow the measurement of the parameters of a 120 GeV Higgs boson, the top quark, and could give information on the sparticle masses in SUSY scenarios in which many states are accessible. We find that the construction of the run plan (the specific energies for collider operation, the mix of initial state electron polarization states, and the use of special e{sup -}e{sup -} runs) will depend quite sensitively on the specifics of the supersymmetry model, as the decay channels open to particular sparticles vary drastically and discontinuously as the underlying SUSY model parameters are varied. We have explored this dependence somewhat by considering two rather closely related SUSY model points. We have called for operation at a high energy to study kinematic end points, followed by runs in the vicinity of several two body production thresholds once their location is determined by the end point studies. For our benchmarks, the end point runs are capable of disentangling most sparticle states through the use of specific final states and beam polarizations. The estimated sparticle mass precisions, combined from end point and scan data, are given in Table VIII and the corresponding estimates for the mSUGRA parameters are in Table IX. The precision for the Higgs boson mass, width, cross-sections, branching ratios and couplings are given in Table X. The errors on the top quark mass and width are expected to be dominated by the systematic limits imposed by QCD non-perturbative effects. The run plan devotes at least two thirds of the accumulated luminosity near the maximum LC energy, so that the program would be sensitive to unexpected new phenomena at high mass scales. We conclude that with a 1 ab{sup -1} program, expected to take the first 6-7 years

  8. Air Pollution.

    ERIC Educational Resources Information Center

    Fox, Donald L.

    1989-01-01

    Materials related to air pollution are reviewed for the period January 1987, to October 1988. The topics are pollution monitoring, air pollution, and environmental chemistry. The organization consists of two major analytical divisions: (1) gaseous methods; and (2) aerosol and particulate methods. (MVL)

  9. Air Pollution.

    EPA Science Inventory

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  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. Error analysis of numerical gravitational waveforms from coalescing binary black holes

    NASA Astrophysics Data System (ADS)

    Fong, Heather; Chu, Tony; Kumar, Prayush; Pfeiffer, Harald; Boyle, Michael; Hemberger, Daniel; Kidder, Lawrence; Scheel, Mark; Szilagyi, Bela; SXS Collaboration

    2016-03-01

    The Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO) has finished a successful first observation run and will commence its second run this summer. Detection of compact object binaries utilizes matched-filtering, which requires a vast collection of highly accurate gravitational waveforms. This talk will present a set of about 100 new aligned-spin binary black hole simulations. I will discuss their properties, including a detailed error analysis, which demonstrates that the numerical waveforms are sufficiently accurate for gravitational wave detection purposes, as well as for parameter estimation purposes.

  12. 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

  13. Fabrication of 3-{mu}m diameter pin hole array (PHA) on thick W substrates

    SciTech Connect

    Levato, T.; Pathak, N. C.; Ciricosta, O.; Cecchetti, C. A.; Koester, P.; Labate, L.; Giulietti, A.; Gizzi, L. A.; Giulietti, D.; De Angelis, F.; Di Fabrizio, E.; Delogu, P.

    2010-02-02

    Pin-hole arrays are used for a variety of applications including, for example, X-ray imaging of laser-plasmas for fusion relevant studies. More recently, a novel X-ray imaging technique has been proposed (this conference L. A. Gizzi et al.) within the High Power Laser Energy Research Facility (HiPER) to obtain spectrally resolved X-ray imaging using single photon detection. This technique requires a large number of images or, alternatively, large arrays of pin-holes, possibly with very small diameter (<<10 {mu}m). In view of this, a technique was implemented for the fabrication of large arrays of pin-holes in thick metal substrates. Here we report on the optimizations of the laser-matter interaction process to obtain high aspect ratio cylinder-like pin-hole on heavy metal substrate by using a frequency-doubled Ti:Sa femtosecond laser pulses operating at 10 Hz. The influence of an air breakdown and a (ns)prepulse, on the drilled pin-hole, is showed by means of SEM images both for surface effects and internal quality of the channels, with evidence of micro and nano-sized structures. The holes drilled at an intensity just below the laser breakdown threshold for plasma creation in air, have an internal diameter of about 3 {mu}m on a W substrate of 70 {mu}m thickness, a micro-cylinder-like shape and no detectable deviations of the axis from a straight line. Arrays of up to 800 pin-holes were produced with the pin-hole properties being highly stable across the array. The final X-ray transmission is showed by using a mu-focus X-ray source.

  14. The CDF Run IIb Silicon Detector

    SciTech Connect

    M. Aoki; N. Bacchetta; S. Behari et al.

    2004-02-25

    Fermilab plans to deliver 5-15 fb{sup -1} of integrated luminosity to the CDF and D0 experiments. The current inner silicon detectors at CDF (SVXIIa and L00) will not tolerate the radiation dose associated with high luminosity running and will need to be replaced. A new readout chip (SVX4) has been designed in radiation-hard 0.25 {micro}m CMOS technology. Single sided sensors are arranged in a compact structure, called a stave, with integrated readout and cooling systems. This paper describes the general design of the Run IIb system, testing results of prototype electrical components (staves), and prototype silicon sensor performance before and after irradiation.

  15. CMS Full Simulation for Run-2

    NASA Astrophysics Data System (ADS)

    Hildreth, M.; Ivanchenko, V. N.; Lange, D. J.; Kortelainen, M. J.

    2015-12-01

    During LHC shutdown between run-1 and run-2 intensive developments were carried out to improve performance of CMS simulation. For physics improvements migration from Geant4 9.4p03 to Geant4 10.0p02 has been performed. CPU performance has been improved by introduction of the Russian roulette method inside CMS calorimeters, optimization of CMS simulation sub-libraries, and usage of statics build of the simulation executable. As a result of these efforts, CMS simulation has been speeded up by about factor two. In this work we provide description of updates for different software components of CMS simulation. Development of a multi-threaded (MT) simulation approach for CMS will be also discuss.

  16. Impact of running away on girls' pregnancy.

    PubMed

    Thrane, Lisa E; Chen, Xiaojin

    2012-04-01

    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 Health) data from Waves 1 and 2. The odds of pregnancy in the next year were 1.67 times greater for runaways net of other factors. A history of sexual assault and romantic involvement increased the likelihood of pregnancy. The relationship between pregnancy and runaway behavior in the general population is understudied. Our findings suggest that runaway youth have a multiplicity of needs that require a complex array of medical, social, emotional, and academic resources to promote positive sexual health outcomes. PMID:21794907

  17. Running enhances spatial pattern separation in mice

    PubMed Central

    Creer, David J.; Romberg, Carola; Saksida, Lisa M.; van Praag, Henriette; Bussey, Timothy J.

    2010-01-01

    Increasing evidence suggests that regular exercise improves brain health and promotes synaptic plasticity and hippocampal neurogenesis. Exercise improves learning, but specific mechanisms of information processing influenced by physical activity are unknown. Here, we report that voluntary running enhanced the ability of adult (3 months old) male C57BL/6 mice to discriminate between the locations of two adjacent identical stimuli. Improved spatial pattern separation in adult runners was tightly correlated with increased neurogenesis. In contrast, very aged (22 months old) mice had impaired spatial discrimination and low basal cell genesis that was refractory to running. These findings suggest that the addition of newly born neurons may bolster dentate gyrus-mediated encoding of fine spatial distinctions. PMID:20133882

  18. Stream air temperature relations to classify stream ground water interactions in a karst setting, central Pennsylvania, USA

    NASA Astrophysics Data System (ADS)

    O'Driscoll, Michael A.; DeWalle, David R.

    2006-09-01

    SummaryStream-ground water interactions in karst vary from complete losses through swallow holes, to reemergences from springs. Our study objective was to compare stream-air temperature and energy exchange relationships across various stream-ground water relationships in a carbonate watershed. It was hypothesized that ground water-fed stream segments could be distinguished from perched/losing segments using stream-air temperature relationships. Two types of computations were conducted: (1) comparisons of stream-air temperature relationships for the period of October 1999-September 2002 at 12 sites in the Spring Creek drainage and (2) detailed energy budget computations for the same period for ground water-dominated Thompson Run and Lower Buffalo Run, a stream with negligible ground water inputs. Weekly average air temperatures and stream temperatures were highly correlated, but slopes and intercepts of the relationship varied for the 12 sites. Slopes ranged from 0.19 to 0.67 and intercepts ranged from 3.23 to 9.07 °C. A two-component mixing model with end members of ground water and actual stream temperatures indicated that the slope and intercept of the stream-air temperature relationship was controlled by ground water inputs. Streams with large ground water inputs had greater intercepts and lesser slopes than streams that were seasonally losing, perched, and/or distant from ground water inputs. Energy fluxes across the air-water interface were greatest for the ground water-fed stream due to increased longwave, latent, and sensible heat losses from the stream in winter when large temperature and vapor pressure differences existed between the stream and air. Advection of ground water was an important source and sink for heat in the ground water-fed stream, depending on season. In contrast, along the seasonally losing stream reach, advection was of minimal importance and stream temperatures were dominated by energy exchange across the air- water interface. Overall

  19. Air Cleaning Technologies

    PubMed Central

    2005-01-01

    water molecules and form cluster ions which are attracted to airborne particles. The cluster ion surrounds the airborne particle, and the positive and negative ions react to form hydroxyls. These hydroxyls steal the airborne particle’s hydrogen atom, which creates a hole in the particle’s outer protein membrane, thereby rendering it inactive. Because influenza is primarily acquired by large droplets and direct and indirect contact with an infectious person, any in-room air cleaner will have little benefit in controlling and preventing its spread. Therefore, there is no role for the Plasmacluster ion air purifier or any other in-room air cleaner in the control of the spread of influenza. Accordingly, for purposes of this review, the Medical Advisory Secretariat presents no further analysis of the Plasmacluster. Review Strategy The objective of the systematic review was to determine the effectiveness of in-room air cleaners with built in UVGI lights and HEPA filtration compared with those using HEPA filtration only. The Medical Advisory Secretariat searched the databases of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, INAHATA (International Network of Agencies for Health Technology Assessment), Biosis Previews, Bacteriology Abstracts, Web of Science, Dissertation Abstracts, and NIOSHTIC 2. A meta-analysis was conducted if adequate data was available from 2 or more studies and where statistical and clinical heterogeneity among studies was not an issue. Otherwise, a qualitative review was completed. The GRADE system was used to summarize the quality of the body of evidence comprised of 1 or more studies. Summary of Findings There were no existing health technology assessments on air cleaning technology located during the literature review. The literature search yielded 59 citations of which none were retained. One study was retrieved from a reference list of a guidance document from the United States Centers for Disease Control and Prevention, which

  20. Tropospheric ozone in the vicinity of the ozone hole: 1987 Airborne Antarctic Ozone Experiment

    SciTech Connect

    Gregory, G.L.; Warren, L.S. ); Hypes, W.D. ); Tuck, A.F.; Kelly, K.K. ); Krueger, A.J. )

    1989-11-30

    Tropospheric ozone measurements over Antarctica aboard the NASA DC-8 aircraft are summarized. As part of the August/September 1987 Airborne Antarctic Ozone Experiment, the aircraft flew 13 missions covering a latitude of 53{degree}-90{degree}S, at altitudes to 13 km. Ozone mixing ratios as high as several hundred parts per billion by volume (ppbv) were measured, but in all cases these ratios were observed in pockets or patches of upper atmospheric air. These pockets were observed both in the vicinity of and away from the location of the ozone hole. At times, and as a result of these pockets, the ozone levels at the flight altitude of the aircraft, as averaged beneath the boundaries of the stratospheric ozone hole, were 2-3 times higher than background tropospheric values. The data suggest that the ozone-rich air seldom penetrated below about 9-km altitude. Background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed during the experiment. During the early flights (August 28 through September 2), encounters with ozone-rich air were limited and background tropospheric ozone (at the flight altitude) appeared to decrease beneath the hole. For many of the later flights, and as the hole deepened, the reverse was noted, in that ozone-rich air was frequently observed in the vicinity of the hole and, as noted earlier, average ozone at the flight altitude was frequently higher than background values.